[ntp:questions] Re: Query: Interest in clock synthesizer module -- useful for stabilizing PC timekeeping (among other things)

John Ackermann N8UR jra at febo.com
Thu Aug 17 12:36:20 UTC 2006

Eugen COCA said the following on 08/17/2006 01:53 AM:
> Very interesting ideea, but I have a question: Did you take into
> consideration the temperature ?
> I made some empirical observations and the main problem of the 14 MHz
> crystal on the motherboard is the temperature. If you compensate the
> mainboard crystal the results are great.
> A good ideea is to replace the crystal itself with an OCXO but the
> price is higher enough to discourage a self-starter.

The idea behind the ClockBlock is to replace the crystal with something
tied to an external reference.  For example, if your motherboard has a
66MHz crystal, the Clock-Block could be programmed to generate that
frequency using a 5 or 10MHz OCXO, GPSDO, Rb or Cs, or whatever as a
reference input.  The reality is that virtually any oscillator will be
better than the 29 cent rock that's on the motherboard, but obviously
the better the reference the better the timekeeping.

> As we see here:
> http://www.mirror99.com/20050701/symmetricom_announces_new_9210b_military_ocxo_crystal_jde.jspx
> at this price we could buy a rubidium oscillator.
> If you have to replace something on the motherboard, an ideea is to
> replace the crystal with a better one:
> http://www.rfx.co.uk/pages/ocxoindex.html.
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