1
GATE ECE 2013
+1
-0.3
For a periodic signal v(t) = 30 sin 100t + 10cos 300t + 6sin $${\rm{(500t + }}\,\pi /4)$$, the fundamental frequency in rad/s is
A
100
B
300
C
500
D
1500
2
GATE ECE 2010
+1
-0.3
Consider an angle modutated signal $$x(t) = 6\,\,\cos \,[2\,\pi \, \times {10^6}t + 2\sin (8000\pi t)\,4\cos (8000\pi t)]$$ V.

The average power of x(t) is

A
10 W
B
18 W
C
20 W
D
28 W
3
GATE ECE 2006
+1
-0.3
A solution for the differential equation $$\mathop x\limits^.$$(t) + 2 x (t) = $$\delta (t)$$ with intial condition $$x({0^ - }) = 0$$ is
A
$${e^{ - 2t}}\,u(t)$$
B
$${e^{2t}}\,u(t)$$
C
$${e^{ - t}}\,u(t)$$
D
$${e^t}\,u(t)$$
4
GATE ECE 2006
+1
-0.3
The Dirac delta function $$\delta (t)$$ is defined as
A
$$\delta (t) = \left\{ {\matrix{ {1,} & {t = 0} \cr {0,} & {otherwise} \cr } } \right.$$
B
$$\delta (t) = \left\{ {\matrix{ {\infty ,} & {t = 0} \cr {0,} & {otherwise} \cr } } \right.$$
C
$$\delta (t) = \left\{ {\matrix{ {1,} & {t = 0} \cr {0,} & {otherwise\,\,\,and\,\,\int\limits_{ - \infty }^\infty {\delta (t)\,dt = 1} } \cr } } \right.\,\,$$
D
$$\delta (t) = \left\{ {\matrix{ {\infty ,} & {t = 0} \cr {0,} & {otherwise\,\,\,and\,\,\int\limits_{ - \infty }^\infty {\delta (t)\,dt = 1} } \cr } } \right.\,\,$$
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