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pico-tracker/sim/si_fir_filter
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Richard Meadows 5aea2ccd50 Improved RSID with new si filter profile, leave some time for si startup 2015-07-11 20:07:30 +01:00
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README.md New notebook for si_fir_filter 2015-04-02 19:50:42 +01:00
si_fir_filter.ipynb Fixed APRS pre-emphasis using custom FIR filter. Not sure on the deviation yet but it looks good in audacity 2015-06-26 01:37:26 +01:00
si_fir_filter_rsid.ipynb Improved RSID with new si filter profile, leave some time for si startup 2015-07-11 20:07:30 +01:00

README.md

Design of the Si TX Spectral Shaping Filter

The SI contains a 17-tap digital FIR filter for use in GFSK modes.

We use this in aprs mode to filter the gpio squarewave into a sensible afsk signal.

There's some notes in a ipython notebook si_fir_filter.ipynp on this. This notebook is also used to calculate the deviation values.

Prerequisites

sudo apt-get install ipython libblas-dev liblapack-dev gfortran
pip install scipy matplotlib

Yes you need a fortran compiler!!!

Python Usage

ipython notebook

Calcuating new coefficients

There's an awesome calculator here here

So

The python script is from here