I have to design Chebyshev type I analog lowpass filter and transform it to digital filter using impinvar() and bilinear(). Then I have to plot the gain response for both methods and do comparisons. However, the gain response take in the input of g of 20log10(H)?? function X = invariance(fs) fs = 100000; wp = 10000*2/fs; ws = 30000*2/fs; rp = 0.4; rs = 50; [n,wn] = cheb1ord(wp,ws,rp,rs); [b,a]= cheby1(4,0.4,0.2,'s'); [H,w] = freqz(b,a,512); len = length(H); [z,p,g] = cheb1ap(4,0.4) [bz,az] = impinvar(b,a,100000) plot(w*fs/(2*pi),20*log10(abs(H))); title('Gain Response for Impulse Invariance'); xlabel('Frequency (Hz)'); ylabel('Gain (dB)'); % bilinear plot(w*fs/(2*pi),20*log10(abs(H))); title('Gain Response for Bilinear Transformation'); xlabel('Frequency (Hz)'); ylabel('Gain (dB)'); grid;
gain response
Started by ●April 25, 2007