.. _pylab_examples-psd_demo_complex: pylab_examples example code: psd_demo_complex.py ================================================ .. plot:: /home/tcaswell/src/p/matplotlib/doc/mpl_examples/pylab_examples/psd_demo_complex.py :: """This is a ported version of a MATLAB example from the signal processing toolbox that showed some difference at one time between Matplotlib's and MATLAB's scaling of the PSD. This differs from psd_demo3.py in that this uses a complex signal, so we can see that complex PSD's work properly """ import numpy as np import matplotlib.pyplot as plt import matplotlib.mlab as mlab prng = np.random.RandomState(123456) # to ensure reproducibility fs = 1000 t = np.linspace(0, 0.3, 301) A = np.array([2, 8]).reshape(-1, 1) f = np.array([150, 140]).reshape(-1, 1) xn = (A * np.exp(2j * np.pi * f * t)).sum(axis=0) + 5 * prng.randn(*t.shape) fig, (ax0, ax1) = plt.subplots(ncols=2) fig.subplots_adjust(hspace=0.45, wspace=0.3) yticks = np.arange(-50, 30, 10) yrange = (yticks[0], yticks[-1]) xticks = np.arange(-500, 550, 200) ax0.psd(xn, NFFT=301, Fs=fs, window=mlab.window_none, pad_to=1024, scale_by_freq=True) ax0.set_title('Periodogram') ax0.set_yticks(yticks) ax0.set_xticks(xticks) ax0.grid(True) ax0.set_ylim(yrange) ax1.psd(xn, NFFT=150, Fs=fs, window=mlab.window_none, pad_to=512, noverlap=75, scale_by_freq=True) ax1.set_title('Welch') ax1.set_xticks(xticks) ax1.set_yticks(yticks) ax1.set_ylabel('') # overwrite the y-label added by `psd` ax1.grid(True) ax1.set_ylim(yrange) plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)