[time-nuts] Favorite counters (current production)?

Tom Van Baak tvb at LeapSecond.com
Sat Nov 11 07:44:53 EST 2017

> Also, as being reported by the friends at Norwegian NMI, there is 
> something funky about. They got to borrow one from Ole Petter Rønningen.
> It was there in the York EFTF 2016 poster session, and I even made a few 
> folks aware of it as "interesting". If I had more time, it would be 
> interesting to dig deeper into that issue.

Way back in the time-nuts archives there are discussions now and then about some other low-level effects in these counters.

> A trouble with some of these modern counters is that sometimes their 
> processing isn't as transparent as it used to be. The trouble with that 

I agree 100%. They get "too clever" for their own good and the internal design is not released. This is one reason why the TAPR TICC is so welcome. Totally open h/w and s/w. Ok, it doesn't quite compete with 20 ps full-featured high-end counters, but it's also 10x cheaper.

That said, I want to point out that the latest GPSDO / counter from Stanford Research continues their tradition of relatively open design. If you have an hour, go through the very detailed user manual, which includes theory of operation and BOM and schematics, just like the old days:


It's rather understated: they call it a "GPS time and frequency system" but it does frequency synthesis and pulse generation, frequency counting and time tagging, stats including ADEV, etc. You can see how they combined pieces of several other products all into this one modern instrument. Perhaps there's no need for them to ever refresh the SR620 now that the FS740 exists.

> That said, I hope Keysight can straight it out. I'm not out to bash 
> them, but I'm not as excited about their products as I was back in the 
> HP and early Agilent days.

Right. That's also why I mentioned that if someday there's a Keysight B version of the 53230 I'm all in. Surely someone at Keysight is looking into this. They just need someone with a time nut mentality to clear up all the loose ends. Meanwhile the FS740 is on my Christmas list.

> What current production freq counters do people like for general 
> time-nuttery these days? There's a chance I can get a decent counter 
> for work, so I'm looking for suggestions. Bonus points for fanless. 
> Don't need anything past 200 MHz or so. Prefer ethernet over USB or GPIB.
> The SR620 looks to be pretty big and a little dated. The 53230A seems 
> to have better specs and screen than the Tek/Fluke FCA3k series. Am I 
> missing any?

So, Scott, give the FS740 a try. See if SRS will loan you one for a few weeks and report back to us on what you think.


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