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 2π B) Periodic but with no fundamental period
C) Non-periodic and discontinuous D) Non-periodic but continuous
 
Answer & Explanation Answer: C) Non-periodic and discontinuous

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.

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20
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
 
Answer & Explanation Answer: D) A triangular pulse of duration 2T

Explanation: Not available for this question

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13
Q:

Two sequences x₁ (n) and x₂ (n) are related by x₂ (n) = x₁ (- 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
 
Answer & Explanation Answer: B) Reciprocal of each other

Explanation: Not available for this question

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16
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
 
Answer & Explanation Answer: C) E/100

Explanation: Not available for this question

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15
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
 
Answer & Explanation Answer: B) All coils in series

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.

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14
Q:

A PT is a device which is ___________

A) Electrostatically coupled B) Electrically coupled
C) Electromagnetically coupled D) Conductively coupled
 
Answer & Explanation Answer: C) Electromagnetically 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.

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16
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
 
Answer & Explanation Answer: C) 17

Explanation: Not available for this question

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14
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
 
Answer & Explanation Answer: A) Infinite

Explanation: From any Impulse train waveform, we can infer that it is a kind of signal having infinite discontinuity.

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