# A2D and D2A Converters

This set of Digital Signal Processing Multiple Choice Questions & Answers (MCQs) focuses on “A2D and D2A Converters”.

1. Which of the following should be done in order to convert a continuous-time signal to a discrete-time signal?**a) Sampling**

b) Differentiating

c) Integrating

d) None of the mentioned

2. The process of converting discrete-time continuous valued signal into discrete-time discrete valued (digital) signal is known as ____________

a) Sampling**b) Quantization**

c) Coding

d) None of the mentioned

3. The difference between the unquantized x(n) and quantized xq(n) is known as ___________

a) Quantization coefficient

b) Quantization ratio

c) Quantization factor**d) Quantization error**

4. Which of the following is a digital-to-analog conversion process?

a) Staircase approximation

b) Linear interpolation

c) Quadratic interpolation**d) All of the mentioned**

5. The relation between analog frequency ‘F’ and digital frequency ‘f’ is?

a) F=f*T(where T is sampling period)**b) f=F*T**

c) No relation

d) None of the mentioned

6. What is output signal when a signal x(t)=cos(2*pi*40*t) is sampled with a sampling frequency of 20Hz?

a) cos(pi*n)

b) cos(2*pi*n)**c) cos(4*pi*n)**

d) cos(8*pi*n)

7. If ‘F’ is the frequency of the analog signal, then what is the minimum sampling rate required to avoid aliasing?**a) F**

b) 2F

c) 3F

d) 4F

8. What is the nyquist rate of the signal x(t)=3cos(50*pi*t)+10sin(300*pi*t)-cos(100*pi*t)?

a) 50Hz

b) 100Hz

c) 200Hz**d) 300Hz**

9. What is the discrete-time signal obtained after sampling the analog signal x(t)=cos(2000*pi*t)+sin(5000*pi*t) at a sampling rate of 5000 samples/sec?

a) cos(2.5*pi*n)+sin(pi*n)**b) cos(0.4*pi*n)+sin(pi*n)**

c) cos(2000*pi*n)+sin(5000*pi*n)

d) none of the mentioned

10. If the sampling rate Fs satisfies the sampling theorem, then the relation between quantization errors of analog signal(eq(t)) and discrete-time signal(eq(n)) is?**a) eq(t)=eq(n)**

b) eq(t)<eq(n)

c) eq(t)>eq(n)

d) not related

11. The quality of output signal from 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

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