Difference between revisions of "GFSK Mod"

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(Make it clearer how to replicate the results on the flowgraph)
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: Print modulation data to files?
: Print modulation data to files?

; Unpack
; Unpack (depreciated in GNU Radio 3.8)
: Unpack input byte stream?
: Unpack input byte stream?

Revision as of 07:43, 21 December 2021

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

The input is a byte stream (unsigned char) and the output is the complex modulated signal at baseband.


Samples per baud >= 2 (integer)
Given to the Frequency Mod
Gaussian filter bandwidth * symbol time (float)
Print information about modulator?
Print modulation data to files?
Unpack (depreciated in GNU Radio 3.8)
Unpack input byte stream?

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
Block definition