[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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