Answer Happy

(a) Design a lowpass digital filter that has 1. Passband = 0.5 rad/sample 2. Stopband = 1 лrad/sample 3. Allowable passband ripple = ±2dB 4. Minimum stopband attenuation = 80 dB (b) Plot the frequency response of the designed filter above
clear, close all Wp = Ws 0.4; % normalized passband edge freq 0.6; % normalized stopband edge freq Rp = 1; % max passband ripple Rs = 60; % min stopband attenuation [Nf, Wn] = buttord (Wp, Ws, Rp, Rs); % design filter order [num, den] = butter (Nf, Wn); % design the filter freqz (num, den, 1024); % plot frequency response 0.6; % normalized passband edge freq Ws = 0.4; % normalized stopband edge freq Rp = 1; % max passband ripple = Wp Rs = 60; % min stopband attenuation [Nf, Wn] = buttord (Wp, Ws, Rp, Rs); % design filter order [num, den] = butter (Nf, wn, 'high'); % design the filter figure, freqz (num, den, 1024); % plot frequency response