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examples/fir: plot input and output signals

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1 parent 1c0f636 commit b00e8fa826f14c067b70b630acd72d1d439bd0b8 @sbourdeauducq sbourdeauducq committed Jun 7, 2012
Showing with 18 additions and 10 deletions.
  1. +18 −10 examples/fir.py
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@@ -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()

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