[time-nuts] fts 4050 performance

[Brooke Clarke]

Hi Chris:

If the source of a pulse is 50 Ohms and it's TTL level at open circuit ( 
0 to 5 volts) and the load is 50 Ohms, then when  you connect a 50 Ohm 
load the pulse is 0 to 2.5 volts and so setting the trigger to 2.5 volts 
is just on the edge of not working.  It's best to put a "T" connector 
and have a look with a scope.  If the above is the case then a trigger 
level of 1.25 might work better.

Have Fun,

Brooke Clarke

-- 
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Christopher Hoover wrote:

>Attached is what I'm seeing in terms of adev and mdev on my "new" FTS
>4050.  
> 
>The performance is worse than I had expected, as compared to the
>datasheet.
> 
>I'm not 100% confident in my test setup, but I'm not seeing any obvious
>outliers in the data.
>
>Test setup is as follows:
> 
>Counter: HP 53132A
>Timebase: external, 10MHz from Z3801A
>Start: 1 PPS from Z3801A, DC, 50Z, 2v5 trigger level
>Stop: 1 MHz from FTS 4050, AC, 50Z, auto trigger
>
>-ch
>  
>
>
> ------------------------------------------------------------------------
>
>
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