1
GATE ECE 2008
MCQ (Single Correct Answer)
+1
-0.3
Consider the amplitude modulated (AM) signal $$A_c\cos\omega_ct\;+\;2\cos\omega_mt\;\cos\omega_ct$$. For demodulating the signal using envelope detector, the minimum value of Ac should be
A
2
B
1
C
0.5
D
$$0$$
2
GATE ECE 2005
MCQ (Single Correct Answer)
+1
-0.3
Which of the following analog modulation scheme requires the minimum transmitted power and minimum channel bandwidth?
A
VSB
B
DSB-SC
C
SSB
D
AM
3
GATE ECE 2004
MCQ (Single Correct Answer)
+1
-0.3
An AM signal and a narrow-band FM signal with identical carriers, modulating signals and modulation indices of 0.1 are added together. The resultant signal can be closely approximated by
A
broadband FM
B
SSB with carrier
C
DSB-SC
D
SSB without carrier
4
GATE ECE 2004
MCQ (Single Correct Answer)
+1
-0.3
An AM signal is detected using an envelope detector. The carrier frequency and modulating signal frequency are 1 MHz and 2 KHz respectively. An appropriate value for the time constant of the envelope detector is
A
500 µsec
B
20 µsec
C
0.2 µsec
D
1 µsec
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