wolffd@0: % mag = FreqResp(filter, f, fs)
wolffd@0: % Find the frequency response (in dB) of a filter (1x5 vector) at
wolffd@0: % frequency f and sampling rate fs.
wolffd@0: 
wolffd@0: % (c) 1998 Interval Research Corporation  
wolffd@0: 
wolffd@0: function mag=FreqResp(filter,f,fs)
wolffd@0: cf = exp(i*2*pi*f/fs);
wolffd@0: mag = (filter(3) + filter(2)*cf + filter(1)*cf.^2) ./ ...
wolffd@0: 	(filter(5) + filter(4)*cf + cf.^2);
wolffd@0: mag = 20*log10(abs(mag));