1
GATE ECE 2003
MCQ (Single Correct Answer)
+2
-0.6
Let $$m\left(t\right)\;=\cos\left[\left(4\mathrm\pi\times10^3\right)t\right]$$ be the message signal and $$c\left(t\right)\;=5\cos\left[2\mathrm\pi\times10^6t\right]$$ be the carrier.

c(t) and m(t) are used to generate an AM signal. The modulation index of the generated AM signal is 0.5. Then the quantity $$\frac{Total\;sideband\;power}{Carrier\;power}$$ is

A
1/2
B
1/4
C
1/3
D
1/8
2
GATE ECE 2003
MCQ (Single Correct Answer)
+2
-0.6
A DSB-SC signal is to be generated with a carrier frequency fc = 1MHz using a nonlinear device with the input-output characteristic $$v_0=a_0v_i\;+\;a_1v_i^3$$.where a0 and a1 are constants. The output of the nonlinear device can be filtered by an appropriate band-pass filter. Let $$v_0=A_c'\;\cos\left(2{\mathrm{πf}}_\mathrm c'\mathrm t\right)\;+\;m\left(t\right)$$ where m(t) is the message signal. Then the value of $$f_c'$$ (in MHz) is
A
1.0
B
0.333
C
0.5
D
3.0
3
GATE ECE 2000
MCQ (Single Correct Answer)
+2
-0.6
In an FM system, a carrier of 100 MHz is modulated by a sinusoidal signal of 5 KHz. The bandwidth by Carson’s approximation is 1 MHz. If y(t) = (modulated waveform)3, then by using Carson’s approximation, the bandwidth of y(t) around 300 MHz and the and the spacing of spectral components are, respectively.
A
3 MHz, 5 KHz
B
1 MHz, 15 KHz
C
3 MHz, 15 KHz
D
1 MHz, 5 KHz
4
GATE ECE 1993
Numerical
+2
-0
A superheterodyne radio receiver with an intermediate frequency of 455 KHz is tuned to a station operating at 1200 KHz. The associated image frequency is ______ KHz.
Your input ____

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