Changed normalization in _spectral_helper() to obtain conistent scali…

…ng in magnitude_spectrum() and fixed doc string.
matplotlib · tacaswell · Jun 12, 2017 · May 6, 2017 · Jun 11, 2017 · May 10, 2017
commit 76c4d8495a212c5f8f8f68d2317c1fac0c5fbd26
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -6665,8 +6665,7 @@ def magnitude_spectrum(self, x, Fs=None, Fc=None, window=None,
 
         scale : [ 'default' | 'linear' | 'dB' ]
             The scaling of the values in the *spec*.  'linear' is no scaling.
-            'dB' returns the values in dB scale.  When *mode* is 'density',
-            this is dB power (10 * log10).  Otherwise this is dB amplitude
+            'dB' returns the values in dB scale, i.e., the dB amplitude
             (20 * log10). 'default' is 'linear'.
 
         Fc : integer

diff --git a/lib/matplotlib/mlab.py b/lib/matplotlib/mlab.py
@@ -727,12 +727,12 @@ def _spectral_helper(x, y=None, NFFT=None, Fs=None, detrend_func=None,
     elif mode == 'psd':
         result = np.conj(result) * result
     elif mode == 'magnitude':
-        result = np.abs(result)
+        result = np.abs(result) / np.abs(windowVals).sum()
     elif mode == 'angle' or mode == 'phase':
         # we unwrap the phase later to handle the onesided vs. twosided case
         result = np.angle(result)
     elif mode == 'complex':
-        pass
+        result /= np.abs(windowVals).sum()
 
     if mode == 'psd':
 

diff --git a/lib/matplotlib/tests/baseline_images/test_axes/magnitude_spectrum_freqs_dB.png b/lib/matplotlib/tests/baseline_images/test_axes/magnitude_spectrum_freqs_dB.png
diff --git a/lib/matplotlib/tests/baseline_images/test_axes/magnitude_spectrum_freqs_linear.png b/lib/matplotlib/tests/baseline_images/test_axes/magnitude_spectrum_freqs_linear.png
diff --git a/lib/matplotlib/tests/baseline_images/test_axes/magnitude_spectrum_noise_dB.png b/lib/matplotlib/tests/baseline_images/test_axes/magnitude_spectrum_noise_dB.png
diff --git a/lib/matplotlib/tests/baseline_images/test_axes/magnitude_spectrum_noise_linear.png b/lib/matplotlib/tests/baseline_images/test_axes/magnitude_spectrum_noise_linear.png