1. The fourier tranform of one impulse train is also another impulse train with a period of the output equal to the
a) Period of the input
b) Reciprocal of the period of input signal
c) Half the period of input
d) Twice the period of the input
Explanation: When we perform fourier tranform on one impulse train we will get another impulse train with its period reciprocally related to each other
2. The process in which the top of each pulse in the output samples retains the shape of the analog segment is called as ________
a) Natural sampling
b) Ideal sampling
c) Aliasing
d) None of the mentioned
Explanation: In the method of natural sampling, the top of each pulse in the sampled sequence retains the same shape of the analog input signal
3. The effects of aliasing are ________
a) Attenuation of high frequency spectral replicates
b) Non uniform spectral gain applied to desired baseband spectrum
c) Attenuation and non uniform spectral gain
d) None of the mentioned
Explanation: Aliasing is due to undersampling and its effects are attenuation and non uniform spectral gain.
4. Aliasing can be removed using
a) Prefiltering
b) Postfiltering
c) Prefiltering & Postfiltering
d) None of the mentioned
Explanation: Aliasing can be removed using both prefiltering and postfiltering but prefiltering is most effective and preferred.
5. Which process is more economical?
a) Undersampling
b) Oversampling
c) Aliasing
d) None of the mentioned
Explanation: Oversampling is most economic way of sampling or for converting analog information to digital as performing signal processing using digital system is less costlier than doing it with high performace analog system
6. Flat top sampling or practical sampling has
a) Same frequency
b) Same amplitude
c) Same time difference
d) None of the mentioned
Explanation: In flat top sampling the top of the pulses are flat which in turn means that they have the same amplitude.
7. Multiplication of input signal with pulse train is done in ________ sampling.
a) Impulse sampling
b) Natural sampling
c) Flat top sampling
d) None of the mentioned
Explanation: In impulse sampling the input signal is multiplied with impulse train and in natural sampling it is multiplied with pulse train
8. The main sources of corruption are
a) Sampling and quantizing effects
b) Channel effects
c) Sampling, quantizing and channel effects
d) None of the mentioned
Explanation: The analog signal obtained from sampling quantization and transmitted pulses will have corruption from several sources in which the two main sources are quantizing and sampling effect and channel effect
9. The distortion in quantization is called as
a) Round off error
b) Truncation error
c) Round off & Truncation error
d) None of the mentioned
Explanation: After sampling and quantization of input signals, the ouput sampled sequence consists of some distortion which can be called as round off error or truncation error
10. In quantization process, the amount of quantization noise is _______________ to number of levels.
a) Directly proportional
b) Inversely proportional
c) Independent
d) None of the mentioned
Explanation: The distortion introduced to approximate the analog signal is called as quantization noise. The amount of this noise is inversely proportional to number of levels employed in quantization process