Reorganize code.

show.py

@@ -0,0 +1,9 @@
+def spectrogram(t, x):
+    ax1 = pylab.subplot(211)
+    pylab.plot(t, x)
+
+    pylab.subplot(212, sharex=ax1)
+    Pxx, freqs, bins, im = pylab.specgram(x,
+        NFFT=NFFT, Fs=Fs, noverlap=NFFT/2, cmap=pylab.cm.gist_heat)
+
+    pylab.show()