In the linear convolution of two equal length sequences M and N, the length of the output is length(A)+length(B)-1, and if we apply the DFT property of converting convolution into multiplication, the output is equal Max (length (M) or length (N)).
a) If there a simple way to predict how many edge points are contaminated by circular convolution if we were interested in extracting only the linear convolution section from DFT? Suppose, one does not want to do zero padding in DFT to obtain linear convolution.
b) Secondly, if we wish to do true linear convolution via DFT, should we use zero padding up to length(M)+length(N)-1. This is a figure from a PhD thesis obtainable from ResearchGate pg 18, why does it say if the length of DFT >length(M)+length(N)-1, then results are valid. Is the linear convolution not restricted to the length of length(M)+length(N)-1.