Analog to Digital (A2D) Converter MCQ Quiz – Objective Question with Answer for Analog to Digital (A2D) Converter

11. The quality of the output signal from the A/D converter is measured in terms of ___________

A. Quantization error
B. Quantization to signal noise ratio
C. Signal to quantization noise ratio
D. Conversion constant

Answer: C

The quality is measured by taking the ratio of noises of the input signal and the quantized signal i.e., SQNR, and is measured in terms of dB.

12. Which bit coder is required to code a signal with 16 levels?

A. 8 bit
B. 4 bit
C. 2 bit
D. 1 bit

Answer: B

To code a signal with L number of levels, we require a coder with (log L/log 2) number of bits. So, log16/log2=4 bit coder is required.

13. What is the period of a signal x(t)?

A. T
B. 2T
C. T/2
D. None of the mentioned

Answer: A

A signal is said to be periodic if the duration of one complete cycle is T and it repeats itself after this duration.

14. Which of the given signals are periodic?

A. x(t) = 4 cos(5πt)
B. x(t) = u(t) – 1/2
C. x(t) = 4u(t) + 2sin(3t)
D. x[n] = 2sin(3n)

Answer: A

T=2π / 5π = 2/5, periodic with period 2/5.

15. Check whether the signal is periodic or not?
x(t) = cos(4t) + 2sin(8t)

A. Periodic with period π/2
B. Periodic with period 2
C. Periodic with period 2/π
D. Not periodic

Answer: A

T1=2π /4

T2=2π /8

T1/T2 = 2 T

=T1 or 2T2

T=π /2.

The signal x(t) = cos(4t) + 2sin(8t) periodic with period π/2

16. Find the periodicity of the following signal. x(t)=cos((2π/7)t)sin((3π/5)t)

A. 30
B. 7
C. 35
D. 5/3

Answer: C

T1=2π/2π/7 = 7,

T2=2π/3π/5=5/3,

T1/T2=5/21,

T=21T1

5T2, T=35.

17. Find the fundamental period of 1+sin^2 (3π/5)n.

A. 10/3
B. 5
C. 3π/5
D. None of the mentioned

Answer: B

sin2(3π/5)n = (1-cos(6π/5)n)/2

= 1/2-1/2cos(6π/5)n

; period = 6π/(5*2π)

= k/N = 3/5 ; N=5.

18. Which signal is called an energy signal?

A. Finite energy and zero power
B. Finite energy and non-zero power
C. Infinite energy and zero power
D. Infinite energy and non-zero power

Answer: A

A signal is said to be an energy signal if it has finite energy and zero average power.

19. Which signal is said to be a power signal?

A. Infinite power and zero energy
B. Infinite power and non-zero energy
C. Finite power and infinite energy
D. Finite power and zero energy

Answer: C

A signal is said to be a power signal if it has finite power and infinite energy.

20. Determine the periodicity and also find whether it is a power or energy signal?
e(-at)u(t)

A. Periodic and energy signal
B. Non-periodic and energy signal
C. Periodic and power signal
D. Periodic and energy signal

Answer: B

This is non-periodic as it does not repeat itself after any period. And on calculating we will get energy as 1/2a which is finite. Thus it is an energy signal.

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