@Bloodline
I dug around my notes, I dunno if you will find this useful.
For a given N-Tap filter, the ith output value is
O = Sum(n=0 to N-1) { Cn . I[i-n]}
where
N = number of taps
O = output samples
I = input samples
C = filter coefficients of the N tap filter.
Depending on how you calculate Cn, you can create high, low, bandpass and notch reject filters.
For a basic low pass filter:
Cn = Sn . Wn
where
S are the impulse samples
W is the hamming window
Sn = sin(2.pi.Fcp.(n-(N-1)/2)/2.5/Fmax) / pi.(n-(N-1)/2)
where
n is the tap number of interest
N is the total number of taps
Fcp is the filter cut-off frequency
Fmax is the maximum possible input frequncy
The 2.5 factor is to satisfy the Nyquist rate such that the sampling frequency is 2.5*Fmax
The Hamming Window (W) is used to get a better filter behaviour, eliminating unwanted ripple:
Wn = cos(1) + (1-cos(1)).cos({2.pi.(n-(N-1)/2)}/(N-1))
By adjusting the function for S, you can create all kinds of resonance effects.
Enjoy :-)
