psd(x, NFFT=256, Fs=2, detrend=<function detrend_none at 0x436d04ac>, window=<function window_hanning at 0x436b3dac>, noverlap=0)[source]

Wrapper for matplotlib.mlab.psd().

Always returns a onesided psd (positive frequencies only), corrects for this fact by scaling with a factor of 2. Also, always normalizes to 1/Hz by dividing with sampling rate.

Deprecated since version 0.11.0: This wrapper is no longer necessary. Please use the matplotlib.mlab.psd() function directly, specifying sides=”onesided” and scale_by_freq=True.


For details on all arguments see matplotlib.mlab.psd().


When using window=welch_taper (obspy.signal.spectral_estimation.welch_taper()) and detrend=detrend_linear (matplotlib.mlab.detrend_linear()) the psd function delivers practically the same results as PITSA. Only DC and the first 3-4 lowest non-DC frequencies deviate very slightly. In contrast to PITSA, this routine also returns the psd value at the Nyquist frequency and therefore is one frequency sample longer.