Re: [Discuss-gnuradio] IQ changing with restart

[Marcus D. Leech]

On 02/11/2014 11:57 AM, Martin Braun wrote:
> On 11.02.2014 06:19, Sylvain Munaut wrote:
> > Hi,
> >
> > > I've done my homework on this one, crawled through the web & talked to
> > > colleagues. If I am missing something obvious please point it out - 
> > > it's not
> > > for lack of effort on my part!
> >
> > I'm not really sure what you're expecting. Of course the phase
> > alignement between the Tx and Rx is going to be random depending on
> > restart.
> >
> > Using the same clock will prevent it from drifting, but the initial
> > phase alignement is random. This is usually resolved by using training
> > sequence, headers, differential encoding, ...
>
> I had the same thought -- it looks like a phase change. This is a PSK 
> signal, right? Have you looked at the constellation diagram?
>
> MB
>
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Neither synthesizer will start with any particular phase offset, either.



--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org