worst case timestamp error during holdover
periods are actually MTIE values. Is there any way to estimate the
latter from Allan deviations specs? Would an ADev of 65 x 10^-9 over
100s imply up to 6.5us of error after 100s?
Any thoughts? Thanks,
Tony H
and probably raise a
few more.
Well yes, but that will cost time and money - I was hoping to get some
recommendations/suggestions from people who have some experience with
low cost GPS modules, so as to narrow the field down a bit before
experimenting myself.
Thanks, Tony
On 03/05/2014 00:59, ewkeh...@aol.com wrote:
Welcome to the nuts Tony
Thanks, Bert.
You are not specifying exactly how accurate time has to be but in my book
and based on tests the most reasonable priced GPS with 1 pps is a
Ublox 6M
that you can get with antenna for less than $ 22 antenna
I guess!
Tony
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On 03/05/2014 18:41, Tom Van Baak (lab) wrote:
Tony, Chris, Bert,
Since all you want is a 10 ns time stamp / data logger you do not need a GPSDO,
or OCXO, or VCXO.
The solution is cheap and very simple.
Your GPS receiver provides a 1PPS to the microprocessor. Use a plain XO or
TCXO
On 06/05/2014 02:24, Chris Albertson wrote:
On Mon, May 5, 2014 at 6:55 AM, Tony tn...@toneh.demon.co.uk wrote:
Yes - that is exactly what I intended. The problem though is maintaining
sufficient accuracy during periods when the GPS clock is unavailable or
unreliable (perhaps due to local
On 10/05/2014 04:19, Chris Albertson wrote:
On Fri, May 9, 2014 at 10:46 AM, Tony tn...@toneh.demon.co.uk wrote:
But isn't that only supported by 'timing' GPS modules that allow you to
specify the location? But they are rather more expensive than the common
navigation type modules
On 10/05/2014 15:15, Attila Kinali wrote:
On Fri, 09 May 2014 18:46:05 +0100
Tony tn...@toneh.demon.co.uk wrote:
Quite a remarkable datasheet for a low cost part - I've not found any
other low cost oscillator with either of those specifications, and even
some (most?) of the OXCO don't specify
which has
a UBLOX MAX-7C module.
Tony
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Said,
On 20/08/2014 15:42, saidj...@aol.com wrote:
Hi Tony,
that's consistent with what I remember. Do you have the capability to count
the number of 10MHz pulses per second to see if it is phase-coherent with
the UTC 1PPS pulse?
I don't have any means to do that at the moment - when I
Specification
V14' the only clue as to the clocking characteristics is that the
timepulse output must be configured with a minimum high or low time of
50ns or pulses may be lost. Make of that what you will!
Tony
On 21/08/2014 04:25, David J Taylor wrote:
Tony, any chance you could do a quick
other required configuration hadn't been done,
causing a conflict.
I've not yet found any detailed documentation specifying exactly which
messages/features these modules do support.
Tony H
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that I know next to nothing about GSM standards
other than that the base stations have access to a high quality clock.
If its not possible to do this reliably, are their any low cost ( $20)
combined GSM/GPRS + GPS modules which provide timing accurate to a few
10s of us or so?
Thanks
Tony
only have a
micro-controller with limited memory.
Tony H
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Greetings,
I have run some time interval test and it did not quite calculate correctly. I
used a TADD2 that is configured for 2 outputs at 100 Hz, 2 outputs at 10 Hz,
and two outputs at 1 PPS. The HP5370B clock output was used as the input for
the TADD2. The output of the TADD2 was feed to
In the back of my head, I beleive that project red shift did fly, but they
dumped the hydrogen masers to use brand new lighter weight and much smaller
rubidiums.
GET FREE SMILEYS FOR YOUR IM EMAIL - Learn more at
Has anyone found a suitable replacement or a source for the fan/blower in the
HP53131A ? I have talked to Agilent and the fan/blower is not a seperate item,
its part of the power supply board.
TRY FREE IM TOOLPACK at
About 50 years ago I ran into a Frequency Division Multiplexer that used a
redundant master frequency system. I beleive they combined the same frequency
for the master oscillator, but it was something like a special hybrid
combiner. I remember that they used a phase angle of 135 degrees -
://fanf.livejournal.com/98545.html
Tony.
--
f.anthony.n.finch d...@dotat.at http://dotat.at/
Trafalgar: Cyclonic in northwest, otherwise mainly northerly or northwesterly
5 or 6. Slight or moderate. Showers in northwest. Good.
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Are there any basic steps I should take to improve the reception quality
of a radio clock? I have a cheap and cheerful DCF77 receiver for
connecting to some GPIO pins, but its PPS output is basically noise with
maybe a one-second period. Perhaps it's just cheap and nasty.
I am in Cambridge.
Tony
-level_peripherals#GPIO_Driving_Example_.28C.29
though I had to look at the data sheet for the GPIO read address
#define GPIO_GET gpio[13]
The shell / filesystem interface to the kernel GPIO driver was also handy
for testing.
Tony.
--
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Humber, Thames
is pretty horrid in this regard. The
other possibly relevant thing is the HDMI connection to the display.
Tony.
--
f.anthony.n.finch d...@dotat.at http://dotat.at/
Viking: Northeast veering east 4 or 5, occasionally 6 later. Slight or
moderate. Occasional rain in southwest. Moderate or good
So it might just have been the weather. I'm getting quite good reception
this evening - losing one bit in every 200 or so. Enough to write a crappy
decoder that can display the time and the DCF77 leapsecond warning bit. 25
minutes to go, ish!
Tony.
--
f.anthony.n.finch d...@dotat.at http
... It looks like the analogue MSF clock next to my desk kicks out
lots of radio interference when resetting itself at 01:00 ...
Tony.
--
f.anthony.n.finch d...@dotat.at http://dotat.at/
North FitzRoy, Sole: Westerly or southwesterly 4 or 5, increasing 6 or 7 for a
time. Moderate or rough
.
Tony.
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f.anthony.n.finch d...@dotat.at http://dotat.at/
Tyne, Dogger: South 5 or 6, decreasing 3 or 4. Slight or moderate. Rain, fog
patches developing. Good, becoming moderate, occasionally very poor.
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service.
Tony.
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Faeroes: East or northeast 4 or 5, increasing 6 or 7 for a time. Moderate.
Occasional rain. Moderate or good.
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).
Tony.
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Trafalgar: Northerly 5 to 7, but mainly 4 in northwest. Moderate. Fair.
Moderate or good.
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three paragraphs of http://fanf.livejournal.com/70049.html are
particularly relevant.
Tony.
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THAMES: SOUTHWEST 5 TO 7. MODERATE OR ROUGH. SHOWERS. GOOD.
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https
,
otherwise it wouldn't be a universal unit of measurement. When the SI
second is used to create a timescale then it must be referred to a
standard frame of reference. In the case of TAI and UTC, the frame of
reference is the rotating geoid.
Tony.
--
f.anthony.n.finch d...@dotat.at http://dotat.at/
South
, David Prerau has
collected many many examples. http://www.seizethedaylight.com/
Tony.
--
f.anthony.n.finch d...@dotat.at http://dotat.at/
Fair Isle: Northerly or northeasterly 4 or 5 increasing 5 or 6, but 6 or 7 in
far west at first. Moderate or rough. Rain or showers. Moderate or poor
Jose Camara camar...@quantacorp.com wrote:
Thanks for the book recommendation.
I'm enormously pleased you enjoyed it. Sounds like you had the same
unexpected reaction that I did!
Tony.
--
f.anthony.n.finch d...@dotat.at http://dotat.at/
Northwest FitzRoy, Sole, Lundy, Fastnet: Westerly
is shipped with a very large maximum polling
interval. Try reducing it.
Also, ntpd does not work well on machines that are often suspended. I
don't know if Apple have done anything to fix that.
Tony.
--
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Viking, North Utsire, South Utsire, Forties
as the volume of 10 lb water.
Tony.
--
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Portland, Plymouth, Biscay: West 7 to severe gale 9, occasionally storm 10
later. Very rough or high, occasionally very high. Squally thundery showers.
Moderate, occasionally poor
factors. (The relation between length, volume, and
mass is elegantly simple.) Customary measures are based on artefacts whose
size cannot be recovered if they are lost, with irregular subdividing
factors and no commonality between the units for different physical
dimensions.
Tony
://theodoregray.com/periodictable/AlkaliBangs/
Tony.
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f.anthony.n.finch d...@dotat.at http://dotat.at/
South Utsire, Forties, Cromarty, Forth: Southerly, 5 or 6, occasionally 7,
veering southwesterly 4 or 5, then veering northerly 3 or 4 later. Slight or
moderate, occasionally rough in South Utsire
/products/csac
That's really neat. You should do a version with an ethernet interface and
NTP and IEEE 1588 support :-)
Tony.
--
f.anthony.n.finch d...@dotat.at http://dotat.at/
Rockall: West, backing south, 3 or 4, increasing 5 or 6. Moderate or rough.
Fair then occasional rain. Moderate or good
Hal Murray hmur...@megapathdsl.net wrote:
Internally, Linux (and most other modern OSes) use UTC. The API doesn't
include the TAI offset. There is no way to talk about the extra second.
See adjtimex(2) for a description of the leap second API.
Tony.
--
f.anthony.n.finch d...@dotat.at
ed the leap second the respect that it deserves and now has
> it under control.
Most Cisco routers had to be disconnected from NTP to avoid a
leapsecond-related crash.
Large cloud providers are doing leap smear not leap seconds.
Hundreds of servers in the NTP pool got it wrong.
It's still a
cy.
I don't think it does have a resonant frequency, any more than the Earth
does: the angular velocity of the pendulum is sqrt(g/h) where h is the
height of the pendulum; give it more energy, it swings higher, so h is
smaller, so the frequency is higher.
Tony.
--
f.anthony.n.finch <d...@dotat
ch I find curious.
Maybe it is to do with the grid origin not being on the meridian?
https://en.wikipedia.org/wiki/Ordnance_Survey_National_Grid
Tony.
--
f.anthony.n.finch <d...@dotat.at> http://dotat.at/ - I xn--zr8h punycode
Plymouth, Biscay: Variable 3 or 4, becoming north
e clock in Trinity College is a smaller version of the Big Ben clock and
has its own web site with interesting technical details:
http://trin-hosts.trin.cam.ac.uk/clock/
(I suspect its keeper might be willing to show visiting time nuts around!)
Tony.
--
f.anthony.n.finch <d...@dotat.at>
Esa Heikkinen <tn1...@nic.fi> wrote:
>
> Only Google may be stupid enough to grow one second lasting minor timing
> issue to ten hours lasting serious timing issue with even longer effects
Not only Google...
https://pairlist6.pair.net/pipermail/leapsecs/2016-September/00
BsundialWalk.pdf
The Royal Greenwich Observatory was housed next to Cambridge University's
Institute of Astronomy for several years before it was finally shut down.
I don't know of any notable timekeeping activities, though.
Tony.
--
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://bhi.co.uk/museum/the-bhi-museum-trust/
Tony.
--
f.anthony.n.finch <d...@dotat.at> http://dotat.at/ - I xn--zr8h punycode
Fisher: Cyclonic becoming north 4 or 5, occasionally 6 at first. Moderate.
Rain then showers. Moderate or good.
___
time
Tom Leedy via time-nuts <time-nuts@febo.com> wrote:
>
> A very worthwhile, and often overlooked, museum is located at The
> Worshipful Company of Clockmakers
Note that it moved to the Science Museum 18 months ago.
Tony.
--
f.anthony.n.finch <d...@dotat.at> http://dot
ckier :-)
My version is at http://fanf.livejournal.com/93771.html
Wikipedia has a version
https://en.wikipedia.org/wiki/Julian_day#Julian_or_Gregorian_calendar_from_Julian_day_number
Tony.
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Shannon, South
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