Barry Lotz wrote:

>    I also have been using digital filtering with one of my computers with
an smt-8
> style vertical. I tried IIR filtering but ran into numerical stability
problems. I
> found better luck with multipole FIR filtering. I made a program in Basic
to
> create the filter coefficients for a desired shape and then have an option
in my
> data acquisition program to use the filter file created. It works quite
well on a
> 386. What I like is you can create various filter responses in different
frequency
> ranges and if this doesn't work for the noise you just change the
coeficients not
> the hardware. I am trying to have the program create it's own filter based
on the
> long term background noise. Currently this consideration is included in my
trigger
> routine.
> Regards
> Barry

This is exactly the kind of thing I have been thinking about (except for the
automated filter tuning).  I would be very interested in seeing your code if
you would be willing to post it or send me a copy.  I have a pretty good
background in analog active filter design but I know virtually nothing about
digital filters.

Larry Conklin


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