[time-nuts] DSP-93 Source For WWV/H

[John C. Westmoreland, P.E.]

Hello Time Nuts,

Indeed Hal!

Wow - thanks!  Good stuff to go over.

And - for those that are new to SDR and I/Q stuff - his docs go over that
pretty well.

73's,
John
AJ6BC


On Mon, Oct 19, 2020 at 3:33 AM Hal Murray <hmurray at megapathdsl.net> wrote:

> > I wonder if anyone has taken this source and done that already.
>
> The NTP package that comes from
>    http://support.ntp.org/bin/view/Main/SoftwareDownloads
> has a driver for WWV/H
>   ntpd/refclock_wwvb.c
>
>  * Audio WWV/H demodulator/decoder
>  *
>  * This driver synchronizes the computer time using data encoded in
>  * radio transmissions from NIST time/frequency stations WWV in Boulder,
>  * CO, and WWVH in Kauai, HI. Transmissions are made continuously on
>  * 2.5, 5, 10 and 15 MHz from WWV and WWVH, and 20 MHz from WWV. An
>  * ordinary AM shortwave receiver can be tuned manually to one of these
>  * frequencies or, in the case of ICOM receivers, the receiver can be
>  * tuned automatically using this program as propagation conditions
>  * change throughout the weasons, both day and night.
>  *
>  * The driver requires an audio codec or sound card with sampling rate 8
>  * kHz and mu-law companding. This is the same standard as used by the
>  * telephone industry and is supported by most hardware and operating
>  * systems, including Solaris, SunOS, FreeBSD, NetBSD and Linux. In this
>  * implementation, only one audio driver and codec can be supported on a
>  * single machine.
>  *
>  * The demodulation and decoding algorithms used in this driver are
>  * based on those developed for the TAPR DSP93 development board and the
>  * TI 320C25 digital signal processor described in: Mills, D.L. A
>  * precision radio clock for WWV transmissions. Electrical Engineering
>  * Report 97-8-1, University of Delaware, August 1997, 25 pp., available
>  * from www.eecis.udel.edu/~mills/reports.html. The algorithms described
>  * in this report have been modified somewhat to improve performance
>  * under weak signal conditions and to provide an automatic station
>  * identification feature.
>  *
>  * The ICOM code is normally compiled in the driver. It isn't used,
>  * unless the mode keyword on the server configuration command specifies
>  * a nonzero ICOM ID select code. The C-IV trace is turned on if the
>  * debug level is greater than one.
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
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