[time-nuts] Using 5335 frequency counter for timing

[Bob kb8tq]

HI

Timing resolution of what we’re talking about:

5334 	2 ns single shot.    	http://literature.cdn.keysight.com/litweb/pdf/5952-7900.pdf?id=1000072178:epsg:dow <http://literature.cdn.keysight.com/litweb/pdf/5952-7900.pdf?id=1000072178:epsg:dow>
5335 	1 ns single shot	http://www.keysight.com/upload/cmc_upload/All/EPSG084786.pdf <http://www.keysight.com/upload/cmc_upload/All/EPSG084786.pdf>
53131	0.5 ns single shot	http://www.keysight.com/upload/cmc_upload/All/EPSG084786.pdf <http://www.keysight.com/upload/cmc_upload/All/EPSG084786.pdf>
53132	0.15 ns singla shot 	(above)
5370	0.02 ns single shot	http://literature.cdn.keysight.com/litweb/pdf/05370-90031.pdf?id=713250 <http://literature.cdn.keysight.com/litweb/pdf/05370-90031.pdf?id=713250>
TICC	0.05 ns single shot. https://www.febo.com/pages/TICC/ <https://www.febo.com/pages/TICC/>

Many of the devices above will do strange (and possibly incorrect) things to generate some extra digits here and there. Most toss
up all sorts of extra digits in frequency mode. We have discussed the issues with those extra digits at great length here many times
before.

Random piece of coax around the shop will have a delay of < 1 us. A 1 ppm timebase on a scope will give you 
an accuracy of 1 ppm out of 1 us. That would be 1 ps. If you have a scope that will show you better than 1 ps, 
that’s even faster than what I would call a real fast scope. 

Bob






On May 8, 2017, at 12:48 AM, Jerry Hancock <jerry at hanler.com> wrote:
> 
> I tried reading the 5335 over GPIB.  In the case where I am measuring frequency I get the expected number of digits.  In the case where I am measuring A->B, I only get nanoseconds (e.g 3E-9; or 4E-9).  On my scopes, I was able to measure the delta at 3.28 nanoseconds with both scopes close within .01 nanoseconds.  I was measuring the delta between 1M and 11.5” of RG316 cable.  With a published velocity factor of .695 and 3.28E-9 seconds difference, the delta came out to 27” vs the measured 27.87”.  Of course the RG316 VF wasn’t accurate to the number of digits needed to get any closer.  I was demonstrating the precision of the equipment I was using to my son who is becoming somewhat of a mad scientist like his father.
> 
> 
>> On May 7, 2017, at 8:15 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>> 
>> 
>> jerry at hanler.com said:
>>> I thought I had seen somewhere where people were getting higher resolution
>>> using software along with the 5335, no?
>> 
>> I don't know about the 5335, but if you talk to a 5334 via GPIB, you can get 
>> more digits than fit on the display.
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
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