Intuitive understanding of how 'overlap save' works in contrast to 'overlap add'

1. What is the difference between overlap-add and overlap save?
2. How does overlap-add work?
3. How do you overlap a save method?
4. Why do we use overlap save method?

What is the difference between overlap-add and overlap save?

Two methods that make linear convolution look like circular convolution are overlap-save and overlap-add. The overlap-save procedure cuts the signal up into equal length segments with some overlap. Then it takes the DFT of the segments and saves the parts of the convolution that correspond to the circular convolution.

How does overlap-add work?

The overlap-add method breaks a long sequence, x(n) , into signals of shorter length and calculates the convolution of each block independently. To arrive at the final result, we need to apply an appropriate time shift to the convolution of the blocks and add them together.

How do you overlap a save method?

Overlap Save Method

Let the length of input data block = N = L+M-1. Therefore, DFT and IDFT length = N. Each data block carries M-1 data points of previous block followed by L new data points to form a data sequence of length N = L+M-1. First, N-point DFT is computed for each data block.

Why do we use overlap save method?

The overlap–save algorithm can be extended to include other common operations of a system: additional IFFT channels can be processed more cheaply than the first by reusing the forward FFT. sampling rates can be changed by using different sized forward and inverse FFTs.