Hi I would add the HP 5335 to the list of counters to look for. The surplus market can be really weird. A 5334 *should* be less than a 5335, but on any given day, that may not be true. The 5370 and 5345 are also worth looking for. Target price (at least for me) wold be < $150 for a quick buy and < $70 if I was willing to shop for a while.
Getting data *out* of the older counters will involve GPIB. If you are not already set up to do that, there will be the cost of a cable and a simple adapter. If you want to move up a generation, the 53131 and 53132 are higher resolution devices than the 5334 and 5335. They give you the benefit of a serial port. No GPIB stuff to bother with. Finding one at price lower than the TAPR counter …. probably not. Bob > On Apr 3, 2018, at 3:04 PM, Tom Van Baak <[email protected]> wrote: > > Hi Gary, > > One solution is to look for used hp, Fluke, or Racal time interval counters > on eBay. 1 or 2 ns is pretty easy to find with a $100 or $200 budget. Look > for Racal 1992 or hp 5334B as examples. If you plan to collect lots of data, > you'll want GPIB (or RS232 / USB) connections to a PC and that will add to > your net cost. > > Another solution is to homebrew your own 1 ns counter. The downside is you > will spend a month working out the bugs before you trust the data. Plus if > you don't already have another counter to compare it against it makes > development even harder. > > Third solution is the TICC from TAPR. It's new and works out of the box. Lots > of us use them. John did a very good job with the design. Highly recommended. > It's a dual-channel *time stamping* counter so you can collect 1PPS data on > two separate GPS receivers at the same time if you want. In that respect it's > 2x as useful as a commercial *time interval* counter. > > You mention jitter, not ADEV. I don't think you need a fancy timebase if all > you want to measure is jitter. You can get a good feel for the jitter of a > GPS / 1PPS output within a few samples. Even a minute of data is usually > enough to establish the rms jitter value. If you want a full ADEV plot, then > yes, you'd probably want at least an Rb for your reference. > > See paragraph "Timing Stability" at http://leapsecond.com/pages/MG1613S/ for > an example of what jitter from a GPS receiver looks like; in this case it's > primarily sawtooth. > > Right, the picPET has 400 ns resolution and so it is not the right tool for > your nanosecond needs. I do have a 10 ns version that I use, but that's still > a bit coarse for GPS work. > > I have spare FEI Rb here; I'll send it if you want it. That way you can > afford a TICC. > > /tvb > > > ----- Original Message ----- > From: "Gary E. Miller" <[email protected]> > To: "time-nuts" <[email protected]> > Sent: Tuesday, April 03, 2018 10:47 AM > Subject: [time-nuts] Cheap jitter measurements > > > Time-nuts! > > With care I can measure GPS jitter on a RasPi to a bit over 300 nano sec > resolution. That is the smallest increment of the RasPi 3B clock with > a 64-bit kernel. That is clearly not time-nuts accuracy. > > What would you guys suggest as the cheapest way to see jitter down to > around 1 nano second? > > I'm thinking maybe something like a rubidium standard (FE-5680A) and > a TICC-TAPR? But that would put me out around $400. > > The picPET does not look accurate enough. Maybe a clever way to use it > for more accuracy? Is there a picPET like thing cheaper than the > TICC-TAPR? > > Ideas? > > RGDS > GARY > --------------------------------------------------------------------------- > Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 > [email protected] Tel:+1 541 382 8588 > > Veritas liberabit vos. -- Quid est veritas? > "If you can’t measure it, you can’t improve it." - Lord Kelvin > _______________________________________________ > 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.
