fix: added check for value of Fs

Stefan Mitic · Stefan Mitic · commit 7069072d8847 · 2020-03-10T11:28:35.000-04:00
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -7649,6 +7649,8 @@ def specgram(self, x, NFFT=None, Fs=None, Fc=None, detrend=None,
         Z = np.flipud(Z)
 
         if xextent is None:
+            if Fs is None:
+                Fs = freqs[-1] * 2  # default set in mlab._spectral_helper()
             # padding is needed for first and last segment:
             pad_xextent = (NFFT-noverlap) / Fs / 2
             xextent = np.min(t) - pad_xextent, np.max(t) + pad_xextent
