# Signals & Systems Mcqs

Q:

Given the signal
X (t) = cos t, if t<0
X (t) = Sin t, if t?0
The correct statement among the following is?

 A) Periodic with fundamental period 2? B) Periodic but with no fundamental period C) Non-periodic and discontinuous D) Non-periodic but continuous

Explanation: From the graphs of cos and sin, we can infer that at t=0, the function becomes discontinuous.
Since, cos 0 = 1, but sin 0 = 0
As 1 ? 0, so, the function X (t) is discontinuous and therefore Non-periodic.

64
Q:

The auto-correlation function of a rectangular pulse of duration T is _____________

 A) A rectangular pulse of duration T B) A rectangular pulse of duration 2T C) A triangular pulse of duration T D) A triangular pulse of duration 2T

Explanation: Not available for this question

71
Q:

Two sequences x? (n) and x? (n) are related by x? (n) = x? (- n). In the z-domain, their region of convergences are _______________

 A) The same B) Reciprocal of each other C) Negative of each other D) Complementary

Explanation: Not available for this question

69
Q:

If a signal f(t) has energy E, the energy of the signal f(100t) is equal to ____________

 A) E B) 100E C) E/100 D) 400E

Explanation: Not available for this question

92
Q:

The CT supplies current to the current coil of a power factor meter, energy meter and, an ammeter. These are connected as?

 A) All coils in parallel B) All coils in series C) Series-parallel connection with two in each arm D) Series-parallel connection with one in each arm

Explanation: Since the CT supplies the current to the current coil, therefore the coils are connected in series so that the current remains the same. If they were connected in parallel then the voltages would have been same but the currents would not be the same and thus efficiency would decrease.

57
Q:

A PT is a device which is ___________

 A) Electrostatically coupled B) Electrically coupled C) Electromagnetically coupled D) Conductively coupled

Explanation: A PT cannot be electrostatically coupled since CRO are electrostatically coupled. Also, they cannot be conductively coupled. But since they are kind of electrically coupled hence electromagnetically coupled is the only correct option.

127
Q:

Given a signal f (t) = 3t2+2t+1, which is multiplied by 2 unit delayed version of impulse and integrated over period -? to ?. The resultant is ______________

 A) 1 B) 6 C) 17 D) 16

Explanation: Not available for this question

116
Q:

One of the types of signal is an Impulse train. The type of discontinuity in an impulse train is ______________

 A) Infinite B) Zero C) One D) Finite