[time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[Bob Camp]

Hi

It's most commonly done with things like a Soekris 45xx series board. You don't need anything very exotic for the frequency conversion. The jitter in the PC is way worse than what the external chips will be creating. 

The real question is - what is the "magic frequency" on the particular mother board you are going to modify? Once upon a time they all were a pretty predictable 14.xxx MHz. These days, who knows what's going in where…

Bob

On Nov 30, 2012, at 4:55 PM, Sarah White <kuzetsa at gmail.com> wrote:

> Has anyone ever used a TAPR clock block or other frequency synthesizer
> to sort the clock drift / timing problems on a regular computer? I'll
> probably end up with a used dell or IBM workstation for this purpose.
> 
> Recently, I came across a low-cost frequency synthesizer capable of
> using a 10mhz frequency reference (planning on using the thunderbolt
> GPSDO I'm working with once I manage to sort out the temperature issues)
> 
> http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf
> 
> ^ TAPR "Clock Block" has an installation example for how to do what I'm
> planning with a Soekris net4501 low-cost / low-power embedded device...
> 
> What I'm hoping to figure out is how to do the same, except on a proper
> computer such as the local used ones I'm able to get for less than $200
> with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this
> should be fine for what I'm planning.
> 
> Example of what I'm trying to do, though based on the low-power embedded
> Soekris net4501 system from the TAPR manual's example section:
> 
> http://www.febo.com/time-freq/ntp/soekris/index.html
> 
> ^Aren't those the photos from clock block frequency synthesizer manual?
> 
> Again, I'm wondering if anyone has opinions or experience about doing
> such things with NOT an embedded system (as I said, can get a nice 2ghz
> or so machine for less than $200 locally at a brick and mortar shop
> within walking distance)
> 
> Thanks in advance,
> Sarah
> 
> 
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