msoko...@ivan.harhan.org said:
But I _*REFUSE*_ to do it that way. You've mentioned UTC: that's one thing
I'm taking great care to avoid in my solution. I want my system to be
completely insulated from whatever evil things the ITU may do to UTC and
leap seconds. ...
I think you have two
Maybe I missed it, but did somebody think about the uBlox LEA-6 rx? has
two timemark outputs, which are programmable.. so you can have both 1PPS
and 1000PPS.
Achim
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Chris Albertson albertson.ch...@gmail.com wrote:
It's even less logical than that. With rubber seconds tied to the
Earth's rotation. You ultra stable cesium clock is no longer running
at a fixed frequency.
Wait a minute here, Chris... Weren't you just telling me the other day
how
That said of all the systems I like the Mayan one best. They defined
the year as 360 days. Then after 360 days they stopped counting and
had a party while they waited for the priest to watch the sun and
declare the start of a new year. They got a week off.
Chris Albertson
Redondo Beach,
On Wed, 03 Aug 2011 07:39:28 +0200
Achim Vollhardt avoll...@physik.uzh.ch wrote:
Maybe I missed it, but did somebody think about the uBlox LEA-6 rx? has
two timemark outputs, which are programmable.. so you can have both 1PPS
and 1000PPS.
I thought the same when reading this discussion.
The
On Tue, Aug 2, 2011 at 09:18, Michael Sokolov msoko...@ivan.harhan.orgwrote:
2. When/if the muggle/mainstream UTC stops being acceptable as a form
of mean solar time (i.e., when DUT1 passes the 1.0 s mark and no leap
second is inserted to correct for it), I will take the matters into
my
2. At the higher user-friendly level, rubber duckies like the one I'm
about to build take this fancy non-Earth-rotation-based techie time
as input and produce old-fashioned Earth orientation time on output,
or more precisely produce a synthetic timescale that is rubberized to
On 8/2/11 10:47 PM, David J Taylor wrote:
That said of all the systems I like the Mayan one best. They defined
the year as 360 days. Then after 360 days they stopped counting and
had a party while they waited for the priest to watch the sun and
declare the start of a new year. They got a week
Le 02/08/2011 04:35, Michael Sokolov a écrit :
snip
Henry Hallamhe...@pericynthion.org wrote:
The parameters you'll want for conversion between MCAT and mean solar
time are given daily in the IERS bulletins:
http://hpiers.obspm.fr/eop-pc/products/bulletins/bulletins.html
Yes, I know.
By
Hello again,
Thank you all for your recommendations. It looks like I will go with a
ThunderBolt: I have found Trimble's manual online, read all of it, and
it looks like the unit will do exactly what I am after.
I will feed all 3 outputs from the TBolt (10 MHz, 1 PPS, EIA-232) to a
custom
On Tue, Aug 2, 2011 at 9:12 AM, Michael Sokolov
msoko...@ivan.harhan.org wrote:
Hello again,
Thank you all for your recommendations. It looks like I will go with a
ThunderBolt: I have found Trimble's manual online, read all of it, and
it looks like the unit will do exactly what I am after.
Chris Albertson albertson.ch...@gmail.com wrote:
Why such complex a system when you don't need it?An FPGA???
Fixing a logic mistake in an FPGA involves editing a Verilog source file
and recompiling; fixing a logic mistake in discrete logic involves a
board respin. I much prefer editing
stopping
you of course. :P
regards,
Fred
From: Michael Sokolov msoko...@ivan.harhan.org
To: time-nuts@febo.com
Sent: Tuesday, August 2, 2011 6:52 PM
Subject: Re: [time-nuts] GPSDO for my rubber duckie
Chris Albertson albertson.ch...@gmail.com wrote:
Why
On Tue, Aug 2, 2011 at 9:52 AM, Michael Sokolov
msoko...@ivan.harhan.org wrote:
Fixing a logic mistake in an FPGA involves editing a Verilog source file
and recompiling; fixing a logic mistake in discrete logic involves a
board respin. I much prefer editing ASCII text source files and
Chris Albertson albertson.ch...@gmail.com wrote:
NTP software can keep system time within a few milliseconds of UTC.
No custom hardware, no FPGA or PCB.
But I _*REFUSE*_ to do it that way. You've mentioned UTC: that's one
thing I'm taking great care to avoid in my solution. I want my system
Subject: Re: [time-nuts] GPSDO for my rubber duckie
Chris Albertson albertson.ch...@gmail.com wrote:
NTP software can keep system time within a few milliseconds of UTC.
No custom hardware, no FPGA or PCB.
But I _*REFUSE*_ to do it that way. You've mentioned UTC: that's one
thing I'm
At 05:33 PM 8/2/2011, Chris Stake wrote...
If you live your life on a timescale that is anchored to mean solar
time,
what happens on February 29th?
Nothing. From the OP:
I want MJD numbers instead of Gregorian dates, or GPS week numbers /
day-of-week / time-of-day.
measurement
Subject: Re: [time-nuts] GPSDO for my rubber duckie
At 05:33 PM 8/2/2011, Chris Stake wrote...
If you live your life on a timescale that is anchored to mean solar
time,
what happens on February 29th?
Nothing. From the OP:
I want MJD numbers instead of Gregorian dates, or GPS week
On Tue, Aug 2, 2011 at 3:49 PM, Chris Stake st...@btinternet.com wrote:
I don't get it.
Does that mean that leap days are OK but leap seconds are unacceptable?
It's even less logical than that. With rubber seconds tied to the
Earth's rotation. You ultra stable cesium clock is no longer
Le 03/08/2011 00:49, Chris Stake a écrit :
I don't get it.
Does that mean that leap days are OK but leap seconds are unacceptable?
Chris
For the moment yes, as they are animals from two different species. Leap
seconds form part of the current definition of UTC which is a time
scale, even
Yep, Lady Heather does several versions of the Mayan, Aztek, and Druid
calendars you can specify the correlation constant to suit your
interpretation of the reference date.
That said of all the systems I like the Mayan one best. They defined the year
as 360 days.
Message-
From: msoko...@ivan.harhan.org (Michael Sokolov)
Sender: time-nuts-boun...@febo.com
Date: Tue, 2 Aug 2011 19:33:17
To: time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] GPSDO for my rubber duckie
Chris
Hello time-nuts,
I've been on this list for several years now and I've made a few little
comments on occasion, but this will be my first real technical post.
I desire to build a timekeeping apparatus which I have nicknamed the
rubber duckie, or a Rubber Time Generator. As I've voiced very
You left out the most important requirements.
1) How acurate does this all need to be? Is 1/10 of a second good
enough or is this all to run at the handful of nano seconds level?
2) How is the time to be output or displayed? Are we driving an
analog clock with sweep second hand or a time code
Hi
Without knowing the full objective it's always hard to offer up suggestions.
I'm going to *assume* that you want a PPS that is good to 1 ms on your custom
time scale. I'm also assuming that sidereal time is a reasonable analog to what
you are trying to do. I think your approach is overly
Michael,
GPS provides leapsecond information, BUT, to my knowledge, does not implement
it. The GPS time reported by GPS is the invariant time of the Cesium references
that are used to steer the BIRDS.
That said, any software that displays UTC would have to take the GPS time and
add
or subtract
The below could work but even it is overly complex. Try this..
1) Get any computer and install NTP. Use any decent timing GPS as a
reference.Now you have a computer with system time accurate to UTC
and the sub millisecond level. This is a 100% conventional setup, no
rocket science.
2)
Hi
or drop the GPS and just run NTP. Simpler still run SNTP on something
small. You won't hit 1ms in either case. You will be plenty good by wall clock
standards.
Bob
On Aug 1, 2011, at 6:27 PM, Chris Albertson albertson.ch...@gmail.com wrote:
The below could work but even it is
I think that a Thunderbolt GPSDO with Lady Heather should be able to do what
you want. It can be set up for GPS time (no leapseconds) or UTC time. It can
handle time zone offsets to the second for fine tuning your whacko time scales.
It can display the date in JD, MJD, ISO, and a bunch of
Chris Albertson albertson.ch...@gmail.com wrote:
In engineering something like this it is very impotent NOT to mix up
primary requirements, derived requirements, implementation
details.
primary requirements describe the thing you want, NOT how it works.
Derived ones are the logical fallout
On Mon, Aug 1, 2011 at 6:18 PM, Michael Sokolov
msoko...@ivan.harhan.org wrote:
At the present moment I can satisfy my requirement simply by looking at
a WWVB-synced wristwatch: WWVB transmits UTC, and
OK this defines your require accuracy very well. ideally are required
to be without 1/2
Another possible solution is to use a Rubidium stabilised oscillator
like a LPRO which has been set to your preferred frequency.
If my aged brain remembers my calculation correctly, it is spec'd to
be accurate to one second in 30 years,
so you might have to correct your clock every decade or
The parameters you'll want for conversion between MCAT and mean solar
time are given daily in the IERS bulletins:
http://hpiers.obspm.fr/eop-pc/products/bulletins/bulletins.html
By making use of these you should be able to do much better than the
slightly inelegant leap second
Chris Albertson albertson.ch...@gmail.com wrote:
I think you can do just fine without GPS and GPSDXO oscillators and
the like. NTP over the Internet is an order of magnitude better then
you need.
No, I really don't want anything NTP-based. Or let's put it another
way: part of my objective
Henry Hallam he...@pericynthion.org wrote:
The parameters you'll want for conversion between MCAT and mean solar
time are given daily in the IERS bulletins:
http://hpiers.obspm.fr/eop-pc/products/bulletins/bulletins.html
Yes, I know.
By making use of these you should be able to do much
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