一个输出Sine Sweep Wave文件的Python程序

{{{
#!python
# this porgram output sine sweep wave file
# HYRY Studio 2007/01/17

from math import *
from time import clock
import array
import wave
import psyco
psyco.profile()
    
def sinesweep(f0, f1, sweeptime, samplingrate, peak):
    k = exp(log(float(f1)/f0)/sweeptime)
    data = array.array("h", "\x00"*sweeptime*samplingrate*2)
    dt = 1.0/samplingrate
    t = 0.0
    p = 2*pi*f0/log(k)
    for i in xrange(sweeptime*samplingrate):
        data[i] = int(peak*sin( p*(pow(k,t)-1) ))
        t += dt
    return data

def sindata(f0, time, samplingrate, peak):
    data = [int(peak*sin(2*pi*f0*x/samplingrate)) for x in xrange(int(time*samplingrate))]
    return array.array("h", data)
    
if __name__ =="__main__":
    SAMPLING_RATE = 44100
    SWEEP_TIME = 50
    F0 = 20
    F1 = 20000
    PEAK = 0x2000
    start = clock()
    data = sinesweep(F0, F1, SWEEP_TIME, SAMPLING_RATE, PEAK)
    print clock() - start
    f = wave.open("sweep.wav","wb")
    f.setnchannels(1) # mono wave
    f.setsampwidth(2) # 16bit
    f.setframerate(SAMPLING_RATE) #sampling rate
    f.setnframes((6+SWEEP_TIME)*SAMPLING_RATE)
    f.setcomptype("NONE","NONE")
    f.writeframes("\x00" * 2 * 2 * SAMPLING_RATE)
    f.writeframes(sindata(1000, 0.1, SAMPLING_RATE, 0x6000).tostring())
    f.writeframes("\x00" * int(2 * 1.9 * SAMPLING_RATE))
    f.writeframes(data.tostring())
    f.writeframes("\x00" * 2 * 2 * SAMPLING_RATE)
    f.close()
}}}
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