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From: Pete Fraser on 1 Jul 2010 13:02
"Fred Marshall" <fmarshallx(a)remove_the_xacm.org> wrote in message
> Hi Pete! How have you been?
I'm doing well thanks.
Working on a couple of interesting projects.
> Well, I looked into it a bit and found that I'm pretty far removed from
> the filter design toolbox / notation, etc.
> What have you done so far? any code samples?
> What were the results?
> Maybe that will get me going further.
I think I'll just do it the brute force way (using Matlab),
then post the code I used.
Hopefully then folks can tell me how I _should_ have done it.
From: Pete Fraser on 1 Jul 2010 13:23
"Vladimir Vassilevsky" <nospam(a)nowhere.com> wrote in message
> Check the FDLS method of Greg Berchin. That is one of the most elegant
> methods of designing to a prototype.
That looks like a very useful tool.
I'll play with the code this morning.
I'm still curious about freqsamp though.
WhereGreg talks about the pseudoinverse, I had intended
to give Matlab the exact number of points to correctly
determine the inverse. Obviously I can do this with an explicit
matrix inversion, but had assumed that freqsamp was intended
to do that. Did I just assume wrong, or am I using it incorrectly?
From: Steve Pope on 1 Jul 2010 13:42
Pete Fraser <pfraser(a)covad.net> wrote:
>I'm still curious about freqsamp though.
Near as I can tell there is not sufficient information in the
matlab documentation to state exactly (or perhaps, even generally)
what they are doing here.
If you're lucky someone from Mathworks will see your question
and answer it for you. I believe you can also ask this on the Mathworks
site, after registering.
From: Pete Fraser on 1 Jul 2010 14:05
"Steve Pope" <spope33(a)speedymail.org> wrote in message
> Near as I can tell there is not sufficient information in the
> matlab documentation to state exactly (or perhaps, even generally)
> what they are doing here.
I thought perhaps I was looking in the wrong area.
The Mathworks help is a model of clarity, with lots of
well-thought-out examples, but when I try to dig a
little deeper I come up short.
> If you're lucky someone from Mathworks will see your question
> and answer it for you. I believe you can also ask this on the Mathworks
> site, after registering.
I'll try that. Thanks.
From: gretzteam on 2 Jul 2010 15:33
>Pete Fraser wrote:
>> "Vladimir Vassilevsky" <nospam(a)nowhere.com> wrote in message
>>>But why would anyone want to emulate Butterworth magnitude response in a
>>>linear phase FIR filter whereas it is very straightforward to do the
>>>(**exact) Butterworth as IIR filter?
>> Butterworth will be one of several possible responses
>> from the same hardware.
>> I'd rather not deal with Butterworth's phase issues.
Maybe this could help:
In the 'Z plane design' option, you pretty much can give it your desired
magnitude response and press 'search'...
At the very least, it's quite interesting to look at the genetic algorithm