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Re: [Discuss-gnuradio] raised cosine filter taps implementation


From: Nowlan, Sean
Subject: Re: [Discuss-gnuradio] raised cosine filter taps implementation
Date: Sun, 20 Nov 2011 22:53:53 +0000

Yes, perhaps gr_cpm belongs in gr-digital. Still, there are modulators 
implemented in C++ (gmskmod, cpmmod, etc.) in gr-digital that aren't even being 
used in the benchmark_tx/rx programs. It looks like the filters taps are 
generated either by gr_firdes or using calls to numpy. Is there a reason the 
C++ classes were not used?

Thanks,
Sean

-----Original Message-----
From: address@hidden [mailto:address@hidden On Behalf Of Martin Braun
Sent: Thursday, November 17, 2011 3:50 AM
To: address@hidden
Subject: Re: [Discuss-gnuradio] raised cosine filter taps implementation

On Wed, Nov 16, 2011 at 10:07:23PM +0000, Nowlan, Sean wrote:
> More in general, is there a reason why the CPM modulator in the gr-digital 
> package generates its own filter taps instead of using the functions in 
> gr_cpm?

All of the modulators from digital_cpmmod_bc use the taps from gr_cpm, so 
that's fine--however, you could argue that gr_cpm belongs into gr-digital.

> Also, it seems that gr_cpm has other filters implemented through the 
> phase_response function that belong in gr_firdes (which I assume stands for 
> FIR design).

Personally, I would not like to see that happen. firdes already has a lot of 
stuff which could be somewhere else (like window functions, which have other 
uses than filter design) and the CPM phase response taps are really specific 
and belong close to the appropriate modulator.

MB
--
Karlsruhe Institute of Technology (KIT)
Communications Engineering Lab (CEL)

Dipl.-Ing. Martin Braun
Research Associate

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Building 05.01
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Phone: +49 721 608-43790
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