am exercises 1
TRANSCRIPT
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7/21/2019 AM Exercises 1
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JABATAN KEJURUTERAAN KOMUNIKASI
FAKULTI KEJURUTERAAN ELEKTRIK DAN ELEKTRONIK
UNIVERSITI TUN HUSSEIN ONN MALAYSIA
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BEE31803 ELECTRONIC COMMUNICATION SYSTEMS
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AM Exercises
Name:______________________________
Matric No:_______________________
Q1. What is amplitude modulation? Why we need modulation? With appropriate
block diagram, explain how to generate amplitude modulation wave?
Q2 (a) Base on the amplitude modulation equation, proof the equation below.
tttfv cAM )2010(cos3769.6251cos32sin8
(4 marks)
(b) From the equation in (a), find;
(i) peak amplitude of the modulating signal,
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JABATAN KEJURUTERAAN KOMUNIKASI
FAKULTI KEJURUTERAAN ELEKTRIK DAN ELEKTRONIK
UNIVERSITI TUN HUSSEIN ONN MALAYSIA
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BEE31803 ELECTRONIC COMMUNICATION SYSTEMS
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(ii) modulation coefficient and percent modulation,
(iii) the upper and lower side frequency voltages,
(iv) the carrier frequency,
(v) the frequency of modulating signal,
(vi) maximum and minimum amplitudes of the envelope,
(vii) draw the output spectrum, and
(viii) sketch the output in time domain.
(16 marks)
Q3. For the AM waveform shown in Figure 1, determine
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JABATAN KEJURUTERAAN KOMUNIKASI
FAKULTI KEJURUTERAAN ELEKTRIK DAN ELEKTRONIK
UNIVERSITI TUN HUSSEIN ONN MALAYSIA
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BEE31803 ELECTRONIC COMMUNICATION SYSTEMS
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Vmax
= 18 Vp
Vmin
= 2 Vp
Vm
Vc
Figure 1: AM envelope
(i) Peak amplitude of the upper and lower side frequencies
(2)(ii) Peak amplitude of the unmodulated carrier
(2)
(iii) Peak change in the amplitude of the envelope
(2)
(iv) Coefficient of modulation
(2)
(v) Percent modulation
(2)
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JABATAN KEJURUTERAAN KOMUNIKASI
FAKULTI KEJURUTERAAN ELEKTRIK DAN ELEKTRONIK
UNIVERSITI TUN HUSSEIN ONN MALAYSIA
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BEE31803 ELECTRONIC COMMUNICATION SYSTEMS
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(10 marks)
Q4. a) List FOUR (4) receiver parameters that commonly used to evaluate the
ability of a receiver.
( 4 marks)
b) A 1500-W AM carrier signal has a modulation index of 0.5. The carrier is
suppressed by 60%.
i) How much power is taken away from the carrier?
ii) If this power is instead added to the sidebands, how many dB hasthe sidebands increased?
(6 marks)