Poul-Henning,
I mentioned yesterday about integrator windup, this problem is similar but
happens even without any I term present:
The problem is that the ocxo maintains its frequency even though the EFC
control voltage is changing. Thus phase error is accruing making the efc larger
and larger
time-nuts@febo.com said:
The problem is that the ocxo maintains its frequency even though the EFC
control voltage is changing. Thus phase error is accruing making the efc
larger and larger due to the P term.
Then at some point the crystal 'snaps' and jumps in frequency, overshooting
the
In message 9bc23a13-646f-49c6-9ff9-d42fa5ec8...@aol.com, Said Jackson writes:
Then at some point the crystal 'snaps' and jumps in frequency, overshooting
the desired frequency and causing the P term to start pushing in the opposite
direction repeating the cycle.
If your hardware does
, but it's what I did.
Burt, K6OQK
From: Poul-Henning Kamp p...@phk.freebsd.dk
Subject: Re: [time-nuts] LTE-Lite module
In message 9bc23a13-646f-49c6-9ff9-d42fa5ec8...@aol.com, Said
Jackson writes:
Then at some point the crystal 'snaps' and jumps in frequency, overshooting
the desired
Hi Hal,
This behavior is called hysteresis and it is related to vendors, and related to
the chips used (or varactor diode) inside the tcxo/ocxo. It is so subtle that
most vendors are not even aware that their oscillator is doing it. Some vendors
have product lines that do it and others that
would happen. I have detailed pictures if
anyone is interested.
I don't know if the above offers any input of value, or even how scientific
it is according to deep Time-Nuts standards, but it's what I did.
Burt, K6OQK
From: Poul-Henning Kamp p...@phk.freebsd.dk
Subject: Re: [time-nuts
Great insight thanks. You nailed it: out with the old oscillator and in with
one
that doesn't have that problem.
Btw the mechanical tuning issue you mentioned is essentially the same exact
problem: even the slightest turn will make the frequency jump too high or too
low. It can drive you
Hi John,
while I can't tell you which vendors are affected and which are not (Its
like asking an angler for his secret angling spot :), I can say that most low
cost TCXOs exhibit this behavior, and are thus not really suitable for
GPSDOs.
The ones we used on the LTE-Lite are quite good
Also have this problem with capacitor-adjusted tuning. No matterhow careful
you turn, stiction causes the adjustment to jump in the direction of the turn.
Don
John Miles
Great insight thanks. You nailed it: out with the old oscillator and in with
one
that doesn't have that problem.
Btw the
for each clock. They'll run
for a long time on those.
Burt
From: Said Jackson saidj...@aol.com
Subject: Re: [time-nuts] LTE-Lite module and the pendulum...
Burt,
Great insight thanks. You nailed it: out with the old oscillator and
in with one that doesn't have that problem.
Btw
described, the DAC sits within about
10 of 27450, and that's where my units are happy. By the way, I've
got two 1.5 KVA UPS's in my shoppe, one for each clock. They'll run
for a long time on those.
Burt
From: Said Jackson saidj...@aol.com
Subject: Re: [time-nuts] LTE-Lite module
Hi
Depending on how much you spend on a mechanical piston trimmer, the innards
will be coaxial to some tolerance. To the extent they rotate or “swing” as one
piece moves in and out of the other, the capacitance will be more linear or
less linear vs rotation of the trimmer.
What you want - a
In message 20141019233526.znmkx...@smtp11.mail.yandex.net, Charles Steinmetz
writes:
A proper digital filter that computes a new
running value at least every second will be more
complex than that, but you're right, it's not an unfathomable task.
No, it will not, a simple running
Poul-Henning wrote:
PLLs are really not that hard [context: we have been discussing
all-digital PLLs (ADPLLs)]
Yes, I know -- I have designed more than a few. I have also reviewed
more than a dozen hobbyist designs and modeled some of them, and
found that few hobbyists seem to have
Hi
We tend to focus on this or that enhanced feature in a piece of code. It’s fun
to talk about. That’s not what keeps most designs from doing what they should.
By focusing on this rather than the testing required, we set people up to fail.
If you start off the project believing you mostly
Bob wrote:
We tend to focus on this or that enhanced feature in a piece of
code. It's fun to talk about. That's not what keeps most designs
from doing what they should. By focusing on this rather than the
testing required, we set people up to fail. If you start off the
project believing you
http://phk.freebsd.dk/time/20141018.html
PHK,
This is the best news I've heard in a long time; an overhaul of NTP!
One suggestion I'd like to make. You've seen the GPSDO simulator code I started:
http://leapsecond.com/tools/gpsim1.c
And you've seen the growing collection of GPS receiver and
On Mon, Oct 20, 2014 at 6:48 AM, Bob Camp kb...@n1k.org wrote:
Hi
We tend to focus on this or that enhanced feature in a piece of code. It’s
fun to talk about. That’s not what keeps most designs from doing what they
should. By focusing on this rather than the testing required, we set people
In message 60CC0E034928B664249EAC88407F@pc52, Tom Van Baak writes:
http://phk.freebsd.dk/time/20141018.html
PHK,
This is the best news I've heard in a long time; an overhaul of NTP!
Indeed :-)
Instead of tweaking GPSDO algorithms or tuning parameters and
having to wait days to
In message CAGVVbuGv_-cFDAA=T6hGE1ey32=omxxcg-cxub5scusao_t...@mail.gmail.com
, Brian Lloyd writes:
So why not do the GPSD hardware, software, [...]
It would be a really worthwhile project in general, and it could be
made very general with very little trouble.
I would find a cheap ARM
Hi Brian, Bob, Charles, et. al.
Bob has a great point about the difference between a one-off in a basement
lab, and a commercial product that has to work under any circumstances,
wether flying at 50,000 feet at -56C, or in an urban canyon, or under whatever
other stress could be thrown at
Said
Having some fun reading your posts on time-nuts.
I placed an order last Friday or Saturday for one 20 Mhz unit. But a couple
of funny things seemed to happen like ebay saying 2 units ordered I
corrected that.
But today I received an email reminding me to pay you for the unit.
I have the
Hi
PHK has a roughly 6 line code snippet that does a basic PLL. Add two more lines
to check / clamp the integrator if you wish. That’s 8 lines. If you want a D
term (to give it an FLL component) add 2 more lines. We’re up to 10 lines.
It’s just a control loop, not a full GPSDO. There’s not a
Hi
The problem is that there are no “magic coefficients”. What you run depends
very much on the exact OCXO you have, the environment you run it in, and the
result you are after.
For instance, Bert is after frequency stability. Tom is after the right time.
Each of them will have very
Hi
The top of my list for “new NTP” would be to bring the 1588 hardware packet
time tagging into the NTP code base. There’s a pretty good base of hardware out
there that tags. It should help things on a loaded system.
Bob
On Oct 20, 2014, at 3:41 PM, Poul-Henning Kamp p...@phk.freebsd.dk
Paul,
I will answer you offline.
Guys please don't post items like this that aren't really of interest to all
the others on the list.
Thanks,
Said
Sent From iPhone
On Oct 20, 2014, at 13:41, paul swed paulsw...@gmail.com wrote:
Said
Having some fun reading your posts on time-nuts.
I
I absolutely did not intend to email time-nuts with my question on the
order.
I am embarrassed that happened and sorry everyone for the noise.
Regards
Paul
WB8TSL
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
Hello Jean-Louis,
unfortunately the 20MHz kits sold-out already so Ebay took down the page.
We only had 50pcs with 20MHz TCXOs. We are contacting the factory now to
see if we can get more on a quick turn.
Looks like instead of getting 50x 19.2MHz units we should have gotten more
20MHz
Allow me to clarify.
I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3
month + burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12.
Only two have been tested for ADEV and are close to 1 E-12, 2X not 10 X.
Bert Kehren
In a message dated 10/20/2014
Thanks much Charles,
just to remind everyone that the main idea of making the boards available
was to get folks a good disciplined TCXO, not to work as a development
platform to discipline external OCXOs.. Also as mentioned in the FAQ, the
typical performance plots I have been sending and
No worries, Paul. This was minor.
Actually, there have been quite a few postings in the past month that I suspect
went to the entire list instead of one recipient. It may have to do with the
recent changes to the mail list server (e.g., to accommodate AOL domains)? I'm
not really sure. It's
,
low-noise, low-drift quartz oscillators.
/tvb
- Original Message -
From: Bert Kehren via time-nuts time-nuts@febo.com
To: time-nuts@febo.com
Sent: Monday, October 20, 2014 4:01 PM
Subject: Re: [time-nuts] LTE-Lite module
Allow me to clarify.
I started out with 7 MV 89 one
here is the ADEV plot from my overnight test with the DOCXO. * * *
This was done without any loop adjustment whatsoever, same board and
software that drives the on-board TCXO. I will let the result speak
for itself,
save to say the loop, the DAC, the DAC reference, and the GPS with a
@febo.com
Sent: Monday, October 20, 2014 6:42 PM
Subject: Re: [time-nuts] LTE-Lite module
To add to Bert's note...
Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent,
almost by definition. What matters is phase noise and short-term stability,
neither of which you can
Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Monday, October 20, 2014 6:42 PM
Subject: Re: [time-nuts] LTE-Lite module
To add to Bert's note...
Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent,
almost
and frequency measurement time-nuts@febo.com
Sent: Monday, October 20, 2014 6:42 PM
Subject: Re: [time-nuts] LTE-Lite module
To add to Bert's note...
Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent,
almost by definition. What matters is phase noise and short-term
; Discussion of precise time and frequency
measurement time-nuts@febo.com
Sent: Monday, October 20, 2014 7:21 PM
Subject: Re: [time-nuts] LTE-Lite module
Bob,
You are on the right track!
Large changes in EFC can cause hysteresis, meaning you go back to an initial
voltage but the crystal does
that will keep the DAC stable when
loading new code.
Thanks!
Bob
From: Said Jackson saidj...@aol.com
To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency
measurement time-nuts@febo.com
Sent: Monday, October 20, 2014 7:21 PM
Subject: Re: [time-nuts] LTE-Lite module
: Re: [time-nuts] LTE-Lite module
Hi Bill,
I think it makes perfect sense. But I have no idea how the units' loop
stability would be with the 10811. That kind of testing is on the plate.
You would preferably set the OCXO to a nominal tuning voltage of 1.5V using the
mechanical adjustment
Bill wrote:
How tough would it be to mate the 10Mhz version up to a really good 10811?
* * * I was thinking of throwing the LTE-Lite and the 10811 in a box.
Unfortunately, to get the best out of the local oscillator, the
control PLL must be carefully adjusted so that the oscillator
In message 20141019155055.osmik...@smtp11.mail.yandex.net, Charles Steinmetz
writes:
zeroes). That would need to be done by changing the PLL parameters
internal to the LTE-Lite, which are inaccessible. Without such
reprogramming, the LTE-Light can never get the best out of an OCXO.
Poul-Henning wrote:
zeroes). That would need to be done by changing the PLL parameters
internal to the LTE-Lite, which are inaccessible. Without such
reprogramming, the LTE-Light can never get the best out of an OCXO.
It certainly can and it's not even hard:
Configure the LTE to emit a
In message 20141019183956.dt4ss...@smtp2o.mail.yandex.net, Charles Steinmetz
writes:
Configure the LTE to emit a suitable frequency relative to the
OCXO and use an analog PLL to steer the OCXO's EFC.
Then do it digital, it's not like it's rocket science...
Take the analog phase
Hi
The phase comparison part of the PLL is pretty straightforward if you are
looking at two RF frequencies. An XOR gate is one solution, there are many
others. Getting something like 100 to 200 ns full scale on the phase comparator
makes the rest of the gizmo much easier. A 12 bit ADC on a MCU
Hi
On Oct 19, 2014, at 3:35 PM, Charles Steinmetz csteinm...@yandex.com wrote:
Bob wrote (alluding also to something Poul-Henning wrote):
The phase comparison part of the PLL is pretty straightforward if you are
looking at two RF frequencies. An XOR gate is one solution, there are many
With all the work around if you want very good performance use a Shera. We
have super results with a Morion, Shera and ublox M7
Bert Kehren
In a message dated 10/19/2014 4:08:32 P.M. Eastern Daylight Time,
kb...@n1k.org writes:
Hi
On Oct 19, 2014, at 3:35 PM, Charles Steinmetz
Bob wrote (alluding also to something Poul-Henning wrote):
The phase comparison part of the PLL is pretty
straightforward if you are looking at two RF
frequencies. An XOR gate is one solution, there
are many others. Getting something like 100 to
200 ns full scale on the phase comparator
On 10/19/14, 1:08 PM, Bob Camp wrote:
Hi
On Oct 19, 2014, at 3:35 PM, Charles Steinmetz
csteinm...@yandex.com wrote:
Bob wrote (alluding also to something Poul-Henning wrote):
The phase comparison part of the PLL is pretty straightforward if
you are looking at two RF frequencies. An XOR
Hi
On Oct 19, 2014, at 5:00 PM, Jim Lux jim...@earthlink.net wrote:
On 10/19/14, 1:08 PM, Bob Camp wrote:
Hi
On Oct 19, 2014, at 3:35 PM, Charles Steinmetz
csteinm...@yandex.com wrote:
Bob wrote (alluding also to something Poul-Henning wrote):
The phase comparison part of the PLL
At the low end of the spectrum, I tried to make the simplest possible
GPSDO what would still work. Assuming you have a GPS with 1PPS
output, an OCXO and a small DC power supply I was able to get the
entire parts for the controller, board, hookup wire and all for under
$5. I purposely took the
We did the same using a 1 KHz out of the $ 14 ubolx M7 and a Morion .
Results better than 1 E-10. Some time nuts are now assembling and testing the
same. Total cost less than $ 10 not counting OCXO or GPS. Most expensive item
is the filter capacitor.
Bert Kehren
In a message dated
Hi
We seem to have swung from “it’s impossible, don’t even try” to “it’s trivial,
you should have it done in a few minutes” :) (Yes I know that’s *not* at all
what was said in either case. We have swung a ways though)
Yes, I can do it for less than $1 in parts. That’s not to say it’s the
I look forward to the app note. Might be the incentive to get me to
actually USE the Express PCB software I have.
Jim
On 10/17/2014 4:40 PM, S. Jackson via time-nuts wrote:
Hi there,
I don't know how much the Wenzel units are, but if someone is not able to,
or willing to build one on
On 17 Oct 2014 19:33, S. Jackson via time-nuts time-nuts@febo.com wrote:
Hello Jim,
let me answer through Time Nuts as this may interest other parties as
well.
Yes, using a fast flip flop to generate 10MHz out of the 20MHz TCXO 3.0V
CMOS output from the LTE-Lite module will preserve the
Hi
For a lab reference, “clean” is a relative term. Most (as in every one I’ve
ever seen) instruments expect a dirty signal on the reference input. They phase
lock an internal oscillator to clean it up. Past some (unfortunately variable)
offset, the reference signal has no impact on the
Hi guys,
lots of questions, let me try to answer some of these. Bob, David, et. al,
thanks for answering some of these already!
Dave, as Bob said it depends on your application -- and your time frame.
Also, please check the FAQ for an answer on the external TCXO requirement,
specifically
Guys,
we have been getting a good number of emails with questions that have
already been addressed in the user manual or the FAQ, see the below link. We
spent a lot of time putting the collateral together, may I please ask that
you first look into these two documents to see if your
Hal,
attached is the superimposed plot of the standard 20MHz TCXO Phase Noise
and the 10MHz output of my bare-bones divide by 2 flip-flop. The green trace
is the new 20MHz plot, the blue the one I had sent out yesterday at 10MHz,
both sourced from the same TCXO.
You can nicely see that
Guys,
one last email. The board will not fit into the Hammond enclosure without
reworking the enclosure or removing the TCXO socket. We initially planned to
ship the board without the socket, now all of them will have it. The
board was designed to be used without the TCXO/Socket to fit
Said:
Your email app note was VERY clear, thanks.
You also mentioned somewhere that the synthesizer output of 10 MHz is
cleaner than most freq counters, etc., need, so I will probably just use
that for the test equipment. I will use the 20 MHz as reference for
microwave LOs, and will do the
Hi Bill,
I think it makes perfect sense. But I have no idea how the units' loop
stability would be with the 10811. That kind of testing is on the plate.
You would preferably set the OCXO to a nominal tuning voltage of 1.5V using the
mechanical adjustment, then let the LTE Lite do the rest.
Said,
How tough would it be to mate the 10Mhz version up to a really good 10811?
I have one that I acquired from Corby some time ago. I was going to spin
my own but I wont realistically get to that with everything else I have
going on. I was thinking of throwing the LTE-Lite and the 10811 in a
I am sorry, but I can't follow the circuit diagram. It is not clear to me
what pins are joined, and what are not. Sometimes you have used a filled
circle to indicate lines are joined, and in another case there's a
semicircle to indicate that they are not. But on some of the others, I
don't
Hi
The 20 MHz connects only to pin 3.
+3V connects to pin 4 , but not pins 2 or 3.
Pin 6 hooks only to pin 2 and nothing else.
Bob
On Oct 18, 2014, at 8:23 PM, Dr. David Kirkby (Kirkby Microwave Ltd)
drkir...@kirkbymicrowave.co.uk wrote:
I am sorry, but I can't follow the circuit
-nuts@febo.com
Sent: Saturday, October 18, 2014 5:40 PM
Subject: Re: [time-nuts] LTE-Lite module
Dave, et.al.,
upon popular request I put together a PDF of my email describing how I
generated a low-phase-noise 10MHz output from the CMOS 20MHz output of the
LTE-Lite GPSDO. Here
Thanks for helping out Bob,
sometimes I get ahead of myself.
Dave, you can also trace the wiring on the photo I had sent of the actual
module, its more or less clearly visible under the lupe. Please note that
on that module I mounted the IC upside down, with the pins sticking up, and
, 2014 5:40 PM
Subject: Re: [time-nuts] LTE-Lite module
Dave, et.al.,
upon popular request I put together a PDF of my email describing how I
generated a low-phase-noise 10MHz output from the CMOS 20MHz output of the
LTE-Lite GPSDO. Here it is.
No guarantees whatsoever guys, and it does
#ht_411wt_664
600+ MHz cmos 3.5 volt
Tom
- Original Message - From: S. Jackson via time-nuts
time-nuts@febo.com
To: kc0...@gmail.com; time-nuts@febo.com
Sent: Saturday, October 18, 2014 5:40 PM
Subject: Re: [time-nuts] LTE-Lite module
Dave, et.al.,
upon popular request I
Hello Jim,
let me answer through Time Nuts as this may interest other parties as
well.
Yes, using a fast flip flop to generate 10MHz out of the 20MHz TCXO 3.0V
CMOS output from the LTE-Lite module will preserve the phase noise (actually
improve it by up to 6dB due to the 20log(n/m) noise
I have emailed Wenzel about pricing and whether or not they will sell
small quantities. Will advise.
Jim
wb4...@amsat.org
On 10/17/2014 2:32 PM, S. Jackson via time-nuts wrote:
Hello Jim,
let me answer through Time Nuts as this may interest other parties as
well.
Yes, using a fast flip
Hi there,
I don't know how much the Wenzel units are, but if someone is not able to,
or willing to build one on their own then this could be a viable
alternative.
I will look into writing a short appnote describing how a low-noise
div-by-2 can be built at home with minimal components
How much would we guess that Wenzel blue-top would run you?
Relative to the low cost GPSDO, my understanding is the Wenzel parts are
priced appropriately to their quality.
On Fri, Oct 17, 2014 at 11:32 AM, S. Jackson via time-nuts
time-nuts@febo.com wrote:
Hello Jim,
let me answer
And lastly the entire setup as tested:
In a message dated 10/17/2014 11:32:49 Pacific Daylight Time,
saidj...@aol.com writes:
Hello Jim,
let me answer through Time Nuts as this may interest other parties as
well.
Yes, using a fast flip flop to generate 10MHz out of the 20MHz TCXO
Jim,
Here is the resulting 10MHz phase noise plot from the 20MHz TCXO output:
In a message dated 10/17/2014 11:32:49 Pacific Daylight Time,
saidj...@aol.com writes:
Hello Jim,
let me answer through Time Nuts as this may interest other parties as
well.
Yes, using a fast flip flop to
Jim, et. al.,
I spent some time today and put together a Divide-by-2 circuit. Attached
are the schematics, I will send some photos in additional mails so we don't
overload the mail system.
Some comments:
* I grab the 3.0V from capacitor C6 on the eval board. That is the
low-noise
Some photos of the divider module I built:
In a message dated 10/17/2014 11:32:49 Pacific Daylight Time,
saidj...@aol.com writes:
Hello Jim,
let me answer through Time Nuts as this may interest other parties as
well.
Yes, using a fast flip flop to generate 10MHz out of the 20MHz TCXO
Said,
What tool(s) did you use to generate that data and output the graph?
Thanks,
John
On Fri, Oct 17, 2014 at 6:10 PM, S. Jackson via time-nuts
time-nuts@febo.com wrote:
Jim,
Here is the resulting 10MHz phase noise plot from the 20MHz TCXO output:
In a message dated 10/17/2014
John,
I used John Miles Timepod and associated application software, now
available from Microsemi, and highly recommended. I fed the output of the DFF
directly into the timepod (via a DC-block and 33 Ohms series resistor).
The reference was an HP 58503A GPSDO which limits the noise floor
On 24/09/2014 12:16 PM, Dave Martindale wrote:
Hello. Please add me to the list of people interested in the LTE-Lite eval
kits.
(I did not send a previous email, and you did not lose it - I've just been
slow in writing).
Thanks,
Dave
On Tue, Sep 23, 2014 at 8:05 PM, S. Jackson via
Said;
It appears that my email (off-list) expressing interest in the eval kit was
one of the ones which were 'eaten', so here I am, on-list, asking to be
placed on your corporate email list.
JimT
On Tue, Sep 23, 2014 at 8:05 PM, S. Jackson via time-nuts
time-nuts@febo.com wrote:
Hello
Hello Time-Nuts,
we put together an email list with the large number of email info-requests
I got for the LTE-Lite eval kits over the weekend.
I have just sent an email to everyone on that email list from my corporate
email account.
Unfortunately my AOL account has a tendency to eat
Hello. Please add me to the list of people interested in the LTE-Lite eval
kits.
(I did not send a previous email, and you did not lose it - I've just been
slow in writing).
Thanks,
Dave
On Tue, Sep 23, 2014 at 8:05 PM, S. Jackson via time-nuts
time-nuts@febo.com wrote:
Hello Time-Nuts,
Said,
Please also add me to the list of interested parties for the LTE-lite eval
kit.
thanks
-eric
On Tue, Sep 23, 2014 at 5:05 PM, S. Jackson via time-nuts
time-nuts@febo.com wrote:
Hello Time-Nuts,
we put together an email list with the large number of email info-requests
I got for
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