Easy Bandpass Filter

Simplified band-pass filtering without external toolboxes.

It performs band-pass filtering of a time series with the rectangle window in frequency domain, "without external toolboxes". An example code is given as follows to filter a time series in the pass band of 200~300 Hz:
Fs = 1000;
t = linspace(0,1,Fs);
x = cos(2*pi*100*t)+0.5*randn(size(t));
y = bpfilt(x,200,300,1000);