[time-nuts] fast switching quiet synthesizer
jimlux at earthlink.net
Tue Oct 7 23:21:04 EDT 2014
On 10/7/14, 2:26 PM, Poul-Henning Kamp wrote:
> In message <20141007200046.02AA9406060 at ip-64-139-1-69.sjc.megapath.net>, Hal Mu
> rray writes:
>> Timing on Ethernet is as good as RS-232 if you have a point to point link
>> rather than a huge network full of crappy software.
> That is a "truth" with an almost uncountable number of footnotes...
> If we're only talking about timing in 99% of the cases, then yes, but
> that last one percent will make you tear your hair out.
> We did 20 microsecond jitter on 10GE for the ESO ELT adaptive optics
> prototype, and that was seriously pushing things near the edge.
> Five microseconds is trivially possible with a good $20 RS232 cable.
And in my case, I have (or can make) a sync line, so I'd only trust
USB/Ethernet to "load the number" and want to have a hardware "execute now"
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