25 Oct
2005
25 Oct
'05
3:57 p.m.
This is a huge can of worms you're opening here ...
A simple sawtooth wave is going to have a lot of aliasing, unless you
specifically use an algorithm that produces a band-limited approximation,
at which point you've already left me far behind ;-)
For FFT, my needs have been very modest, I just eyeball stuff in Snd.
There is also www.baudline.com , very slick but it is merely free and not Free.
-PW
On 10/25/05, Mark Knecht <markknecht(a)gmail.com> wrote:
On 10/25/05, Paul Winkler <pw_lists(a)slinkp.com>
wrote:
--
http://www.slinkp.com
Awk is powerful and concise, but it's not my
friend - I can never remember how
the heck it works ;-)
I'd probably do like Paul D. suggests and use existing tools - e.g.
find something
to generate an appropriate soundfile, then feed it through sox.
But just for fun, here's something silly I just whipped up:
$ ./sine_hex.py
Usage: ./sine_hex.py frequency [sampling rate] [bits]
Print one cycle of a sine wave of approximately the
given frequency.
Values given in hex with *bits* precision at *sampling rate*.
Default sampling rate is 44100. Default bits is 16.
pwinkler@Winkler-P-LT2K ~
$ ./sine_hex.py 24000 48000
0000
ffff
pwinkler@Winkler-P-LT2K ~
$ ./sine_hex.py 3000 48000
0000
31f1
61f7
8e39
b504
d4da
ec82
fb14
ffff
fb14
ec82
d4da
b504
8e39
61f7
31f1
And here's the source. Most of it is argument handling :-)
http://www.slinkp.com/~paul/sine_hex.py
Intereing. Another country heard from.
One question that comes to mind, as I play with these solutions, is
deciding how to evaluate the outputs. For instance I was fiddling with
generating a sawtooth from Marcus' s method. I could do the same with
this, but how do I know each of them is really implementing what I'm
interested in?
What tools do people use for FFT analysis on files like this?
Cheers,
Mark