Steven W. Smith

Most filters have one of the four standard frequency responses: low-pass, high-pass, band-pass or band-reject. This chapter presents a general method of designing digital filters with an arbitrary frequency response, tailored to the needs of your particular application. DSP excels in this area, solving problems that are far above the capabilities of analog electronics. Two important uses of custom filters are discussed in this chapter: deconvolution, a way of restoring signals that have undergone an unwanted convolution, and optimal filtering, the problem of separating signals with overlapping frequency spectra. This is DSP at its best.