DOC: clarity specgram's returned values

phobson · phobson · commit fb2ea821b5c8 · 2018-03-26T15:34:23.000-07:00
diff --git a/examples/images_contours_and_fields/specgram_demo.py b/examples/images_contours_and_fields/specgram_demo.py
@@ -24,14 +24,15 @@
 nse = 0.01 * np.random.random(size=len(t))
 
 x = s1 + s2 + nse  # the signal
-NFFT = 1024       # the length of the windowing segments
+NFFT = 1024  # the length of the windowing segments
 Fs = int(1.0 / dt)  # the sampling frequency
 
-# Pxx is the segments x freqs array of instantaneous power, freqs is
-# the frequency vector, bins are the centers of the time bins in which
-# the power is computed, and im is the matplotlib.image.AxesImage
-# instance
 fig, (ax1, ax2) = plt.subplots(nrows=2)
-line, = ax1.plot(t, x)
+ax1.plot(t, x)
 Pxx, freqs, bins, im = ax2.specgram(x, NFFT=NFFT, Fs=Fs, noverlap=900)
+# The `specgram` method returns 4 objects. They are:
+# - Pxx: the periodogram
+# - freqs: the frequency vector
+# - bins: the centers of the time bins
+# - im: the matplotlib.image.AxesImage instance representing the data in the plot
 plt.show()
