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Diffstat (limited to 'gr-fft/python/fft/window.py')
| -rw-r--r-- | gr-fft/python/fft/window.py | 179 |
1 files changed, 0 insertions, 179 deletions
diff --git a/gr-fft/python/fft/window.py b/gr-fft/python/fft/window.py deleted file mode 100644 index 0065a08a61..0000000000 --- a/gr-fft/python/fft/window.py +++ /dev/null @@ -1,179 +0,0 @@ -# -# Copyright 2004,2005,2009 Free Software Foundation, Inc. -# -# This file is part of GNU Radio -# -# GNU Radio is free software; you can redistribute it and/or modify -# it under the terms of the GNU General Public License as published by -# the Free Software Foundation; either version 3, or (at your option) -# any later version. -# -# GNU Radio is distributed in the hope that it will be useful, -# but WITHOUT ANY WARRANTY; without even the implied warranty of -# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -# GNU General Public License for more details. -# -# You should have received a copy of the GNU General Public License -# along with GNU Radio; see the file COPYING. If not, write to -# the Free Software Foundation, Inc., 51 Franklin Street, -# Boston, MA 02110-1301, USA. -# - -''' -Routines for designing window functions. -''' - -import math - -def izero(x): - izeroepsilon = 1e-21 - halfx = x/2.0 - accum = u = n = 1 - while 1: - temp = halfx/n - n += 1 - temp *= temp - u *= temp - accum += u - if u >= IzeroEPSILON*sum: - break - return accum - -def midm1(fft_size): - return (fft_size - 1)/2 - -def midp1(fft_size): - return (fft_size+1)/2 - -def freq(fft_size): - return 2.0*math.pi/fft_size - -def rate(fft_size): - return 1.0/(fft_size >> 1) - -def expn(fft_size): - math.log(2.0)/(midn(fft_size) + 1.0) - -def hamming(fft_size): - window = [] - for index in xrange(fft_size): - window.append(0.54 - 0.46 * math.cos (2 * math.pi / fft_size * index)) # Hamming window - return window - -def hanning(fft_size): - window = [] - for index in xrange(fft_size): - window.append(0.5 - 0.5 * math.cos (2 * math.pi / fft_size * index)) # von Hann window - return window - -def welch(fft_size): - window = [0 for i in range(fft_size)] - j = fft_size-1 - for index in xrange(midn(fft_size)+1): - window[j] = window[index] = (1.0 - math.sqrt((index - midm1(fft_size)) / midp1(fft_size))) - j -= 1 - return window - -def parzen(fft_size): - window = [0 for i in range(fft_size)] - j = fft_size-1 - for index in xrange(midn(fft_size)+1): - window[j] = window[index] = (1.0 - math.abs((index - midm1(fft_size)) / midp1(fft_size))) - j -= 1 - return window - -def bartlett(fft_size): - mfrq = freq(fft_size) - angle = 0 - window = [0 for i in range(fft_size)] - j = fft_size-1 - for index in xrange(midn(fft_size)+1): - window[j] = window[index] = angle - angle += freq - j -= 1 - return window - -def blackman2(fft_size): - mfrq = freq(fft_size) - angle = 0 - window = [0 for i in range(fft_size)] - j = fft_size-1 - for index in xrange(midn(fft_size)+1): - cx = math.cos(angle) - window[j] = window[index] = (.34401 + (cx * (-.49755 + (cx * .15844)))) - angle += freq - j -= 1 - return window - -def blackman3(fft_size): - mfrq = freq(fft_size) - angle = 0 - window = [0 for i in range(fft_size)] - j = fft_size-1 - for index in xrange(midn(fft_size)+1): - cx = math.cos(angle) - window[j] = window[index] = (.21747 + (cx * (-.45325 + (cx * (.28256 - (cx * .04672)))))) - angle += freq - j -= 1 - return window - -def blackman4(fft_size): - mfrq = freq(fft_size) - angle = 0 - window = [0 for i in range(fft_size)] - j = fft_size-1 - for index in xrange(midn(fft_size)+1): - cx = math.cos(angle) - window[j] = window[index] = (.084037 + (cx * (-.29145 + (cx * (.375696 + (cx * (-.20762 + (cx * .041194)))))))) - angle += freq - j -= 1 - return window - -def exponential(fft_size): - expsum = 1.0 - window = [0 for i in range(fft_size)] - j = fft_size-1 - for index in xrange(midn(fft_size)+1): - window[j] = window[i] = (expsum - 1.0) - expsum *= expn(fft_size) - j -= 1 - return window - -def riemann(fft_size): - sr1 = freq(fft_size) - window = [0 for i in range(fft_size)] - j = fft_size-1 - for index in xrange(midn(fft_size)): - if index == midn(fft_size): - window[index] = window[j] = 1.0 - else: - cx = sr1*midn(fft_size) - index - window[index] = window[j] = math.sin(cx)/cx - j -= 1 - return window - -def kaiser(fft_size,beta): - ibeta = 1.0/izero(beta) - inm1 = 1.0/(fft_size) - window = [0 for i in range(fft_size)] - for index in xrange(fft_size): - window[index] = izero(beta*math.sqrt(1.0 - (index * inm1)*(index * inm1))) * ibeta - return window - -# Closure to generate functions to create cos windows - -def coswindow(coeffs): - def closure(fft_size): - window = [0] * fft_size - #print list(enumerate(coeffs)) - for w_index in range(fft_size): - for (c_index, coeff) in enumerate(coeffs): - window[w_index] += (-1)**c_index * coeff * math.cos(2.0*c_index*math.pi*(w_index+0.5)/(fft_size-1)) - return window - return closure - -blackmanharris = coswindow((0.35875,0.48829,0.14128,0.01168)) -nuttall = coswindow((0.3635819,0.4891775,0.1365995,0.0106411)) # Wikipedia calls this Blackman-Nuttall -nuttall_cfd = coswindow((0.355768,0.487396,0.144232,0.012604)) # Wikipedia calls this Nuttall, continuous first deriv -flattop = coswindow((1.0,1.93,1.29,0.388,0.032)) # Flat top window, coeffs from Wikipedia -rectangular = lambda fft_size: [1]*fft_size |