Reply by robert bristow-johnson July 5, 20102010-07-05
On Jul 5, 1:00&#2013266080;pm, Fred Marshall <fmarshallx@remove_the_xacm.org>
wrote:
> Long ago I wrote a Remez exchange program that accepted a continuous > magnitude response specification rather than the P-M fixed band type of > specification. > > Rather than excluding the transition bands, it included them and this > makes using it a bit trickier. &#2013266080;In that sense P-M is better. &#2013266080;Yet, it's > sometimes nice to be able to specify the magnitude response as other > than a set of flat or straight lines. > > Of course, the two could be combined so that the critical passband > (usually not stopband) shapes could be specified and the transition > bands could be left out. > > Ditto on the weighting functions. > > Does anyone know of a modern program that will allow this type of > specification?
i've used MATLAB's firpm() (formerly remez()) so that the spec (both target and weights) was a sorta large set of little broken lines that could fit a given specified function. it worked good enough for me that i hadn't felt motivated to try to redo firpm() from scratch. wasn't a big deel. r b-j
Reply by Fred Marshall July 5, 20102010-07-05
Long ago I wrote a Remez exchange program that accepted a continuous 
magnitude response specification rather than the P-M fixed band type of 
specification.

Rather than excluding the transition bands, it included them and this 
makes using it a bit trickier.  In that sense P-M is better.  Yet, it's 
sometimes nice to be able to specify the magnitude response as other 
than a set of flat or straight lines.

Of course, the two could be combined so that the critical passband 
(usually not stopband) shapes could be specified and the transition 
bands could be left out.

Ditto on the weighting functions.

Does anyone know of a modern program that will allow this type of 
specification?

Fred