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# Pweave Example - Frequency response of a moving average filter
[Matti Pastell](http://mpastell.com/)
Create 11 point moving average filter and plot its frequency response and print the values.
<<>>=
from pylab import *
import scipy.signal as signal
#A function to plot frequency and phase response
def mfreqz(b,a=1):
w,h = signal.freqz(b,a)
h = abs(h)
return(w/max(w), h)
@
Make the impulse response function and use terminal formatted output.
<<term = True>>=
n = 11.
n
b = repeat(1/n, n)
b
@
Calculate the frequency response and plot it:
<<fig = True, caption = 'Frequency response of an 11 point moving average filter'>>=
w, h = mfreqz(b)
#Plot the function
plot(w,h,'k')
ylabel('Amplitude')
xlabel(r'Normalized Frequency (x$\pi$rad/sample)')
show()
@
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