> John > Like your thought. I seem to remember costas loops work like that to > recover the carrier.
Paul, It recovers a bipolar signal to steer the local VCO as well as the data.. It also needs a quadratue hybrid at the VCO frequency (although it might be fairly easy to make a quadrature oscillator vat 60 kHz.) > Had seen it in amsat many years ago. So perhaps an approach is to limit > if possible the incoming signal. I'm not sure if it works properly with clipped (digital) dignals, off hand. > Though further simple dumb thought. A NE602 or SA602 or also teh 612 > series. All the same mixer circuit (Or multiplier)will double the incoming > frequency if you delay the incoming by 90 degrees I think. Sine and Cosine are orthogonal. You need to do (Sine)*(Sine) sin^2 (wt) = 1/2(1 - cos (2wt) >Its a sensitive chip and has a 17 db conversion gain and is $2.40 at > digikey. 8 pin dip. though what ever the delay at 60KC thats a long delay. ;-) The delay (phase shift) is not needed. Best, -John ============= > Regards > Paul > > On Wed, Mar 14, 2012 at 10:12 PM, David I. Emery > <[email protected]>wrote: > >> On Wed, Mar 14, 2012 at 05:13:47PM -0700, J. Forster wrote: >> > Now it looks like they are going to kill WWVB, which is a bit more >> > involved, but works. >> > >> > GPS is not an option without a tall tower. >> >> Everything you say up to this makes perfect sense, but what >> makes >> you think GPS timing fails to work with less than a tall tower ? >> >> I believe it is readily possible to get to the 10-30 ns of >> UTC/TAI TOD area with just reasonable sky view, not 100% as implied by a >> tower. And certainly 1E-11 or 1E-12 frequency accuracy is also readily >> available with less than perfect sky view depending on your taus... >> >> Perhaps ultimate performance requires really unobstructed sky >> view >> in order to absolutely minimize multipath but then you are probably >> talking 1E-13 or better... >> >> >> > This is NOT progress, IMO. >> >> Virtually ANY GPS timing solution ought to easily get you inside >> of >> a couple of microseconds of UTC/TAI, I am pretty sure it is quite >> difficult >> to get within 10-100 us with the current AM modulation of WWVB, possibly >> even 1-10 ms is difficult. And anything close to this requires >> accurate >> knowledge of geographic position and 60 KHz propagation corrections. >> >> I'm not clear how accurately one can resolve the phase transition >> in the new scheme, but I suspect probably unambiguously to 1 cycle of >> the 60 KHz... and from there is merely a function of how accurately one >> can resolve the phase of the 60 KHz. This potentially can supply a >> much higher resolution time hack than the AM envelope. >> >> The real question being how important is preserving backward >> compatibility with antique equipment versus better performance... >> >> I agree that ALWAYS is a trade off... >> >> >> > >> > -John >> > >> > ============== >> > >> > >> > > Hi John: >> > > >> > > They are going to maintain the existing AM modulation format so all >> the >> > > WWVB "Atomic Clocks" will still work. The phase >> > > modulation is added on top of that. >> > > >> > > Yes, I expect my HP 117 may no longer work, but I'd much rather have >> the >> > > improved s/n and timing accuracy. >> > > >> > > Have Fun, >> > > >> > > Brooke Clarke >> > > http://www.PRC68.com >> > > http://www.end2partygovernment.com/Brooke4Congress.html >> > > >> > > >> > > J. Forster wrote: >> > >> All very nice, but if this change renders all existing receivers >> > >> useless. >> > >> How does that improve things? >> > >> >> > >> All it does is wipe out all the existing phase tracking >> infrastructure. >> > >> >> > >> The only benefit is to the government who can reuse the WWVB >> transmitter >> > >> and frequency allocation. Everybody else will have to buy new >> stuff. >> > >> >> > >> Sounds a lot like HDTV fiasco. Making jobs (in China or Korea) by >> making >> > >> scrap. >> > >> >> > >> YMMV, >> > >> >> > >> -John >> > >> >> > >> ============== >> > >> >> > >> >> > >>> Dear Time-Nuts, >> > >>> >> > >>> >> > >>>> I sure would like a WWVB BPSK receiver for the new modulation. >> (..) >> > >>>> >> > >>>> I'm sure in time there will be plenty of low cost ICs designed to >> > >>>> receive the >> > >> [SNIP} >> > >> >> > >> >> > >> _______________________________________________ >> > >> time-nuts mailing list -- [email protected] >> > >> To unsubscribe, go to >> > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > >> and follow the instructions there. >> > >> >> > >> >> > > >> > > >> > >> > >> > >> > _______________________________________________ >> > time-nuts mailing list -- [email protected] >> > To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> > and follow the instructions there. >> >> -- >> Dave Emery N1PRE/AE, [email protected] 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 -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
