Hi Markus and group,
Thank-you very much for the progress report and critique of the many
2200m photons that have been eminating from my back yard over the past
week.
The AD9851 is clocked by a DOCXO that's calibrated against WWV to within
0.1 Hz. Initially, there were rounding errors and an error due to the
resolution (~0.01 Hz). The former was eliminated using higher precision
arithmetic the latter by setting the dds to 16x and dividing the
output enroute to keyer the Decca. It isn't anything fancy or exotic and
perhaps a just bit of good luck.
So it seems the photons are now last reasonably stable, accurate,
monochromatic and exhibit phase coherence. The next steps are to
make them frequency agile (137.555 kHz) and to key them in a manner
that preserves these properties. Perhaps I can code the OP32 directly
in the microprocessor? How long would the minumim message be or would
I be better off using a computer to take care of the keying?
73 to all
Joe VO1NA
On Tue, 18 Jun 2013, Markus Vester wrote:
Hi Joe,
it looks like you've moved your QRG to an exact integer Hz a couple of nights
ago. Just curious how you managed to circumvent the 2^-32 DDS clock raster -
did you just tweak the reference frequency, or employ some sophisticated
fractional-N frequency toggling scheme?
And how about serving some freshly cooked, perfectly coherent Opera-32 to the
world tonight? The famous international reception commitee is awaiting your
signal ;-)
Best 73,
Markus (DF6NM)
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