Power Squelch: Difference between revisions

Latest revision as of 10:23, 14 March 2022

This will either pass the input unchanged, or block it, depending on whether its envelope is over a certain threshold. The envelope is calculated by taking the squared magnitude of the signal and lowpassing it with a single pole IIR filter (with the specified alpha).

The ramp parameter specifies the attack / release time, in samples. A sinusodial ramp is used to progressively mute / unmute the input. If ramp is set to 0, input is muted / unmuted without a ramp.

For realtime applications you'll want to set the gate parameter to false, which produces zeros when the input is muted. If it is true, the block will stop producing samples when in muted state.

The block will emit a tag with the key "squelch_sob" with the value of PMT_NIL on the first item it passes, and with the key "squelch_eob" on the last item it passes.

Parameters

(R): Run-time adjustable

Threshold (R): Threshold (in dB) for power squelch

Alpha (R): Gain of averaging filter. Defaults to 0.0001.

Ramp: Attack/release time in samples; a sinusodial ramp is used. Set to 0 to disable.

Gate: If true, no output if no squelch tone. if false, output 0's if no squelch tone.

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.

Source Files

C++ files: Float Input; Complex Input; Base squelch class, Float Input; Base squelch class, Complex Input

Header files: Float Input; Complex Input; Base squelch class, Float Input; Base squelch class, Complex Input

Public header files: Float Input; Complex Input; Base squelch class, Float Input; Base squelch class, Complex Input

Block definition: Yaml

@@ Line 1: / Line 1: @@
 [[Category:Block Docs]]
-[[Category:Stub Docs]]
+This will either pass the input unchanged, or block it, depending on whether its envelope is over a certain threshold. The envelope is calculated by taking the squared magnitude of the signal and lowpassing it with a single pole IIR filter (with the specified alpha).
-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.
+The ramp parameter specifies the attack / release time, in samples.  A sinusodial ramp is used to progressively mute / unmute the input.  If ramp is set to 0, input is muted / unmuted without a ramp.
+For realtime applications you'll want to set the gate parameter to false, which produces zeros when the input is muted. If it is true, the block will stop producing samples when in muted state.
+The block will emit a tag with the key "squelch_sob" with the value of PMT_NIL on the first item it passes, and with the key "squelch_eob" on the last item it passes.
 == Parameters ==
 (''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span>
-; Param 1 (''R'')
+; Threshold (''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).
+: Threshold (in dB) for power squelch
+; Alpha (''R'')
+: Gain of averaging filter. Defaults to 0.0001.
+; Ramp
+: Attack/release time in samples; a sinusodial ramp is used. Set to 0 to disable.
-; Param 2
+; Gate
-: blah blah blah
+: If true, no output if no squelch tone. if false, output 0's if no squelch tone.
 == Example Flowgraph ==
@@ Line 21: / Line 30: @@
 ; C++ files
-: [https://github.com/gnuradio/gnuradio TODO]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/lib/pwr_squelch_ff_impl.cc Float Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/lib/pwr_squelch_cc_impl.cc Complex Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/lib/squelch_base_ff_impl.cc Base squelch class, Float Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/lib/squelch_base_cc_impl.cc Base squelch class, Complex Input]
 ; Header files
-: [https://github.com/gnuradio/gnuradio TODO]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/lib/pwr_squelch_ff_impl.h Float Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/lib/pwr_squelch_cc_impl.h Complex Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/lib/squelch_base_ff_impl.h Base squelch class, Float Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/lib/squelch_base_cc_impl.h Base squelch class, Complex Input]
 ; Public header files
-: [https://github.com/gnuradio/gnuradio TODO]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/include/gnuradio/analog/pwr_squelch_ff.h Float Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/include/gnuradio/analog/pwr_squelch_cc.h Complex Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/include/gnuradio/analog/squelch_base_ff.h Base squelch class, Float Input]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/include/gnuradio/analog/squelch_base_cc.h Base squelch class, Complex Input]
 ; Block definition
-: [https://github.com/gnuradio/gnuradio TODO]
+: [https://github.com/gnuradio/gnuradio/blob/main/gr-analog/grc/analog_pwr_squelch_xx.block.yml Yaml]

Power Squelch: Difference between revisions

Latest revision as of 10:23, 14 March 2022

Parameters

Example Flowgraph

Source Files

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