Here is a link where you can get all the info to build a GPS controlled frequency standard. This is very useful for locking counters, sig gen's and other instuments to a highly stable external clock.
The PC boards may be ordered from them quite cheaply (or do your own) and the source code may be downloaded. Full circuit and description also on the site. **broken link removed**
My one friend constructed this unit without much problems apart from the DAC that's no longer available but could easily be replaced with something else. (AD1861N)
**broken link removed**
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