On 20 May 2013 00:36, <killybeard91 at gmail.com> wrote: > One more question. Function np.argmax returns max of non-complex numbers ? > Because FFT array of my signal is complex. Use abs() like in my example. This will give the absolute value of the complex numbers: >>> z = 1+1j >>> z (1+1j) >>> abs(z) 1.4142135623730951 Oscar