# Re: doppler correction

**URL:** <https://www.ruby-forum.com/t/re-doppler-correction/233294>\
**Category:** GNU Radio\
**Created:** [December 2, 2014, 9:01am UTC](https://www.ruby-forum.com/t/re-doppler-correction/233294 "2014-12-02T09:01:56Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [December 2, 2014, 9:01am UTC](https://www.ruby-forum.com/t/re-doppler-correction/233294/1 "2014-12-02T09:01:56Z")

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Maria,

You can’t readily do it that way. The demodulator works at baseband,  
opening  
it up to that extent, unless you have a very wideband signal, wouldn’t  
work.  
My solution is to use the frequency translating FIR filter block to  
shift  
your received frequency to baseband. I am doing this at VHF where I only  
need to cope with ±3kHz. You can get Doppler information from a  
prediction  
program. I use predict which has a server mode and can be communicated  
with  
using UDP. I wrote a block as I had other things to do, but if you just  
want  
Doppler I think you can do it relatively easily with UDP, or by running  
another process to call the gnuradio script via XMLRPC.

Mike

Maria Hg (vnisnvoeoi [https://www.ruby-forum.com/user/show/vnisnvoeoi](https://www.ruby-forum.com/user/show/vnisnvoeoi) )

on 2014-11-29 18:44

Hello,

I’m using GNU Radio companion to try to receive a satellite signal in S

band.

As I have read with a doppler shift will be around ~60kHz. This will

affect both the carrier frequency as well as the baseband signal.

I’m trying to set the parameters of the PSK demod (Frequency BW, time

BW, phase BW) to correct the doppler. Right know they are set to 62.8m.

I have been trying to find information about how to configurate this

parameters but I can’t find information anywhere.

Thank you