Bob Camp wrote:
Hi
When there's a leap second, what do you want to do?
Ignore it = GPS time
put in an extra pulse = UTC time
No, this is about which set of corrections to use. The GPS time is what
the navigation solution cranks out, and UTC time is what you then
correct that into for user
Magnus Danielson wrote:
Bob Camp wrote:
Hi
When there's a leap second, what do you want to do?
Ignore it = GPS time
put in an extra pulse = UTC time
No, this is about which set of corrections to use. The GPS time is
what the navigation solution cranks out, and UTC time is what you then
Tom Van Baak wrote:
It also has an option to sync the PPS with GPS or UTC. I thought
they were off by an integral number of seconds so I don't expect any
change. Does anybody know what's going on here?
The GPS broadcast message includes leap second and
a0 and a1 terms which are used to
Bruce Griffiths wrote:
Magnus Danielson wrote:
Bob Camp wrote:
Hi
When there's a leap second, what do you want to do?
Ignore it = GPS time
put in an extra pulse = UTC time
No, this is about which set of corrections to use. The GPS time is
what the navigation solution cranks out, and UTC
The task of the BIPM is to ensure world-wide uniformity of measurements and
their traceability to the International System of Units (SI).
It does this with the authority of the Convention of the Metre, a diplomatic
treaty between fifty-four nations, and it operates through a series of
On Mon, 29 Mar 2010 08:24:00 +0200, Magnus Danielson wrote:
Tom Van Baak wrote:
It also has an option to sync the PPS with GPS or UTC. I thought
they were off by an integral number of seconds so I don't expect any
change. Does anybody know what's going on here?
The GPS broadcast message
The Trimble Thunderbolt is one of the GPS receivers that will report
subframe 4 data. The UTC parameters are in TBolt packet 0x58 type 5. Right
now, the numbers are:
a0 = -0.931 ns and
a1 = -5.33e-15 s/s (which is -0.460 ns/day).
Thanks.
I was close to typing in the same stuff. I got:
So there are 250 clocks, presumably, spread around the World and owned
by the member countries of the BIPM. Their time is somehow compared
centrally and an absolute time is determined from them. Each clock
will then have a delta to apply to it's own time to provide the BIPM
absolute time which
I was close to typing in the same stuff. I got:
-9.31323e-10 -5.32907e-15
In that packet, a0 is double precision. Does anybody know why they need all
those bits?
Hal,
Referring to the GPS ICD, the size of A0 in subframe 4
is a signed scaled 32 bit integer so if a receiver chooses
to
Hi
It's pretty much the way any international standard unit is worked out.
The various national labs come up with a best guess and then they swap
around to see how the guesses all compare with each other. Ultimately they
come up with a way to agree on what the average value is. The math to
Well, mine is driven by a Tek AFG5101 arbitrary function generator. It's
currently clocked by a PTB-100 rubidium time base... got the clock out of a
trashcan...
--
Guess I'm going to have to figure out another way to drive that stepper
motor analog clock. I figured that
Hi
I suspect that generating some sort of 60 Hz sine-ish wave would open up the
selection of clocks considerably.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Mark Sims
Sent: Monday, March 29, 2010 12:32 PM
To:
So the cold ambient temperature was simulating the retuning of the oven
temperature as described here:
http://www.realhamradio.com/z3801a-turning-point.htm and the particular
unit graphed in the article happened to have the oven temperature a bit
high. Sounds like a sunny deck and a cooler
Or some sort of 50 Hz for the ones in other sides of the world :-) .
Ignacio
-
Bob Camp wrote:
Hi
I suspect that generating some sort of 60 Hz sine-ish wave would open up the
selection of clocks considerably.
Bob
-Original Message-
From:
I suspect that generating some sort of 60 Hz sine-ish
wave would open up the selection of clocks considerably.
Bob
Correct. See: http://leapsecond.com/pages/atomic-nixie/
/tvb
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
Referring to the GPS ICD, the size of A0 in subframe 4 is a signed scaled 32
bit integer so if a receiver chooses to convert it to floating point it
needs a double precision format to contain it without loss of precision. A1,
on the other hand, is a signed scaled 24 bit integer and so it just
Below is a nice description of how UTC is generated including
a chart showing how individual timing laboratories, BIPM and
IERS are connected:
http://www.npl.co.uk/science-technology/time-frequency/time/research/the-world-time-system
/tvb
___
When there's a leap second, what do you want to do?
Ignore it = GPS time
put in an extra pulse = UTC time
Nice try, but that's not how it's done. They put in an extra second in the
last minute of the day.
23:59:59
23:59:60
00:00:00
Humm. Isn't that backwards. Don't you want to
Bert
Want to share the results?
More info re the experiment would be of interest as well.
DaveB, NZ
- Original Message -
From: ewkeh...@aol.com
To: time-nuts@febo.com
Sent: Tuesday, March 30, 2010 6:32 AM
Subject: Re: [time-nuts] Making a HP 10811 better
I would not feel comfortable
Hal,
The words insert a pulse is what causes the confusion in
conjunction with leap seconds. There is no extra or missing
pulse; no double pulse, no early or delayed pulse.
The 1PPS output continues to give a pulse at a 1 Hz rate
regardless if there is leap second or not. There is never
any
Referring to the GPS ICD, the size of A0 in subframe 4 is a signed
scaled 32
bit integer so if a receiver chooses to convert it to floating point it
needs a double precision format to contain it without loss of precision.
A1,
on the other hand, is a signed scaled 24 bit integer and so it
or, the map is not the territory?
Don
Tom Van Baak
Hal,
The words insert a pulse is what causes the confusion in
conjunction with leap seconds. There is no extra or missing
pulse; no double pulse, no early or delayed pulse.
The 1PPS output continues to give a pulse at a 1 Hz rate
Now if you really want some fun connect your OCXO to a
one meter cable and let it swing like a pendulum clock. You
should see some very nice sinusoidal FM as it goes back
and forth. Devise some sort of mechanical, compressed air,
or magnetic impulse system to keep it running like that all day.
Hi Tom:
Here's a 2g (turnover) plot for the PRS10 Rb source:
http://www.prc68.com/I/PRS10.shtml#Accel
Have Fun,
Brooke Clarke
http://www.PRC68.com
Tom Van Baak wrote:
Now if you really want some fun connect your OCXO to a
one meter cable and let it swing like a pendulum clock. You
should
Hi
Thermal shifts from tip are a very real issue when you flip around OCXO's.
The acceleration is an instantaneous change. The thermal will have a time
constant out beyond 30 seconds. It's pretty easy to separate the two if you
have something that functions like a strip chart recorder. Stable 32
Bert wrote: would not feel comfortable tearing into the unit.
I tend to agree, First rule is do no harm,
which is why I start with reversible things that can be done using just
external stuff.
The second rule does NOT apply though, Don't fix it, if it aint broken
Of course if it is already
t...@leapsecond.com said:
The words insert a pulse is what causes the confusion in conjunction with
leap seconds. There is no extra or missing pulse; no double pulse, no early
or delayed pulse.
The 1PPS output continues to give a pulse at a 1 Hz rate regardless if there
is leap second or
At 05:59 PM 3/29/2010, WarrenS wrote...
Bert wrote: would not feel comfortable tearing into the unit.
I tend to agree, First rule is do no harm,
I've got this rule that says If I don't know what the insides look
like when it's working, I won't know what to look for when it breaks.
:-)
It is simple to divide the PPS to the square wave, but what is needed is a
simple/surefire method of adding/removing the leap seconds. Preferably one
that works automatically. Any ideas?
Software.
If you want to remove leap seconds, you need a way to insert an extra pulse.
Fortunately,
Use a JK flip flop to divide by 2.
During insertion of the leapsecond take J+K to zero to disable toggling
of the FF.
To delete leap second you could try inserting an extra clock pulse
halfway between a apair of seconds ticks.
If the clock cant cope with the above scheme you may need to use a
I agree with leaving well alone,
But I had a HP10811 which had no EFC control.
I agonised about why this would be and bought a few varicaps,
- I could not find suitable current sources and I had resistors.
When I opened it I found the junction of the varicap diode,
the oscillator capacitor and a
I did retrieve it many times that is why I had all those sand bags with #
strings and that time the cost of an oscillator was much higher and I tried
putting the bags in and out several times before the oscillators went down
there including leak test for moisture penetration.
Bert
In a
Aww, what a bunch of unadventurous louts ;-) Where's the fun in that? Boldly
go... but let's not talk about that core memory stack assembled under 5 tons
of pressure... I wondered why those bolts were so tight...
Bert wrote:would not feel comfortable tearing into the
or was that the capacitor storage in the IBM704?
Don
Mark Sims
Aww, what a bunch of unadventurous louts ;-) Where's the fun in that?
Boldly go... but let's not talk about that core memory stack assembled
under 5 tons of pressure... I wondered why those bolts were so tight...
Hi
The 10811 should respond quickly enough that a few minutes (5 ~10) between
steps should be plenty. If you stretch it out to far, things like aging,
retrace, and ambient change can get into the data. Always return to your
original resistor value to confirm that drift hasn't gotten in the
Steve Rooke wrote:
So there are 250 clocks, presumably, spread around the World and owned
by the member countries of the BIPM.
There is a fair spread geographically, yes. See map:
http://www.bipm.org/en/scientific/tai/tai.html
Their time is somehow compared centrally and an absolute time is
Hi
You can get a *much* more squared output from the mixer than the photos you
show on the scope. The waveform looks a lit like a triangle wave with the tips
chopped off. Normally the fastest edge happens into a capacitive load at RF
that's below about 0.5 J ohms for a 50 ohm mixer.
Bob
On
Brian
You should get even better results if you replace the 330pF cap with a
1/4 wave (at the 20MHz sum frequency) coax cable open circuited stub.
Thats around 2.5m of RG 58 coax for example.
Connecting a series tuned circuit (at the sum frequency) across the
mixer IF output should also
Your poor results at 1kHz have more to do with the 1K +0.1uF low pass
filter which has a cutoff frequency of about 1.6KHz.
This will attenuate the beat frequency harmonics required for high slew
rate at the beat frequency zero crossings.
A filter cutoff of 16kHz (1K + 10nF) should improve the
t...@leapsecond.com said:
a0 = -0.931 ns and
a1 = -5.33e-15 s/s (which is -0.460 ns/day).
It changed at 15:53:40 Pacific time.
Was: -9.31323e-10 -5.32907e-15
Now: -2.79397e-09 -5.32907e-15
--
These are my opinions, not necessarily my employer's. I hate spam.
Your correct - your also keeping me up past my bedtime !- I got to be 90
miles from home tomorrow morning by 7:30 AM
It looks like I got the squarest wave at 150 pF. Lesser capacitance,
give a peaked sinewave, like maybe a second harmonic. Past 200 pF, it
starts rounding. 150pf= XC of
I picked one of these up for $5 this weekend but can find almost
nothing about it. Takes 117V A/C and spits out a BNC 10 MHz.
The only thing on the front is a STBY / ON switch and two LEDs
indicating said switches position.
No surprise, nada from Anritsu.
Anyone seen/had/have one ? Comments ?
42 matches
Mail list logo
