% Program P7_1% Design of a Butterworth Bandstop Digital FilterWs = [0.4 0.6]; Wp = [0.2 0.8]; Rp = 0.4; Rs = 50;% Estimate the Filter Order[N1, Wn1] = buttord(Wp, Ws, Rp, Rs); % Design the Filter[num,den] = butter(N1,Wn1,'stop'); % Display the transfer functiondisp('Numerator Coefficients are ');disp(num);disp('Denominator Coefficients are ');disp(den);% Compute the gain response[g, w] = gain(num,den); % Plot the gain responseplot(w/pi,g);grid axis([0 1 -60 5]);xlabel('\omega /\pi'); ylabel('Gain in dB');title('Gain Response of a Butterworth Bandstop Filter');