Score:0

Recommended application for converting mathematical signal to sound

id flag

I use Ubuntu 22.04. Is there an application for converting mathematical periodical sin/cos formula (functions) to sound? For example is there a way for playing these signals:

  • cos(2π · 440 t)
  • cos t + cos 2^(1/2) t

Features:

  • I only look for free applications.

Note:

  • I have installed FFmpeg version 4.4.2 and GNU Octave, version 6.4.0 on my machine and instructions or web page which describes the way of using those for my purpose is acceptable.
Score:0
ca flag
  1. Create a file with "samples" from your formulas.
    Simple "C" or Python scripting will do the thing, unless Octave itself has means for it.
  2. Install Audacity
  3. Menu: File > Import > ... your sample-file.

Some Python -code to play with...
$ cat rawsnd.py 
#!/bin/env python

import math, sys

# trick to make CSI, ESC[ - sequences work in Windows-stupid-CMD.EXE to activate "ANSI.SYS" (as in old MS-DOS)
import os;os.system("");CSI='\x9B' # terminfo, curses, "ANSI" terminal expected

sps=44100       # sample rate, 44100 for "CD"-like
et=10           # end time, seconds
res=2**16-10        # max value for samples, UNSIGNED, < base-two-binary-max.
halfres=(res)/2     # adjust for SIGNED, Because*sin()/cos() [-1,1]
pi=3.141592653589793

Hz=440          # base frequency, at least for simple cos or sin

top=-1
bot=1

length = math.ceil(math.log(res, 256)) # bytes per sample
sys.stderr.write(str(length)+' bytes /sample\n\n')

f=open('TEST.raw','wb')
for t in range(int(et*sps)): # "t" in "samples"
  timespot=Hz*t/sps
  #
  #> cos t + cos 2^(1/2) t  # note: cos()+cos() may reach [-2,2], so scaled to half.
  #s=int(( math.cos( 2*pi*timespot )+math.cos(1.414*timpespot) )/2*halfres)
  #
  #> cos(2π · 440 t)
  s=int(math.cos( 2*pi*timespot )*halfres)
  #
  print(f'{CSI}A{s}{CSI}K')
  if s>top:
    top=s
  elif s<bot:
    bot=s
  f.write( int.to_bytes(s, length=length, byteorder='big', signed=True) )

print(f'{CSI}AValues: top; {top}, bottom; {bot}{CSI}J')
id flag
Thank you for your reply. I prefer using `Audacity`, at least for experimental usages. Can you provide a link for the syntax for writing complex formula as `raw data` in sample file?
Hannu avatar
ca flag
My recommendation: Look up a tutorial on python programming, then look into what I have included above - you will probably need just a few hours of Python-study.
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