[time-nuts] FSA3011 Frequency Stability Analyzer

[timeok at timeok.it]

   Tom,

   A good test, even if not too numerical, could be ADEV between a good Rubidium like the HP5065A and another
   equal or better reference made both with the TICC and with the FSA3011.

   The comparison of the two graphs would give us a first visual answer about the differences.

   Another question is whether in the case of the FSA3011 there is the problem of the timewrap that would not allow
   the long acquisitions. Can you post a similar chart?

   Luciano


   Da "time-nuts" time-nuts-bounces at lists.febo.com
   A time-nuts at lists.febo.com
   Cc
   Data Fri, 26 Jul 2019 12:02:24 -0700
   Oggetto Re: [time-nuts] FSA3011 Frequency Stability Analyzer
   Yes, I'm evaluating a FSA3011 at the moment. It's a cute little unit.
   Documentation is sparse, the jpg plots are fuzzy, "customer" support is
   nil, but it works. My initial tests show it's ~4x worse than the data
   sheet claims but it turns out the unit is quite dependent on the rise
   time and power of the input signals so YMMV.

   With 10 MHz sine inputs from a tee the noise is about 3 ps @1 s. I'm
   checking different frequency and waveform combinations in an attempt to
   obtain the "<1 ps" value implied by the specs.

   The output is phase difference, about a second. Readings look like
   "0.000000000591884\n". Note that last digit is 1 fs, which is
   ridiculous. It's like marketing said, "let's make this go to 15". In
   fact 11 or 12 digits contain actual information. Then again the
   TAPR/TICC has a similar problem with excessive digits so who am I to
   talk. For the most part, fake digits don't hurt, but realize that
   spitting out 15 decimal places does not in any way imply the device can
   measure to that level.

   The block diagram says it's a dual-mixer. It follows a very minimalist
   design. Just two SMA inputs and a 115.2 kbaud serial-over-USB output. No
   switches, no modes, no input commands, no GUI; a couple of labeled LED's
   -- my kind of "do thing, do it well, and do it quietly" device.
   Startup time (power-up to first reading) is ~1 minute.

   Since it first appeared eBay there are now dozen(s) of clone
   [re]sellers, which often happens these days, especially from far east
   sellers.

   My current feeling is if it were half the price and if the documentation
   were better and if they added clean ZCD the inputs, they'd sell a lot
   of them. Right now, I think they're just reaching for a top price to see
   if it will sell. From the eBay history there have been a couple of
   sales in several months so that's their answer.

   I'll have more info as the evaluation tests continue.

   The sad thing to me is that for ten+ years I kept hoping someone time-nuts would make a similar turn-key phase comparator. A number of
   members have mentioned their dual-mixer prototypes but I've never seen
   anyone take it to the level where it's integrated into a
   working-out-of-the-box board or black box like this FSA. A ps-level
   1-100 MHz RF phase comparator would be (would have been) a perfect TAPR
   product. With TAPR, you get open source, good documentation, reliable
   and peer reviewed circuits, and superb support.

   /tvb


   7/26/2019 8:11 AM, timeok at timeok.it wrote:
   > > Hi, > > for some time now on ebay they have been selling the FSA3011
   > Frequency Stability Analyzer which would seem interesting as a fair >
   compromise between resolution and price. Some have been sold and I >
   would like to know if any of you have had the chance to try it and >
   therefore have an opinion on this instrument. > > Thanks, > > Luciano >
   > timeok _______________________________________________ time-nuts >
   mailing list -- time-nuts at lists.febo.com To unsubscribe, go to >
   http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and >
   follow the instructions there. >

   _______________________________________________
   time-nuts mailing list -- time-nuts at lists.febo.com
   To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
   and follow the instructions there.