GFSK Demod: Difference between revisions

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[[Category:Block Docs]]
[[Category:Block Docs]]
[[Category:Stub Docs]]
Hierarchical block for Gaussian Frequency Shift Key (GFSK) demodulation.
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.
       
The input is the complex modulated signal at baseband.
       
The output is a stream of bits unpacked, 1 bit per byte (the LSB)


As this is a basic template, it's also in the [[:Category:Stub_Docs|"Stub Docs category"]]. Please improve it.
== Parameters ==
 
; Samples/Symbol
: Samples per baud >= 2 (integer)
 
; Sensitivity
: Given to the [[Quadrature Demod]]
 
; Gain Mu
: Controls rate of mu adjustment
; Mu
: Fractional delay [0.0, 1.0]


== Parameters ==
; Omega Relative Limit
(''R''): <span class="plainlinks">[https://wiki.gnuradio.org/index.php/GNURadioCompanion#Variable_Controls ''Run-time adjustable'']</span>
: Sets max variation in omega (float, typically 0.000200 (200 ppm))
 
; Freq Error
: Bit rate error as a fraction


; Param 1 (''R'')
; Verbose
: 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).
: Print information about modulator?


; Param 2
; Log
: blah blah blah
: Print modualtion data to files? (bool)


== 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.


== Source Files ==
The flowgraph below shows an example of the GFSK Mod and GFSK Demod blocks in action. We GFSK modulate 9-bit long bit stream '000111011', and then GFSK demodulate it. Then we compare the two bit streams to make sure that they are the same.
 
[[File:Gfsk_mod_and_demod.png|800px]]
 
When the flowgraph runs, we see that the red and blue signals are the same, meaning that the bit streams before and after the GFSK modulation and demodulation are the same.
 
In order to replicate the results shown below, make sure you do the following:
# Make sure you have a vector of 9 bits in your vector source. For example, I used (0,0,0,1,1,1,0,1,1) in this example.
# Make sure you turn off the unpack function in the GFSK Mod block. You will need to double click the block to bring up the Properties pop-up in order to turn it off. Turn it off. Then you will see "Unpack: Off" show up on the block after you close its Properties pop-up.


; C++ files
[[File:Gfsk_mod_and_demod_in_action.png|800px]]
: [https://github.com/gnuradio/gnuradio TODO]


; Header files
== Source Files ==
: [https://github.com/gnuradio/gnuradio TODO]


; Public header files
; Python files
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-digital/python/digital/gfsk.py]


; Block definition
; Block definition
: [https://github.com/gnuradio/gnuradio TODO]
: [https://github.com/gnuradio/gnuradio/blob/master/gr-digital/grc/digital_gfsk_demod.block.yml]

Latest revision as of 17:45, 4 April 2022

Hierarchical block for Gaussian Frequency Shift Key (GFSK) demodulation.

The input is the complex modulated signal at baseband.

The output is a stream of bits unpacked, 1 bit per byte (the LSB)

Parameters

Samples/Symbol
Samples per baud >= 2 (integer)
Sensitivity
Given to the Quadrature Demod
Gain Mu
Controls rate of mu adjustment
Mu
Fractional delay [0.0, 1.0]
Omega Relative Limit
Sets max variation in omega (float, typically 0.000200 (200 ppm))
Freq Error
Bit rate error as a fraction
Verbose
Print information about modulator?
Log
Print modualtion data to files? (bool)

Example Flowgraph

The flowgraph below shows an example of the GFSK Mod and GFSK Demod blocks in action. We GFSK modulate 9-bit long bit stream '000111011', and then GFSK demodulate it. Then we compare the two bit streams to make sure that they are the same.

Gfsk mod and demod.png

When the flowgraph runs, we see that the red and blue signals are the same, meaning that the bit streams before and after the GFSK modulation and demodulation are the same.

In order to replicate the results shown below, make sure you do the following:

  1. Make sure you have a vector of 9 bits in your vector source. For example, I used (0,0,0,1,1,1,0,1,1) in this example.
  2. Make sure you turn off the unpack function in the GFSK Mod block. You will need to double click the block to bring up the Properties pop-up in order to turn it off. Turn it off. Then you will see "Unpack: Off" show up on the block after you close its Properties pop-up.

Gfsk mod and demod in action.png

Source Files

Python files
[1]
Block definition
[2]
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