Decimating FIR Filter: Difference between revisions

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[[Category:Block Docs]]
[[Category:Stub Docs]]
This is GNU Radio's "normal" FIR Filter.   
This is the template for the [[:Category:Block_Docs|"Page-per-block Docs"]].  This first section should describe what the block does and how to use it, using however many paragraphs necessary.  Note that the title of the wiki page should match the block's name in GRC, i.e. the one defined in the block's .grc file.  Look at the [[FFT]] Block for a good example.


As this is a basic template, it's also in the [[:Category:Stub_Docs|"Stub Docs category"]]. Please improve it.
For a large number of taps, consider using an [[FFT Filter]], see [http://www.trondeau.com/blog/2014/2/27/to-use-or-not-to-use-fft-filters.html]
 
For standard filters such as lowpass, highpass, bandpass, etc., the filter.firdes and filter.optfir classes provide convenient generating methods.


== Parameters ==
== Parameters ==
(''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span>
(''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span>


; Param 1 (''R'')
; Decimation
: Description of parameter, provide any tips or recommended values.  Note that the name of the parameter above should match the param's label that shows up in grc (e.g. Sample Rate).
: Decimation rate.  The output stream will have this decimation applied to it.  A decimation rate of 1 simply means no decimation.  If decimation is set higher than 1, make sure the filter will remove energy outside of the "output region", i.e. -Fs/2 to Fs/2 where Fs is the input sample rate divided by the decimation rate.
 
; Taps (''R'')
: Taps to use in FIR filter.


; Param 2
; Sample Delay
: blah blah blah
: Additional samples to delay by, default is 0 or no delay.


== Example Flowgraph ==
== Example Flowgraph ==


Insert description of flowgraph here, then show a screenshot of the flowgraph and the output if there is an interesting GUI.  Currently we have no standard method of uploading the actual flowgraph to the wiki or git repo, unfortunately. The plan is to have an example flowgraph showing how the block might be used, for every block, and the flowgraphs will live in the git repo.
This flowgraph implements a Broadcast FM stereo receiver using basic blocks.
 
[[File:USRP_FM_stereo_fg.png|644px]]


== Source Files ==
== Source Files ==


; C++ files
; C++ files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/main/gr-filter/lib/fir_filter.cc fir_filter.cc]
 
; Header files
: [https://github.com/gnuradio/gnuradio TODO]


; Public header files
; Public header files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/main/gr-filter/include/gnuradio/filter/fir_filter.h fir_filter.h]


; Block definition
; Block definition
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/main/gr-filter/grc/filter_fir_filter_xxx.block.yml filter_fir_filter_xxx.block.yml]

Latest revision as of 15:21, 27 October 2023

This is GNU Radio's "normal" FIR Filter.

For a large number of taps, consider using an FFT Filter, see [1]

For standard filters such as lowpass, highpass, bandpass, etc., the filter.firdes and filter.optfir classes provide convenient generating methods.

Parameters

(R): Run-time adjustable

Decimation
Decimation rate. The output stream will have this decimation applied to it. A decimation rate of 1 simply means no decimation. If decimation is set higher than 1, make sure the filter will remove energy outside of the "output region", i.e. -Fs/2 to Fs/2 where Fs is the input sample rate divided by the decimation rate.
Taps (R)
Taps to use in FIR filter.
Sample Delay
Additional samples to delay by, default is 0 or no delay.

Example Flowgraph

This flowgraph implements a Broadcast FM stereo receiver using basic blocks.

USRP FM stereo fg.png

Source Files

C++ files
fir_filter.cc
Public header files
fir_filter.h
Block definition
filter_fir_filter_xxx.block.yml
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