This unit on ebay is made from Racal. The complete unit, oscillator and
power supply is the MA259. It is a +/- 5 e-10 day stablity.
This equipment is only good to spend winter time or for museum. Several
newer oscillator,like HP10811/10544, have the same characteristics or
better in smaller
On 9/14/2012 8:00 AM, time-nuts-requ...@febo.com wrote:
For those of you interested in timing mechanical clocks or watches, a wonderful
site to visit is:
http://www.bmumford.com/microset.html
/tvb
So, does this unit include an input for a external reference? I would
be interested in
So, does this unit include an input for a external reference? I would
be interested in knowing what they use for a timing reference...
:)
Dan
Last I checked with Bryan, he has XO and TCXO and GPS options for the Microset
timer.
Realize that most traditional watch/clock people are
Hi
Seconds per 30 day month turned out to be a pretty good unit for the watch
module specs back in the dark ages. More or less divide by 2.5 (or 2.592 if
you have a calculator) and you get ppm.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]
Another rule of thumb is 1 second in a dozen days is almost exactly 1 PPM.
And two seconds before retirement (say, age 65) is close to 1 PPB. Three
seconds a century is also 1 PPB.
Related to that, next time you read a newspaper article about atomic clocks I
guarantee you'll see words like one
I may have the opportunity to bulk purchase several Very high end GPS over
fiber systems. This system is great if you have a long cable run; or in my
case, to isolate my Time and Freq system from lightning strikes. I understand
they are two Antenna systems and they will work with any antenna
This equipment is only good to spend winter time or for museum. Several
newer oscillator,like HP10811/10544, have the same characteristics or
better in smaller size.
The component used ar not the best and you can have fault expecially on
the power supply.
Luciano,
My experience is that
Greetings nuts,
I've been working on a simple GPSDO as a starting point for further
experimentation. I'm using a STM32 microcontroller running at 72MHz as
the heart, with the input capture peripheral comparing the phase of the
pulses-per-second and a 16 bit PWM DAC to drive the VFC. It's all
Hi M.
welcome to the world of GPSDO optimization, one thing you will find is
that there never is a time when there is no chance to improve something :)
On the 1PPS sawtooth correction, the usual convention is for the following
1PPS.
The easiest thing to do rather than trying to guess
On Fri, Sep 14, 2012 at 11:21 AM, Michael Tharp
g...@partiallystapled.com wrote:
Finally, do people think a 16 bit DAC is adequate or should I consider
building a 32-bit one? I looked at a few designs when putting this together
but decided to keep it simple until things were up and running.
Hello Edgardo,
glad you received them well, and within 48 hours from China! Hopefully
they will work as well for you as for me.
I noticed that some of the 60Hz/120Hz artifacts can come through the power
supply into the 10MHz, so pick a power supply that has a case-ground
connection, not
Also you need a super ultra fantastic voltage reference for a 32bit DAC.
Anyway, yes, in my GPSDO the controller has 3 levels: at startup is fast,
then slow and then very slow. The levels trigger when the precision
estimate is 10E-9 and 10E-11. If you have a resolution of 10nS then take 10
GPS over fiber is GPS RF signal over fiber or the PPS over fiber or
something else?
On Fri, Sep 14, 2012 at 7:12 PM, Tom Knox act...@hotmail.com wrote:
I may have the opportunity to bulk purchase several Very high end GPS over
fiber systems. This system is great if you have a long cable run;
The HBE AIRORLITE GPS-1000 2 Channel Tx Rec system uses you existing GPS
antenna and converts the signal in a weather proof box to fiber then a rack
mount rec converts the optical signal back to RF L1 1575 to your GPS receiver.
Thanks;
Thomas Knox
1-303-554-0307
Date: Fri, 14 Sep 2012
Will this be able to discipline a rubidium oscillator as well as a OCXO?
Maybe you could switch in a divider network to close in the trim range as
the oscillator precision improves.
Hope someone makes a PC board available. Count me in for some.
- Original Message -
From: Azelio
Azelio Boriani wrote:
Also you need a super ultra fantastic voltage reference for a 32bit DAC.
Not really, the reference only needs to have low noise and good short
term stability.
Long term drift in the reference voltage will be corrected by the
feedback loop.
Anyway, yes, in my GPSDO
Yes, you are right: but actually I have a 2.5nS simple time interval
counter in the FPGA and the only way to go beyond is the average. The
sophisticated way would be to implement a tapped delay line or vernier
delay line time-to-digital converter in a bigger FPGA than the XC3S50. And,
yes, I have
Hi
In the case of some systems, long term may only cut in past a few hours.
In the case of a Rb, it may be a few days.
If the reference sees room temperature, it's going to need very good
temperature stability for full 32 bit resolution. Something in the 0.2 ppb
/ C range...
Bob
Michael: Actually implementing a 16 bit DAC to its 1-bit minimum
resolution will be headache enough. You will gain a real education in
good grounding practice, shielding, power supply stability and noise,
and other Murphy intrusion. A 32 bit DAC IMHO, is impossible, and that's
the name of that
-- Forwarded message --
From: Don Latham d...@montana.com
Date: Fri, Sep 14, 2012 at 2:01 PM
Subject: Re: [time-nuts] GPSDO control loops and correcting quantization error
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Michael: Actually implementing a
On 09/14/2012 05:31 PM, Chris Albertson wrote:
Michael: Actually implementing a 16 bit DAC to its 1-bit minimum
resolution will be headache enough. You will gain a real education in
good grounding practice, shielding, power supply stability and noise,
and other Murphy intrusion. A 32 bit DAC
d...@montana.com said:
Michael: Actually implementing a 16 bit DAC to its 1-bit minimum resolution
will be headache enough. You will gain a real education in good grounding
practice, shielding, power supply stability and noise, and other Murphy
intrusion. A 32 bit DAC IMHO, is impossible, and
Hello all,
Most voltage controlled XOs have a voltage reference output. Is it necessary
for the DAC output / frequency control input, to track this voltage reference
output?
Thank You
Don O'Connor
___
time-nuts mailing list --
Hi Don,
I don't know if I've misunderstood your question, but as I understand it
the voltage reference output is a fixed voltage from an internal regulator
that can then be used as the supply to an external control circuit.
For example, it could be used as the feed voltage for a variable
If it is a reference then tracking is not the correct term: it shouldn't
move. If it is a reference then can be used for the DAC.
On Sat, Sep 15, 2012 at 12:10 AM, Don Oconnor eg...@wowway.com wrote:
Hello all,
Most voltage controlled XOs have a voltage reference output. Is it
necessary
Nigel,
Yes, you understood and answered the question.
Thank you
Don O
I don't know if I've misunderstood your question, but as I understand it
the voltage reference output is a fixed voltage from an internal regulator
that can then be used as the supply to an external control circuit.
On Fri, 14 Sep 2012 15:08:53 -0700, Hal Murray
hmur...@megapathdsl.net wrote:
d...@montana.com said:
Michael: Actually implementing a 16 bit DAC to its 1-bit minimum resolution
will be headache enough. You will gain a real education in good grounding
practice, shielding, power supply stability
My 2.5nS TIC? Very simple: a 400MHz counter start-stop gated with the two
signal to compare. I have published here the VHDL code for it few months
ago. Really nothing new but simple and useful for a 35-40nS GPSDO PPS
output from an OCXO. The Rb PPS wondering is actually under evaluation
against
Hi
Very few VCXO's have reference outputs. Some OCXO's have reference outputs. The
gotcha there is the oven current. You can easily get multiple mV sort of
changes in the OCXO ground voltage as the oven current cycles over a fairly
narrow range. That significantly impacts the usefulness of
I would expect a problem area would be filtering the PWM output. Anything
you don't filter out will turn into close in spikes. It might be fun to try
to measure them.
64K/72 MHz is about 1 ms. 32bits at 72 MHz is 60 seconds.
Has anybody compared DDS style DACs with PWM? The idea is
The pulse that drives the stepper (in the Casio watch in this case) as Tom
mentioned is detectable on an AM receiver. I have a Grundig Yacht Boy and when
tuned anywhere below 300 Khz with the watch set against the top of the radio a
very clear pop or noise burst is heard at each second. I
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