In message 201011090430.oa94up7y046...@stenn.ntp.org, Harlan Stenn writes:
Using USB serial introduces amusing amounts of jitter. This is usually
not a problem for the NMEA sentences, but I wouldn't want to be
detecting the PPS signal via USB1 or USB2 serial devices.
I've heard that USB3 should
It's not exactly a USB dongle, but if you have a Thunderbolt, Lady Heather
has a time sync command that sets the system clock to Tbolt time. You can have
it set the clock periodically or whenever the system clock diverges from Tbolt
time by a specified amount (including 0 milliseconds).
On 11/09/2010 03:07 AM, Hal Murray wrote:
The Garmin USB 18 was much better. Unfortunately, it wasn't as sensitive as
competing units and it's been replaced by the 18x which has the typical
horrible jitter problems. I don't have a graph of the 18x handy, but here is
data from a USB 18.
This is probably the thousandth time this was asked, but I googled and
didn't get a direct answer.
I want to do a crude (as in to the second or so) time server inhouse to
add into a group of high accuracy servers. This is so that I can go off
grid and still get updates.
I see that there is
Hi
The gotcha is that the NEMA string has a poorly defined transit due to the USB
stack. The jitter is still there. On a loaded system it can be fairly large.
The next layer to the onion is that the location of the PPS within the NEMA
string is also poorly defined on a lot of the cheap(er)
I want to do a crude (as in to the second or so) time server inhouse to add
into a group of high accuracy servers. This is so that I can go off grid
and still get updates.
since USB by its nature won't have an accurate exact dedicated line to let
the GPS toggle to do a time hack to the
jim s wrote:
This is probably the thousandth time this was asked, but I googled and
didn't get a direct answer.
I want to do a crude (as in to the second or so) time server inhouse to
add into a group of high accuracy servers. This is so that I can go off
grid and still get updates.
I see
On Nov 8, 2010, at 10:58 PM, jimlux wrote:
jim s wrote:
This is probably the thousandth time this was asked, but I googled and
didn't get a direct answer.
I want to do a crude (as in to the second or so) time server inhouse to add
into a group of high accuracy servers. This is so that I
Using USB serial introduces amusing amounts of jitter. This is usually
not a problem for the NMEA sentences, but I wouldn't want to be
detecting the PPS signal via USB1 or USB2 serial devices.
I've heard that USB3 should be much better. I haven't touched any of
these yet.
--
Harlan Stenn
On 11/8/2010 5:14 PM, jim s wrote:
This is probably the thousandth time this was asked, but I googled and
didn't get a direct answer.
Here is the reference to the PPS that made me make statements about RS232
http://forums.freebsd.org/showthread.php?t=16507
Here is an actual implementation
Le 09/11/2010 06:50, jim s a écrit :
The other thing I didn't state was that I got the USB receiver out of
a discard frenzy at the place I'm working, and got it to work with a
freebe program on windows XP. It's a Holux GM-210.
They do make an RS232 version, but I got the USB one. It
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