I'm experimenting with an Adafruit receiver (MTK3339) and I'd like to be able
to compute the time error delta between each reported position. I can guess
it's a vector difference between each two successive points converted to ns,
but beyond that, I don't know what to do. IOW, I need to know t
Bert,
Let me know if you can do stable >1s loops in the analog domain with reasonable
cap sizes say <220uF. I would be impressed. I tried.
Bye,
Said
Sent From iPhone
On Nov 3, 2013, at 14:51, ewkeh...@aol.com wrote:
> We are looking at room temperature 5 and 10 MHz XO's for cleaning up Rb and
Magnus you are spot on, Quartz is one of those areas that is still as much art
as science.
Thomas Knox
> Date: Sun, 3 Nov 2013 23:13:20 +0100
> From: mag...@rubidium.dyndns.org
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] The 5MHz Sweet Spot
>
> Hi,
>
> Let me point out one little thi
Bert,
On 11/03/2013 11:51 PM, ewkeh...@aol.com wrote:
> We are looking at room temperature 5 and 10 MHz XO's for cleaning up Rb and
> DDS. Filter time 1 to 20 seconds and thermal mass to keep temperature
> influence low. Hard to find XO's, so what we are testing is older TCXO's
> where
> we
We are looking at room temperature 5 and 10 MHz XO's for cleaning up Rb and
DDS. Filter time 1 to 20 seconds and thermal mass to keep temperature
influence low. Hard to find XO's, so what we are testing is older TCXO's where
we remove the TC and use the tuning circuit for loop control. Any
s
Hi,
Let me point out one little thing. While you can pick up stuff from the
many comments here, remember that this is a field of a whole myriad of
effects and challenges. Different insight at different periods have
provided for different "truths" and design approaches. Some of the
issues can be ha
They have crystals so it would seem so. I wonder are the jumps are model,
brand, or design dependent and to what degree? Also thanks to everyone
contributing their knowledge and experience to the thread. I for one am
learning a great deal. I am still interested if anyone has insights to Magnus's
On 11/03/2013 10:28 PM, Hal Murray wrote:
> Do low cost recycled Rubidiums have any quirks equivalent to frequency jumps
> in crystals?
Consider that they have a crystal as a fly-wheel oscillator, so if that
does a frequency jump, it will show, but be tracked in. If the
oscillator does a phase-jum
The partial answer is: yes as they typically use 10MHz crystals too. But the
loop BW is so wide (10Hz or more) that the crystal jumps get compensated very
quickly.
We have not seen any real frequency jumps in 100's of CSACs we tested that use
vapor cells just like RB's do, so from my experience
Do low cost recycled Rubidiums have any quirks equivalent to frequency jumps
in crystals?
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Hi Warren,
On 11/03/2013 08:55 PM, WarrenS wrote:
>
> Said Jackson posted:
>> Crystal jumps are the biggest menace facing users of
>> crystals/oscillators today.
>
> Are you including both phase jumps and frequency jumps together?
> Is one more or likely to happen than the other?
> Is it mostly a
Forgot one comment: the good parts' plot also shows a very nice crystal
retrace stabilization in the red EFC trace over about the first 6 days or so.
After that the crystal goes into it's long term crystal aging mode.
Retrace is one big reason why its best to let crystals run continuously..
Said Jackson posted:
Crystal jumps are the biggest menace facing users of crystals/oscillators
today.
Are you including both phase jumps and frequency jumps together?
Is one more or likely to happen than the other?
Is it mostly a jump that effects just the phase or freq, or is there
everythin
Hi
Given that a full blown electroless BVA crystal typically costs > $900 a
piece, you are unlikely to find them in sub-$400 oscillators. There is pretty
good evidence that they also can have jumps that need to be screened out….
Testing wise, looking at any part with a 2 to 5 ppt ADEV for sub
On Sun, 3 Nov 2013 09:33:57 -0800
Said Jackson wrote:
> Crystal jumps are the biggest menace facing users of crystals/oscillators
> today and so far I have never been given a reasonable explanation from any
> of the vendors out there what causes it and how to avoid it or how they plan
> to addres
Thanks Jackson, I think I have seen that lately, I thought that was a GPS
problem related to the transition between holdover and locked but I was unable
to reproduce it with a GPS simulator. It is really pronounced on the C-Mac in
the unit.
Thomas Knox
> CC: time-nuts@febo.com
> From: saidj
Bob, et. al.,
Lots of opinions in this discussion, but none of it discusses the elephant in
the room affecting todays' vendors:
Random crystal instability versus manufacturing techniques.
I can buy oscillators from multiple vendors that have -115dBc at 1Hz or better
and noise floors of -182dBc
Hi,
On 11/03/2013 05:22 PM, Tom Knox wrote:
> I am not the right person to explain, So anyone with more knowledge please
> feel free to jump in. I think basically the reasoning is as a single clock
> the system at some point it would need mantainance or repair. So time is
> maintained with an a
I am not the right person to explain, So anyone with more knowledge please feel
free to jump in. I think basically the reasoning is as a single clock the
system at some point it would need mantainance or repair. So time is maintained
with an algorithm that monitors all the clocks and oscillators
My questions exactly. For the moment I think question 4 may be covered in
Archita Hati's paper State-of-the-Art RF Signal Generation From Optical
Frequency Division.
The other questions are what drives many Time-Nuts I know.
Thomas Knox
> Date: Sun, 3 Nov 2013 03:40:40 +0100
> From: mag...@
On 11/3/13 4:27 AM, Magnus Danielson wrote:
Hi Jim,
Ground-based GPS-like transmitters could be a nice option to consider.
Well, that's basically what we do today. We transmit a very stable
carrier with some tones or a PN sequence modulated onto it. The
spacecraft recovers it, generates a
Hi
Rubiola is looking at resonators he can buy off the shelf. They are constrained
by the commonly available packages. The Q x F product does not suddenly stop
going up at 5 MHz. There is good documentation that it keeps on going as the
frequency goes down. Is Q everything - of course not. Howe
Hi Bob
I've seen this topic discussed here before and it does seem to raise some
quite strong emotions and there does seem to be some confusion.
I can remember quite clearly, historically at least, 5MHz being commonly
promoted as the optimum frequency for crystal oscillators on the basis t
Hi Tom,
On Sat, 2 Nov 2013 16:06:06 -0600
Tom Knox wrote:
> Our house standard F1 a cesium fountain is used roughly one month every
> few months to characterize roughly 12 5071A cesium standards steering
> about 5 MHM 2010 cleaned up with a number of 8607 option 08 oscillator.
What is the reas
Hi Jim,
On 11/03/2013 05:21 AM, Jim Lux wrote:
> On 11/2/13 7:40 PM, Magnus Danielson wrote:
>> On 11/03/2013 02:45 AM, Bob Camp wrote:
>>> Hi
>>>
>>> I believe that you are talking to two very different groups, one who
>>> actually design the crystals and the other who use the products that
>>> a
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