def firwin_lpf(N_taps, fc, fs = <NUM_LIT:1.0>):
return signal.firwin(N_taps,<NUM_LIT:2>*fc/fs)<EOL>
Design a windowed FIR lowpass filter in terms of passband
critical frequencies f1 < f2 in Hz relative to sampling rate
fs in Hz. The number of taps must be provided.

Mark Wickert October 2016