# Digital Signal Processing Questions and Answers – Signals, Systems and Signal Processing

«
»

This set of Digital Signal Processing Multiple Choice Questions & Answers (MCQs) focuses on “signals, Systems and Signal Processing”.

1. Which of the following is common independent variable for speech signal, EEG and ECG?
a) Time
b) Spatial coordinates
c) Pressure
d) None of the mentioned

Explanation: Speech, EEG and ECG signals are the examples of information-bearing signals that evolve as functions of a single independent variable, namely, time.

2. Which of the following conditions made digital signal processing more advantageous over analog signal processing?
a) Flexibility
b) Accuracy
c) Storage
d) All of the mentioned

Explanation: Digital programmable system allows flexibility in reconfiguring the DSP operations by just changing the program, as the digital signal is in the form of 1 and 0’s it is more accurate and it can be stored in magnetic tapes.

3. Which property does y(t)=x(1-t) exhibit?
a) Time scaling
b) Time shifting
c) Reflecting
d) Time shifting and reflecting

Explanation: First the signal x(t) is shifted by 1 to get x(1+t) and it is reflected to get x(1-t). So, it exhibits both time shifting and reflecting properties.

4. If x(n)=(0,1,2,3,3,0,0,0) then x(2n) is?
a) (0,2,4,6,6,0,0,0)
b) (0,1,2,3,3,0,0,0)
c) (0,2,3,0,0,0,0,0)
d) None of the mentioned

Explanation: Substitute n=0,1,2… in x(2n) and obtain the values from the given x(n).

5. If x(n)=(0,0,1,2,3,4,0,0) then x(n-2) is?
a) (0,0,2,4,6,8,0,0)
b) (0,0,1,2,3,4,0,0)
c) (1,2,3,4,0,0,0,0)
d) (0,0,0,0,1,2,3,4)

Explanation: The signal x(n) is shifted right by 2.

6. If x(n)=(0,0,1,1,1,1,1,0) then x(3n+1) is?
a) (0,1,0,0,0,0,0,0)
b) (0,0,1,1,1,1,0,0)
c) (1,1,0,0,0,0,0,0)
d) None of the mentioned

Explanation: First shift the given signal left by 1 and then time scale the obtained signal by 3.

7. If a signal x(t) is processed through a system to obtain the signal (x(t)2), then the system is said to be ____________
a) Linear
b) Non-linear
c) Exponential
d) None of the mentioned

Explanation: Let the input signal be ‘t’. Then the output signal after passing through the system is y=t2 which is the equation of a parabola. So, the system is non-linear.

8. What are the important block(s) required to process an input analog signal to get an output analog signal?
a) A/D converter
b) Digital signal processor
c) D/A converter
d) All of the mentioned

Explanation: The input analog signal is converted into digital using A/D converter and passed through DSP and then converted back to analog using a D/A converter.

9. Which of the following block is not required in digital processing of a RADAR signal?
a) A/D converter
b) D/A converter
c) DSP
d) All of the mentioned

Explanation: In the digital processing of the radar signal, the information extracted from the radar signal, such as the position of the aircraft and its speed, may simply be printed on a paper. So, there is no need of an D/A converter in this case.

10. Which of the following wave is known as “amplitude modulated wave” of x(t)?
a) C.x(t) (where C is a constant)
b) x(t)+y(t)
c) x(t).y(t)
d) dx(t)/dt

Explanation: The multiplicative operation is often encountered in analog communication, where an audio frequency signal is multiplied by a high frequency sinusoid known as carrier. The resulting signal is known as “amplitude modulated wave”.

11. What is the physical device that performs an operation on the signal?
a) Signal source
b) System
c) Medium
d) None of the mentioned 