function [output] = ksfilter(freq, fs, input)
%Filters an input signal through the Karplus-Strong string synthesis
%filter at a given frequency freq and sample rate fs.

L = fs/freq-0.5;
delta = L-floor(L);
L = floor(L);
a = (1-delta)/(1+delta);
L_delay = zeros(1, L-2);
R = 0.99999;
B = [(a/2), (a/2+1/2), 1/2, L_delay];
A = [1, a, L_delay, (-a/2*R^L), -(a/2*R^L+1/2*R^L), (-0.5*R^L)];
output = filter(B,A,input);
end