Discrete-Time Signal Processing

Digital Communications Systems

This set of Advanced Digital Signal Processing Questions & Answers focuses on “Discrete-Time Processing of Continuous Time Signals”.

1. When the frequency band is selected we can specify the sampling rate and the characteristics of the pre filter, which is also called as __________ filter.
a) Analog filter
b) Anti aliasing filter
c) Analog & Anti aliasing filter
d) None of the mentioned

2. What are the main characteristics of Anti aliasing filter?
a) Ensures that bandwidth of signal to be sampled is limited to frequency range
b) To limit the additive noise spectrum and other interference, which corrupts the signal
c) All of the mentioned
d) None of the mentioned

3. In general, a digital system designer has better control of tolerances in a digital signal processing system than an analog system designer who is designing an equivalent analog system.
a) True
b) False

4. The selection of the sampling rate Fs=1/T, where T is the sampling interval, not only determines the highest frequency (Fs/2) that is preserved in the analog signal but also serves as a scale factor that influences the design specifications for digital filters.
a) True
b) False

5. What is the configuration of system for digital processing of an analog signal?
a) Analog signal|| Pre-filter -> D/A Converter -> Digital Processor -> A/D Converter -> Post-filter
b) Analog signal|| Pre-filter -> A/D Converter -> Digital Processor -> D/A Converter -> Post-filter
c) Analog signal|| Post-filter -> D/A Converter -> Digital Processor -> A/D Converter -> Pre-filter
d) None of the mentioned

6. In DM, further the two integrators at encode are replaced by one integrator placed before comparator, and then such system is called?
a) System-delta modulation
b) Sigma-delta modulation
c) Source-delta modulation
d) None of the mentioned

7. What is the system function of the integrator that is modeled by the discrete time system?
a) H(z)=z−11−z−1
b) H(z)=z−11+z−1
c) H(z)=zz11−z1
d) H(z)=zz11+z1

8. What is the z-transform of sequence {dq(n)} i.e., Dq(z)= ?
a) Hs(z)X(z)−Hn(z)E(z)
b) Hs(z)X(z)+Hn(z)E(z)
c) Hs(n)X(z)+Hn(n)E(z)
d) Hn(z)X(z)−Hs(z)E(z)

9.The performance of the SDM system is determined by the noise system function Hn(z), which has a magnitude of?
a) |Hn(z)|=2|sinπFFs|
b) |Hn(z)|=4|sinπFFs|
c) |Hn(z)|=3|sinπFFs|
d) |Hn(z)|=|sinπFFs|

10. The in-band quantization noise variance is given as?
a) σ2n=∫B−B|Hn(F)|3Se(F)dF
b) σ2n=∫B−B|Hn(F)|2Se(F)dF
c) σ2n=∫B−B|Hn(F)|1Se(F)dF
d) None

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