Your approach is correct. Rather than using interp1, use the Signal Processing Toolbox resample (link) function. It incorporates an anti-aliasing filter, and is preferred for signal processing purposes. A useful lowpass filter design prototype is:
Fs = 360;
Fn = Fs/2;
Wp = 100/Fn;
Ws = 101/Fn;
Rp = 1;
Rs = 150;
[n,Ws] = cheb2ord(Wp,Ws,Rp,Rs);
[z,p,k] = cheby2(n,Rs,Ws);
[soslp,glp] = zp2sos(z,p,k);
figure(3)
freqz(soslp, 2^16, Fs)
filtered_signal = filtfilt(soslp, glp, original_signal);
Make appropriate changes for your signal.
Best Answer