Re: Slow varying inputs

On Fri, 2005-03-04 at 09:37 +0000, Bernd Porr wrote:
> Give it to me. ;-) I'll add it to comedirecord. Once we've got 
> everything working as we want we can start thinking of comedi-routines.
> 
> My idea for a comedi command is that it is sampling in the background 
> and performing averaging. Either with a syncrounus command or with a 
> soft timer for simpler cards. The user then can get averaged data 
> whenever he/she wants it and then issues a reset so that averaging 
> starts over again.
> 

Averaging is only good for random noise.  Filters are better.

I'm not at work, and the ones at work are usually specific to the code,
so I hacked a new one with good documentation.  Also an example program.

Compile with C99 on:

gcc -std=c99 example_low_pass_filter.c low_pass_filter.c

The example program feeds a square wave into the low_pass_filter and
prints out a count, filter input and filter output.  I'll leave it to
you to plot, but you can use gnuplot:

gnuplot> plot '< ./a.out'
gnuplot> replot '< ./a.out' using 1:3