ANSWER KEY IN PRE-TEST

1. A trunk is ___a. The base of a

communication towerb. A line connecting oe

telephone set to the PABXc. The structure where

antennas are attachedd. A telephone line connecting

two Cos

2. The simplest form of coding is __________.

a. Diphase b. Hybridc. Compressedd. Lineare. Quadratic

3. Whether or not polarization of an antenna is linear depends on __________.

a. Changes in direction in which the electric plane is radiated.

b. The direction in which the electric plane is radiated.

c. The horizontal or vertical plane of the electric wave

d. The direction in which the magnetic wave is radiated

4. In practice, the transmission lines are most connected to antennas that have a _______.

a. Resistive load whose resistance is greater than the characteristics impedance of the line

b. Resistive load whose resistance is less than the characteristic impedance of the line

c. Resistive load at the resonant frequency

d. Capacity Load

5. Sampling the analog wave produces _________.

a. Impulse Noiseb. Phase Distortionc. Pulse Amplitude Modulationd. Frequency Coherence

6. When the transmission line is matched to the load, it _______.

a. Transfers maximum current to the load

b. Transfers maximum voltage to the load

c. Transfers maximum power to the load

d. Reduces the load current

7. The equation f > 2BW is known as _________.

a. Shannon Theoremb. Nyquist Criterionc. Erlang Lawd. Edison Effect

8. Waveguide is a ________.a. Device used to determine

the wavelength of a signalb. Hollow metal tube used for

transmission of Microwave Energy

c. Plastic tubular transmission line for high RF network

d. Braided wire used for transmission of HF

9. Memory is added to the telephone set to

a. Allow more digits to be dialed

b. Allow faster dialingc. Allow automatic redialing of

the last number dialedd. None of these

10. The value of the resistor creating thermal noise is doubled, the noise power generated is therefore ______.

a. Halvedb. Quadrupledc. Doubledd. Unchanged

11. What is the function of the diode rectifier bridge in the line circuit of a telephone?

a. Lower the voltage to the telephone electronics

b. Raise the voltage to the telephone

c. Short out the line when the set is on-hook

d. Protect the set against polarity reversals on the line

12. Satellite that orbit in a circular pattern with an angular velocity equal to that of the earth is __________.

a. Geostationaryb. Early Bird Ic. Syncom Id. Stationary Satellite

13. Between two quantizers, the quality of one with the lower Signal to Quantizing Noise Ratio (SQR) will be ________.

a. Higherb. Lowerc. The samed. Not measurable

14. The signal path from transmitter to satellite is __________.

a. Uplink Signalb. Reflected Signalc. Incident Signald. Downlink Signal

15. If the code is only 4-bits for a T-1 system with a frame of 193 bits, how many channels can be transmitted?

a. 48b. 64c. 6d. 24

16. Which office class is the local central office?

a. 2b. 3c. 4d. 5

17. What bad electrical effect happens when the switchook is opened?

a. A high voltage transient is generated

b. The line is shorted outc. The line is openedd. No bad effects happen

18. The _________ angle measures the satellite position clockwise from the direction of true North is

a. Azimuthb. Elevationc. Depressiond. Critical

19. If the code word is 4 bit for T-1 system with a frame of 193 bits, what is the bit rate in mbps?

a. 0.722b. 3.008c. 1.544d. Coverage Area

20. The earth’s area that the satellite can receive from or transmit to is ______.

a. Footprintb. Primary Areac. 1.544d. 1.024

21. The most common carrier frequencies used for satellite communications are ________.

a. 6/4 and 14/12 GHz Bandsb. 8/6 and 16/14 GHz Bandsc. 20/18 and 28/26 GHz

Bandsd. 12/10 and 18/16 GHz

Bands

22. It represents energy that has neither been radiated into space nor

completely transmitted. a. Standing Wavesb. Captured Wavesc. Incident Wavesd. Modulated Waves

23. The signal path from satellite to earth-based receiver is ___________.

a. Downlink Signalb. Uplink Signalc. Incident Signald. Reflected Signal

24. _____________ refers to the ratio of phasor fields E and H for a plane (TEM) wave in an unbounded medium.

a. Wave impedanceb. Load impedancec. Intrinsic Impedanced. Characteristics Impedance

25. __________ is the quotient of maximum radiation intensity over the average radiation intensity.

a. Aperture gainb. Directivity gainc. Transmission gaind. Power gain

26. Another term for Amplitude Modulation (AM) is ___________.

a. Double Sideband Full Carrier (DSBF)

b. Single Sideband Suppressed Carrier (SSBC)

c. Frequency Modulation (FM)d. Pulse Code Modulation

(PCM)

27. Fold-over distortion of aliasing is _______________.

a. Eliminated by filtering out frequencies below 300 Hz

b. Another name for Crosstalkc. The Presence by Spurious

Frequencies caused by having high frequencies in the sampled signal

d. Eliminated by using Twisted Wires

28. A pulse Amplitude Modulator uses a modulating signal whose frequency is 3 KHz maximum. The practical sampling frequency is ________.

a. 6 KHzb. 7.25 KHzc. 2.5 KHzd. 3 KHz

29. The main purpose of a 19 KHz pilot in a stereo multiplexed signal in FM

is for the receiver to ______.a. Indicate stereo receptionb. Demodulate c. Modulated. Overmodulate

30. ______________ is an operation performed at the transmitter to achieve efficient and reliable information transmission.

a. Transmissionb. Filteringc. Modulationd. Multiplexing

31. Another name for multiplier circuit is ______.

a. Balanced modulatorb. Discriminatorc. Clipperd. Integrator

32. A process that uses the orthogonality of sines and cosines that makes possible to transmit and receive to different signals simultaneously on the same carrier frequency is:

a. Time Division Multiplexing (TDM)

b. Frequency Division Multiplexing (FDM)

c. Quadrature Multiplexingd. Duplexing

33. One section in a D-1 channel bank handles _________ voice channels

a. 12b. 20c. 24d. 48

34. The information of an AM signal resides in the

a. Upper Sideband Onlyb. Lower Sidebandc. Upper and Lower Sideband

onlyd. Carrier Signal

35. The process of varying some characteristics of high frequency sine wave in accordance with the variation of the modulating signal is called ______.

a. Communicationb. Propagationc. Restorationd. Modulation

36. Best HF radio communications between two distant countries is achieved when the F-1 and F-2 layers of the ionosphere recombine and other layers disappear during _____________.

a. Night timeb. Noon timec. Break timed. Both a and b

37. Cellular mobile telephone service ___.

a. Uses many low power transmitters with computer control rather than a few high power transmitters

b. Is a concept of improving frequency utilization by restricting users to a single or home area called a cell

c. Is another name of IMTSd. Uses high power

transmitters

38. ___________ is the sound energy per unit area at right angles to the propagation direction per unit of time.

a. Sound stressb. Coherencec. Sound Intensityd. Loudness

39. A _____ filter passes the lower frequency portion of a signal but attenuates the higher frequency portion of the same signal.

a. Low Passb. High Passc. Band Stopd. Band Pass

40. Modulation is used to __________.a. Increase the carrier powerb. Reduce the bandwidth usedc. Allow the use of practical

antennasd. Shorten the transmission

channel

41. In radio communication the maximum permissible departure by the center frequency of the frequency band occupied by an emission from assigned channel or, by the characteristic frequency of an emission from the reference frequency __________.

a. Frequency Toleranceb. Assigned Frequencyc. Frequency Bandwidthd. Center Frequency

42. A pre-emphasis circuit improves the signal-to-noise ratio of an FM signal by _____.

a. Amplifying the higher audio

frequenciesb. Boosting the bass

frequenciesc. Amplifying the whole

frequency bandd. Increasing the carrier power

43. A superheterodyne receiver with an IF of 455 KHz is tuned to a signal to 1100 KHz. The image frequency is ____.

a. 645 KHzb. 910 KHzc. 1555 KHzd. 2010 KHz

44. Grounding resistance should be kept as low as possible and should not exceed _______ ohms for outside plant telephone poles, manholes and customer premises

a. 5b. 25c. 0d. 50

45. In a communications system, noise is most likely to affect the signal ______.

a. At the transmitterb. In the channelc. In the information sourced. At the destination

46. In a standard TV broadcast channel, the AM picture carrier signal is

a. 0.25MHzb. 0.6MHzc. 1.25MHzd. 4MHze. 3.75MHz

47. Frequencies in the UHF range propagate by means of __

a. Ground wavesb. Surface wavesc. Sky wavesd. Space waves

48. In superheterodyne receivers, refers to the erroneous frequency difference resulting in an incorrect frequency being fed to the IF amplifier

a. Crosstalkb. Crosslinec. Intermodulationd. Mixing errore. Tracking errorf.

49. The ground wave eventually disappear as it moves farther away from the transmitter, because of

a. Diffractionb. Interference from skywave

c. Refractiond. Reflectione. Tilting

50. An amplifier has an input of 100mW and an output of 10W. The gain is ___

a. 10b. 20c. 50d. 100e. 200

51. As electromagnetic waves travel in free space, only one of the following can happen to them

a. Absorptionb. Attenuationc. Refractiond. Reflection

52. A matched tapping device for insertion in a CATV cable which introduces a loss of only 1 dB in the through transmission and provides a spur outlet

a. Attenuatorb. Directional couplerc. F-connectord. splittere. T-pad

53. The standard reference antenna for the directive gain

a. Elementary dipoleb. Half-wave dipolec. Hertzian dipoled. Isotropic antennae. Infinitesimal dipole

54. A process applied to a multiple signal for recovering signals combined within it and for restoring the distinct individual channels of these signals

a. De-emphasizingb. Detectionc. Demultiplexingd. Modulation

55. One example of a nonresonant antenna

a. Disconeb. Folded dipolec. Hertz antennad. Marconi antennae. Rhombic antenna

56. Space diversity transmission means transmitting and receiving on__

a. 2 or more different frequencies

b. 2 or more antennas operating on different frequencies

c. 2 or more antennas operating on the same frequency

d. 2 or more identical

frequencies

57. An antenna that is circularly polarized

58. Losses in optical fibers is not caused by___

a. Glass attenuationb. Impuritiesc. Microbendingd. Tyndall dispersione. Stepped index operation

59. EIRP is the actual power radiated by the antenna multiplied by the ___ of the antenna

a. Isotropic power gainb. Free space lossesc. Lengthd. Losse. K factor

60. Known as muting or quieting is a device that cuts off the output in the absence of a carrier to eliminate noise

a. Butterworth filterb. Echo cancellerc. Hybridd. noise limitere. squelch

61. When electromagnetic waves are propagated in a waveguide, they___.

a. Are reflected from walls but not travel along them

b. Travel along the broader walls of the guide

c. Travel along the 4 walls of the waveguide

d. Travel through the dielectric without touching the walls

62. Increasingly, new satellites operate in the Ku-band which are in the ___________ Ghz range.

a. 11 to 13b. 21 to 30c. 11 to 14.5d. 4 to 6

63. Noise that is non-continuous, consisting of irregular pulses or noise spikes of short duration with high amplitudes.

a. White noiseb. Thermal noisec. Galactic noised. Impulse noise

64. A communication network used by one organization over a limited distance that allows users with PCs

to be linked together and share information and resources is called ________.

a. Timesharingb. LANc. Distributed processingd. WAN

65. How can absorptive fading happen?a. K-factorb. Rain attenuationc. Ductingd. Inversion

66. Simultaneous transmission of 2 or more signals over a single medium.

a. Full duplexb. Half duplexc. Full-full duplexd. Simplex

67. In telecommunications signaling concept, the status of the network in the presence of a demand and a connection is __________.

a. Busy hourb. Seizurec. Idled. Grade of service

e. Erasable Binary Coded Decimal Interchange

68. Echo is _____________.a. A signal of the same

amplitude but 180 degrees out of phase from the original and mixed with original signal at the transmitter to produce a more intelligible output signal

b. A wave which has been reflected or otherwise returned with sufficient magnitude and delay for it to be perceptible in some manner as a wave distinct from that directly transmitted

c. The signal having a higher frequency than the original and transmitted back to earth by a passive satellite

d. All of these

69. The slight lowering of resonant frequency due to small amount of capacitance presented by the insulators and wire loop that ties the insulator to the antenna is known as ______.a. Miller Effectb. Dellinger Effectc. End effectd. Ramsauer Effecte. Skin effect

70. The frequency range over which antenna operation is satisfactory and is generally taken between half power or 3 dB down points.

a. Bandwidthb. Beamwidthc. Polarizationd. Carrier Frequency

71. The property of an antenna that causes it to receive signals better than one direction than in others is _____.

a. Directivityb. Radiation Patternc. Reciprocityd. Front-to- Back Ratioe. Harmonic Operation

72. It shortens the physical length of antenna by an equivalent effect of adding capacitance in series with the antenna, reducing its totalcapacitive reactance.

a. Counterpoiseb. Top Hatc. Loading Coild. Microstripe. None of these

73. The digital to analog converter in a synchronous modem sends signals to the ____.

a. Modulatorb. Transmission Linec. Terminald. Equalizere. Tuner

74. A radiations system consisting of grouped radiators or elements placed close together to be within each other’s induction field to produce a certain radiation pattern.

a. Dipole Arraysb. Quarterwave Matchingc. Delta Matchingd. Parasitic Elementse. Quaggi

75. The gain of a parabolic antenna is influenced by the ____.

a. Aperture Ratiob. Capture Areac. Mouth Diameterd. Illumination Efficiencye. All of these

76. Which of the following transmission media is not readily suitable to CSMA operation

a. Radiob. Optical Fibersc. Coaxial Cabled. Twisted Pair

e. None of these

77. The core of an optical fiber has ___.a. A lower index of refraction

than airb. A lower index of refraction

than the claddingc. A higher index of

refraction than the cladding

d. Equal index of refraction to that of the cladding

78. At microwave frequencies, the LOS distance is sometimes extended through the occurrence of ___.

a. Ionospheric Reflectionsb. Fogc. Sporadic Ed. Dellinger Dropoutse. Ducting

79. The best system configuration to overcome multipath fading on “over-the water” propagation

a. Angle diversityb. Frequency diversityc. Non-diversityd. Space diversity

80. Layer 1 of the OSI model isa. Link layerb. Network layerc. Physical layerd. Session layer

81. Color TV is made possible through the combination of the primary colors of

a. blue, yellow, greenb. red, green, bluec. red, white , blued. white, red, green

82. A type of modulation technique that conveys audio information from one station to another by varying the carrier frequency at the audio rate

a. Amplitude modulationb. Frequency modulationc. Quadrature modulationd. Phase modulation

83. The applications layer of the OSI model is the

a. First layerb. Second layerc. Seventh layerd. Sixth layere. Third layer

84. Causes modulation either in its internal circuitry or in another associated circuit

a. Detectorb. Modulatorc. Multivibratord. Multiplexere. Phasor

85. The half-power points of the beamwidth of the front lobe of a

directional antenna is the point equal to

a. 0.707b. 0.636c. 0.318d. 0.5e. 1.414

86. A tuned amplifier uses___ loada. Capacitiveb. Inductivec. LC tankd. Resistive

87. When a single antenna is intended to be used for transmitting and receiving , it is necessary to use__

a. Combinerb. Diplexerc. Duplexerd. Multiplexere. Transponder

88. The receiver’s ability to receive both very weak and extremely strong stations without introducing distortion

a. Dynamic rangeb. Effective rangec. Figure of meritd. Sensitivitye. Selectivity

89. The T-1 North American digital system has 24 channels and require a transmission speed of

a. 64 kbpsb. 640 kbpsc. 960 kbpsd. 1.54 Mbpse. 2.048 Mbps

90. It a system which provides the longest digital transmission distances

a. Computer busb. Digital PBXc. Local area networkd. Voice band modem

91. When modulating frequency is disabled , the modulation index is halved, and the modulating voltage remains constant. The modulating system is __

a. Amplitude modulationb. Frequency modulationc. Phase modulationd. Pulse modulation

92. Which of the functions is not provided as part of the basic Ethernet design?

a. Access controlb. Addressingc. Automatic retransmissiond. Multiple virtual networks

93. The frequency the oscillator must be set at for an output of 95 kHz if the output of the oscillator is being fed to two frequency triplers connected in cascaded form

a. 6.3 MHz

b. 9.65 MHzc. 10.56 MHzd. 15.8 MHz

94. A resonant circuit contains ___ element

a. R and Lb. Only Rc. R and Cd. L and C

95. At resonance, a circuit behaves as a ___ load

a. Capacitiveb. Inductivec. magneticd. PN junctione. Resistive

96. Pre-emphasis and de-emphasis are used in the FM stereo multiplex system to improve__

a. Current ratiob. CMRRc. Power ratiod. Standing wave ratioe. Signal-to-noise ratio

97. At series resonance, the voltage across L is___ voltage across C

a. Equal to but in phase withb. Equal to out of phase withc. Greater than but in phase

withd. Less than but in phase with

98. Audio pitch refers to _________.a. Frequencyb. Harmonicsc. Amplituded. Phase

99. A characteristic of radio receiver to amplify a peak signal and produce a desirable intelligence at the output of the speaker.

a. Sensitivityb. Selectivityc. Reliabilityd. Fidelity

100. As the modulation level is increased, the carrier power ______.

a. Is increasedb. Is decreasedc. Remains the samed. Either a or b

1. The slight lowering of resonant frequency due to small amount of capacitance presented by the insulators and wire loop that ties the insulator to the antenna is known as ______.f. Miller Effectg. Dellinger Effect

h. End effecti. Ramsauer Effectj. Skin effect

2. According to the Philippine Electronics Code, the minimum allowable vertical clearance above the ground is at least ___ meters when wires are crossing or installed along public thoroughfares in urban areas.

a. 5.5b. 4.5c. 4.0d. 3.5e. 3.0

3. The frequency range over which antenna operation is satisfactory and is generally taken between half power or 3 dB down points.

a. Bandwidthb. Beamwidthc. Polarizationd. Carrier Frequency

4. According to this law, passing the Board Examinations administered by the PRC may be converted into equivalent Civil Service Eligibility to pass preparatory requirements for government service.

a. RA 1080b. PD 1081c. RA 184d. RA 3850e. RA 6511

5. The property of an antenna that causes it to receive signals better than one direction than in others is _____.

a. Directivityb. Radiation Patternc. Reciprocityd. Front-to- Back Ratioe. Harmonic Operation

6. According to the Philippines Electronics Code, grounding rods must take the shortest route connected directly to master ground bus or direct to earth without any intervening splices or sharp bends. The standard diameter for grounding rods is _____.

a. AWG Nr 10b. AWG Nr 2c. AWG Nr 33d. AWG Nr 12e. AWG Nr 16

7. ______ consists of radials supported above the ground and is used as a substitute for ground screen in areas of low conductivity.

a. Counterpoiseb. Grounding rodc. Lightning rodd. Spark-Gape. Top Hat

8. The scrambler in a synchronous modem is in the _____.

a. Control Sectionb. Receiver Sectionc. Transmitter Sectiond. Terminal Sectione. Antenna

9. Ungrounded antennas which are normally used for frequencies above 3 Megahertz are called ____.

a. Hertz Antennasb. Marconi Antennac. Yagi-Udad. LPDAe. Zepp Antenna

10. Binary codes are sometimes transformed in modems into ____.

a. Hexadecimalb. Huffman codesc. Gray coded. Complementary codese. Supplementary codes

11. It shortens the physical length of antenna by an equivalent effect of adding capacitance in series with the antenna, reducing its total capacitive reactance.

a. Counterpoiseb. Top Hatc. Loading Coild. Microstripe. None of these

12. The digital to analog converter in a synchronous modem sends signals to the ____.

a. Modulatorb. Transmission Linec. Terminald. Equalizere. Tuner

13. A radiations system consisting of grouped radiators or elements placed close together to be within each other’s induction field to produce a certain radiation pattern.

a. Dipole Arraysb. Quarterwave Matchingc. Delta Matchingd. Parasitic Elementse. Quaggi

14. ____ created the Board of Communications (BOC) which became the first quasi- judicial body with adjudicatory powers on matters involving telecommunications services.

a. RA 1476

b. Integral Reorganization Law of 1972

c. EO Nr 546d. PD 55e. PD 1081

15. A multi- element antenna in which all the elements are excited through a transmission line _____.

a. Driven Arrayb. Parasitic Arrayc. Phased Arrayd. Loop Arraye. None of these

16. _________ integrated the Telecommunications Bureau created in 1974 and the Board of Communications into one entity now known as the National Telecommunications Commission, under the administrative control of the Ministry of Transportation and Communications and was empowered to supervise, adjudicate and control all telecommunications services throughout the country.

a. E.O. 546b. RA 3846c. RA 5734d. E.O. 109e. E.O. 125

17. In an antenna array, the ___ elements are not connected to the transmitter output, rather, the elements obtain their power through coupling to another element and they may act as reflectors or directors.

a. Parasiticb. Drivenc. Compoundd. Complexe. None of these

18. According to the Philippine Electronics Code, the minimum threshold current (in RMS) in a circuit whereby ventricular fibrillation will most likely occur is ____ and may therefore be classified as hazardous to humans whose wet skin resistance is about 1500 Ohms.

a. 0.030 Amperesb. 300 Amperesc. 30 Amperesd. 3 Amperes e. None of these

19. A parasitic element which is longer than the driven element in an antenna array and acts like a concave mirror is called _____.

a. Reflectorb. Directorc. Collimator

d. Phasore. None of these

20. To prevent hazards of electric shock, what protection method/s must an ECE use?

a. Shielding and Groundingb. Voltage Limitingc. Direct Bonding, Surge

Arresterd. Discharge Gaps and Fusee. All of these

21. A linear antenna array whose arrangement consists of a number of dipoles of equal size, equally spaced along a straight line with all dipoles fed in the same phase from the same source and whose radiation is towards the side of the array.

a. Broadside Arrayb. Endfire Arrayc. Phased Arrayd. LPDAe. None of these

22. Acoustic shock results from abnormally high sound level, the physical effects of which may vary from minor discomfort to serious injury. The amplitude of sound pressure must not exceed ____ above 2x 10-4 microbar at 1000 Hertz reference tone.

a. 0 dBb. 30 dBc. 33 dBd. 120 dBe. 200 dB

23. A single turn coil consisting of 2 elements, one is directly fed and the other conductively coupled at the ends. It carries RF current mostly in phase and has an impedance of 300 Ohms, almost four times that of a Hertz dipole.

a. Folded Dipoleb. Yagi- Udac. Quaggid. Zepp Antennae. Discone Antenna

24. According to the Philippine Electronics Code, the average resistance of a dry adult human body is about ___.

a. 1 MegOhmb. 1500 Ohmsc. 1 KiloOhmd. 2 KiloOhmse. None of these

25. The gain of a parabolic antenna is influenced by the ____.

a. Apperture Ratiob. Capture Areac. Mouth Diameter

d. Illumination Efficiencye. All of these

26. Refers to the set of rules and regulations of the construction, installation, establishment operation of radio stations and the possession, ownership, manufacture, purchase, sale and transfer of transceiver

a. DO Nr. 88b. DO Nr. 11c. DO Nr.69d. Do. Nr.55e. DO Nr. 33

27. The effective area of the parabolic reflector calculated from power receiver in comparison with the power density of the received signal

a. Capture areab. Collimation factorc. Edge taperd. Front-to-back ratioe. Spill-over

28. In the code of professional ethics and conduct, the moral philosophy guiding the ECE are

a. Courage, integrity and loyalty

b. Duty, country and honorc. Honesty, justice and

courtesyd. Duty, honor and loyalty

29. A type of feed mechanism to improve the directivity of a parabolic antenna whereby a hyperboloid secondary reflector is used and rays from the feedhorn are reflected from paraboloidal mirror which renders therays para;;e; or collimated to each other

a. Cassegrain feedb. Horn antennac. Offset paraboloidd. Small dipole arraye. Spherical reflector

30. The official seal of the ECE board has a diameter of 1 and 7/8 inches. It is composed of the markings”Electronics and Communications Engineering Board of Examiners” except

a. Atoms and electronsb. Circumferential dots and

dashesc. Lightningd. Satellite antenna

31. Microwave antennas used for frequencies 10 Gigahertz and above, collimates and straightens out wavefronts by greatly slowing down the portion of the wave in the center

a. Cass-hornb. Conical hornc. Hog hornd. Lens antennase. Skeptical horn

32. This law requires radio franchise and certificate of public convenience and necessity (CPCN) for the operation of communications utilities, wire or wireless telephone or telegraph systems and other similar public telecommunications utilities

a. EO 546 of 1979b. DO 88 of 1988c. RA 3846 of 1931d. RA 3850e. DO 11 of 1951

33. The function of a lens antenna is to ensure that signals are in phase after they have passed through the antenna. For lower microwave frequencies or strongly curved wavefronts, problems of excessive thickness and absorption of large portion of radiation is experienced in lens antenna. This problem of thickness is solved by___

a. Focusingb. Jumpingc. Steppingd. Zoning

34. The receive equalizer in a synchronous modem

a. Adaptiveb. Compromisec. Impairmentd. Statisticale. terminator

35. A type of antenna used for broadband VHF /UHF transionospheric communications and has circular polarization

a. Antenna arrayb. Cass hornc. Disconed. Helical antennae. Parabolic antenna

36. Otherwise known as “Ship Radio Station Law”

a. RA 3396b. RA 3846c. RA 5734d. RA7925e. RA1476

37. An antenna array consisting of a number of electrically connected dipoles of different lengths and spacing fed from 2 wire lines transposed between each adjacent pair of dipoles fed from the narrow end where maximum radiation occurs

a. Broadside arrayb. Endfire arrayc. Log periodic dipole

arrayd. Helical arraye. Quanggi

38. The receive equalizer reduces relay distortion using

a. Diode matrixb. Descramblerc. Difference engined. Gearshifte. Tapped delay line

39. In the XMODEM protocol, the sender waits for what character from the receiver before beginning transmission

a. ACKb. EOTc. NAKd. RVIe. WACK

40. The CCITT V.26 modem has a modulation rate of__

a. 1200 Hzb. 1200 baudsc. 1560 cpsd. 2400 kbpse. 6400bps

41. If each character in an XMODEM block has an ASCII value of 50, what would be the value of checksum added to the block?

a. 23b. 25c. 41d. 50e. 100

42. The transmission signal coding method used for T-1 carrier

a. Bipolarb. Binaryc. Hollerithd. Manchestere. NRZ

43. Which of the following is not a valid rule for XOR?

a. 0 XOR 0 =0b. B XOR B = 0c. 1 XOR 1 = 1d. A XOR A = 0e. 1 XOR 0 =1

44. Multiplexing is___a. The process of increasing

bandwidth on a channelb. Mailing letters at the Post

Officec. A technique which

enables more than one data source to share the use of a common line

d. The ability to share frequency by time

45. How many messages may be outstanding (unacknowledged ) on a BiSync kink?

a. 1b. 2c. 4d. 8e. 10

46. One of the reasons frequency division multiplexing has essentially been replaced by time division multiplexing is because:

a. There is more time than frequency

b. It is difficult to place channels side by side

c. Noise is amplified with voice when an FDM system is used

d. Most available frequencies have been used

47. Which code set is used in Bisync when using VRC/LRC but is not operating in transparency code?

a. EBCDICb. ASCIIc. SBTd. Field datae. Trellis Code

48. When the amplitude of pulses is varied to represent analog information, the method is called _____.

a. PCMb. PWM c. PAMd. PPMe. WDM

49. Which of the following transmission systems provide the highest data rate to an individual device?

a. Voice Band Modemb. Local Area Networkc. Computer Busd. Digital PBXe. None of these

50. The PCM sampling rate is 8000 samples per second because ____.

a. That represents the maximum rate technology supports

b. This rate allows unique values

c. This rate allows the faithful reconstruction of an analog signal

d. This rate is easily produced by a sampling chip

51. The data rate of the ISDN Basic Access B channel is ____.

a. 32 kbpsb. 64 kbps

c. 144 kbpsd. 192 kbpse. None of these

52. In general, digital transmission provides a higher level of signal quality than analog transmission because ____.

a. Repeaters regenerate digital pulses and remove distortion while amplifiers increase an analog signal, including any prior signal distortion.

b. Digital signals are smaller than analog signals and cannot be easily distorted.

c. Analog signals are continuous and are not easily distorted.

d. Digital signals are easier to sample than analog signals

e. Both (b) and (d)53. The data rate of the IDSN Basic

Access D channel is _____.a. 64 kbpsb. 16 kbpsc. 8 kbpsd. 144 kbpse. 356 kbps

54. The D-4 framing pattern contains a sequence of ____.

a. 24 bitsb. 4 terminal and 8 framing

bitsc. 8 terminal and 4 framing

bitsd. 12 bitse. 36 bits

55. The equation that defines the composition of an ISDN Basic Access Line is____.

a. 2B + Db. B+ Dc. B+ 2Dd. 2B+ 2De. 3B + 4D

56. Bipolar signaling is used in place of unipolar signaling on T-1 lines because _____.

a. Bipolar produces twice as many marks as a unipolar signal

b. It allows transmission at polar locations

c. It allows transformers to be spaced far from one another which reduces the cost of transmission

d. Bipolar signaling reduces residual voltage build- up, allowing a digital signal to be

separated from power through the use of a transformer.

e. None of these57. In North America, the equation

that defines the composition of an ISDN Primary Access line is ____.

a. 30B +Db. 2B +Dc. B + Dd. 23B + De. 35 B+ 6D

58. B7 Zero Code Suppression is a technique which ____.

a. Allows data to flow on a digital line

b. Ensures each byte has at least one mark bit

c. Is the latest clear channel encoding technique developed by Bell Laboratories

d. Provides clear channel transmission capability allowing 64 kbps data transmission on a voice channel

e. None of these59. Which of the following systems

provides the longest digital transmission distances?

a. Parallel transmissionb. Unlimited Expansionc. Low cost access for low

bandwidth channelsd. Application independent

interfacese. None of these

60. International bipolar violations _____.

a. Represent coding errors caused by line impairments

b. Result in successive marks having opposite polarities

c. Are used to convey information or maintain a minimum number of ones on a digital line.

d. Occur only in laboratoriese. Occur at the North and

South Poles simultaneously

61. Which of the following transmission media is not readily suitable to CSMA operation

a. Radiob. Optical Fibersc. Coaxial Cabled. Twisted Paire. None of these

62. Demultiplexing by a Time Division Multiplexer occurs based on ___.

a. The position of data within a frame

b. The position of a frame within a group of frames

c. The activity of a connected device

d. The priority assigned to a connected device

63. Which of the following functions is not provided as part of the basic Ethernet design?

a. Access Controlb. Addressingc. Automatic Message

Retransmissiond. Multiple Virtual Networks

64. The requirements for a successful transmission system using light are ___.

a. Powerful, reliable light source

b. Strong glassc. Reliable, low cost

transmission mediumd. Powerful amplifiese. Both (a) and (c)

65. Which of the following is not a useful property of a Manchester line code for an Ethernet?

a. Continuous Energyb. Continuous Clock

Transitionsc. No DC Componentd. No signal change at 1 to

0 transitione. All of these

66. The core of an optical fiber has ___.a. A lower index of refraction

than airb. A lower index of refraction

than the claddingc. A higher index of

refraction than the cladding

d. Equal index of refraction to that of the cladding

67. The network interface that will permit equipment without an ISDN interface to be connected into an ISDN interface is known as ____.

a. TE-1b. TE-2c. TAd. TM-1e. TM-2

68. For single- mode fibers, the core diameter is about ____.

a. 10 times the Fiber Radiusb. 3 times the wavelength

of light carried in the fiber

c. 15 Micrometers

d. 10 times the wavelength of the light carried in the fiber

69. Which of the following data communications functions is generally provided for in a LAN?

a. Data Link Controlb. Applications Processingc. Flow Controld. Routinge. None of these

70. Over a period of 30 years, a kilometer of fiber optic cable is likely to be broken ____.

a. Not at allb. Oncec. 10 timesd. 2 or 3 timese. None of these

71. The purpose of the preamble in an Ethernet is____.

a. Clock Synchronizationb. Error Checkingc. Collision Avoidanced. Broadcaste. None of these

72. Deposition of dopants on fiber performs is done by__

a. Axial depositionb. Inside vapor depositionc. Outside vapor depositiond. All of these

73. Which of the following is possible in a token-passing bus network?

a. In-service expansionb. Multiple time divisionc. Unlimited number of

stationsd. Unlimited distances

74. A light emitting diode is able to couple how much power into an optical fiber?

a. 10 wattsb. 10 Milliwattsc. 100 microwattsd. 1 picowatte. 1 watts

75. A LAN architecture which can be expanded to the greatest total system bandwidth

a. Broadband cable systemb. CSMA/CD basebandc. Digital PBXd. Token-passing network

76. Avalanche photodiode receivers can detect bits of transmitted data by receiving

a. 1 photonb. 10 photonsc. 100 photonsd. 200 photonse. 1000 photons

77. The number of channels on which different operations can occur simultaneously on one ISDN basic access line

a. 1b. 2c. 3d. 4e. 5

78. When the index of refraction is greater than material 1 than it is in material 2, the velocity of propagation in material 1 compared to material 2 is__

a. Equal to or greater thanb. Greater c. Lesserd. Equale. None of these

79. Which of the following systems is the most capable of servicing a wide range of applications?

a. Broadband cable systemb. CSMA/CD basebandc. Digital PBXd. Token-passing network

80. The different angles of entry of light into optical fiber where the diameter of the core is many times the wavelength of the light transmitted are called__

a. Emittersb. Modesc. Sensorsd. Refractorse. Reflectors

81. Digital telephones and integrated voice-data work stations are examples of this type of ISDN equipment

a. NT2b. TAc. TEd. TMe. TP

82. In a single-mode fibers, a large fraction of the power is propagated in the:

a. Airb. Claddingc. Junctions or splicesd. Sheathe. Core

83. A characteristic of toke passing ring as opposed to a token passing bus

a. Flexible polling interfaceb. Passive interfacec. Priority access capabilitiesd. Signal quality control

84. The loss in signal power as light travels down a fiber

a. Absorptionb. Attenuation

c. Propagationd. Scatteringe. Reflection

85. Not a motivation for digitizing a voice signal in the telephone of a digital PBX

a. Fewer wire pairsb. Lower cost telephonesc. Multiplexed voice and

data channelsd. Simplified control

signaling86. The coupling efficiency of an LED

light source to an optical fiber with a numerical aperture of 0.2 or more is

a. 0.1%b. 2%c. 10%d. 30%e. 60%

87. The electrical state of the control leads in a serial interface is a concern of__

a. Link layerb. Data link layerc. Physical layerd. Network layer

88. The FT 3C light wave system contains the following number of fibers__

a. 12b. 64c. 128d. 144e. 256

89. Not a characteristic of the hub architecture of ARCnet

a. Directionalized transmission

b. RIM port isolationc. Zero insertion loss

amplifiersd. Alternative routing

90. A geostationary satellite used for communications systems is not/does not__

a. Remains stationary relative to earth’s surface

b. Rotates with the earthc. Stationary in the sky

91. The X.25 standard specifies a__a. Data bit rateb. DTE/DCE interfacec. Technique for dial accessd. Technique for start-stop

data92. Multiple repeaters in

communications satellites are known as__

a. Detectorsb. Diplexersc. Modulatorsd. Stations

e. transponders93. The transmission of data on an

ISDN line between a customer’s premises and a carrier central office is encoded using__

a. 2BIQ encodingb. Hexadecimal encodingc. BCH encodingd. Octal encodinge. QAM

94. The bandwidth required to send 132 voice-grade channels by FDM on an international satellite system

a. 10 MHZb. 50MHZc. 500MHzd. 1320 MHze. 22.5GHz

95. The X.25 standard is__a. Complete description of a

public data networkb. Required for all packet

switching networksc. A recommendation of

the CCITTd. Used by all packet

terminals96. Communications protocols

always have a____a. BCC b. Start-stop bitsc. Set of symbolsd. Start of headere. Special flag symbols

97. Cannot be provided in broadband LAN

a. CCTVb. Frequency agile modemsc. Fiber optic

transmissionsd. Voice circuits

98. The Baudot Code uses how many bits per symbol

a. 4b. 5c. 7d. 8e. 9

99. Not possible in a digital(data) PBX using twisted pair transmission

a. Computer port concentration

b. 64 kbps circuitsc. High speed file transfersd. Transmission up to

several thousand feet100. When transmitting odd

parity coded symbols, the number of bits that are zeroes in each symbol is:

a. Evenb. Oddc. Unknown

d. None of these101. The electrical state of the

control leads in a serial interface is a concern of the ___layer protocol

a. datab. Linkc. Networkd. Physicale. Session

102. The Hamming distance between the characters 1001101 and 1011011

a. 0b. 1c. 2d. 3e. 4

103. Not considered a primary objective of data networking

a. Accuracyb. Packet switchingc. Securityd. Timeliness

104. Radiation of electrical energy is practicable only above__kHz

a. 5b. 10c. 30d. 12e. 15

105. The X.25 standard specifies a__

a. Data bit rateb. DTE/DCEc. Technique for dial accessd. Technique for start-stop

data106. Which of these statements

is false? Convolutional codes ___a. Are a form of block codeb. Are also called recurrent

codec. Are used with forward

error correctionsd. Depend on both current

characters to be encoded and those that have been endoded previously

107. On a point-to-point data channel using an analog circuit, transfer rate of information bits(TRIB) is___

a. Equal to the modem bit rate

b. Lower than the modem bit rate

c. Not related to the modem bit rate

d. Higher than the modem bit rate

108. Modulation is done in___a. The antenna

b. Between transmitter and receiver

c. Radio receiverd. Transmitter

109. The X.25 standard is___a. A recommendation of the

CCITTb. A complete description of

a public data networkc. Required for all packet

switching networkd. Used by all packet

terminals110. Type of CRT-based

terminals most closely resembles the KSR teletypewriter configuration

a. Buffered terminalb. Bus terminalc. Dumb terminald. Smart terminale. Terminal island

111. The block length that gives maximum TRIB___

a. Decreases as the error rate increases

b. Increases as the error rate increases

c. Is not related to error rated. Is called the optimum

block length112. In a radio transmitter__ is

used.a. Colpitts Oscillatorb. Crystal oscillatorc. Hartley oscillatord. RC phase –shift oscillatore. Wien –bridge oscillator

113. The X.25 for packet network is analogous to___

a. Local loop standards for a telephone network

b. Handset standards for a telephone

c. PBX for a telephone network

d. Switching standards for a telephone network

114. Not generally used as a stand-alone data communication terminal

a. Magnetic media transceivers

b. Mainframe computersc. Microcomputerd. Minicomputer

115. Smart TDMsa. Are always better than

FDMb. May be better than dumb

TDMs if the data terminals have a low duty cycle

c. Are always better than dumb TDMs

d. Are the same as modems sharing devices

116. In an AM wave, useful power is carried by___

a. Both sidebands and carrier

b. Carrierc. Sidebandsd. None of these

117. The value of the “A” field in a LAPB frame specifies_____

a. The calling DTE for a virtual call

b. The data sink for a VC or PVC

c. The called DTE for a virtual call

d. One of the two ends of a serial interface

118. Which of the following standards or organizations produce standards which are NOT generally used in the US?

a. ANSIb. CCITTc. ISOd. UL

119. FDM devices can operatea. Like modem sharing

devicesb. On multipoint analog data

channelsc. More efficiently than

dumb TDMsd. More efficiently than

smart TDMs120. In this wave phenomenon,

each little parcel of air vibrates in some fashion and passes on the disturbance to its neighbors

a. Electromagnetic interference

b. Lightc. Magnetic fieldd. Sound

121. A group of packets from a source through an X.25 jacket system to a sink___

a. Arrive in the same order send for VC, but not for PVC

b. Arrive in the same order for PVC but not for VC

c. Arrive in the same order for both PVC and VC

122. The difference between synchronous and asynchronous data transmission can beobserved by noting___

a. How accurate the clock isb. How fast the data is

transmitted on the circuitc. When start and stop

pulses are used

123. Protocol converters are___a. The same as multiplexersb. Same as TDMs c. Usually operated in pairsd. Usually not operated in

pairs124. In this situation, a

significant amount of sound energy is literally lost

a. Absorptionb. Condensationc. Radiationd. Sublimatione. Vibration

125. A protocol is a set of rules governing a time sequence of events that must take place___

a. Across an interfaceb. Between nonpeersc. Between peersd. Between superiors

126. Some characteristics of the EBCDIC code are___

a. It is binary coded decimal code expanded to allow the transmission of letters and control characters

b. EBCDIC can easily be transformed into ASCII-8 by adding hexadecimal constant to the ASCII-8 code

c. It is used exclusively on OBM computers

127. Null modems area a type of___

a. Demultiplexerb. Multiplexerc. Modemd. Modem eliminatore. Protocol converter

128. Distinctly spaced reflection are discrete and perceptible

a. Diffuse reflectionb. Echoc. Irregularityd. Non-linear effectse. Reverberation

129. The OSI Reference Model defines the functions for seven layers of protocols____

a. Including the user and communications medium

b. Including the communications medium but not the user

c. Not including the user or communications medium

d. Including the user but not the communications medium

130. Which of the following techniques will not help to correct transmission line errors?

a. Algorithmic conversionb. Checksumc. N of M codesd. Parity checking

131. A basic technique for isolating data communication faults is____

a. Calling the DTE service department

b. Calling telephone company

c. Performing a loopback test

d. Simulating the system on a special purpose computer

132. What transient beginning or ending is generated when a steady sound source is turned ON or OFF?

a. Early reflectionb. Diffuse reflectionc. Impulsive soundd. Reverberant sound

133. The X.25 standard covers how many OSI layers?

a. Threeb. Fourc. Sevend. Ten

134. The primary consideration when designing an error control system for data communications is___

a. How many errors the system will detect and correct

b. The overall function and needs of the networks

c. The efficiency of the code that results from the design

135. The main purpose of a data link content monitor is to___

a. Determine the type of switching used in a data line

b. Determine the type of transmission used in a data link

c. Detect problems in protocols

136. The total absorption area of a room of 2000 square meter surface area, if half of this surface has absorptivity of 0.1 and the other half is 0.3

a. 400 sq. mb. 800 sq.mc. 750 sq. md. 5000 sq .me. 13,333.33 sq. m

137. Architecturally, link protocols are at a level___

a. Lower than physical protocols

b. The same as physical protocols

c. Higher than physical protocols

138. Which of the following statements is false?

a. Cyclic Redundancy Checking can find all of certain kinds of errors, and more than 99.3% of most other kinds.

b. A Hamming Code of distance 5 can detect and correct 4 errors in transmission.

c. Parity checking is capable of providing enough information to detect and correct errors

d. Checksums detect errors more effectively than checking

139. The most sophisticated type of data communications test equipment is the ___.

a. Simulatorb. Protocol Analyzerc. DTEd. Breakout Boxe. Synthesesizer

140. What is the reverberant sound level of the 100 cubic meter room, reverberation time of 1.2 seconds and moderately vigorous speaking voice can produce acoustic power in the order of 100 microwatts?

a. 60 dBb. 58.8 dBc. 64.2 dBd. 75 dBe. 120 dB

141. A data packet is a packet header together with ____.

a. A network layerb. An administrative layerc. User datad. A packet switche. Either (a) or (b)

142. Pulse Duration Modulation is ___.

a. Similar to FMb. Difficult to detect

accuratelyc. Not widely usedd. Vulnerable to noisee. Similar to wave division

multiplexing

143. Full capability dialed up backup of a multipoint full- duplex 4800 bps private line having 4 remote drops requires ____.

a. 4 callsb. Either 4 or 8 callsc. 8 callsd. 16 callse. Can’t tell

144. What is the basic function of a Public Address System (PAS)?

a. Distortionless Sound Reproduction

b. Maximum Powerc. Intelligible Information

Transferd. Frequency Responsee. None of these

145. A network node joining three or more links is a ____.

a. DSEb. DTEc. DCEd. DTE and DCEe. None of these

146. Pulse Amplitude Duration Modulation is ___.

a. Similar to amplitude modulation in the analog world

b. Used in radio communications

c. Relatively insensitive to noise distortion

d. A version of frequency modulation

e. None of these147. The X.25 standard

specifies how many separate protocol layers at the serial interface gateway?

a. 8b. 2c. 4d. 3e. 6

148. What unit equalizes the time arrival for the sound reinforcement wavefront and the direct sound wavefront at the listening position?

a. High Powe Amplifierb. Hi- Fi amplifierc. Mixerd. Time Delaye. Reverb

149. Ducting in the atmosphere may cause microwave signals to ___.

a. Travel Longer Distancesb. Increase Signal Intensityc. Travel Shorter Distancesd. Improve C/N Ratioe. None of these

150. A 24 voice channel is sampled at 8,000 hertz and encoded into an 8- bit PCM word. The approximate rate of the data stream is ___.

a. 2.048 Mbpsb. 6.28 Mbpsc. 44.735 Mbpsd. 1.544 Mbpse. 2.056 Mbps

151. The (Link Access Procedure Balanced) LABP frame structure and the frame structure of SDLC are:

a. Oppositeb. Identicalc. Reversedd. Amorphouse. None of these

152. What is an early sound arriving from infront of the listener or from the ceiling overhead may leave a feeling of remoteness from the source?

a. Direct soundb. Reverberant soundc. Freedom from noised. Envelopmente. Flutter

153. At microwave frequencies, the LOS distance is sometimes extended through the occurrence of ___.

a. Ionospheric Reflectionsb. Fogc. Sporadic Ed. Dellinger Dropoutse. Ducting

154. The best system configuration to overcome multipath fading on “over-the water” propagation

a. Angle diversityb. Frequency diversityc. Non-diversityd. Space diversity

155. Establishing a virtual connection is functionally equivalent to:

a. Connecting a virtual memory

b. Experimental with virtual reality

c. Physically connecting a DTE and DCE

d. Placing a telephone call prior to a connection

156. How much acoustic power must a public address be able to put out in order to create SPL= 100dB for a musical show in a 105

m3 auditorium with reverberation time of 1.2 seconds?

a. 28.6 watts

b. 33 wattsc. 31.4 wattsd. 29.8 wattse. 300 watts

157. The quality of digital transmission is measured in terms of

a. Beamwidthb. BERc. Distortiond. Modulation usede. Traffic density

158. In a radio system, noise was measured at 58dBrn. What is its value in dBm?

a. 32b. -32c. 90d. 98e. 148

159. In X.25 network layer protocol, the data packets normally contain:

a. One octet of header plus data

b. Two octets of header plus data

c. Three octets of header plus data

d. Four octets of header plus data

160. Spectrum of a changing source which is continually updated during the change with no incoming data ignored

a. Digital analysisb. Heterodyne analyzerc. Tunable filterd. Real-time analysise. Tunable filter

161. The standing wave ratio of a transmission line can be measured by a:

a. Bolometerb. Power meterc. Reflectometerd. Stroboscopee. Voltmeter

162. In measuring noise, a circuit indicated 58dBrnc with tone and a 33dBrnc in C-notch reading. The S/N ratio of the circuit is__

a. 19 dBb. 25 dBc. 33 dBd. 52 dBe. 91 dB

163. The OSI reference model isa. A protocolb. Not a protocolc. A polling sequenced. Sequence

164. The reference level for sound in air

a. 6 x 10-6 pa2/Hzb. 4 x 10-3 pa2/Hzc. 4 x 10-10 pa2/Hzd. 6 x 10-4 pa2/Hz

165. One method of producing a broadband tuned circuit is by way of

a. Critical couplingb. Loose couplingc. Overcouplingd. Undercoupling

166. An transmitter is rated 100 watts at 100% modulation. The power required for the carrier is__

a. 33.33 wattsb. 50 wattsc. 66.67 wattsd. 86.67 wattse. 100 watts

167. Layer 1 of the OSI model isa. Link layerb. Network layerc. Physical layerd. Session layer

168. The pressure spectrum level at 2 kHz

a. 25.78dBb. 33.47 dBc. 45.32 dBd. 62.51dBe. 120 dB

169. Color TV is made possible through the combination of the primary colors of

a. blue, yellow, greenb. red, green, bluec. red, white , blued. white, red, green

170. A type of modulation technique that conveys audio information from one station to another by varying the carrier frequency at the audio rate

a. Amplitude modulationb. Frequency modulationc. Quadrature modulationd. Phase modulation

171. The applications layer of the OSI model is the

a. First layerb. Second layerc. Seventh layerd. Sixth layere. Third layer

172. Causes modulation either in its internal circuitry or in another associated circuit

a. Detectorb. Modulatorc. Multivibratord. Multiplexer

e. Phasor173. The half-power points of

the beamwidth of the front lobe of a directional antenna is the point equal to

a. 0.707b. 0.636c. 0.318d. 0.5e. 1.414

174. A tuned amplifier uses___load

a. Capacitiveb. Inductivec. LC tankd. Resistive

175. When a single antenna is intended to be used for transmitting and receiving , it is necessary to use__

a. Combinerb. Diplexerc. Duplexerd. Multiplexere. Transponder

176. The receiver’s ability to receive both very weak and extremely strong stations without introducing distortion

a. Dynamic rangeb. Effective rangec. Figure of meritd. Sensitivitye. Selectivity

177. The T-1 North American digital system has 24 channels and require a transmission speed of

a. 64 kbpsb. 640 kbpsc. 960 kbpsd. 1.54 Mbpse. 2.048 Mbps

178. A tuned amplifier is used in ___ applications

a. Audio frequencyb. Low frequencyc. Optical frequencyd. Radio frequency

179. The higher the Q of a circuit, the __ is the frequency bandwidth

a. Broaderb. Low selectivec. Higher stabilityd. Narrower

180. Considered as an FM demodulators

a. Foster-Seely Discriminator

b. Phase-locked loopc. Radio detectord. All of thesee. None of these

181. What is the image frequency when the receiver is tuned to9.81 MHz, the local oscillator is tuned above the desired signal, and the intermediate frequency is 455 kHz?

a. 8.355 MHzb. 8.9 MHzc. 10.265 kHzd. 10. 720 MHze. 11.72 MHz

182. One of the main functions of the RF amplifier in a superheterodyne receiver is to__

a. Improve the rejection of the image frequency

b. Increase tuning range of the receiver

c. Permit better adjacent-channel rejection

d. Provide improve tracking183. At resonance, the circuit

power factor is__a. 0b. 1c. 0.5d. 0.8e. Infinity

184. In broadcast superheterodyne receiver, the__

a. Local oscillator operates below the signal frequency

b. Mixer input must be tuned to the signal frequency

c. Local oscillator frequency is normally double the IF

d. RF amplifier normally works at 455 kHz above the carrier frequency

185. The voltage gain of a tuned amplifier is __ at resonant frequency

a. Halfway between minimum and maximum

b. Maximumc. Minimumd. zero

186. In an FM stereo multiplex transmission, the __

a. Difference signal modulates the 38 KHz subcarrier

b. Difference signal modulates the 67 KHz subcarrier

c. Difference signal modulates the 19 KHz subcarrier

d. Sum signal modulates the 19 KHz subcarrier

187. At parallel resonance, the line current is__

a. Maximumb. Minimumc. Between maximum and

minimumd. Zero

188. In amplitude modulation, bandwidth is ___ the audio signal frequency

a. Thriceb. Four timesc. Twiced. Five timese. Six times

189. At series resonance, the circuit offers __ impedance

a. Infinityb. Negativec. Maximumd. Minimume. Zero

190. It a system which provides the longest digital transmission distances

a. Computer busb. Digital PBXc. Local area networkd. Voice band modem

191. When modulating frequency is disabled , the modulation index is halved, and the modulating voltage remains constant. The modulating system is __

a. Amplitude modulationb. Frequency modulationc. Phase modulationd. Pulse modulation

192. Which of the functions is not provided as part of the basic Ethernet design?

a. Access controlb. Addressingc. Automatic

retransmissiond. Multiple virtual networks

193. The frequency the oscillator must be set at for an output of 95 kHz if the output of the oscillator is being fed to two frequency triplers connected in cascaded form

a. 6.3 MHzb. 9.65 MHzc. 10.56 MHzd. 15.8 MHz

194. A resonant circuit contains ___ element

a. R and Lb. Only Rc. R and Cd. L and C

195. For a monoaural FM receiver, it only receives the__

signal of a stereo multiplex transmission

a. L-Rb. L+Rc. R-Ld. 2R + Le. R + 2L

196. At resonance, a circuit behaves as a ___ load

a. Capacitiveb. Inductivec. magneticd. PN junctione. Resistive

197. The purpose of the preamble in an Ethernet is__

a. Broadcastb. Clock synchronizationc. Error checkingd. Collision avoidance

198. Pre-emphasis and de-emphasis are used in the FM stereo multiplex system to improve__

a. Current ratiob. CMRRc. Power ratiod. Standing wave ratioe. Signal-to-noise ratio

199. At series resonance, the voltage across L is___ voltage across C

a. Equal to but in phase withb. Equal to out of phase

withc. Greater than but in phase

withd. Less than but in phase

with200. The frequency tolerance

for the RF carrier in the standard AM radio broadcast band is___

a. Zerob. ± 20 Hzc. ± 25 Hzd. ± 75 Hze. ± 1000 Hz

201. The TV visual carrier uses a ____transmission

a. Lincompexb. Pilot carrier systemc. SSBSCd. Vestigial sideband

202. When either L or C is increased, the resonant frequency of LC circuit___

a. Decreasesb. Increasesc. Remains the samed. None of these

203. Phosphor colors for a tricolor picture tube

a. Red, yellow, greenb. Blue, red, yellow

c. Red, blue , magentad. Red, green , bluee. Red, white, blue

204. At parallel resonance____a. IL < IC

b. IL = IC

c. Ic > IL

d. IL>> IC

e. IL << IC

205. In parallel LC circuit, if the input signal is increased above resonant frequency, then___

a. XL decreases XC increasesb. XL increases XC decreasesc. Both XL and XC increased. Both XL and XC decrease

206. In amplitude modulation___ of carrier is varied according to the strength of the signal.

a. Amplitudeb. Frequencyc. Phased. period

207. The Q of an LC circuit is given by__

a. XL/Rb. R/XL

c. XL x Rd. R2/XL

e. LC/R208. In AM wave, the majority

of the power is in____.a. Equal tob. Less thanc. Greater than

209. The exact vertical field scanning frequency for color TV

a. 3.579545MHz b. 59.94Hzc. 15,734.27Hzd. 3.58 MHz

210. Any deviation in frequency of reproduced sound from the original frequency

a. Consonanceb. Flutterc. Reverberationd. Rumblee. Wow

211. If Q of an LC circuit increases, the bandwidth

a. Is decreasedb. Is increasedc. Remains the same

212. If L/C ratio of a parallel LC circuit is increase, the Q of the circuit ____.

a. Is increasedb. Is decreasedc. Remains the samed. Either (a) or (b)

213. The transmit frequency range of a cellular telephone system is ____.

a. 140-50 MHzb. 138-174 MHzc. 156-165 MHzd. 825-845 MHz

214. At resonance, the phase angle between applied voltage and circuit current is ____.

a. 90°b. 180°c. 0°d. 270°

215. The channel spacing in a cellular telephone is ____.

a. 1 HKzb. 30 KHzc. 1 MHzd. 150 Hze. 25 Hz

216. If the resistance of a tuned circuit is increase, the Q of the circuit _____.

a. Remains the sameb. Is decreasedc. Is increasedd. Either (a) or (c)

217. The separation between transmit and receive signals in cellular phones is____.

a. 15b. 25c. 35d. 45e. 55

218. A parallel LC circuit draws a line current of 1 mA at resonance. If Q of the circuit is 100, then each branch current is ____.

a. 0.01 mAb. 100 mAc. 0.5 mAd. 50 mAe. 300 mA

219. The Automatic Power Control Circuit of a cellular phone causes the transmitter power to ____ based on an input control signal from the MTSO.

a. Change or decreaseb. Remain constantc. Reverberated. Bounce back and forth

220. The resonant frequency of an LC circuit is 1 Megahertz. If L is doubled but C is reduced to one eighth of the original value, the resonant frequency will be ____.

a. 500 KiloHertzb. 250 KiloHertzc. 1 MegaHertzd. 2 MegaHertz

221. A DC signal derived from the demodulator and used to tell the MTSO about received signal strength is called _____.

a. VU meterb. SWR Indicatorc. Received Signal Strength

Indicatord. Dosimeter

222. The Q of a tuned circuit refers to the property of ____.

a. Selectivityb. Sensitivityc. Fidelityd. Conductivity

223. The third harmonic of 400 Hertz is___

a. 300 Hzb. 400 Hzc. 800 Hzd. 1200 Hze. 1600 Hz

224. A coil has XL = 1000 ohms and 5 ohms internal resistance. Its Q is equals to ___.

a. 0.005b. 200c. 1000d. 2000e. 5000

225. The section of the cellular transceiver that interprets the serial digital data from the cell site and the MTSO is the ____ unit

a. Arithmeticb. Bufferc. CPUd. Finale. Logic

226. In a parallel LC circuit, if the signal frequency is decreased below resonant frequency , then ___

a. XL decreases and XC

increasesb. XL increases and XC

increasesc. XL and XC both decrease

current is minimumd. Line current is minimum

227. How many microprocessors do most cellular transceivers contain?

a. 1b. 2c. 3d. 4e. 5

228. The sharpness of a resonance curve depends upon ___ of the tuned circuit

a. Fidelityb. Friction of electronsc. Particle dispersion

d. Qe. Sensitivity

229. When the speed of a radio signal is known, radar can be used to determine ___ of a target

a. Altitudeb. Blind speedc. Directiond. Doppler shifte. Range

230. For frequencies above the resonant frequency, parallel LC circuit behaves as a _____ load

a. Capacitiveb. Inductivec. Resistived. Reverse biased

231. In cellular telephones, the receive frequency range is between ___ Megahertz

a. 138-174b. 140-150c. 500-600d. 800-900e. 825-845

232. The directivity of RADAR antenna determines the ____ of a target

a. Azimuthb. Angle of elevationc. bearingd. either a or ce. Either a or b

233. Printed documents to be transmitted by fax are converted into a baseband electrical signal by the process called___

a. Light variationb. Modulationc. Photostatd. Scanninge. Reflection

234. The elapsed time between a radiating radar signal and receiving its echo is 43.2 microseconds. The target distance is___ nautical miles

a. 3.5b. 4.5c. 5.5d. 6.5e. 7.5

235. The most commonly used light sensor in a modern fax machine is a ___

a. Charge coupled deviceb. Liquid crystal displayc. LASCRd. Phototransistore. Phototube

236. A waveguide assembly that lets the radar transmitter and receiver share an antenna is called___

a. Diplexerb. Duplexerc. Flip-flopd. Translatore. Toggle switch

237. Resolution which produces the best quality fax

a. 96 lines/inchb. 150 lines/inchc. 200 lines/inchd. 300 lines/inche. 400 lines/inch

238. Most commonly used component in a RADAR transmitter is a/an__ tube

a. Cyclotronb. Dynatronc. Magnetrond. Twystrone. Voltron

239. Group of two (2) fax machines uses ____ modulation

a. SSBb. FSKc. Independent Sidebandd. PSKe. Vestigal Sideband

240. A radar using multiple antennas to shape the beamwidth and automatically adjust directivity is known as _____.

a. Phased Arrayb. Continuous Wavec. Pulserd. Search and Rescue

241. In television systems, the spacing between sound and picture carrier is _______ Megahertz

a. 6b. 4.5c. 63.6d. 525

242. Most fax machines are of which type?

a. Impactb. Thermalc. Electrosensitived. Laser Xerographic

243. The transmission speed of Group four (4) fax machine is ____.

a. 4800 Baudsb. 9600 Baudsc. 56 Kbpsd. 192 kbps

244. A popular half-wavelength antenna is the ____________.

a. Ground-planeb. End-firec. Collineard. Dipole

245. The maximum frequency deviation of a cellular transmitter is ______.

a. 6 KHzb. 12 KHzc. 30 KHzd. 45 KHZ

246. Popular vertical antenna is the

a. Collinearb. Dipolec. Ground-planed. Broadside

247. The master control center for a cellular telephone system is the ______.

a. Cell siteb. Mobile Telephone

Switching Officec. Central Officed. Branch Office

248. The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization in

a. Verticalb. Horizontalc. Circulard. Elliptic

249. Each cell site contains a _____.

a. Repeaterb. Control computerc. Direct link to a PABXd. Touch-tone processor

250. Cellular telephones operate in _____ mode, whereas trunking radios operate _______mode, respectively.

a. Simplex, simplexb. Full-duplex, half-duplexc. Triplex, full-duplexd. Half-duplex, simplex

251. An antenna that transmits or receives equally well in all directions or receives equally well in all directions is said to be _______.

a. Omnidirectionalb. Birectionalc. Unidirectionald. Quasidirectional

252. The output power of a cellular radio is controlled by ___________.

a. User or Callerb. Cell sitec. Called partyd. MTSO

253. Treble tome corresponds to _____.

a. High frequenciesb. Low frequencyc. High amplitudes

d. Low amplitudes254. When a signal from a

mobile cellular unit drops below a certain level, what action occurs?

a. The unit is “handed-off” to a closer cell

b. The cellphone searches for lost signal

c. The cell site switches antennas

d. The cell is terminated255. Typical loudspeaker

impedance rating is _________.a. 1 Ohmb. 8 Ohmsc. 100 Ohmsd. 5000 Ohms

256. Time from the transmission of a radar pulse to its reception is 0.12 msec. The distance to the target is _________ nautical miles.

a. 4.85b. 11.2c. 18.4d. 9.7

257. Typical output from a magnetic microphone is _________

a. 1 mVb. 500 mVc. 1 voltd. 2 volts

258. The ability of the radar to determine the bearing to a target depends upon the _________________.

a. Antenna Directivityb. Speed of lightc. Speed or targetd. Effective capture area

259. At series resonance, the voltage across L or C is ______ the applied voltage

a. Equal tob. Less thanc. Much mored. Either a or b

260. The 45° - 45° system refers to stereo for ________.

a. Magnetic tape recordersb. Photograph recordsc. Crystal microphonesd. Loudspeakers

261. For frequencies below the resonant frequency, a parallel LC circuit behaves as a _________ load

a. Resistiveb. Capacitivec. Inductived. Either a or b

262. The tape speed for cassette tape recorders, I inches per second is

a. 1 7/8b. 3 ¾

c. 45d. 15

263. In series resonance, there is ______.

a. Voltage amplificationb. Current amplificationc. Both voltage and current

amplificationsd. Power attenuation

264. Which of the following would apply to the audio power output stage?

a. Low-level signalb. Complementary

symmetryc. Class cooperationd. Very little distortion

265. In parallel resonance, there is __________.

a. Current Amplificationb. Voltage Amplificationc. Both a and bd. Power Attenuation

266. To Match 8 Ohms to 200 Ohms, an audio output transformer must have turns ratio of

a. 1:1b. 1:5c. 1:8d. 1:400

267. In a parallel LC circuit, each branch current carries a current of 1 at resonance. If the Q of the circuit is 100, then line circuit is _________.

a. 100 x Ib. 200/Ic. 100/Id. I/100

268. Negative feedback is used in audio amplifiers to

a. Increase gainb. Increase distortionc. Reduce distortiond. Operate class c

269. For frequencies below resonant frequency, a series LC circuit behaves as a _____________ load

a. Resistiveb. Capacitivec. Inductived. Either a and b

270. Less capacitive reactance in shunt with audio amplifier has the effect of

a. Bass cutb. Treble boostc. Treble cutd. More negative feedback

271. For frequencies above resonant frequency, a series of LC circuit behaves as a _______ load.

a. Inductiveb. Capacitivec. Resistived. Purgative

272. The auxiliary input jacks of a ratio receiver require audio output of _________.

a. 0.1 to 0.5 mVb. 1 to 5 mVc. 200 to 500 mVd. 5 to 10 volts

273. Tuning is generally accomplished by charging ________ of the tuning circuit

a. Both L and Cb. Lc. Cd. RL

274. Two 4 Ohm speakers in series have a total impedance of

a. 2 Ohmsb. 4 Ohmsc. 8 Ohmsd. 16 Ohms

275. If a high degree of selectivity is desired, then tuned circuits should have _______ coupling

a. Looseb. Tightc. Criticald. Both b and c

276. The gain of an RF amplifier with a tuned LC circuit for the collector is maximum at resonance at the resonant frequency because of ___.

a. Series resonanceb. Parallel resonancec. Low Qd. High Emitter Resistance

277. If the coupling between tuned circuits is increased, the level of resonance curve _______

a. Remains the sameb. Is raisedc. Is loweredd. Either a or c

278. The Q of a single tuned circuit is lower when its

a. Series R, is reducedb. Shunt RD is reducedc. Shunt RD is increasedd. Capacitance is reduced

279. Double tuned circuits are used in ____________ stages of a radio receiver

a. IFb. Outputc. Audiod. RF

280. The pulse duration of a RADAR signal is 600 nanoseconds.

The PRF is 185 pulses per second. The duty cycle is ______.

a. 0.01%b. 5.5%c. 31%d. 47%

281. Snow in a TV picture is a result of ______.

a. High Q in the tuned circuits

b. Excessive gainc. Random noise in the

signald. Insufficient wavetraps

282. Doppler effect allows which characteristic of a RADAR target to be measured?

a. Distanceb. Speedc. Size of Targetd. Azimuth

283. The response curve of a double-tuned circuit shows two peaks when the transformer has ___________.

a. Loose couplingb. Critical couplingc. Tight couplingd. Excessive dampling

284. The Doppler effect is a change in what signal characteristic produced by relative motion between RADAR set and a target?

a. Amplitudeb. Phasec. Frequencyd. Duty cycle

285. Which of the following methods can not be used to increase the bandwidth for cascaded RF amplifier stage?

a. A shunt damping resistor across each tuned circuit

b. Stagger tuningc. Wave traps in each staged. Double-tuned

transformers with tighter coupling

286. The most widely used oscillator in a radar transmitter is

a. Klystronb. Magnetronc. TWTd. Power Transistor

287. Which of the following circuits has the greatest bandwidth?

a. fr is 50 MHz with Q of 50b. fr is 455 KHz with Q of

100c. fr is 1 MHz with Q of 100d. fr is 1 MHz with Q of 10

288. Low power radar transmitters and receiver local oscillator use

a. Ga As FETb. Twystronc. Gunn Dioded. Varactor

289. When both primary and secondary resonant circuits of a double-tuned transformer have a Q of 50, the value of critical coupling Kc is _____.

a. 50b. 0.5c. 1d. 1/50 or 0.2

290. Most radar antennas use a _____.

a. Dipoleb. Broadside arrayc. Horn and parabolic

reflectord. Collinear array

291. Two main parts of a tank circuit are _______.

a. R and Cb. R and Lc. R and an NPN Transistord. L and C

292. The most common radar display is ______.

a. A-scopeb. Color CRTc. Liquid Crystal Displayd. Plan Position Indicator

293. When L is doubled and C is halved, the resonant frequency (fr) is

a. Doubleb. One-halfc. One quarterd. The same

294. A radar antenna using multiple dipoles or slot antennas in a matrix with variable phase shifters is called ________.

a. A-scanb. Phased Arrayc. Broadside arrayd. Endfire array

295. Positive feedback is the same as _____.

a. Regenerationb. Degenerationc. Negative feedbackd. Frequency synthesis

296. The black and white or monochrome brightness signal in TV is called _________.

a. RGBb. Color subcarrierc. Q and Id. Luminance Y

297. The oscillator that uses a tapped coil in the LC tuned circuit is the __________.

a. Pierceb. Colpittsc. Hartleyd. Wien

298. The assembly around the neck of the TV picture tube that produces the magnetic fields to deflect and scan the electron beam is called _______.

a. Shadow maskb. Phosphorc. Electron gund. Yoke

299. The circuit that uses a capacitive voltage divider to provide feedback is the _____________.

a. Colpittsb. Hartleyc. Armstrongd. Multivibrator

300. What type of circuit is used to modulate and demodulate the color signals of television?

a. Phase Locked Loopb. Differential Peak Detectorc. Quadrature Detectord. Balanced Demodulator

301. RF feedback oscillator are usually tuned by varying the _____.

a. Biasb. Supply Voltagec. L or Cd. Load Impedance

302. What TV receiver circuit is used to develop the high voltage needed to operate the picture tube?

a. Low voltage power supplyb. Horizontal Outputc. Vertical sweepd. Sync separator

303. The oscillator with the best frequency stability and accuracy is the

a. Hartleyb. Colpittsc. Ticker feedbackd. Crystal controlled

304. The technique used to allow hundreds of TV signals to share a common cable is ________

a. Frequency Modulationb. Mixingc. Time division multiplexingd. Frequency division

multiplexing305. When a 5 MHz crystal is

followed by a frequency tripler, the output will be _____.

a. 6 MHz

b. 12 MHzc. 18 MHzd. 54 MHz

306. The varactor in a Voltage Controlled Oscillator (VC0) needs ____.

a. Audio signal below 1000Hz

b. Reverse DC control voltage

c. Forward biasd. Parallel capacitance more

than 5 microfarads307. The phase comparator in a

PLL circuit is used to provide a. One-half of the crystal

oscillator frequencyb. RF output with audio

modulationc. DC Control voltaged. Double the crystal

oscillator signal308. In which of the following

frequency bands are the standard AM broadcast stations?

a. MFb. HFc. VHFd. UHF

309. The commercial FM radio broadcast band is

a. 535 to 1605 KHzb. 27 to 29 KHzc. 88 to 108 MHzd. 300 to 3000 MHz

1. The RF power output of a transmitter in a cellular mobile telephone system authorized by NTC for use in the Philippines.a. 20.5 dBm c 31.5 dBm b. 34.8 dBm d. 22.1 dBm

2. In telephony, M88 loading coil (88-mH loading coil) is placed at an interval of ______ feet.a. 5000 c. 7500 b. 8000 d. 9000

3. MPEG 21 is the standard that aims at defining an open framework for MULTIMEDIA applications with standard namea. ISO/IEC 14496 c.

ISO/IEC 2100 b. ISO/IEC 15938 d.

ISO/IEC-13818

4. In digital television, 480 p format means _____

a. 480 x 640 pixels interlace b. 480 x 640 pixels progressivec. 640 x 480 pixels interlace d. 640 x 480 pixels progressive

5. The average absorption of a person is

a. 1.7 sabines b. 4.7 sabines c. 47 sabinesd. 7.4 sabines

6. For TV broadcasting stations, median field strengths required for various grades of service are oftentimes expressed in dBu. It signifies the field strength in decibels above______a. one microvolt per ft b. one microvolt per km c. one microvolt per meterd. one millivolt per meter

7. OSI network layer which has aninter-host communicationa. network layer b. physical layerc. presentation layer d. session layer

8. The IEEE 802.4 standarda. Token passing for bus

topologyb. Token passing for ring

topologyc. Token passing for mesh

topologyd. Token passing for star

topology

9. Code assigned to duly authorized local access network providers for 3G Network Operators.a. 100 c. 209b. 306 d. 404

10. Among the connectors and transmission lines for coaxial, which is the least expensive as is widely used for CATV, VCRs, and TV sets?a. F – type c. PL – 529 b. L-type d. RG -11

11. A section which would be a complete antenna by itselfa. bay c. gayb. hay d. hertz

12. In accordance with the Philippine Electronics Code, the maximum radiation from electronics equipment must not exceed ____ per week in order not to experience genetic and somatic damage to cells.

a. 1 rem c. 100 rems b. 10 rems d. 50 rems

13. Determine BW efficiency for QPSK modulation at rate 10 Mbps.

a. 1 bit/cycle c. 3 bits/cycle

b. 2 bits/cycle d. 4 bits/cycle

14. To make the tape speed the same in playback as in recording, the tape speed is regulated by the

a. audio track b. control-track pulses c. erase headd. video slant tracks

15. Luminance signal or Y signal componentsa. 21 % red, 52 % green & 31 %

blue b. 30 % red, 59 % green, & 11 %

bluec. 60 % red, 28 % green, & 32 %

blue d. 30 % red, 11 % green, & 59 %

blue

16. Iridium is an example of LEO, and has a mean elevation ofa. 48 miles b. 84 miles b. 840 miles d. 480 miles

17. NTC has defined Outdoor Radio Equipment Devices used for Wireless Data Network as those effective power exceeds _____a. 150 mW b. 175 mW c. 200 mWd. 250 mW

18. The period for a single time slot in a GSM-TDMA slot structure is ____ μseca. 577 b. 57.7 c. 75.7 d. 757

19. The formula used to calculate the overall noise performance of a receiver or of multiple stages of RF amplification is the _____ formula

a. Arceo’s c. .Frii’s b. Hartley’s d.

Shannon’s

20. Mandatory date of compliance to NTC requirement of installing NAVTEX receiver by cargo and passenger vessels/ships engaged in coastwise trade is on or before ______

a. 30 September 2002 b. 30 September 2003 c. 30 Sept 2004 d. 30 Sept 2005

21. High speed networks as defined by the National Telecommunications Commission(NTC) memorandum circular are networks in ICT that

have a capacity of at least _______a. 1.024 Mbps c. 2.048

Mbpsb. 512 kbps d. 4.096

Mbps

22. The instrument used to measure the interval height of a layer in the ionosphere used for wave propagationa. Altimeter c. iconoscope b. ionosonde d. ionoscope

23. Horizontal polarization is nothing but

a. Circular polarizationb. Elliptical polarizationc. X-polarizationd. Y-polarization

24. The maximum electronic efficiency of reflex klystron

a. 40% c. 22.7%b. 50% d. 35%

25. Directional couplera. Amplifierb. Non-reciprocal devicec. Oscillatord. Reciprocal device

26. The maximum unambiguous range in a system depends on:

a. Maximum power of the transmitter

b. Pulse repetition frequencyc. Width of the transmitted

pulsed. Sensitivity of the radar

receiver

27. To calculate the Thevenin’s equivalent value in a circuit

a. All independent voltage sources are opened and all independent current sources are short circuited

b. All voltage and current sources are shorted

c. All voltage sources are shorted while current sources are opened

d. Both voltage and current sources are open circuited

28. The characteristic impedance of a low pass filter in attenuation band is

a. Complex quantityb. Purely imaginaryc. Real valued. Zero

29. The real part of the propagation constant shows:

a. Reduction in voltage, current values of signal

amplitudeb. Reduction of only voltage

amplitudec. Variation of phase

shift/position of voltaged. Variation of voltage and

current on basic unit

30. The control system of electronic switching systems are called as

a. Combination Switching System

b. Crossbar Systemsc. Gigantic Switching Systemd. Stored Program Control

Systems

31. A fully connected network supports full duplex communication using unidirectional links. The total number of links in such a network with n nodes is

a. nC2 c. 2 x nC2

b. n2 d. 2n

32. Near-end crosstalk refers to:a. Coupling form a transmitter

into a receiver at a common location

b. Interference caused by other cables routed close to the cable of interest

c. Unwanted coupling into a received from transmitter at a distant location

d. None of these

33. The horizontal resolution of a picture is decided by:

a. Aspect ratiob. No. of horizontal linesc. No. of vertical linesd. Pixel

34. The chrominance signal isa. Result of colour difference

signalsb. Resultant of modulated

quadrature colour difference signals

c. Sum of colour difference signals

d. Sum of primary colours

35. The patter of scanning lines in a video system

a. Interfaceb. Rasterc. Resolutiond. Retrace

36. With an increase in temperature, the Fermi level in an intrinsic semiconductor

a. Moves closer to the conduction band edge

b. Moves closer to the valence band edge

c. Moves into the conduction band

d. Remains at the centre of forbidden gap

37. The purpose of impedance matching between the output of previous stage and input of next stage in a cascaded amplifier

a. To achieve high efficiencyb. To achieve reduced

distortionc. To achieve maximum

power transferd. To achieve reduced noise

38. If one of the diode in a full wave bridge rectifier opens the output is

a. 0 Vb. ¼ of the amplitude of the

input voltagec. A half wave rectified

voltaged. A 120 Hz voltage

39. The expression for carrying C in the half adder with inputs A and B is given by

a. ABb. A.Bc. ABd. None of these

40. Bandwidth of MSK is ___ that of QPSK

a. Equal tob. Higher thanc. Less than or equal tod. Lower than

41. Which of the following modulation schemes provides 4 bits per baud?

a. QPSKb. 16-QAMc. 8-PSKd. 64- AQAM

42. Hamming weight (Si) of a code Si is defined as the

a. No of 0’s in codeword Sib. No. of 1’s in codeword Sic. No. of 1’s in even locations

of Sid. No. of 0’s in even locations

of Si

43. In the eye pattern, as eye closesa. ISI decreasesb. ISI increasesc. Timing jitter decreasesd. Timing jitter increases

44. The CRC circuit is basicallya. Adder circuitb. Decoder circuitc. Multiplexer circuitd. Shift register circuit

45. When a thyristor gets turned on, the gate drive

a. May or may not be removedb. Should be removedc. Should be removed in order

to avoid increased losses and higher junction temperature

d. Should benot be removed as it will turn-off the SCR

46. The intersection of a V-I curve with the load line is called the

a. Load pointb. Q-pointc. Transfer curved. Transition point

47. If a single diode in a center tapped full-wave rectifier opens, the output

a. 0Vb. Half-wave rectifiedc. Reduced in amplituded. Unaffected

48. The purpose of a small capacitor placed across the output of an IC regulator is to

a. Couple the output signal to the load

b. Filter the acc. Improve transient responsed. Protect the IC regulator

49. When the collector resistor in a CE amplifier is increased in value , the voltage gain

a. Becomes erraticb. Decreasesc. Increasesd. Is not affected

50. The place where telephone companies terminate customer lines and locate switching equipment to interconnect those lines with other networks

a. Central officeb. Customer care centrec. Customer premises endd. Network service providers

51. ___ layers of OSI model send frames with the necessary synchronization, error control and flow control

a. Data linkb. Networkc. Physical d. Transport

52. In___ coding scheme, 0 is transmission from high to low in middle of interval and 1 is the transition from low to high in middle of interval

a. Bipolar AMIb. Differential Manchesterc. Manchesterd. Pseudoternary

53. The ISDN encodinga. 2B1Q encoding c. 4B2Q

encoding b. 1B2Q d. 2B2Q

54. Typical PBX configurationa. Star topology c. bus

topologyb. ring topology d. mesh

topology

55. 3G wireless technology that has a Broadband-like data speeda. WIFI c. EDGEb. WIMAX d. ZIGBEE

56. One of the following if NOT a system specification for 3G wireless system.a. IMT 2000 c.

TC/CDMAb. CDMA 2000 d. WCDMA

57. 3G wireless technology that has a Broadband-like data speedc. WIFI b. EDGE c. WIMAX

d. ZIGBEE

58. One of the following if NOT a system specification for 3G wireless system.c. IMT 2000 c.

TC/CDMA d. CDMA 2000 d.

WCDMA

59. Room whose boundaries absorbs effectively all incident sounda. acoustic roomb. anechoic roomc. Helmholtz resonator d. Helmholtz room

60. Navigational display that provides range versus azimuth.a. A-scope c. B-scanb. PPI d. RHI

61. An 802 standard used for wireless regional area network.a. 802.25 b. 802.16 c. 802.19

d. 802.22

62. In broadband ISDN (B-ISDN), the

channel rate of H21 is ______

a. 43 to 45 Mbps c. 132 Mbps

b. 138.24 Mbps d. 32.786 Mbps

63. Type of antenna array consisting of a linear arrangement of a simple dipoles fed 90˚ out of phase and have radiation pattern of maximum directivity in plane of the array.a. broadside arrayb. collinear arrayc. end-fire array d. parasitic array

64. In integrator, the feedback element is a

a. Capacitorb. Diodec. Inductord. Resistor

65. Wein-bridge oscillations are based on

a. High gainb. Negative feedbackc. Piezoelectric effectd. Positive feedback

66. A feature in which a data frame has a field to hold the sequence number of the frame as well as sequence number for acknowledgement

a. Flow controlb. Go-back-Nc. Piggy backingd. Stop and wait

67. The data rate provided by DS-I transmission format is

a. 2.048 Mbpsb. 64 kbpsc. 1.544 Mbpsd. 51.84 Mbps

68. Virtual Circuit Packet Switching needs

a. Dedicated pathb. Fixed bandwidthc. Non-dedicated pathd. None of the above

69. In ___ avoidance, the network alerts end systems to growing congestion they intrn reduce the offered load to the network

a. Implicit congestionb. Explicit congestionc. Both a and bd. None of the above

70. IEEE 802.ID specification defines the protocol architecture for__

a. LANSb. Bridgesc. Gateways

d. None of the above

71. In a transmission line terminated by characteristic impedance, Zo

a. The incident current is zero for any applied signal

b. The reflection is maximum due to termination

c. There are a large number of maximum and minimum on the line

d. There is no reflection of the incident wave

72. For a coil with inductance L and resistance R in series with a capacitor C has

a. Resonance impedance as infinity

b. Resonance impedance as zero

c. Resonance impedance L/RC

d. Resonance impedance R

73. All pass filtera. Passes all frequencies with

very low attenuationb. Passes all frequencies

without attenuation but phase is changed

c. Passes whole of the audio band

d. Passes whole of the radio band

74. A series resonant circuit is inductive at f = 1000Hz. The circuit will be capacitive somewhere at f 1000 Hz.

a. f 1000 Hzb. f 1000 Hzc. f equal to 1000 Hz and by

adding a resistance in seriesd. F = 1000 + fo ( resonance

frequency)

75. Compensation theorem is applicable to

a. Non-linear networkb. Linear and non-linear

networksc. Linear networksd. None of the above

76. In fast frequency hopping (FFH)a. Hopping rate is equal to or

greater than the bit rate of baseband signal

b. Hopping rate is equal to or less than the bit rate of baseband signal

c. The desired frequency and interference protection is less

d. None of the above

77. The use of non-uniformquantization levels lead to

a. Increase in maximum SNRb. Increase in SNR for low

level signalsc. Reduction in transmission

bandwidthd. Simplification of

quantization process

78. Which encoding method uses alternating positive and negative values for 1s?

a. NRZ-Ib. RZc. AMId. Manchester

79. CDMA technique is not used in satellite communication because of

a. Complexity of operationb. Increase in delayc. Wastage of bandwidthd. Wastage of power

80. In PCM system, the amplitude levels are transmitted in a 7 unit code. The sampling is done at rateof 10 kHz. The bandwidth should be

a. 35 kHzb. 5 kHzc. 5 MHzd. 70 kHz

81. The horizontal deflection circuit helps in the following processes

a. Horizontal and vertical deflection

b. Horizontal deflectionc. Horizontal deflection and

H,V generationd. Synchronization

82. In a TV receiver, the colour killera. Cuts off the chroma stages

during monochrome reception

b. Ensures that no colour is transmitted to monochrome receivers

c. Makes sure that the colour burst is not mistaken for sync pulses by cutting off reception during the back porch

d. Prevents overloading

83. CSMA stands fora. Carrier sense multiple

accessb. Central station mobile

applicationsc. Chart security maintenance

applicationd. Common signaling multi-

tone access

84. Materials which can store electrical energy are called

a. Magnetic materialsb. Semi-conductorc. Dielectric materialsd. Super conductor

85. A FET hasa. Current controlled featuresb. Forward biased p=n

junctionc. Very high input resistanced. Very low input resistance

86. A PN junction offereda. Conducts in forwarded

direction onlyb. Conducts in reverse

direction onlyc. High resistance in

forwarded as well as reverse direction

d. Low resistance in forwarded as well as reverse direction

87. Wireless access network unit (WANU) consists of:

a. Base station transceiversb. Access managerc. Radio controllerd. All of the above

88. The design process of selecting and allocating channel groups for all cellular base station within a system is called:

a. Adjacent channel interference

b. Co-channel interferencec. Frequency planningd. Near far affect

89. If the subscriber moves from one cell to other cell within BSC then this type of hand off is called:

a. Inter MSC handoverb. Inter-cell-inter BSC

handoverc. Inter-cell-intra BSC

handoverd. Intra-cell-intra BSC

handover

90. The expression Pe = Q (2Eb/No)1/2

is probability of error for which of the following:

a. QPSKb. BPSKc. DPSKd. /4 QPSK

91. If the bandwidth of signal is greater than that of channel then it is:

a. Fast fading

b. Frequency selective fadingc. Multipath fadingd. Slow fading

92. The major problem in a unipolar format of coding

a. Aliasingb. Complexityc. DC componentd. Synchronization

93. The detector that minimizes Pe if P(S1)= P(S2) is known as

a. Ratio detectorb. Minimum likelihood

detectorc. Discriminatord. Maximum likelihood

detector

94. Shannon’s Hartley Law isa. C = B log (1 +S/N) bits/secb. B = C log ( 1 + S/N) bits/secc. C= B log ( (1+S)/N) bits/secd. C = B log (1/N +S) bits/sec

95. Which protocol working at the Transport layer provides a connectionless service between hosts?

a. IPb. ARPc. TCPd. UDP

96. In OSI network architecture , the dialogue control and token management are responsibility of

a. Data link layerb. Network layerc. Session layerd. Transport layer

97. A routera. Determines on which

outgoing link a packet is to be forwarded

b. Forwards a packet to all outgoing links

c. Forwards a packet to the next free outgoing link

d. Forwards a packet to all outgoing links except the link upon which the packet originated

98. In AM a message signal of 5 kHz is modulated by a carrier of 100 kHz, the bandwidth of the modulated signal is

a. 5 kHzb. 10 kHzc. 100 kHzd. 105 kHz

99. An FM signal with a deviation is

passed through a mixer, and it has frequency reduction fivefold. The deviation at the output of the mixer is

a. b. 5c. /5d. 25

100.If the transmission line is properly matched, then the VSWR is

a. Ob. 1c. Less than 1d. Greater than 1

1. The discrete-time signal x (n) = (-1)n is periodic with fundamental period(A) 6 (B) 4(C) 2 (D) 0

2. The frequency of a continuous time signal x (t) changes on transformationfrom x (t) to x (α t), α > 0 by a factor(A) α . (B) 1/α(C) α2. (D) √α.

3. A useful property of the unit impulse (t) is that(A) (at) = a (t) . (B) (at) = (t) .(C) (at)=

(D) (at) = [ (t)]a.

4. Two sequences x1 (n) and x2 (n) are related by x2 (n) = x1 (- n). In the z- domain, theirROC’s are(A) the same. (B) reciprocal of each other.(C) negative of each other. (D) complements of each other.

5. The Fourier transform of the exponential signal ejw

0t is

(A) a constant. (B) a rectangular gate.(C) an impulse.(D) a series of impulses.

6. If the Laplace transform of f (t ) is ( ), then the value of

(A) cannot be determined. (B) is zero.

(C) is unity. (D) is infinity.

7. The unit impulse response of a linear time invariant system is the unit stepfunction u(t ). For t > 0, the response of the system to an excitation e-at u(t), a > 0, will be(A) ae-at

(B)

(C) a(1 - e-at) (D) (1 - e-at)

8. The auto-correlation function of a rectangular pulse of duration T is

(A)a rectangular pulse of duration T.(B) a rectangular pulse of duration

2T.(C) a triangular pulse of duration T.(D)a triangular pulse of duration

2T.

9. The FT of a rectangular pulse existing between t = -T / 2 to t = T / 2 is a

(A)sinc squared function. (B) sinc function.(C) sine squared function.(D) sine function.

10. An analog signal has the spectrum shown in Fig. The minimum samplingrate needed to completely represent this signal is(A) 3 KHz .(B) 2 KHz .(C) 1 KHz .(D) 0.5 KHz .

11. A given system is characterized by the differential equation:

The system is:(A) linear and unstable.(B) linear and stable.(C) nonlinear and unstable. (D) nonlinear and stable.

12. The system characterized by the equation y(t ) = ax(t )+ b is(A) linear for any value of b.

(B) linear if b > 0.(C) linear if b < 0. (D) non-linear.

13. Inverse Fourier transform of u(w) is

(A)

(B)

(C)

(D)

14. The impulse response of a system is h(n) = an u(n). The condition for the system to be BIBO stable is(A) a is real and positive. (B) a is real and negative(C) a > 1. (D) a < 1.

15. If R1is the region of convergence of x (n) and R2 is the region of convergence ofy(n), then the region of convergence of x (n) convoluted y (n) is(A) R1+R2 . (B) R1 - R2 .(C) R1 R2 .(D) R1 R2 .

16. The continuous time system described by y(t) = x (t2) is

(A)causal, linear and time varying.(B) causal, non-linear and time

varying.(C) non causal, non-linear and time-

invariant.(D)non causal, linear and time-

invariant.

17. If G(f) represents the Fourier Transform of a signal g (t) which

is real and odd

symmetric in time, then G (f) is(A) complex.

(B) imaginary.(C) real.

(D) real and non-negative.

18. If white noise is input to an RC integrator the ACF at the output is proportional to

(A)

(B)

(C) (D)

19. x(n) = a|n|, |a|<1 is(A)an energy signal.(B) a power signal.(C) neither an energy nor a power

signal.(D)an energy as well as a power

signal.

20. The spectrum of x (n) extends from - 0 to + 0 , while that of h(n) extends from -2 0 to + 2 0. The spectrum of y(n) = extends from(A) -4 0 to + 4 0.(B) -3 0 to + 3 0.(C) -2 0 to + 2 0. (D) - 0 to + 0

21. The signals x1(t ) and x2 (t) are both bandlimited to (- 1, + 1) and (- 1, + 1) and respectively. The Nyquist sampling rate for the signal x1(t) x2 (t) will be(A) 2 1 if 1 > 2

(B) 2 2 if 1 < 2

(C) 2 1 + 2)(D) 1 + 2)/2

22. If a periodic function f(t) of period

T satisfies f(t) = -f(t + T/2), then in its Fourierseries expansion,

(A) the constant term will be zero.(B) there will be no cosine terms.(C) there will be no sine terms.(D) there will be no even harmonics.

23. A band pass signal extends from 1 KHz to 2 KHz. The minimum sampling frequency needed to retain all information in the sampled signal is(A) 1 KHz. (B) 2 KHz.(C) 3 KHz. (D) 4 KHz.

24. The region of convergence of the

z-transform of the signal 2n u(n) -3n u(-n – 1)(A) is |z| >1. (B) is |z| <1.(C) is 2 < |z| < 3 .(D) does not exist.

25. The number of possible regions of convergence of the function

is

(A) 1. (B) 2.(C) 3. (D) 4.

26. Given a unit step function u(t), its time-derivative is:(A) a unit impulse.(B) another step function.(C) a unit ramp function. (D) a sine function.

27. The impulse response of a system described by the differential equation

will be

(A) a constant. (B) an impulse function..(C) a sinusoid. (D) an exponentially decaying function.

28. The function is denoted by:

(A) sin c( u). (B) sin c(u).(C) signum. (D) none of these.

29. The order of a linear constant-coefficient differential equation representing a systemrefers to the number of(A) active devices. (B) elements including sources.(C) passive devices. (D) none of those.

30. z-transform converts convolution of time-signals to(A) addition. (B) subtraction.(C) multiplication. (D) division.

31. Region of convergence of a causal LTI system(A) is the entire s-plane. (B) is the right-half of s-plane.(C) is the left-half of s-plane. (D) does not exist.

32. The DFT of a signal x(n) of length N is X(k). When X(k) is given and x(n) is computed from it, the length of x(n)(A) is increased to infinity(B) remains N(C) becomes 2N – 1 (D) becomes N2

33. The Fourier transform of u(t) is

(A) (B)

(C) (D) none of these.

34. The system having input x(n) related to output y(n) as y(n) = log10 x(n) is:(A) nonlinear, causal, stable.(B) linear, noncausal, stable.(C) nonlinear, causal, not stable. (D) linear, noncausal, not stable.

35. To obtain x(4 – 2n) from the given signal x(n), the following precedence (or priority)rule is used for operations on the independent variable n:(A) Time scaling Time shifting

Reflection.(B) Reflection Time scaling

Time shifting.(C) Time scaling Reflection

Time shifting.(D)Time shifting Time scaling

Reflection.

36. The unit step-response of a system with impulse response h(n) = (n) – (n – 1) is:(A) (n – 1). (B) (n).(C) u(n – 1). (D) u(n).

37. Zero-order hold used in practical reconstruction of continuous-time signals is mathematically represented as a weighted-sum of rectangular pulses shifted by:(A) Any multiples of the sampling interval.(B) Integer multiples of the sampling interval.(C) One sampling interval.(D) 1 second intervals.

38. The region of convergence of the z-transform of the signal x(n) ={2, 1, 1, 2}is (A) all z, except z = 0 and z = (B) all z, except z = 0.(C) all z, except z = . (D) all z.

39. When two honest coins are simultaneously tossed, the probability of two heads on anygiven trial is:(A)1 (B) 3/4(C)1/2 (D) ¼

40. A continuous-time periodic signal x(t) , having a period T, is convolved withitself. The resulting signal is(A) not periodic

(B) periodic having a period T(C) periodic having a period 2T (D) periodic having a period T/2

41. If the Fourier series coefficients of a signal are periodic then the signal must be(A) continuous-time, periodic (B) discrete-time, periodic(C) continuous-time, non-periodic (D) discrete-time, non-periodic

42. The region of convergence of a causal finite duration discrete-time signal is(A) the entire z-plane except z = 0(B) the entire z-plane except z = (C) the entire z-plane(D)a strip in z-plane enclosing j -axis

43. The transfer function of a stable system is H(z) =

Its impulse response will be(A) (0.5)n u[n] + (2)n u[n](B) (0.5)n u[-n – 1] + (2)n u[n](C) (0.5)n u[n] − (2)n u[-n −1] (D) − (0.5)n u[-n −1] − (2)n u[-n −1]

44. The probability cumulative distribution function must be monotone and(A) increasing (B) decreasing(C) non-increasing (D) non-decreasing

45. Convolution is used to find:(A) The impulse response of an LTI System(B) Frequency response of a System(C) The time response of a LTI system(D)The phase response of a LTI system

46. The Fourier Transform of a rectangular pulse is(A) Another rectangular pulse (B) Triangular pulse(C) Sinc function (D) Impulse.

47. The property of Fourier Transform which states that the compression in timedomain is equivalent to expansion in the frequency domain is

(A) Duality. (B) Scaling.(C) Time Scaling. (D) Frequency Shifting.

48. What is the Nyquist Frequency for the signal x(t) =3cos 50 t +10 sin 300 t – cos100 t?(A) 50 Hz (B) 100 Hz(C) 200 Hz (D) 300 Hz

49. The step response of a LTI system when the impulse response h(n) is unit stepu(n) is(A) n+1 (B) n(C) n-1 (D) n2

50. The function which has its Fourier transform, Laplace transform, and Z transformunity is(A) Gausian (B) impulse(C) Sinc (D) pulse