Hi A splitter with a phase error of < 1 degree at exactly 10 MHz is pretty simple to build. It’s mostly a matter of how much you want to spend on the splitter. Network analyzers can be calibrated to measure it. You can poke at a part to get it “right”. The same thing is true on phase shifters. As you add up mismatch errors things get a bit weird, but it’s a single frequency not broadband. This is the old HP buying parts for a calibrator. Who knows what the budget was, or how much thought went into it.
Bob > On Jul 9, 2017, at 12:41 AM, Orin Eman <orin.e...@gmail.com> wrote: > > FWIW, the "Theory" section here may help: > > http://www.g8wrb.org/data///HP/Better_than_100_ps_Accuracy_in_HP_5370B_Time_Interval_Measurements_Through_Bias_Error_Reduction.pdf > > Phase errors through the splitters seem to be taken into account. > > The J06-59992A manual merely claims 100ps absolute accuracy is possible > with the 5370A/B. > > > > On Sat, Jul 8, 2017 at 7:48 PM, Bob kb8tq <kb...@n1k.org> wrote: > >> Hi >> >> Based on a quick read of the use of the device, they seem to be relying on >> it to be << 100 ps >> off from “ideal”. How much it being non-ideal matters …. not clear. If >> you are correcting for various errors >> and eliminating both unknown source errors and destination errors it >> likely gets messy. >> >> Bob >> >>> On Jul 8, 2017, at 9:14 PM, Tom Van Baak <t...@leapsecond.com> wrote: >>> >>> I knew we had talked about this before: >>> https://www.febo.com/pipermail/time-nuts/2006-August/021649.html >>> >>> The J06-59992A manual, schematic, app note, and patent are here: >>> http://rubidium.dyndns.org/~magnus/instruments/hp/J06-59992A/ >>> >>> It was designed for the hp 5370 (20 ps) so perhaps the tolerances are >> less stringent if only used for hp 53132 (150 ps). Maybe one of you RF guys >> can tell from the schematic? >>> >>> Mark writes: >>>> Yes, they do show up... but usually for big-ish bucks. I want to >> build a small affordable replacement that anybody with a 531xx can have. >>> >>> I don't recall them being expensive at all, just unusual. But making a >> modern one for time nuts is a great idea -- both 5370 and 53131/53132 >> users. Also, when someone gets around to creating a smart analog front-end >> to John's TAPR TICC board, your 59992A clone will come in handy. >>> >>> Note also this recent document by Bill Riley: >>> >>> http://www.stable32.com/A%20High-Resolution%20Time% >> 20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and% >> 20TICC%20Modules.pdf >>> >>> Hal writes: >>>> What does "good" mean? >>>> I'd expect the variations due to power or temperature would be easy to >> measure. >>>> Delay through classic CMOS is linear with absolute temperature and >> inverse linear with supply voltage. >>> >>> When John created the TAPR TADD-2-mini board I tested the jitter using a >> TimePod (integrated phase noise mode). I'm looking for the web page or >> email now, but I recall it was under 2 ps. This is partly due to the fact >> that the PIC 12F is a fully synchronous MCU; no tricks with double clock >> edges or PLL's. >>> >>> /tvb >>> >>> >>> ----- Original Message ----- >>> From: "Bruce Griffiths" <bruce.griffi...@xtra.co.nz> >>> To: "Mark Sims" <hol...@hotmail.com>; "Discussion of precise time and >> frequency measurement" <time-nuts@febo.com> >>> Sent: Saturday, July 08, 2017 4:48 PM >>> Subject: Re: [time-nuts] J06 HP-59992A time interval calibrator for >> HP-531xx counters >>> >>> >>>> A run of the mill 2 way power splitter has better than 10ps phase >> matching at 100MHz there are few digital devices that offer that degree of >> matching at best they are usually 10x worse. >>>> >>>> Bruce >>>> >>>>> >>>>> On 09 July 2017 at 06:58 Mark Sims <hol...@hotmail.com> wrote: >>>>> >>>>> Yes, they do show up... but usually for big-ish bucks. I want to >> build a small affordable replacement that anybody with a 531xx can have. >>>>> >>>>> My design is currently leaning towards a board with the clock >> generator and a 5V reference for the gain calibration (they spec 5V +/- >> 1mV). I was going to use a couple of 2P4T slide switches to route open >> circuit, 5V, normal clock, and inverted clock to the two output connectors. >>>>> >>>>> I think the cost to build would be in the $20 range and fit on a >> 2x2" or so circuit board... certainly more attractive than a $500 big >> ancient box with unobtainium parts in it. The board should be able to >> perform all the calibration steps for the counter. >>>>> >>>>> I don't think the signal requirements are super critical. They are >> using 1:2 splitters and splitter/180 degree phase shifters and relays to >> generate the output signals passively from the inputs. I think a digital >> clock generator would be a LOT more accurate than those phase shifters. >>>>> >>>>> ---------------- >>>>> >>>>>>> >>>>>> Actually, you can get J06 HP-59992A calibrators on eBay. >>>>>> >>> >>> _______________________________________________ >>> 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. >> > _______________________________________________ > 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.