[time-nuts] E1938A oscillator pinning

Bruce Griffiths bruce.griffiths at xtra.co.nz
Mon Aug 27 22:34:05 UTC 2007


SAIDJACK at aol.com wrote:
> Hi there,
>  
> I'll break the silence :)
>  
> does anyone know about the EFC voltage compatibility range for the E1938A  
> oscillator? Is it 0V to 5V, or -5V to +5V etc?
>  
> How about the serial interfaces mentioned on Tom's website, are there  any 
> datasheets, user-manual, schematics etc available that explain these in more  
> detail?
>  
> Thanks,
> Said
>
>
>
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Said

Since the AD7714 (0 - +5V input range with gain = 1 and 2.5V reference)
monitors the EFC voltage, unless there is an input attenuator and/or
level shift circuit in front of the AD7714, the EFC voltage will not
exceed 5V nor go below 0V.

There is also an EFC DAC (at least according to the osc.pdf paper on
Rick's site) which suggests that it may be possible to eliminate an
external DAC when the E1938A is locked to an external reference such as
the PPS output of a GPS timing receiver.

Bruce




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