matplotlib
diff --git a/‎doc/api/api_changes/2017-06-11-DB_magnitude_spectrum.rst
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+Correct scaling of :func:`magnitude_spectrum()`
+```````````````````````````````````````````````
+
+The functions :func:`matplotlib.mlab.magnitude_spectrum()` and :func:`matplotlib.pyplot.magnitude_spectrum()` implicitly assumed the sum
+of windowing function values to be one. In Matplotlib and Numpy the
+standard windowing functions are scaled to have maximum value of one,
+which usually results in a sum of the order of n/2 for a n-point
+signal. Thus the amplitude scaling :func:`magnitude_spectrum()` was
+off by that amount when using standard windowing functions (`Bug 8417
+<https://github.com/matplotlib/matplotlib/issues/8417>`_ ). Now the
+behavior is consistent with :func:`matplotlib.pyplot.psd()` and
+:func:`scipy.signal.welch()`. The following example demonstrates the
+new and old scaling::
+
+    import matplotlib.pyplot as plt
+    import numpy as np
+    
+    tau, n = 10, 1024  # 10 second signal with 1024 points
+    T = tau/n  # sampling interval
+    t = np.arange(n)*T
+    
+    a = 4  # amplitude
+    x = a*np.sin(40*np.pi*t)  # 20 Hz sine with amplitude a
+    
+    # New correct behavior: Amplitude at 20 Hz is a/2
+    plt.magnitude_spectrum(x, Fs=1/T, sides='onesided', scale='linear')
+    
+    # Original behavior: Amplitude at 20 Hz is (a/2)*(n/2) for a Hanning window
+    w = np.hanning(n)  # default window is a Hanning window
+    plt.magnitude_spectrum(x*np.sum(w), Fs=1/T, sides='onesided', scale='linear')
+