b...@lysator.liu.se wrote:
I would check the antenna types to be tested at home with a new Garmin to
see if the antennas work with below spec DC voltage.
Hi Bjorn, thats a good suggestion and as a test I just tried my TomTom
vehicle unit which supplies just fractionally over 3v at the
I don't have any more PCBs left for the frequency divider I did last year,
but if there's enough interest, I can get another batch made up. All
outputs re-clocked to input using FF before final line driver stage.
Cheers
Dave
-Original Message-
From: time-nuts-boun...@febo.com
That's also a good move and could also implement a little diagnostics
capability by monitoring the volts/current, but if a standard gps will
do the go /no go test its less to carry (and break) in the field.
Another (possibly crazy) idea is to find some of the old units that you know
and
Do things never break in good weather?
Yes, but only when all the people able to fix them are away on holiday or
off sick, or you've run out of the necessary parts.
D.
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David C. Partridge skrev:
Do things never break in good weather?
Yes, but only when all the people able to fix them are away on holiday or
off sick, or you've run out of the necessary parts.
When ever else?
Things almost always fails when least convenient.
On rare occasions you have a
All,
Does anyone have any experience with the Datum/Efratom LPRO-101
Rubidium standard? There are large amounts of these on e-bay.
The datasheet specifies life time to at least 10 years
and the one that I found on a flea market is dated 1999.
I assume that they are replaced as a planned
I have not had any experience with FEI devices,
the LPRO lamp voltage comes from an amplifier
which monitors some internal voltage. I guess they
scaled it to be similar to other rubidium devices.
The lamp requires a very small amount of rubidium to
provide the vapour, which should be at a low
Do you mean one should use SiGe ECL (or CML) D flipflops or higher
performance devices for the output synchronisers?
It would surely be a little difficult to justify this given the
relatively noisy outputs of most rubidium sources.
A 74HC4017 has a symmetric 1:1 mark space ratio divide by ten
No, you can never improve on what you start out with, I would just eliminate
the jitter you may get with the 90's. I would use a 74xx74 because it clocks
on the positive edge, the 90's on the negative edge. Looking at Jameco you
can get 74xx74 in DIL any where from F to HC. I would not use
Hi, Neville,
is the same with FEI products; Higher voltage when new, decreased with aging?
Predrag Dukic
At 12:17 30.3.2009, you wrote:
Hi,
they finish their life when the lamp fades out.
When you stoke it up there is a lamp monitoring voltage that
is about 10 volts when new but drops
In my opinion the best way is still to use two 74xx90 connected divide by
five and divide by two. That gives a symmetrical output. That is why you can
not
use a 390. The A output should subsequently be applied to a D or JK flip
flop with the clock input connected to the 10 MHz. The D or JK
Hi,
they finish their life when the lamp fades out.
When you stoke it up there is a lamp monitoring voltage that
is about 10 volts when new but drops below 4 volts at end of life.
Otherwise, if it will lock on it is probably a good unit. New users
tend not to understand that the frequency trim
Magnus Danielson wrote:
David C. Partridge skrev:
Do things never break in good weather?
Yes, but only when all the people able to fix them are away on holiday or
off sick, or you've run out of the necessary parts.
Or the customer has used up all the spares to expand the network :-)
David C. Partridge wrote:
I don't have any more PCBs left for the frequency divider I did last year,
but if there's enough interest, I can get another batch made up. All
outputs re-clocked to input using FF before final line driver stage.
Cheers
Dave
-Original Message-
From:
Is it possible to lock down, or control, the EFC on a Z3801 or Z3805?
Putting it into Holdover allows the system to steer it according to
its learnt characteristics, but I would quite like to bolt it down to
see how stable, or otherwise, the oscillator is. Unlike on the
Thunderbolt, I can't
Bill,
What's wrong with Tom's (/tvb) PIC divider ?
http://www.leapsecond.com/tools/PPSDIV.ASM
Rgds,
Kit
**
Message: 2
Date: Sun, 29 Mar 2009 20:28:57 -0700
From: Bill Janssen bi...@ieee.org
Subject: [time-nuts] state of the art devide by ten
To: Discussion of precise time
Kit
Probably the higher jitter and periodic phase modulation due to
simultaneous switching of multiple outputs at different frequencies.
The magnitude of the latter will depend on the loads driven by each output.
The cure is to use an external flipflop to resynchronise the outputs to
the 10Mhz
Tom Van Baak skrev:
Kit
Probably the higher jitter and periodic phase modulation due to
simultaneous switching of multiple outputs at different frequencies.
The magnitude of the latter will depend on the loads driven by each output.
The cure is to use an external flipflop to resynchronise
Tom
Tom Van Baak wrote:
Kit
Probably the higher jitter and periodic phase modulation due to
simultaneous switching of multiple outputs at different frequencies.
The magnitude of the latter will depend on the loads driven by each output.
The cure is to use an external flipflop to
When Bruce raised the question a bit earlier, I was curious so set up a
quick experiment.
I happen to have two 10 MHz to 1 PPS dividers based on Tom's code. They
lack the higher order outputs, so the modulation effects Bruce spoke of
aren't present, but they should be a good test for general
John
John Ackermann N8UR wrote:
When Bruce raised the question a bit earlier, I was curious so set up a
quick experiment.
I happen to have two 10 MHz to 1 PPS dividers based on Tom's code. They
lack the higher order outputs, so the modulation effects Bruce spoke of
aren't present, but they
John,
Thanks for sharing your experimental results.
I am surprised that the PIC divider outputs were
85 ms apart when driven from the same source. I
am ignorant of their internal workings, but I would
expect the jitter results to be significantly impacted
by this.
Any thoughts on the origin of
Over 1000 measurements at 1 PPS, I got a standard deviation of 46.9 ps.
The delta between minimum and maximum readings was 330 ps. Since we
were testing two independent dividers, I suppose you could divide the
standard deviation by the square root of 2, which gives about 33 ps.
I then did
Tom Van Baak wrote:
Over 1000 measurements at 1 PPS, I got a standard deviation of 46.9 ps.
The delta between minimum and maximum readings was 330 ps. Since we
were testing two independent dividers, I suppose you could divide the
standard deviation by the square root of 2, which gives about
In message 49d16637.60...@febo.com, John Ackermann N8UR writes:
Therefore, the PIC divider is a bit above the 5370B noise floor, but not
much.
Many years ago, I did a similar experiment, but to eliminate the
timebases from the measurement I used the PPS output as start
and the 10MHz input
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