[time-nuts] What is the best counter for a Time Nuts?

SAIDJACK at aol.com SAIDJACK at aol.com
Thu Oct 9 08:40:57 UTC 2008


Hi Tom, Ulrich,
 
can't seem to get 12 digits/s out of my 53132A in frequency mode when doing  
measurement offset of -10MHz. I only get 11 digits/s for some reason. Have to 
go  to 10s + gate time to get better resolution.
 
But I think I discussed this before on this forum, the highest resolution  
time interval counter available at hobby price points on Ebay is the  Wavecrest 
DTS series, and several members of this forum use these quite  successfully. 
They have a nice Windows based user interface via GPIB, or  front-panel 
operation.
 
DTS-2075 for example has 0.8ps(!) hardware resolution, 10ps typical  noise 
rms (I see more like <3ps rms noise on my units), and +/-30ps single  shot 
accuracy. They are self-calibrating using front panel buttons and some SMA  cables.
 
Lastly they can do cable-length measurements to below 1ps resolution!
 
That combined with 40K samples/s gives a lot of bang (for the buck).
 
You can measure period jitter against the internal oven with a typ. noise  
floor of 3ps, or frequency stability against an external reference. Low end  
units will measure DC to above 1GHz.
 
I have bought working units on Ebay for less than $500 in the past. But  they 
won't please everyone, they are clunky/noisy, and consume a lot of  power.
 
bye,
Said
 
 
In a message dated 10/9/2008 00:30:04 Pacific Daylight Time,  
tomduck at comcast.net writes:

Ulrich,

Check out a Pendulum Instruments CNT-91 time stamping  counter. You'll find
much better resolution. This counter doesn't work the  way other
direct/reciprocal counters do. It has 50 ps resolution time  resolution and
12 digits per second display.

Tom
Tom  Duckworth
510-886-1396




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