ieee1139_randomwalk_fm does not work out the box

[paganelle76]

Hello,
I would suggest to replace:

f_fi, psd_fi = noise.numpy_psd(signal.detrend(fi[:len(fi)/20]), fs)
f_x,  psd_x = noise.numpy_psd(x[:len(x)/20], fs)

to:

#f_fi, psd_fi = noise.numpy_psd(signal.detrend(fi[:int(len(fi)/20)]), fs)
#f_x,  psd_x = noise.numpy_psd(x[:int(len(x)/20)], fs)

To avoid "TypeError: slice indices must be integers or None or have an index method"
Or just remove dividing by 20?