[time-nuts] 1PPS users?

Scott Stobbe scott.j.stobbe at gmail.com
Sun Dec 18 21:22:35 EST 2016

Part of the reason 1PPS needs to be so clean is because you are
continuously integrating phase noise of the LO (hopefully an OCXO). While
10 uS is pretty trivial off a gps receiver. Without gps, 10 us over 24 hrs
with a plane jane AT-cut crystal subject environmental dynamics becomes
ludicrous. More than likely the short term stability of GPSDO is cleaner
than it needs to be for many applications, but that is so holdover over an
hour or day remains reasonable.

On Sun, Dec 18, 2016 at 6:16 PM, Bob Stewart <bob at evoria.net> wrote:

> One thing I've never really understood is who actually uses the
> high-quality 1PPS output from a GPSDO.  I have spent a lot of time, effort,
> and money on developing my GPSDO without a whole of thought to the user
> base.  It was just a quest for the best result I could obtain with a
> particular technology.  The frequency standard users was a no brainer.
> Everyone who wants a frequency standard eventually understands they need to
> get a GPSDO, or an Rb, or a Cs.  And that's all I thought I had: a good
> frequency standard.  And then Tom prodded me a bit and showed me the
> shortcomings of what I was doing, and I did something about it.  So, if an
> NTP user can get his time fix directly from a noisy receiver, who actually
> needs a time-accurate, low jitter 1PPS pulse?
> Bob - AE6RV
>  -----------------------------------------------------------------
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