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 <hmur...@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. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.