discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] multi-rtl phase synchronization


From: jmfriedt
Subject: Re: [Discuss-gnuradio] multi-rtl phase synchronization
Date: Fri, 7 Jul 2017 13:42:21 +0200

> The I/Q plot show complex cross-correlation between two noise signals at
> 100 MHz center frequency (2.4 MHz bandwidth noise). The phase of the signal
> can be converted into time and Allan deviation, but I never did. I was just
> happy to see a straight line.

I continued the measurement this morning after having the temperature of the 
dongles 
stabilized overnight: I gain a factor 10 stability on a 2 hour measurement: 
http://jmfriedt.sequanux.org/3allan.pdf

Actually I just discovered something fascinating: I was contemplating which 
radio
source would be best suited for the passive radar experiment. Not being able to
find any suitable source while scanning the environment with a yagi antenna, I 
decided
to tune to the 143.05 MHz frequency of the GRAVES [1] bistatic emitter which 
happens not to
be too far away. To my great surprise, after replacing the quartz (drifting far 
too much)
with a hydrogen maser referenced synthesized tuned to 28.8 MHz, I get amazing 
doppler
shifted traces of reflectors between the emitter and my receiver. I didn't 
expect
such a low quality receiver to be able to extract this signal: example of a 
waterfall trace
at http://jmfriedt.sequanux.org/graves.pdf

JM

[1] https://en.wikipedia.org/wiki/Graves_%28system%29

-- 
JM Friedt, FEMTO-ST Time & Frequency/SENSeOR, 26 rue de l'Epitaphe,
25000 Besancon, France



reply via email to

[Prev in Thread] Current Thread [Next in Thread]