Wellll as they say. I am most likely going to use a simple phase flipper. That preserves all of the Nist stuff and traceability and such. A flipper is simply a invert or non inverted signal and a switch. It is subject to propagation. But no more so than the original receivers. The remodulator gets rid of the carrier for time clocks. Both are actually reasonable to implement. Enough said other things to do. Paul
On Mon, Jun 17, 2013 at 9:29 PM, David I. Emery <d...@dieconsulting.com>wrote: > On Mon, Jun 17, 2013 at 06:11:15PM -0400, Bob Camp wrote: > > Hi > > > > > The Costas loop already has the AM component available. There's no > > need for a second receiver, just wire the AM output over to the output > > modulator. > > That is standard for most Costas loops with an I arm... haven't > looked at his schematics carefully yet... possibly one might need some > kind of AGC to use it as input to a second double balanced mixer > serving as modulator in order to get the right 14 (?) db AM as signal > fades slowly. Not sure how deep the diurnal fades are... > > But I guess if everything is quite linear over enough of a range > one could perhaps just remodulate without AGC and create a replica of > both the modulation and fades on the local 60 KHz carrier. > > > > > > > > Bob > > > > On Jun 17, 2013, at 5:57 PM, "David I. Emery" <d...@dieconsulting.com> > wrote: > > > > > On Mon, Jun 17, 2013 at 02:41:13PM -0700, Burt I. Weiner wrote: > > >> Chris, > > >> > > >> The 8170 was originally intended to be a frequency reference source > > >> tied to the USFS (United Stated Frequency Standard). It also gave > > >> the time of day, but I believe that wasn't it's primary purpose. As > > >> I recall, there were some versions that did not have the clock > > >> readout and some that had a chart recorder. Back in the 80's I used > > >> to drool (it was a disgusting sight!) over the Spectracom receivers > > >> with the chart recorders. At that time I was usuing a Gertsch RLF-1 > > >> with an external Moseley 680 chart recorder. The remodulator > > >> precludes it from being used as a frequency standard, but in my > > >> opinion, so does the fact that WWVB is now phase shifted a bunch. > > >> > > >> The 8170 uses a coherent detector and that's where the problem > > >> lies. While the 8170 still locks to the WWVB carrier, the new BPSK > > >> scheme causes the detector to output bad data in spite of the > > >> original dips in the carrier still being present. I had always > > >> wondered how it was able to pull the data out the noise, but never > > >> had a manual until just recently. I had naively assumed that the > > >> WWVB new BPSK scheme would not affect the time of day aspect of the > > >> 8170. Like I said, I only use it as a clock in my shoppe, and being > > >> an old dog I don't easily learn new tricks such as looking in a > > >> different direction for one of the other clocks. > > > > > > I suppose I am stating the obvious, but why not combine Paul > > > Swed's Costas loop and this scheme to output a phase locked 60 Khz > > > with the right AM modulation ? > > > > > > > > > > > > -- > > > Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, > Mass 02493 > > > "An empty zombie mind with a forlorn barely readable weatherbeaten > > > 'For Rent' sign still vainly flapping outside on the weed encrusted > pole - in > > > celebration of what could have been, but wasn't and is not to be now > either." > > > > > > _______________________________________________ > > > time-nuts mailing list -- time-nuts@febo.com > > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > -- > Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, > Mass 02493 > "An empty zombie mind with a forlorn barely readable weatherbeaten > 'For Rent' sign still vainly flapping outside on the weed encrusted pole - > in > celebration of what could have been, but wasn't and is not to be now > either." > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
