add windowing computations and window definitions

ba3e3993 · Juan David González Cobas · 9d3daa44 · ba3e3993 · ba3e3993
Commit ba3e3993 authored Jan 21, 2011 by Juan David González Cobas
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Showing with 18 additions and 12 deletions

FFTSignal.py FFTSignal.py +13 -10

Signal.py Signal.py +5 -2

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--- a/FFTSignal.py
+++ b/FFTSignal.py
+from numpy import *
+
 class FFTSignal(object):
    """a representation of a frequency-domain signal
    """
-    
-    WINDOW_TYPES = [
-        'RECTANGULAR',
-        'HANN',
-        'HAMMING',
-        'TUKEY',
-        'COSINE',
-        'LANCZOS',
-        'BARTLETT_HANN'
-    ]
+
+    window_function = {
+        'No window' : ones,
+        'BARTLETT' : bartlett,
+        'BLACKMAN' : blackman,
+        'HAMMING' : hamming,
+        'HANNING' : hanning,
+        'KAISER' : kaiser,
+    }
+
+    WINDOW_TYPES = window_function.keys()

    def __init__(self, fft, dB = None, time_domain = None):
        """initialize an FFTSignal object

--- a/Signal.py
+++ b/Signal.py
@@ -118,7 +118,7 @@ class Signal(object):
        inl = cumsum(dnl)
        return inl, max(abs(inl))

-    def FFT(self, navg, window):
+    def FFT(self, navg=1, window='No window'):
        """Compute the amplitudes (in dB) of the FFT of signal, averaging navg
        slices of it and applying window to it

@@ -127,7 +127,10 @@ class Signal(object):

        returns: an FFTSignal object
        """
-        return FFTSignal(self.data, 1, 1)
+        print 'using window ', window
+        win = FFTSignal.window_function[window](self.nsamples)
+        dft = 10*log10(abs(fft.rfft(self.data * win)))
+        return FFTSignal(dft, dB=True, time_domain=self.data)

 def makesine(samples, periods, bits, amplitude=1, noise=0):