[time-nuts] Comparison of Logic Standards for Clock Distribution

Stephan Sandenbergh stephan at rrsg.ee.uct.ac.za
Mon Oct 30 16:01:04 UTC 2006


Hi Bruce,

Snip:>>
> Whilst there are many books available of clock distribution within
> digital systems (eg http://cva.stanford.edu/books/dig_sys_engr/) and
> within VLSI chips, there is little specific info published in book form
> on precision clock/frequency standard distribution on the larger scale
> such as within or between buildings.

What could the reason for this lack of information be? Is the topic just not
interesting, or is the distribution of accurate clock signals not a big
issue? I can't really imagine that either of these are the case.

> The difficulties associated with high speed clock distribution in
> silicon VLSI chips currently limits the maximum clock speed of such
> chips to around 4GHz or so.
> Simply using higher resolution lithography to produce smaller
> transistors doesn't help much. Optical techniques for clock distribution
> on chip are being investigated.
> 
> One can glean some idea of how this may best be done by looking at how
> NIST, USNO, NIST, PTB, etc pipe the standard frequencies from their
> various atomic standards around. Current designs for modern radio
> telescope arrays such as the Atacama millimeter array and upgrades of
> various existing instruments give a good indication of current best
> practice for such instruments that require state of the art timing
> stability.

It is strange that these guys know how it is done and not publishing it. I
guess there are a few papers available on this issue. Could you maybe point
me to some of them?


Thanks for the help,

Stephan Sandenbergh





More information about the Time-nuts_lists.febo.com mailing list