Wednesday, 15 March 2017

Convolution and Correlation algorithms

The basic mathematical operations of convolution (Linear, Circular) and correlation(Auto, Cross) were studied and practically implemented in this session.It was observed that linear convolution produced a causal output for a causal input. Circular convolution however produced an aliased output.That means first few values of the output got overlapped with the values beyond 'N' where N acted as the length of input and output signals.Correlation was used to test the degree of similarity between two signals.It was observed that auto correlation signal always turned out to be an even signal.C programming language was used to construct the test codes.

13 comments:

  1. Signal having values for n < 0 what will u call it as?

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    1. We interpret such signals as anti causal signals.The thing to note here is that we consider such signals only in theory, practical approach suggests non existence of anti causal signals.

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  2. What is the significance of y(0) in autocorrelation of a signal?

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    1. In auto correlation, y(0) always equals the energy of the signal.

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  3. What about auto correlation of delayed signal?

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    1. It is same as that of auto correlation of the input signal.

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  4. Anti aliasing filter could be used to remove the aliasing if it occurs. Aliasing occurs only when N<L+M-1.

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    1. Yes practically talking, an anti aliasing filter strictly band limits the input signal thereby avoiding the problem of aliasing i.e adjacent values getting overlapped.

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  5. The experiment was performed by executing C program.Linear convolution gives output of a system

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    1. We used linux ubuntu as a platform for executing the C code.

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    2. We used linux ubuntu as a platform for executing the C code.

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