Hi Scott,
I do understand the reasons that these users want this quality of output. It's
who these users are, what fields, industries, etc, that I didn't quite
understand.
Bob -----------------------------------------------------------------
AE6RV.com
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Scott Stobbe <[email protected]>
To: Bob Stewart <[email protected]>; Discussion of precise time and frequency
measurement <[email protected]>
Sent: Sunday, December 18, 2016 8:22 PM
Subject: Re: [time-nuts] 1PPS users?
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 <[email protected]> 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
----------------------------- ------------------------------ ------
AE6RV.com
GFS GPSDO list:
groups.yahoo.com/neo/groups/ GFS-GPSDOs/info
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