Added script for plotting the spectrum of signal dumps

impl/utils/plot_spectrum.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+
+import sys
+
+import numpy as np
+import matplotlib.pyplot as pp
+
+with open(sys.argv[1], 'rb') as infile:
+    header = infile.read(4)
+    if header != b'CPX_':
+        print(f"Error: not a complex signal file. Format {header} not implemented yet.")
+        exit(1)
+
+    T = np.fromfile(infile, dtype=np.float32, count=1)
+    data = np.fromfile(infile, dtype=np.complex64)
+
+    f = np.arange(-1/(2*T), 1/(2*T), 1/T/data.size)
+
+    spec = 20*np.log10(np.absolute(np.fft.fftshift(np.fft.fft(data))) / data.size)
+
+    pp.plot(f, spec, 'b-')
+    pp.legend(['Spectrum'])
+    pp.xlabel('Frequency [Hz]')
+    pp.show()