Generating sin/square waves sound

[mblume]

Am Fri, 30 Dec 2011 07:17:13 +0000 schrieb Paulo da Silva:

> Hi,
> Sorry if this is a FAQ, but I have googled and didn't find any
> satisfatory answer.
> 
> Is there a simple way, preferably multiplataform (or linux), of
> generating sinusoidal/square waves sound in python?
> 
> Thanks for any answers/suggestions.

Have a look at the wave module, available under Windows and Linux,
which operates on .WAV files. The following snippet might get you going:

#!/usr/bin/python
import math, wave, struct

def signal(t, freq):
	return math.sin(2.0*math.pi*freq*t)
		
		
wout      = wave.open("sample.wav", "wb")
nchan     = 1
sampwidth = 2
framerate = 8000
nframes   = 7 * framerate
comptype  = "NONE"
compname  = "no compression"		


wout.setparams((nchan, sampwidth, framerate, nframes, comptype, compname))

ts = 1.0 / framerate
t  = 0.0
n  = 0
data = []
vals = []
while n < nframes:
	vals.append(signal(t, 517.0))
	n = n + 1
	t = t + ts
	
mx   = max((abs(x) for x in vals))
vals = [ x/mx for x in vals ]	
data = ""
for v in vals:
	data = data + struct.pack("<h", int(v*32766.0))
wout.writeframes(data)
wout.close()


Alternatively you might just generate (t,signal) samples, write them to 
a file and convert them using "sox" (under Linux, might also be available
under Windows) to another format.

HTH
Martin