examples/fir: plot input and output signals

diff --git a/examples/fir.py b/examples/fir.py
index 0212fdb23b713a7fbfdffa0af8d4a85e5d5c4d92..e10ff94e046279b6d2e682674645cfb65b749ff6 100644 (file)
--- a/examples/fir.py
+++ b/examples/fir.py
@@ -3,6 +3,7 @@
 
 from math import cos, pi
 from scipy import signal
+import matplotlib.pyplot as plt
 
 from migen.fhdl.structure import *
 from migen.fhdl import verilog
@@ -58,15 +59,22 @@ def main():
        # Compute filter coefficients with SciPy.
        coef = signal.remez(80, [0, 0.1, 0.1, 0.5], [1, 0])
        fir = FIR(coef)
-       tb = TB(fir, 0.3)
-       # Combine the FIR filter with its test bench.
-       fragment = autofragment.from_local()
-       sim = Simulator(fragment, Runner())
-       sim.run(200)
-       # Print data from the input and output waveforms.
-       # When matplotlib works easily with Python 3, we could
-       # display them graphically here.
-       print(tb.inputs)
-       print(tb.outputs)
+       
+       # Simulate for different frequencies and concatenate
+       # the results.
+       in_signals = []
+       out_signals = []
+       for frequency in [0.05, 0.07, 0.1, 0.15, 0.2]:
+               tb = TB(fir, frequency)
+               fragment = autofragment.from_local()
+               sim = Simulator(fragment, Runner())
+               sim.run(100)
+               in_signals += tb.inputs
+               out_signals += tb.outputs
+       
+       # Plot data from the input and output waveforms.
+       plt.plot(in_signals)
+       plt.plot(out_signals)
+       plt.show()
 
 main()