This chapter presents two important DSP techniques, the overlap-add method, and FFT convolution. The overlap-add method is used to break long signals into smaller segments for easier processing. FFT convolution uses the overlap-add method together with the Fast Fourier Transform, allowing signals to be convolved by multiplying their frequency spectra. For filter kernels longer than about 64 points, FFT convolution is faster than standard convolution, while producing exactly the same result.

The Scientist and Engineer’s Guide to Digital Signal Processing, ©1997-1998 by Steven W. Smith. For more information visit the book’s website at: www.DSPguide.com