Hi If you re-tune the Rb, the already divided down output on the pps will be at a really odd rate. You can use it, but unwrapping the phase is going to be "interesting" (= it will wrap a lot).
There are other ways to do things. One is to synthesize a highly accurate 100Hz off of the Rb output. That's going to require some dividers. You also get into the multiple phase wrap issue quicker than with a pps. Bob On Sep 17, 2013, at 9:07 PM, Bob Stewart <[email protected]> wrote: > D'oh! But is there a way I can run for let's say 200 pulses on the B channel > and see the count on the A channel? > > > > > >> ________________________________ >> From: Bob Camp <[email protected]> >> To: Discussion of precise time and frequency measurement >> <[email protected]> >> Sent: Tuesday, September 17, 2013 7:54 PM >> Subject: Re: [time-nuts] My FE-5680A Came In Today >> >> >> Hi >> >> For checking things like GPSDO's the pps is actually much more useful than >> the 10 MHz. Just do the count one to the other trick and you have a very >> good way to test what's going on. In it's normal configuration it should >> tune to within about 1 ppt of the proper frequency. That would be 10,000,000 >> Hz / 1,000,000,000,000 or 1 ns every thousand seconds on the pps. >> >> Bob >> >> On Sep 17, 2013, at 8:37 PM, Bob Stewart <[email protected]> wrote: >> >>> Hi, >>> >>> I'm just looking for an accurate standard for my GSPDO PLL coding. As it >>> is, I've been depending on others who have these to tell me the code works. >>> I understand that when these are retuned to 10MHz, they're .005Hz off due >>> to the DDS. I'm good with that. =) >>> >>> Bob >>> >>> >>> >>> >>> >>>> ________________________________ >>>> From: Bob Camp <[email protected]> >>>> To: Discussion of precise time and frequency measurement >>>> <[email protected]> >>>> Sent: Tuesday, September 17, 2013 7:30 PM >>>> Subject: Re: [time-nuts] My FE-5680A Came In Today >>>> >>>> >>>> Hi >>>> >>>> Keep in mind that these things make a pretty awful 10 MHz standard. They >>>> are spur monsters in a big way. They won't drive your counter nuts, but >>>> for anything that wants signal purity - watch out. >>>> >>>> Bob >>>> >>>> On Sep 17, 2013, at 8:14 PM, Bob Stewart <[email protected]> wrote: >>>> >>>>> Hi Bob, >>>>> >>>>> Yeah, I figured that retuning it would lose the 1PPS. No biggie. There >>>>> are a number of those little connectors in this device, and the two that >>>>> have cables connected use a flat 90 degree connector with a coax that's a >>>>> bit smaller than RG-174. I just want to snap a pigtail on it and lead it >>>>> out through a notch in the cover where the DB-9 connector is. There are >>>>> several examples on the web where people solder wires to the connector >>>>> and to the RS-232 header. I'd just as soon avoid soldering wires if I >>>>> can. >>>>> >>>>> Bob >>>>> >>>>> >>>>> >>>>> >>>>> >>>>>> ________________________________ >>>>>> From: Bob Camp <[email protected]> >>>>>> To: Discussion of precise time and frequency measurement >>>>>> <[email protected]> >>>>>> Sent: Tuesday, September 17, 2013 7:06 PM >>>>>> Subject: Re: [time-nuts] My FE-5680A Came In Today >>>>>> >>>>>> >>>>>> Hi >>>>>> >>>>>> If you retune it, you probably will throw off the pps. The pps drive >>>>>> strength is a bit weak, so you need to be careful looking for it. On >>>>>> some units there is a software command to enable / disable it (as in pps >>>>>> only when warmed up and locked - like a gps). The can / cover on the >>>>>> unit is mu metal (Rb's are mag sensitive). If you drill a hole in it, >>>>>> you are likely to impact it's mag shielding properties. >>>>>> >>>>>> Bob >>>>>> >>>>>> >>>>>> On Sep 17, 2013, at 6:21 PM, Bob Stewart <[email protected]> wrote: >>>>>> >>>>>>> My FE-5680A Rb standard came in today. After the usual inspections >>>>>>> etc, I fired it up and I have the purple haze. The native output is >>>>>>> 8.38860798/9 (last digit jitter) as read on my 5335A using my GPSDO as >>>>>>> an external standard. I've got a ways to go before it's all setup, but >>>>>>> this is looking good. Does it warmup and change frequency at all, or >>>>>>> can I retune it to 10MHz and use it as a reference without any further >>>>>>> ado? >>>>>>> >>>>>>> Can someone tell me what type of socket that is where you tap off the >>>>>>> RF? It looks sort of like a uFL connector, but a bit bigger. I'd >>>>>>> rather avoid hacking and soldering on this if I can. >>>>>>> >>>>>>> Bob - AE6RV >>>>>>> _______________________________________________ >>>>>>> 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. >>>> >>>> _______________________________________________ >>>> 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. >> >> >> > _______________________________________________ > 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.
