# A Question on Polyphase Channelizer - PFB block

**URL:** <https://www.ruby-forum.com/t/a-question-on-polyphase-channelizer-pfb-block/228952>\
**Category:** GNU Radio\
**Created:** [May 14, 2013, 7:54am UTC](https://www.ruby-forum.com/t/a-question-on-polyphase-channelizer-pfb-block/228952 "2013-05-14T07:54:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![LD\_Zhang](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/90ced4/32.png) [@LD\_Zhang](https://www.ruby-forum.com/u/LD_Zhang)\
**Post date:** [May 14, 2013, 7:54am UTC](https://www.ruby-forum.com/t/a-question-on-polyphase-channelizer-pfb-block/228952/1 "2013-05-14T07:54:16Z")

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Hi,

I am experimenting with a way to do multi-channel filtering of a  
wideband  
signal to put out multiple narrower bands. The PFB block appears to be  
the  
one that can do it. There is very little documentation on it. Online  
documents indicate this as version gnuradio 3.6.4 C++ API. I am running  
gnuradio 3.6.2. Am I OK running 3.6.2? Do I have to upgrade to 3.6.4?

Thanks,

LD

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<div class="post-metadata">

**Author:** ![LD\_Zhang](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/90ced4/32.png) [@LD\_Zhang](https://www.ruby-forum.com/u/LD_Zhang)\
**Post date:** [May 14, 2013, 6:51pm UTC](https://www.ruby-forum.com/t/a-question-on-polyphase-channelizer-pfb-block/228952/2 "2013-05-14T18:51:36Z")

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On Tue, May 14, 2013 at 6:53 AM, LD Zhang [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Thanks,
> 
> LD

Really? I thought these are among the better-documented blocks:  
[http://gnuradio.org/doc/doxygen/page\_pfb.html](http://gnuradio.org/doc/doxygen/page_pfb.html)

There are also examples of using it:  
gr-filter/examples/channelize.py.  
gr-filter/examples/chirp\_channelize.py.

3.6.2 is fine:

> **[GNU Radio 3.6.2 C++ API: Polyphase Filterbanks](https://www.gnuradio.org/doc/doxygen-3.6.2/page_pfb.html)**

Tom