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INDIAN INSTITUTE OF TECHNOLOGY GUWAHATI
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Sampling and signal reconstruction
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1) With increasing sampling frequency fs, the mean square error of the reconstructed output w.r.t the original signal
increases.
remains uneffected.
almost zero.
remains constant after initial decrease.
2) From the observation in exp-4(c) what can you say about the delay introduced in the reconstructed output w.r.t original signal by the first order hold ?
No delay is introduced
A delay of one sample period is introduced
A delay of two sample periods is introduced
3) The main cause of aliasing distortion observed in frequency domain in sampling of a continuous time signal is
the signal spectra being band-limited.
the signal spectra being non band-limited.
sampling in time domain.
4) Linear interpolation based reconstruction process
maintains the value of the previous sampling instant till next sampling instant.
joins the adjacent sampling points by a straight line.
joins the adjacent sampling points by a second-order polynomial.
5)The role of zero padding in DFT based signal analysis is
to reduce the aliasing distortion.
to increase the frequency resolution
to reduce the picket fence effect
6) What is over sampling ?
Sampling a signal with sampling frequency significantly higher than the bandwidth of the signal being sampled.
Sampling a signal with sampling frequency significantly lower than the bandwidth of the signal being sampled.
Sampling a signal with sampling frequency significantly higher than twice the bandwidth of the signal being sampled.
Sampling a signal with sampling frequency three times higher than the bandwidth of the signal being sampled.
7) From the observation in exp-4(c) what can you make out about delay introduce by zero order hold ?
Zero
One
Two
8) What do you mean by under sampling ?
Sampling the signal at Nyquist rate.
Sampling the signal below the Nyquist rate.
Sampling the signal greater than or equal to Nyquist rate.
9) What is the use of anti-aliasing filter ?
It is used for reconstruction of a signal.
It is used to restrict the bandwidth of a signal to satisfy the sampling theorem and to prevent aliasing.
10) A signal can be reconstructed from its samples by using which method?
Filtering.
Resampling.
Auto-correlation.
11) Computation of DFT involves
Sampling in time domain.
Sampling in frequency domain.
No sampling.
Sampling in both time and frequency domain.
12) What should be done to resolve two very closely spaced sinusoids presents in a signal?
Small data length with appropriate zero padding must be done.
Length of data sufficiently large should be taken.
