Filter PPG signal using FIR filter instead of IIR Filter

I am using following code to high pass filter PPG signal. But I want to use some alternate FIR filter in order to perform the same task. Can you please advise some alternate FIR filter with same response and small order n

t = linspace(0, numel(ppg_head), numel(ppg_head))/fs;
Fs = 960;                                                   % Sampling Frequency (Hz)
Fn = Fs/2;                                                  % Nyquist Frequency (Hz)
Wp = 24.5/Fn;                                               % Stopband Frequency (Normalised)
Ws = 25.0/Fn;                                               % Passband Frequency (Normalised)
Rp =   1;                                                   % Passband Ripple (dB)
Rs =  50;                                                   % Stopband Ripple (dB)
[n,Ws] = cheb2ord(Wp,Ws,Rp,Rs);                             % Filter Order
[z,p,k] = cheby2(n,Rs,Ws,'high');                           % Filter Design, Sepcify Bandstop
[sos,g] = zp2sos(z,p,k);                                    % Convert To Second-Order-Section For Stability
figure(2)
freqz(sos, 2^16, Fs)                                        % Filter Bode Plot
ppg_head_data = filtfilt(sos, g, ppg_head);                 % Filter Signal

Answer 1

[Star Strider]

Try this:

Fs = 960;
fcomb = [24.5 25];
mags = [1 0];
dev = [0.8 0.1];
[n,Wn,beta,ftype] = kaiserord(fcomb,mags,dev,Fs);
hh = fir1(n,Wn,ftype,kaiser(n+1,beta),'noscale');

figure
freqz(hh, 1, 2^20, Fs)
set(subplot(2,1,1), 'XLim',[0 50])                                  % Optional
set(subplot(2,1,2), 'XLim',[0 50])                                  % Optional

Then use filtfilt to do the actual filtering.

[Syed Muhammad Abubakar]

Thanks for your response. The filtfilt() function performs the zero-phase filtering. How can I get zero-phase filter through fdatool? Actually I want to implement the filter on the hardware.

[Star Strider]

My pleasure!

I believe fdatool is now filterDesigner in the DSP Toolbox (that I do not have so I cannot help you with it).

Realising a FIR filter in hardware is not something I have ever done (my experience is limited to IIR filter realisation). I have no idea how you want to do it, however there is apparently a way to do that. The approach in fdatool to fpga will likely get you started in the correct direction.

[Star Strider]

‘Alright can you help me with implementing IIR filter realisation?’

Unfortunately, no. I do not have the DSP Toolbox.

Also, I have only used op-amps to realise continuous-time filters in hardware, not discrete filters.