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BTS-3Issue 2December 1997

Spectrum Management

Broadcast Transmission Standard

Television Broadcasting

Aussi disponible en français - NER-3

Television Broadcasting BTS-3

Table of Contents

Page

1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2. Basic Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.1 Channel Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2 Video Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.3 Synchronizing Signal Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.4 Colour TV Video Signal Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.5 Radiated TV Signal Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3. Multichannel Television Sound Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.1 MTS Standards, General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.2 BTSC Stereophonic Sound Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.3 BTSC Second Audio Program Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.4 BTSC Sound Encoding Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.5 BTSC Subsidiary Communication Subcarrier Standards. . . . . . . . . . . . . . . . . . . . . 123.6 BTSC MTS Baseband. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4. Vertical Blanking Interval Signal Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.1 General Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134.2 Line Allotment Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134.3 Standards for the Ghost Cancelling Reference Signal. . . . . . . . . . . . . . . . . . . . . . . . 144.4 Line 21 Data Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154.5 Television Broadcast Videotext Data Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5. Digital Data in the Video Portion of TV Transmissions . . . . . . . . . . . . . . . . . . . . . 16

5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16


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1. Scope

This document contains the standards governing TV broadcasting systems in Canada. Thestandards ensure satisfactory monochrome and colour television broadcasting services basedon the 525 line NTSC colour system. The system is known as NTSC/M.

2. Basic Standards

2.1 Channel Characteristics

2.1.1 Television stations are assigned channels with numbers and frequencies asdesignated in Table 2.1. The width of the television broadcast channel shall be6 MHz. The visual carrier frequency shall be nominally 1.25 MHz above thelower boundary of the channel. The aural carrier frequency shall be 4.5 MHzabove the visual carrier frequency.

Table 2.1

Television Channel Frequencies

Channel No. Frequency Band (MHz) Visual Carrier (MHz) Aural Carrier (MHz)

2 54-60 55.25 59.753 60-66 61.25 65.754 66-72 67.25 71.755 76-82 77.25 81.756 82-88 83.25 87.757 174-180 175.25 179.758 180-186 181.25 185.759 186-192 187.25 191.75

10 192-198 193.25 197.7511 198-204 199.25 203.7512 204-210 205.25 209.7513 210-216 211.25 215.7514 470-476 471.25 475.7515 476-482 477.25 481.7516 482-488 483.25 487.7517 488-494 489.25 493.7518 494-500 495.25 499.7519 500-506 501.25 505.7520 506-512 507.25 511.7521 512-518 513.25 517.7522 518-524 519.25 523.7523 524-530 525.25 529.7524 530-536 531.25 535.7525 536-542 537.25 541.75


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Channel No. Frequency Band (MHz) Visual Carrier (MHz) Aural Carrier (MHz)

26 542-548 543.25 547.7527 548-554 549.25 553.7528 554-560 555.25 559.7529 560-566 561.25 565.7530 566-572 567.25 571.7531 572-578 573.25 577.7532 578-584 579.25 583.7533 584-590 585.25 589.7534 590-596 591.25 595.7535 596-602 597.25 601.7536 602-608 603.25 607.7538 614-620 615.25 619.7539 620-626 621.25 625.7540 626-632 627.25 631.7541 632-638 633.25 637.7542 638-644 639.25 643.7543 644-650 645.25 649.7544 650-656 651.25 655.7545 656-662 657.25 661.7546 662-668 663.25 667.7547 668-674 669.25 673.7548 674-680 675.25 679.7549 680-686 681.25 685.7550 686-692 687.25 691.7551 692-698 693.25 697.7552 698-704 699.25 703.7553 704-710 705.25 709.7554 710-716 711.25 715.7555 716-722 717.25 721.7556 722-728 723.25 727.7557 728-734 729.25 733.7558 734-740 735.25 739.7559 740-746 741.25 745.7560 746-752 747.25 751.7561 752-758 753.25 757.7562 758-764 759.25 763.7563 764-770 765.25 769.7564 770-776 771.25 775.7565 776-782 777.25 781.7566 782-788 783.25 787.7567 788-794 789.25 793.7568 794-800 795.25 799.7569 800-806 801.25 805.75


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2.2 Video Characteristics

2.2.1 The number of scanning lines per picture (frame) shall be 525, interlaced two to onein successive fields.

2.2.2 The chrominance subcarrier frequency shall be 3.579545 MHz. The tolerance is± 10 Hz and the rate of frequency drift shall not exceed 0.10 Hz per second.

2.2.3 The horizontal scanning frequency shall be 2/455 times the chrominance subcarrierfrequency. This corresponds nominally to 15 570 Hz with an actual value of15 734.264 ± 0.044 Hz.

2.2.4 The vertical scanning frequency is 2/525 times the horizontal scanning frequency.This corresponds nominally to 60 Hz with an actual value of 59.94 Hz.

2.2.5 The aspect ratio of the transmitted television picture shall be 4 units horizontally to3 units vertically.

2.2.6 During active scanning intervals, the scene shall be scanned from left to righthorizontally and top to bottom vertically, at uniform velocity.

2.2.7 The nominal and peak levels of the composite video signal expressed in % shall beas follows: (see Figure 1)

(a) blanking level (reference level) 0(b) peak white level 100(c) synchronizing level !40(d) peak level including chrominance signal 120

2.3 Synchronizing Signals Characteristics

2.3.1 Line Synchronization. The details of the line synchronizing signal are given inTable 1, Figure 1 and Figure 5. The durations specified are measured betweenthe half-amplitude points of the appropriate edges.

Table 1 - Details of Line Synchronization

Symbol Characteristics M NTSC/M(Fig. 1) Monochrome Colour

H 63.492 63.5555Nominal line period (FFs)

a 10.2 to 11.4 10.9 ± 0.2Line-blanking interval (FFs)


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c 1.27 to 2.54 1.27 to 2.22Front porch (FFs)

d 4.19 to 5.71 4.7 ± 0.1Synchronizing pulse (FFs)

e Built-up time (10 to 90 %) ofthe edges of the line-blankingpulse (FFs)

�� 0.64 �� 0.48

f Build-up time (10 to 90 %) ofthe edges of theline-synchronizing pulses (FFs)

�� 0.25 �� 0.25

2.3.2 Field Synchronization. The details of the field synchronizing signal are given in

Table 2, Figure 2 and Figure 5. The durations specified are measured betweenthe half-amplitude points of the appropriate edges.

Table 2 - Details of Field Synchronization


v Field period (ms) 16.667 16.6833

j Field-blanking interval 19 to 21H + a 19 to 21H + a(for H and a, see Table 1)

- Build-up time (10 to 90 %) ofthe edges of field-blankingpulses (FFs)

�� 6.35 �� 6.35

- Interval between front edge of 1.5 ± 0.1 1.5 ± 0.1field-blanking interval and frontedge of first equalizing pulse(FFs)

l Duration of first sequence of 3H 3Hequalizing pulses

m Duration of sequence of 3H 3Hequalizing pulses

n Duration of second sequence of 3H 3Hequalizing pulses

EM ' E Ý % [E ´

Qsin(Tt%33°) % E Í cos(Tt%33°)]

E Í ' &0.27(E ´

B&E Ý) % 0.74(E ´

R&E Ý)

E ´Q ' 0.41(E ´

B&E Ý) % 0.48(E ´

R&E Ý)

E Ý ' 0.30E ´

R % 0.59E ´G % 0.11EB´


5


p 2.3 ± 0.1 2.3 ± 0.1Duration of equalizing pulse (FFs)

q Duration of field-synchronizing 27.1 nominal 27.1 nominalpulse (FFs)

r Interval between 4.7 ± 0.1 4.7 ± 0.1field-synchronizing pulse (FFs)

s Build-up time (10 to 90%) ofsynchronizing and equalizingpulses (Fs)

�� 0.25 �� 0.25

2.4 Colour TV Video Signal Characteristics

2.4.1 The equation of the composite colour signal is

The symbols in the above equations have the following significance:

E = the total video voltage, corresponding to the scanning of a particularM

picture element, applied to the modulator of the visual transmitter.

E3 = the gamma-corrected voltage of the monochrome (black and white)Y

portion of the colour picture signal, corresponding to the givenpicture element.


6

E3 , E3 = the amplitude of the two orthogonal components of theQ I

chrominance signal corresponding respectively to narrow-band andwide-band axes.

E3 , E3 , E3 = the gamma-pre-corrected primary signals corresponding toR G B

red, green and blue signals during the scanning of the givenpicture element.

T = the angular frequency and is 2B times the frequency of thechrominance subcarrier.

The portion of the complete equation between the brackets represents thechrominance subcarrier signal that carries the chrominance information. Thephase reference in the E equation is the phase of the burst i.e. 180 as shown inM

o

Figure 3. The burst corresponds to amplitude modulation of a continuous sinewave.

2.4.2 The equivalent bandwidth assigned before modulation to the colour differencesignals E3 and E3 are as follows:Q I

Q - channel bandwidth:

At 400 kHz, less than 2 dB attenuationAt 500 kHz, less than 6 dB attenuationAt 600 kHz, equal to or greater than 6 dB attenuation

I - channel bandwidth:

At 1.3 MHz, less than 2 dB attenuationAt 3.6 MHz, equal to or greater than 20 dB attenuation

2.4.3 The gamma-corrected voltages E3 , E3 and E3 are suitable for a colour pictureR G B

tube having primary colours with the chromaticities in the CIE (Commissioninternationale de l'éclairage) system of specification as follows:

Colour x y

Red (R) 0.67 0.33Green (G) 0.21 0.71Blue (B) 0.14 0.08

G ' [(E ´I )

2% (E ´

Q)2]½


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The assumed transfer gradient (gamma exponent) of the receiver for which theprimary signals are pre-corrected is 2.2.

2.4.4 The radiated chrominance subcarrier vanishes on the reference white of thescene. The numerical values of the signal specification assume that this conditionwill be produced as CIE Illuminant C (x = 0.310, y = 0.316).

2.4.5 E3 , E3 , E3 and the components of these signals shall match each other in timeY Q I

to 0.05 FFs.

2.4.6 The angles of the subcarrier measured with respect to the burst phase, whenreproducing saturated primaries and their complements at 75% of full amplitude,shall be within ± 10 degrees and their amplitudes within 20% of the valuesspecified above. The ratios of the measured amplitudes of the subcarrier to theluminance signal for the same saturated primaries and their complements shallfall between the limits of 0.8 and 1.2 of the values specified for their ratios.

2.4.7 The type of subcarrier modulation produced by the chrominance componentsshall be suppressed carrier amplitude modulation of two subcarriers inquadrature.

2.4.8 The bandwidth of the chrominance sidebands relative to the subcarrier frequencyshall be:

fsc + 620 kHz ! 1300 kHz

The amplitude of the chrominance subcarrier shall be

2.4.9 The chrominance subcarrier shall be synchronized by a subcarrier burst on thehorizontal blanking back porch. The start of the subcarrier burst shall be 4.71 to5.71 FFs (5.3 FFs nominal) after the front edge of horizontal sync. and at least0.38 FFs after the trailing edge of the horizontal sync. signal. The duration of thesubcarrier burst shall be 2.23 to 3.11 FFs (9 ± 1 cycles).

2.4.10 The peak-to-peak value of the chrominance subcarrier burst shall be 4/10 of thedifference between blanking level and peak white level. The phase of thechrominance subcarrier burst shall be 180 relative to the (E3 ! E3 ) axis (seeo

B Y

Figure 3). The chrominance subcarrier shall be blanked following each equalizingpulse during the broad synchronizing pulses in the field-blanking interval (SeeFigure 5).


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2.5 Radiated TV Signal Characteristics

2.5.1 The frequency spacing of the radiated signal is shown in Figure 4. The nominalradio-frequency channel bandwidth shall be 6 MHz. The sound carrier relative tothe vision carrier shall be 4.5 MHz. The nearest edge of the channel relative tovision carrier shall be !1.25 MHz. The nominal width of the main sideband andthe vestigial sideband shall be 4.2 and 0.75 MHz respectively.

2.5.2 The minimum attenuation of the vestigial sideband shall be:

20 dB at !1.25 MHz42 dB at !3.58 MHz

2.5.3 The type and polarity of the vision modulation shall be C3F negative.

2.5.4 The levels in the radiated signal expressed in % of peak carrier shall be:

(i) Synchronizing pulse level 100(ii) Blanking level 75 ± 2.5(iii) Peak white level 12.5 ± 2.5

2.5.5 The precorrected group delay of the radiated signal shall be 0 nanosecond to3 MHz and decreases linearly to 170 nanoseconds at 3.58 MHz. The toleranceon the group delay shall be as shown in Figure 6.

2.5.6 The type and polarity of the sound modulation shall be F3E.

2.5.7 The peak frequency deviation of the sound carrier shall be ± 25 kHz formonophonic inputs and ± 75 kHz for stereophonic or composite inputs.

2.5.8 Pre-emphasis having a time constant of 75 FFs shall be used.

2.5.9 The effective radiated power of the aural transmitter shall not be less than 10%nor more than 20% of the peak radiated power of the visual transmitter.

3. Multichannel Television Sound Standards

3.1 MTS Standards, General

3.1.1 The modulating signal for the main channel shall consist of the sum of thestereophonic (biphonic, quadraphonic, etc.) input signals.


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3.1.2 The instantaneous frequency of any baseband subcarrier shall, at all times, bewithin the range of 15 kHz to 120 kHz. Either amplitude or frequencymodulation of the subcarrier may be used.

3.1.3 One or more pilot subcarriers between 16 kHz and 120 kHz may be used toswitch a TV receiver between the stereophonic and monophonic receptionmodes or to activate a stereophonic mode indicator, and one or more subcarriersbetween 15 kHz and 120 kHz may be used for any other authorized purpose.However stations transmitting the BTSC system of stereophonic sound andaudio processing shall transmit a pilot subcarrier at 15 734 Hz ± 2 Hz. Othermethods of multiplex subcarrier or stereophonic aural transmission systems shalllimit energy at 15 734 Hz ± 20 Hz, to no more than ± 0.125 kHz aural carrierdeviation.

3.1.4 Aural baseband information above 120 kHz shall be attenuated 40 dB referencedto 25 kHz main channel deviation of the aural carrier.

3.1.5 When transmitting MTS, the main channel of the aural transmission shall meetthe standards of System NTSC/M and those contained in the appropriate RadioStandards Specification for the transmitting equipment involved.

3.1.6 Multiplex subcarrier or stereophonic aural transmission systems shall be capableof producing and shall not exceed ± 25 kHz main channel deviation of the auralcarrier.

3.1.7 The arithmetic sum of non-multiphonic baseband signals between 15 kHz and120 kHz shall not exceed ± 50 kHz deviation of the aural carrier.

3.1.8 Total modulation of the aural carrier shall not exceed ± 75 kHz.

3.1.9 During any mode of transmission, monophonic, stereophonic, multiplex, thespectrum of the radiated signal or occupied bandwidth of the aural transmittershall be within the following limits:

(a) not greater than !25 dB, when referred to the level of the unmodulatedcarrier, for any frequency removed from the carrier by between 120 kHz and240 kHz;

(b) not greater than !35 dB, when referred to the level of the unmodulatedcarrier, for any frequency removed from the carrier by between 240 kHz and600 kHz.


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3.2 BTSC Stereophonic Sound Standards

3.2.1 Television broadcast stations may transmit stereophonic sound by employing asubcarrier on the aural carrier. The main channel modulating signal shall be thestereophonic sum signal; the subcarrier modulation shall be the stereophonicdifference encoded signal.

3.2.2 The subcarrier shall be the second harmonic of the pilot signal which istransmitted at a frequency equal to the horizontal line rate of 15 734 Hz ± 2 Hz.If the station is engaged in stereophonic sound transmission accompanied bymonochrome picture transmission, this horizontal scanning frequency shall beemployed.

3.2.3 The subcarrier shall be double sideband amplitude modulated with suppressedcarrier and shall be capable of accepting a stereophonic difference encoded signalover a range of 50 - 15 000 Hz.

3.3 BTSC Second Audio Program Standards

3.3.1 Television broadcast stations may transmit a subcarrier carrying a second audioprogram.

3.3.2 The subcarrier frequency shall nominally be equal to the fifth harmonic of thehorizontal line rate.

3.3.3 The second program encoded signal shall frequency modulate the subcarrier to apeak deviation of ± 10 kHz.

3.3.4 The second audio program (SAP) subchannel shall be capable of acceptingsecond program encoded signals over a range of 50 - 10 000 Hz.

3.3.5 The modulation of the aural carrier by the second audio program subcarrier shallnot exceed ± 15 kHz deviation.

3.4 BTSC Sound Encoding Standards

3.4.1 The stereophonic difference audio signal and the second program audio signalshall be encoded prior to modulating their respective subcarriers. A diagram ofone method of obtaining this encoding is shown as Figure 7.

Note: When the SAP channel is used for subsidiary communications signals,encoding is not specified.

3.4.2 This encoding shall have the following characteristics, where f is expressed inkilohertz (kHz).

F(f) '[ jf0.408

% 1][ jf2.19

% 1]

[ jf5.23

% 1][ jf62.5

% 1]

P(f) '

jf0.0354

( jf0.0354

% 1)( jf2.09

% 1)

S(f,b) '1 %

jfF

(b%51)b%1

1 %

jfF

(b%51b)b%1

, where b'10d20


11

3.4.2.1 Fixed pre-emphasis F(f) whose function is as follows:

3.4.2.2 Wide-band amplitude compression wherein:

3.4.2.2.1 The decibel gain (or loss) applied to the audio signal duringencoding is equal to minus one times the decibel ERMS valueof the encoded signal (the result of the encoding process),weighted by a transfer function P(f) as follows:

3.4.2.2.2 The exponential time weighting period T of the ERMS1

detector is 34.7 ms.

3.4.2.2.3 The zero decibel reference ERMS value for the encodedsignal is 8.99% modulation of the subcarrier at 0.300 kHz.

Note: This reference results in 0 dB gain through theencoding process at 14.1% modulation using 0.300 kHz tone,when the output band limiting filter (see 3.4.2.5) gain is 0 dBat 0.300 kHz.

3.4.2.3 Spectral compression wherein:

3.4.2.3.1 The transfer function S(f,b) applied to the audio signal duringencoding is:

F=20.1 kHz; d=decibel rms value and b is the decibel ERMSvalue of the encoded signal (the result of the encodingprocess) weighted according to a frequency transfer functionQ (f) as follows:

Q(f) '( jf5.86

)3

[( jf7.66

)2%

jf7.31

% 1]( jf26.9

%1)( jf3.92

%1)


12

where the exponential time weighting period T of the ERMS2

detector is 11.4 ms and the ERMS zero decibel reference forthe encoded signal is 5.16 % modulation of the subcarrier at8 kHz.

Note: This reference results in +18.4 dB gain through theencoding process at 32.0% modulation using an 8 kHz tone,when the output band limiting filter [(see 3.4.2.5)] gain is0 dB at 8 kHz.

3.4.2.4 Overmodulation protection which functionally follows the encodingdescribed in this section (3.4.2).

3.4.2.5 Band limiting to appropriately restrict bandwidth which functionallyfollows the encoding described in this section (3.4.2).

3.5 BTSC Subsidiary Communications Subcarrier Standards

3.5.1 In addition to the requirements in 3.1, when the stereophonic and second audioprogram subchannels are transmitted, multiplexing of the aural carrier bysubsidiary communications subchannels is subject to the following requirements.

3.5.1.1 The maximum modulation of the aural carrier by the subsidiarycommunications subcarrier is ± 3 kHz.

3.5.1.2 The instantaneous frequency of the subsidiary communicationssubcarrier shall have the average value of six and one half times thehorizontal scanning frequency with a tolerance of ± 500 Hz.

3.5.2 When only the stereophonic subcarrier is transmitted, the instantaneousfrequency of the subsidiary communications subcarrier shall lie between 47 kHzand 120 kHz with a tolerance of ± 500 Hz.

3.6 BTSC MTS Baseband

3.6.1 The BTSC MTS baseband, Figure 8, is composed of a main channel, anAM-DSB-SC stereo channel, a second audio program (SAP) channel and a PROchannel.


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4. Vertical Blanking Interval Signal Standards

4.1 General Standards

4.1.1 The vertical blanking interval may be used for the transmission of ancillarysignals.

4.1.2 Subject to certain constraints, the ancillary signals shall be inserted in the intervalbeginning with line 10 and continuing to line 21.

4.1.3 Any type of ancillary signal, whether program related or not, may be carried inthe blanking interval provided the operation is implemented on a non-interferingbasis to regular picture transmission.

4.2 Line Allotment Standards

4.2.1 Lines 10 through 20 may be used for the transmission of any ancillary signal.

4.2.2 The level of VBI transmissions should not exceed +70 IRE on lines 10-15, and+80 IRE on lines 16-20.

4.2.3 Line 19 shall be used only for the transmission of the Ghost Cancelling Reference(GCR) signal developed by Philips Laboratories.

4.2.4 Line 21 may be used for the transmission of "closed captioning" a programrelated data signal which, when decoded, presents visual informationrepresentative of the audio signal of the program.

4.2.5 When line 21 is not being used for the transmission of the "closed captioning"signal, other types of ancillary signals may be transmitted.

4.2.6 Line 21 will also provide rating data to the program blocking circuitry(commonly known as V-Chip). The underlying technology needed for theimplementation of the program blocking system is the same as the one forclose-captioning. The tentative plan for implementing the system is to add theprogram rating information to line 21 of field no. 2, along with theclosed-captioning information. Line 21 is also being used for newer "extendeddata services" (XDS) which provides scheduling information and station callletters to the viewers. The complexity of the content rating system, which ispresently under development, will impact on the three data signals that are to befitted in line 21.

f(t) ' A2B

[mS

0[cos(bT2) % jsin(bT2)]W(T)expjTtdT %

m0

&S

[cos(bT2) & jsin(bT2)]W(T)expjTtdT]


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4.3 Standards for the Ghost Cancelling Reference Signal

4.3.1 The Ghost Cancelling Reference (GCR) signal provides a reference signal with agroup delay linearly related to frequency. This signal is transmitted in an eightfield sequence of changing polarity (+,!,+,!,!,+,!,+). The GCR starts 12 Fsafter the leading edge of the horizontal sync and ends 35.5 Fs later (refer toFigure 9). It allows to cancel ghosts from !3 Fs to +45 Fs relative to the mainsignal.

4.3.2 The GCR signal is placed on line 19 and the corresponding line in the followingfield. To avoid constraining the performance of the ghost cancelling device, thelines immediately preceding and following line 19 should not contain any timevarying information such as teletext. Also, it is highly recommended not to haveany type of eight field sequence pattern in the lines adjacent to line 19. This typeof sequence will greatly affect the performance of the system.

The above constraints on the content of the lines immediately following andpreceding line 19 do not apply when the GCR signal is not inserted on line 19.

4.3.3 Waveforms of the GCR signal are shown in Figure 9 and represent line A andline B respectively. Line A and line B have the same pedestal height V1=30 IRE,but GCR polarity is inverted from line A to line B. Numerical values of thereference signal as a function of time can be calculated from the followingequation:

W(T) ' m

B

c

&

B

c

[[ 12%

12

cos(ct)][ 12Bm

S1

&S1expj(td(]]exp&jTtdt


15

W(T) is the window function:

Where the constants: A, b, S, c and S1 are given in the table below.

Parameters for GCR

A 3.592×10 Volts-7

b 0.53656×10 sec/radian-12 2

S 2B×4.3×10 radian/sec6

c 0.917998×10 radian/sec6

S1 2B×4.15×10 radian/sec6

4.4 Line 21 Data Signal

4.4.1 The program related data signal shall conform to the format described inFigure 10a.

4.4.2 A reference pulse for a decoder associated adaptive multipath equalizer filtermay replace the data signal every eighth frame. The reference pulse shallconform to the format described in Figure 10b.

4.4.3 A decoder test signal consisting of data representing a repeated series ofalphanumeric characters may be transmitted at times when no program relateddata is being transmitted.

4.4.4 A framing code to be used by the data decoder may be transmitted during thefirst half of Line 21 Field 2 when data reference pulse and test signals arepresent. The format of the framing code is shown in Figure 10c.

4.4.5 The data signal shall be coded using a non-return-to-zero (NRZ) format and shallemploy standard ASCII 7 bit plus parity character codes.

4.4.6 The signals on field 1 and 2 shall be distinct data streams, for example, to supplycaption in different languages.


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Note: For more information on data formats and specific data packets, refer toEIA-608, Line 21 Data Services for NTSC available from theElectronics Industries Association.

4.5 Television Broadcast Videotext Data Signal

4.5.1 The digital data signal representing text and pictorial information shall be inaccordance with the parameters outlined in Broadcast Specification No. 14.

4.5.2 The data shall be non-return-to-zero (NRZ) binary encoded.

4.5.3 The transmission bit rate shall be 5 727 272 ± 16 bits per second. The data signalshall be phase locked to the colour subcarrier when inserted into a colourtelevision transmission and to the horizontal line scanning rate when inserted intoa monochrome television transmission.

5. Digital Data in the Active Video Portion of TV Transmissions

5.1 General

Digital data may be inserted in the active video portion of the TV transmission. Theinsertion of the data should comply with the following conditions:

5.1.1 The data should be inserted in the active video portion of the TV transmission.The active video is defined as the portion of the TV transmission starting fromline 22 and continuing through the end of each field. The active video portiondoes not include the portion of each line reserved for horizontal blanking.

5.1.2 A station may only use a data insertion method that has been approved inadvance by Industry Canada.


17


18


19


20


21


22

Figure 6


23


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Figure 9a: GCR signal lines A and B (left and right respectively)

Figure 9b: Magnitude of the spectrum of the GCR signal

GCR signal frequency limit 4.1 MHz Duration of pedestal (T3) 35.5 µsec

GCR signal frequency stop limit 4.3 MHz Start of GCR (T4) 12.0 µsec

Pedestal height (V1) 30 IRE First peak of GCR (T5) 16.7 µsec

Start of pedestal (T1) 9.5 µsec Lowest level of GCR (V2) -10 IRE

Finish of pedestal (T2) 58.5 µsec Highest level of GCR (V3) +70 IRE


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bts-3 - television broadcastingfile/bts-3.pdf · television broadcasting bts-3 1 1. scope this...

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