def pwd(x, w):
N = len(x)
w = h.zeropad(w, N)
w_ = w[::-1].conj()
X_pwd = []
points = range(0, N)
for i in points:
x_subset = h.subset(x, i, N)
fft_subset = fft(w * w_ * x_subset * x_subset[::-1].conj())
X_pwd.append(fft_subset)
X_pwd = array(X_pwd).transpose()
return X_pwd
def stft(x, w, L=None):
# L is the overlap, see http://cnx.org/content/m10570/latest/
N = len(x)
#T = len(w)
if L is None:
L = N
# Zero pad the window
w = h.zeropad(w, N)
X_stft = []
points = range(0, N, N//L)
for i in points:
x_subset = h.subset(x, i, N)
fft_subset = fft(x_subset * w)
X_stft.append(fft_subset)
X_stft = array(X_stft).transpose()
return X_stft
def stft(x, w, L=None):
# L is the overlap, see http://cnx.org/content/m10570/latest/
N = len(x)
#T = len(w)
if L is None:
L = N
# Zero pad the window
w = h.zeropad(w, N)
X_stft = []
points = range(0, N, N // L)
for i in points:
x_subset = h.subset(x, i, N)
fft_subset = fft(x_subset * w)
X_stft.append(fft_subset)
X_stft = array(X_stft).transpose()
return X_stft
from __future__ import division
from pylab import *
from numpy import *
from numpy.fft import *
# from pytfd import stft
from pytfd.stft import *
from pytfd.windows import *
import pytfd.helpers as h
N = 4096
T = 64
for window_name in ('ones', 'hanning', 'gaussian', 'blackman'):
window_function = globals()[window_name]
w = window_function(T)
W = fft(h.zeropad(w, N))
figure()
subplot(1, 2, 1)
title(window_name)
plot(h.zeropad(w, 2*T))
axis([0, 2*T, 0, 2])
subplot(1, 2, 2)
title("FT(%s)"%window_name)
plot(linspace(0, 2*pi, N), fftshift(log10(abs(W)+1)))
savefig(window_name)
