diff options
| -rw-r--r-- | gnuradio-core/src/python/gnuradio/window.py | 43 |
1 files changed, 16 insertions, 27 deletions
diff --git a/gnuradio-core/src/python/gnuradio/window.py b/gnuradio-core/src/python/gnuradio/window.py index fb4a10675..f89831375 100644 --- a/gnuradio-core/src/python/gnuradio/window.py +++ b/gnuradio-core/src/python/gnuradio/window.py @@ -153,32 +153,6 @@ def riemann(fft_size): j -= 1 return window -def blackmanharris(fft_size): - a0 = 0.35875 - a1 = 0.48829 - a2 = 0.14128 - a3 = 0.01168 - window = [0 for i in range(fft_size)] - for index in xrange(fft_size): - window[index] = a0 - window[index] -= a1*math.cos(2.0*math.pi*(index+0.5)/(fft_size - 1)) - window[index] += a2*math.cos(4.0*math.pi*(index+0.5)/(fft_size - 1)) - window[index] -= a3*math.cos(6.0*math.pi*(index+0.5)/(fft_size - 1)) - return window - -def nuttall(fft_size): - a0 = 0.3635819 - a1 = 0.4891775 - a2 = 0.1365995 - a3 = 0.0106411 - window = [0 for i in range(fft_size)] - for index in xrange(fft_size): - window[index] = a0 - window[index] -= a1*math.cos(2.0*math.pi*(index+0.5)/(fft_size - 1)) - window[index] += a2*math.cos(4.0*math.pi*(index+0.5)/(fft_size - 1)) - window[index] -= a3*math.cos(6.0*math.pi*(index+0.5)/(fft_size - 1)) - return window - def kaiser(fft_size,beta): ibeta = 1.0/izero(beta) inm1 = 1.0/(fft_size) @@ -187,4 +161,19 @@ def kaiser(fft_size,beta): 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 |