1
GATE ECE 2008
MCQ (Single Correct Answer)
+2
-0.6
Noise with double-sided power spectral density of K over all frequencies is passed through a RC low pass filter with 3-dB cut-off frequency of fc. The noise power at the filter output is
A
K
B
K fc
C
K $$\pi $$ fc
D
$$\infty $$
2
GATE ECE 2008
MCQ (Single Correct Answer)
+2
-0.6
The signal $$\cos\;\omega_ct\;+\;0.5\;\cos\;\omega_mt\;s\mathrm{in}\;\omega_ct$$ is
A
FM only
B
AM only
C
both AM & FM
D
neither AM nor FM
3
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
$$0$$
4
GATE ECE 2008
MCQ (Single Correct Answer)
+2
-0.6
A certain system has transfer function $$G\left(s\right)=\frac{s+8}{s^2+\alpha s-4}$$, where $$\alpha$$ is a parameter. Consider the standard negative unity feedback configuration as shown below GATE ECE 2008 Control Systems - Stability Question 13 English Which of the following statements is true?
A
The closed loop system is never stable for any value of $$\alpha$$
B
For some positive values of $$\alpha$$, the closed loop system is stable, but not for all positive values
C
For all positive values of $$\alpha$$, the closed loop system is stable
D
The closed loop system is stable for all values of $$\alpha$$, both positive and negative
EXAM MAP