[time-nuts] Upgrading TS2100 from TCXO to OCXO

[Greg Dowd]

Well the units are 100ns each so if you set offset to 3, it should shift the 1pps output by 300ns.  Another point is that there is significant asymmetry in the ntp packet processing if you are looking at accuracy.  For the 1996 time of day requirement of 100ms, it was moot.  If you set the box up in GPS mode and look at the 1pps output from the box, and set the offset so that the 1pps is within 1 usec of a known UTC reference, you will see that the transmit timestamps on ntp replies are a few ms late due to the tx latency in the device.  The rx timestamps errors are more interrupt latency (10-100 microseconds).  The net result is that your network clients will see a bias in the TS2100 clock (bias = rt/2).  If you use the offset command, you can correct this bias but it will be at the cost of moving your hardware 1pps output off an equivalent amount in the opposite direction.


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of Jason Rabel
Sent: Friday, April 01, 2011 10:21 AM
To: time-nuts at febo.com
Subject: Re: [time-nuts] Upgrading TS2100 from TCXO to OCXO

Greg,

I guess I had to wait until my coffee kicked in this morning before it clicked that it was in nanoseconds... I'm trying -3000 to see
where that gets me, it seems to be nudging the time more in-line with my other NTP servers.

As others have asked, how do we get this value to be persistent across reboots? Is there a way to write it to the eeprom or nvram or
whatever?

Is there any documentation on all the various commands in the eng/ directory? I want to tinker but I don't want to break my unit!


Thanks as always,
Jason


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