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Re: [aprssig] Re: RE: AO16/LO19 Uplink w ANY PC!



I more than agree that this if FAR from simple!  I spent a week trying for
a reasonable hardware answer using only a single Costas loop.  Both the
data stream clock and a single mark frequency was attempted using dual
loops, both unsatisfactory.  The final answer was the use of the 
discriminator output using the same IF as the the SSB demodulator.  With
very careful alignment this worked fairly well.  I welcome any "dead easy"
solutions I've overlooked!  Kaykin and Gardiner are good theoretical
references, but it is hardware that is the final test.   Cliff K7RR

On Mon, 20 Sep 1999, Ghislain RUY wrote:

> Just right,
> that's exactly what Christophe and i have done for the P3D demodulator : a
> costas loop. But, from my experience and extensive tests i made with low
> Eb/N0, the design of the loop filter of the Costas loop is not as dead simple.
> 
> Ghis, F1HDD.
> 
> Laura Halliday a écrit :
> 
> > This is an artifact of the demodulator, not of PSK itself. It's
> > perfectly straightforward to make a PSK demodulator that tracks
> > Doppler automatically. PLLs and Costas Loops are both dead easy
> > to implement in either hardware or software at these bit rates.
> >
> > References: any decent text on communications. I like Haykin (see
> > http://www.qsl.net/vaeldh/reading.html).
> >
> > Laura Halliday VA3LDH   "Que les nuages soient notre pied
> > Grid: FN03gs                a terre..." - Hospital/Shafte
> 
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