Re: [Discuss-gnuradio] FIR filter 'filterN' method

[Johnathan Corgan]

Johnathan Corgan wrote:

> It does mean that I can't do a generic "adaptive_fir" class that can be
> subclassed and specialized into classes like cma_equalizer,
> noise_reduction, etc.  Instead each one will end up being unique.  I
> guess that's the price you pay for speed.

Well, I've gone back to the original idea of a base class for an
adaptive fir filter with a derived class overriding the error and tap
update methods to create a particular type of adaptive filter. This has
been checked in.

The adaptive FIR class is complete but unoptimized.  Instead of using an
existing gr_fir_xx class, it internally implements a generic dot product
for the FIR output calculation.  It presently is only implemented for
_ccf signature but it would be possible to make it into a template.

I've created a constant modulus filter skeleton with null error and tap
update methods. The default taps start with 1.0 and the remainder are
zeros so the output is identical to the input.

I'll be working on the CMA class tomorrow. Depending on speed it may
make sense to eliminate the base class, but I'm hoping not to have to.

-Johnathan, AE6HO