Re: [Discuss-gnuradio] Channelizing

[Tom Rondeau]

On Jun 24, 2011, at 8:22 AM, "Marcus D. Leech" <address@hidden> wrote:

> On 06/24/2011 01:14 AM, Colby Boyer wrote:
>> 
>> 
>> 
>> Hi Marcus,
>> 
>> Check out a pfb channelizer! 
>> 
>> gnuradio-core/src/python/gnuradio/blks2impl/pfb_channelizer.py is a
>> nice python wrapper for the class and gr_pfb_channelizer_ccf is the
>> C++ name.
>> 
>> Also if you need to carve out a a shifted part of the spectrum, use
>> the gr_freq_xlating_fir_filter_*** block.
>> 
>> These are polyphase implementations so they should be computationally
>> efficient. Lastly, if you need even more efficiency you can see if
>> they are doing the fft implementation of filtering (not sure if they
>> are vs standard computation). As you know, there is the difference
>> between NlogN and N^2
>> 
>> --Colby
> Right, so how do I set the filter taps for the PFB channelizer?  Is it
> just a low-pass filter, or something
>  else?
> 
> 
> -- 
> Principal Investigator
> Shirleys Bay Radio Astronomy Consortium
> http://www.sbrac.org

It's a low pass filter where the bandwidth is the width (or less) of the 
channel, W, and the sample rate is that of the input signal, which is WxN for 
the N channels. By default, the channelized will output channels of bandwidth W 
at sample rate W.

Tom