Difference between revisions of "DC Blocker"

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A computationally efficient controllable DC blocker that blocks the DC component of a signal. This can be useful when working with AM signals, as taking the magnitude of the envelope will always be positive and thus introduce a DC bias on the signal.  
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.
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This block implements a computationally efficient DC blocker that produces a tighter notch filter around DC for a smaller group delay than an equivalent FIR filter or using a single pole IIR filter (though the IIR filter is computationally cheaper).
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The block defaults to using a delay line of length 32 and the long form of the filter. Optionally, the delay line length can be changed to alter the width of the DC notch (longer lines will decrease the width).
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The long form of the filter produces a nearly flat response outside of the notch but at the cost of a group delay of 2D-2.
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The short form of the filter does not have as flat a response in the passband but has a group delay of only D-1 and is cheaper to compute.
  
 
== Parameters ==
 
== Parameters ==
(''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span>
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; Length
 
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: Specifies the length of the delay line used for determining the DC level. Only applicable to the long form.
; Param 1 (''R'')
 
: 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).
 
  
; Param 2
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; Long Form
: blah blah blah
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: When set to True, use the long form DC blocker, with delay line. When set to False, use the short form (faster).
  
 
== Example Flowgraph ==
 
== Example Flowgraph ==

Latest revision as of 04:12, 20 July 2019

A computationally efficient controllable DC blocker that blocks the DC component of a signal. This can be useful when working with AM signals, as taking the magnitude of the envelope will always be positive and thus introduce a DC bias on the signal.

This block implements a computationally efficient DC blocker that produces a tighter notch filter around DC for a smaller group delay than an equivalent FIR filter or using a single pole IIR filter (though the IIR filter is computationally cheaper).

The block defaults to using a delay line of length 32 and the long form of the filter. Optionally, the delay line length can be changed to alter the width of the DC notch (longer lines will decrease the width).

The long form of the filter produces a nearly flat response outside of the notch but at the cost of a group delay of 2D-2.

The short form of the filter does not have as flat a response in the passband but has a group delay of only D-1 and is cheaper to compute.

Parameters[edit]

Length
Specifies the length of the delay line used for determining the DC level. Only applicable to the long form.
Long Form
When set to True, use the long form DC blocker, with delay line. When set to False, use the short form (faster).

Example Flowgraph[edit]

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.

Source Files[edit]

C++ files
TODO
Header files
TODO
Public header files
TODO
Block definition
TODO