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RE: [Discuss-gnuradio] Demo Audio Code
From: |
Joseph DiVerdi |
Subject: |
RE: [Discuss-gnuradio] Demo Audio Code |
Date: |
Wed, 5 Mar 2003 12:35:19 -0700 |
At 10:35 AM -0800 3/5/03, Ettus, Matt wrote:
>> http://xtrsystems.com/vlf/image/wwvb_xy - WWVB real and
>> imaginary channels plotted against each other (my personal favorite)
>
>
>My favorite too! All you need is a good pll, and you can get those cool
>looking circles to look like some not-as-cool-looking-but-way-more-useful
>dots. Then you could just use a simple data slicer to get the data, and the
>PLL frequency would give you your frequency info.
>
>See src/gnu/lib/dtv/GrAtscFPLL.[cc,h] for some sample code. You might even
>be able to use it as is. It was developed for an 8-PAM system, but will
>perform even better for an ASK system since the signal is unipolar. You may
>need to tweak the gains.
>
>Matt
Dear Matt,
Thanks for the code tip. I will look into it but not for WWVB. There is not
phase/frequency modulation on WWVB only the two-level ASK. (So admittedly there
would be two dots.) The timing of the levels carries a binary time code. The
carrier frequency can also be used as a potentially very accurate
phase/frequency reference with the customary limitations on atmospheric
propagation. For my location (only a few miles from the transmitter) it is very
good.
Soon, I hope to be generating such data using only gnu-radio tools and goodies.
Best regards,
Joseph
--
Joseph A. DiVerdi, Ph.D., M.B.A.
http://diverditech.com/ 970.980.5868 (voice)
http://xtrsystems.com/ 970.224.3723 (fax)
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