Assistance or advice appreciated: FIR filter design

"Noodnik" sounds like a russian word which means "humdrum"

You don't mention a sampling rate. You're going to need a delay of something like 10ms to get your attenuation -- does that fit with your sampling rate and your 127 stage filter?

Do this:

• Design a prototype filter frequency response. I like using a flat top equal to 1, a raised cosine for the transition region, and (obviously) zero for the stop band.

• Choose a length a good deal longer than your 127 taps. Computers are fast, choose at least several thousand.

• Put the frequency response into the sampled domain, i.e. express it as the vector that would come out of an FFT, with the first item = DC, and the last item almost = sampling rate. Make the thing symmetrical around DC and the sampling rate (i.e., pay attention to properly aliasing it).

• Take its inverse FFT

• Truncate the result to your 127 taps, pad it out with zeros, and take its FFT -- see if it still works for you.

• Enjoy, or not.

A "Full consultancy" approach for this filter, as you've specified it, should take me less than an hour to do, and less than two hours overall to put into a document & make it pretty -- assuming that you don't have to come back to me for modifications, clarifications, etc. That's a lot less than a weekend on the Oregon coast, so I don't see what's got you hot & bothered by it.

The yiddish interpretation is somewhat different, but same vein :-)

I would use a optimizing (minimizing program. It wouldn't take long. I am surprized that people don't have these progams already written and posted some play. It wouldn't take much time to do using Scilab.

Peter Nachtwey