IIR Bandstop (Notch) Filter design

Im new to filter design and I'd like to design an IIR bandstop filter with the following conditions:

2.01: 200 Hz,

2.02: 15 Hz bandwidth,

2.03: 30 dB depth,

Answer 1

[Star Strider]

I have absolutely no idea what ‘2.01’, ‘2.02’ and ‘2.03’mean.

Here is a prototype bandstop filter design that you can change to produce the filter you want:

Fs = 900;                                                           % Sampling Frequency
Fn = Fs/2;                                                          % Nyquist Frequency
Wp = [48 52]/Fn;                                                    % Stopband Frequency (Normalised)
Ws = [0.9 1.1].*Wp;                                                 % Passband Frequency (Normalised)
Rp =  1;                                                            % Passband Ripple
Rs = 90;                                                            % Passband Ripple (Attenuation)
[n,Wp] = ellipord(Wp,Ws,Rp,Rs);                                     % Elliptic Order Calculation
[z,p,k] = ellip(n,Rp,Rs,Wp,'stop');                                 % Elliptic Filter Design: Zero-Pole-Gain 
[sos,g] = zp2sos(z,p,k);                                            % Second-Order Section For Stability

figure
freqz(sos, 2^18, Fs)                                                % Filter Bode Plot
set(subplot(2,1,1), 'XLim',[0 Fs/5])                                % Optional
set(subplot(2,1,2), 'XLim',[0 Fs/5])                                % Optional

% signal_filt = filtfilt(sos, g, signal);                             % Filter Signal

Un-comment the filtfilt line to filter your signal.

[jiunwei pua]

Well i jus want to design the IIR Bandstop filter with the specify Bandwitdh, Frequency and Depth only. Many thanks for the prototype code :)

[Star Strider]

As always, my pleasure!

[Ahmed Azhari]

what if my specification was 0,8<= | Hd(exp(jw) | <= 1 , 0<=w<=0.2pi 0.7<=w<=pi

| Hd(exp(jw) <=0.2 , 0.3pi<=w<=0.6pi