Convolution and Correlation

DSPP Practicals

           Convolution is used to find the output of a given discrete time signal.

           In linear convolution, if the length of input signal is L and  that of impulse reponse is M then length of output signal should be equal to L+M-1. In our code, if the length was exceeding the length given by the above formula, then the last extra values were getting added to the first corresponding values and this is termed as aliasing.

           In circular convolution the length of the output signal is taken as the maximum of the length of the two input signals. This type of convolution hence uses the method of zero padding.

           Correlation is used to find the degree of similarity between the two input signals.

           Auto-correlation is correlation of two same signals. Hence it is seen that the auto-correalation output is an even signal. Cross-correlation of the input signal and its delayed signal gives a shifted/delayed output signal.