Its a LPF and its not effecting anything. Square waves worked fine actually. But do want to be able to feed an antenna so a bit of filtering plus the loops stick should do the job.
On Wed, Aug 29, 2018 at 9:16 AM, Bob kb8tq <[email protected]> wrote: > HI > > If you are feeding “Time Nuts” gear, a fancy filter on the output of the > WWVB gizmo may be an issue. Temperature impacts the value of the > components and that value change impacts the phase of the signal…. > > Bob > > > On Aug 28, 2018, at 9:33 PM, paul swed <[email protected]> wrote: > > > > LPF filter added 2.2mH choke to a .0022uf cap 1K R pretty simple and > > anttenuators and isolation to drive up to 4 receivers. > > Have not looked at the power amp and loops stick antenna yet. But it > really > > is time for GPS a neo. > > Looking very good. > > > > On Tue, Aug 28, 2018 at 7:29 PM, paul swed <[email protected]> wrote: > > > >> Ed appreciate the details but no intent to generally run a GPSDO in fact > >> the 5 V @ 50 ma is a serious power pig. The chronverter draws 5 ma. > Clearly > >> the TTL is a heater. Chuckle. I do want to drive the chronverter with > GPS > >> as its designed for. > >> Whats pretty interesting is you can adjust its offset. I just jammed > time > >> into it several days and its been fairly good with power ups and down. > Its > >> impressive. Though not in an ultimate time-nuts way. > >> GPS just assures it is accurate. But there is a lot of flexibility. > >> Main goal of this whole project is to replace wwvb if it goes away. If > it > >> does the project doesn't even have to run 24/7. Fire up at 10 pm to 3 am > >> and power down. Thats enough to set my wall clocks for a day. Its just > nice > >> to know it can also set the spectracoms and Truetimes. Icing on the > cake. > >> I am impressed with what Dave did with the 8 pin pic. He has all of the > LF > >> time signals in there. (No wwvb BPSK though) DSTs settings, zone > offsets, > >> half zones, etc. > >> Just looking at low pass filters for the 60 KHz ttl out right now. > Simple > >> LR or RC. Since this particular output feeds coax to the quality > receivers > >> I don't need to be that careful. Its working great without any > filtering. > >> Reality if it draws little power I will let it run 24/7 but then you > just > >> have to stick a display on at that point. > >> Regards > >> Paul > >> > >> On Tue, Aug 28, 2018 at 7:11 PM, ed breya <[email protected]> wrote: > >> > >>> Paul, > >>> If you're going to reference it from a GPSDO anyway, why worry about a > >>> TCXO reference (and power too, for that matter). You can easily make > the 60 > >>> kHz from the 10 MHz. > >>> > >>> For example, with two 74HC390s and a 74HC86 you can make 50 kHz and 10 > >>> kHz and mix them with one EXOR section of the '86 to have 60 kHz > available. > >>> Some fairly simple bandpass filtering should select and clean it up > >>> sufficiently. Two other sections of the '86 can be set up as inverters > and > >>> self-biased as amplifiers - one to convert the 10 MHz sine reference to > >>> logic, and the other from the filter output to logic, if needed. And, > you'd > >>> still have a divide by 5 and an EXOR left over to fool around with. > >>> > >>> The same parts and process can be done at a higher frequency and then > >>> divided down afterward. (5+1) MHz/100, and (500+100) kHz/10 would work > too. > >>> It depends on what frequency you prefer for the BPF. If you go high at > 6 > >>> MHz, you then have the option to make a crystal filter from readily > >>> available parts. > >>> > >>> Going the high way also provides for higher logic frequencies that are > >>> more or less in sync, in case you want to do any I-Q modulation type > stuff > >>> - you can even use synchronous counters instead, to really make sure. > >>> > >>> Overall, I think I'd recommend going at 5+1= 6 MHz, filtering with 6 > MHz > >>> crystals, then dividing down to 60 kHz, with 2f and 4f clocks > available for > >>> I-Q use. I sketched out a quickie circuit that's quite simple and I > think > >>> would do. It would take two HC390s for the dividing, as before. Each > HC390 > >>> is two divide by 10 counters, including a 1/2 and 1/5 in each, usable > >>> separately. So, with two parts, there are four 1/5s and four 1/2s > available. > >>> > >>> Here's a verbal process description: 10 MHz sine convert to logic with > >>> HC86, 10 MHz/2=5, 10 MHz/10=1 with first HC390, add 5+1=6 with EXOR, > BPF 6 > >>> MHz, convert to logic with HC86, 6 Mhz/25=240 kHz=4f, 240/2=120 kHz=2f, > >>> 120/2=60 kHz=f, with second HC390. > >>> > >>> Ed > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> To unsubscribe, go to http://lists.febo.com/mailman/ > >>> listinfo/time-nuts_lists.febo.com > >>> and follow the instructions there. > >>> > >> > >> > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to http://lists.febo.com/mailman/ > listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to http://lists.febo.com/mailman/ > listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
