i'm trying to implement a low-pass this way, as in the Digital signal processing guide
book, but my alfa = 2.660393305517957e-55
which is obviously wrong. Here's the code:
x = exp(-2*pi*20);
a0 = 1 - x;
b1 = x;
eda2(1) = eda_raw2(1);
for n = 2:length(eda_raw2)
eda2(n) = a0*eda_raw2(n) + b1.*eda2(n - 1);
end
The problem is how you are computing the pole (x
) of the discrete-time filter. You are not considering the sampling frequency! The computation should be x = exp(-2*pi*20/fm);
, where fm
is the sampling frequency in Hz.