Some clarifications on the ADC in the ATmega328 and how it is used in the
Arduino GPSDO.
The resolution is 10 bits but you can select Vref. In my Arduino GPSDO it is
set to the internal Vref = 1.1V so 1LSB is 1.1mV. From the beginning I used 5V
as Vref but if you plot the response from the
: Fri, 07 Mar 2014 21:28:31 -0800
From: Hal Murray hmur...@megapathdsl.net
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Cc: hmur...@megapathdsl.net
Subject: Re: [time-nuts] Another atomic clock question
Message-ID:
20140308052831.40d3e406...@ip-64-139-1-69
I think the hardware delay line approach is the only solution for a simple
D FF lead/lag phase comparator. It would be placed ahead of the FF.
Which GPS being built now provide sawtooth info?
73
jim ab3cv
___
time-nuts mailing list --
Every timing GPS receiver has the sawtooth information: uBlox, iLotus,
SkyTraq, Trimble just to name someone.
On Fri, Mar 7, 2014 at 2:25 PM, Jim Miller j...@jtmiller.com wrote:
I think the hardware delay line approach is the only solution for a simple
D FF lead/lag phase comparator. It would
As I am a poor programmer and also lazy (includes hardware and software), I
would like to ask the following question: How much better would a GPSDO like
the Arduino GPSDO be with added sawtooth correction?
Let’s say we assume the 1ns resolution TIC is perfect, no jitter from the uP
and the
On Fri, Mar 7, 2014 at 5:25 AM, Jim Miller j...@jtmiller.com wrote:
I think the hardware delay line approach is the only solution for a simple
D FF lead/lag phase comparator. It would be placed ahead of the FF.
Simple? You are going to need a micro controller and software to (1)
tall the GPS
I have quite often seen the simple D FF lead/lag phase comparator mentioned but
not found any practical implementation in a GPSDO. Has anyone a schematic and
hopefully real data? What is the performance? Is it better than a conventional
GPSDO with a TIC+uP+DAC or is it only simpler?
Lars
On
in the uBlox u-Center software users guide.
Thanks
Jim ab3cv
Message: 3
Date: Fri, 7 Mar 2014 16:26:35 +0100
From: Azelio Boriani azelio.bori...@screen.it
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Another atomic clock question
j...@jtmiller.com said:
I'm new at this obviously. I was just looking at the uBlox-6 info and I
don't see where in the NMEA sentences the sawtooth info is contained. Is it
a manufacturer specific option that needs be turned on? Or is it contained
within a standard NMEA sentence somewhere. I
Chris, about using one Arduino for two GPSDO controllers:
Even if a microcontroller has lots of capacity I would recommend to use
separate controllers for each oscillator. One of the reasons is what Tom van
Baak said about using only one interrupt to avoid jitter and even if you
trigger both
On Fri, Mar 7, 2014 at 9:57 AM, Jim Miller j...@jtmiller.com wrote:
I'm new at this obviously. I was just looking at the uBlox-6 info and I
don't see where in the NMEA sentences the sawtooth info is contained.
There is no NMEA sawthooth sentence. You typically have to put the
serial data
On Fri, Mar 7, 2014 at 10:28 AM, Lars Walenius
lars.walen...@hotmail.com wrote:
Chris, about using one Arduino for two GPSDO controllers:
Even if a microcontroller has lots of capacity I would recommend to use
separate controllers for each oscillator. One of the reasons is what Tom van
Baak
On 3/7/14 12:31 PM, Chris Albertson wrote:
On Fri, Mar 7, 2014 at 10:28 AM, Lars Walenius
lars.walen...@hotmail.com wrote:
Chris, about using one Arduino for two GPSDO controllers:
Even if a microcontroller has lots of capacity I would recommend to use
separate controllers for each
On Fri, Mar 7, 2014 at 12:57 PM, Jim Miller j...@jtmiller.com wrote:
I'm new at this obviously. I was just looking at the uBlox-6 info and I
don't see where in the NMEA sentences the sawtooth info is contained.
u-blox calls it (Time)Pulse Granularity (PG). You're looking for the UBX
clock
jim...@earthlink.net said:
for $20, it's hard to beat.. the only downside is that you can't go down
to radio shack and buy one on the spur of the moment.
At that price, you can keep a couple on the shelf.
--
These are my opinions. I hate spam.
Hi
You can put the LEA-5T or the LEA-6T into a mode where they put out the
sawtooth information on auto pilot. Once you get it set up (which you do each
time you boot) it just keeps going. You must have the T version of the modules
to get the sawtooth out of them.
Bob
On Mar 7, 2014, at 4:10
Let's see what is needed.
The ADC is 10-bits so it can read to one part in 1024. It's a 5 volt
full scale so we are only able to measure 5 millivolt increments
The uP runs about 16 million instructions per second. What if we wait
1000 instructions to read the ADC what will the error be? The
On 3/7/14 3:33 PM, Chris Albertson wrote:
Let's see what is needed.
The ADC is 10-bits so it can read to one part in 1024. It's a 5 volt
full scale so we are only able to measure 5 millivolt increments
if you use the teensy3 it has a 16 bit ADC with realistically, about 13
bits
Hi
With a “real” 12 to 13 bit ADC and a 200 ns TDC pulse you would ideally get
200 / 4096 as your LSB. Nothing like this is ever perfect, so you probably
aren’t going to get 50 ps. You probably will be below 100 ps. That’s plenty
good enough to make sawtooth correction useful.
Bob
On
Hello David,
Not sure what is wrong here - I still can't reach it.
If it isn't too much trouble - can you send me a screen shot off-list - I
can look up the patents as long as the numbers are listed.
Thanks!
John W.
j...@westmorelandengineering.com
On Thu, Mar 6, 2014 at 11:09 PM, David J
On Fri, Mar 7, 2014 at 5:45 PM, Bob Camp li...@rtty.us wrote:
You must have the T version of the modules to get the sawtooth out of them.
Per the documents (and M Tharp) you don't need a T model to get
quantization correction (I only have a T so I don't have first-hand
information). I
Hi
On the 4’s and 5’s you only got a pulse + correction with the T model.
Bob
On Mar 7, 2014, at 8:06 PM, Paul tic-...@bodosom.net wrote:
On Fri, Mar 7, 2014 at 5:45 PM, Bob Camp li...@rtty.us wrote:
You must have the T version of the modules to get the sawtooth out of them.
Per the
On Fri, Mar 7, 2014 at 9:32 PM, Bob Camp li...@rtty.us wrote:
On the 4's and 5's you only got a pulse + correction with the T model.
I have a 6T so I can only read the data sheets for the others but the OP
said uBlox-6.
Perhaps there are various firmware releases but the LEA-5 family is
publish a schematic, code and test results once I have something
working.
Thanks
Jim ab3cv
Date: Fri, 7 Mar 2014 09:23:54 -0800
From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Another atomic
On 07/03/14 19:28, Lars Walenius wrote:
Chris, about using one Arduino for two GPSDO controllers:
Even if a microcontroller has lots of capacity I would recommend to use
separate controllers for each oscillator. One of the reasons is what Tom van
Baak said about using only one interrupt to
On 08/03/14 00:52, Bob Camp wrote:
Hi
With a “real” 12 to 13 bit ADC and a 200 ns TDC pulse you would ideally get
200 / 4096 as your LSB. Nothing like this is ever perfect, so you probably aren’t
going to get 50 ps. You probably will be below 100 ps. That’s plenty good enough
to make
j...@jtmiller.com said:
I may switch the GPS module at a later date to one which provides sawtooth
info if I really feel the need and add a delay line. Frankly I think I'll
never get around to it.
One nasty problem with hanging bridges is that if you don't believe in them,
then you won't
Hello David,
Not sure what is wrong here - I still can't reach it.
If it isn't too much trouble - can you send me a screen shot off-list - I
can look up the patents as long as the numbers are listed.
Thanks!
John W.
Screen-shot and page HTML
David,
Thanks - got it.
Best Regards,
John W.
On Fri, Mar 7, 2014 at 10:53 PM, David J Taylor
david-tay...@blueyonder.co.uk wrote:
Hello David,
Not sure what is wrong here - I still can't reach it.
If it isn't too much trouble - can you send me a screen shot off-list - I
can look up
https://www.febo.com/pages/gps_pps/
It appears the implementation of the sawtooth error correction
severely degrades the performance of the system. There could be many
reasons, which is why it is important to nail down as many of the
error sources as possible.
severely degrades??
Tom and Bob,
It is not obvious to me that it is easier to simply apply a correction in
nS increments
with a range as wide as 100nS. How is this done? Using switched delay lines
or delay gates?
Didier,
If you intend to measure the 1PPS there is no need to correct or adjust it
prior to
Hi,
Agree. If you steer so you keep to be off frequency so you have plenty
of sawtooth you get better resolution. I've been pondering about maybe
write an article to illustrate the effect.
Cheers,
Magnus
On 04/03/14 23:45, Bob Camp wrote:
Hi
Be careful of what you wish for.
One way to
Hi,
You still get hanging bridges, but smaller in amplitude and for the same
oscillator stability much more short-lived.
Cheers,
Magnus
On 06/03/14 00:03, Bob Camp wrote:
Hi
If you are going to decode and use the sawtooth data out of the receiver,
there’s no need to eliminate the hanging
of precise time and frequency measurement
time-nuts@febo.com
Sent: Wednesday, March 05, 2014 3:03 PM
Subject: Re: [time-nuts] Another atomic clock question
Hi
If you are going to decode and use the sawtooth data out of the
receiver, there?s no need to eliminate the hanging bridges
.
/tvb
- Original Message -
From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Wednesday, March 05, 2014 3:03 PM
Subject: Re: [time-nuts] Another atomic clock question
Hi
If you are going to decode and use
To the Mike that posted:
http://www.pst.netii.net/patents.htm - I tried going to your site - can't
reach it. Is the site operational? I wanted to take a look at your
patents.
Thanks,
John Westmoreland
==
Jon,
It's working OK from Edinburgh at 07:08 UTC.
Bob Camp wrote:
Hi
Be careful of what you wish for.
One way to eliminate the hanging bridge is to have the oscillator
exactly on frequency. That sounds fine. The problem is that you
are always in the middle of a bridge.
Bob
That's fine. Just set the oscillator to keep the
Hi
If you are going to decode and use the sawtooth data out of the receiver,
there’s no need to eliminate the hanging bridges. The sawtooth data does that
for you already. Put another way, heating the receiver is *harder* than just
using the decoded data….
Bob
On Mar 5, 2014, at 9:53 AM,
and frequency measurement time-nuts@febo.com
Sent: Wednesday, March 05, 2014 3:03 PM
Subject: Re: [time-nuts] Another atomic clock question
Hi
If you are going to decode and use the sawtooth data out of the receiver,
there’s no need to eliminate the hanging bridges. The sawtooth data does
- Original Message -
From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Wednesday, March 05, 2014 3:03 PM
Subject: Re: [time-nuts] Another atomic clock question
Hi
If you are going to decode and use the sawtooth
-nuts] Another atomic clock question
Hi
If you are going to decode and use the sawtooth data out of the receiver,
there's no need to eliminate the hanging bridges. The sawtooth data does
that for you already. Put another way, heating the receiver is *harder*
than just using the decoded data
Em 05/03/2014 22:43, Didier Juges escreveu:
Tom and Bob,
It is not obvious to me that it is easier to simply apply a correction in
nS increments with a range as wide as 100nS. How is this done? Using
switched delay lines or delay gates?
Using a DS1023 or a DS1124 plus a microcontroller to
- Original Message -
From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Wednesday, March 05, 2014 3:03 PM
Subject: Re: [time-nuts] Another atomic clock question
Hi
If you are going to decode and use the sawtooth data out
Hi
The sawtooth correction on a good GPS will go down to a few hundred ps over a
thirty or so ns range. If you are going to correct, you need a chip that is
accurate to 100 ps over a 30 ns ( 300 tap) range. That’s a tough part to
find. Next you need to worry about jitter in the delay line ….
On Wed, Mar 5, 2014 at 5:43 PM, Didier Juges shali...@gmail.com wrote:
Tom and Bob,
It is not obvious to me that it is easier to simply apply a correction in
nS increments with a range as wide as 100nS. How is this done? Using
switched delay lines or delay gates?
Here is my plan for
Th
On Wed, Mar 5, 2014 at 7:02 PM, Bob Camp li...@rtty.us wrote:
Hi
The disconnect is that there is no need at all to correct for the delay with
some sort of delay line setup. The sawtooth correction simply sums into the
input of your control algorithm for the corrected oscillator. It's
: Re: [time-nuts] Another atomic clock question
Hi
If you are going to decode and use the sawtooth data out of the
receiver, there?s no need to eliminate the hanging bridges. The
sawtooth data does that for you already. Put another way, heating
the receiver is *harder* than just using
What would be more interesting would be to adjust the temperature of the GPS
receiver's oscillator to eliminate the hanging bridges altogether, kind of like
Trimble does with the Thunderbolt, except that they do it directly instead of
indirectly. That may require to characterize the crystal
, 2014 11:00 AM
Subject: Re: [time-nuts] Another atomic clock question
What would be more interesting would be to adjust the temperature of the GPS
receiver's oscillator to eliminate the hanging bridges altogether, kind of
like Trimble does with the Thunderbolt, except that they do it directly
...@febo.com] On
Behalf Of Bob Stewart
Sent: Tuesday, March 04, 2014 12:08 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Another atomic clock question
I suggested yesterday to periodically heat and cool the oscillator, but my
post may have been lost in the noise
: Tom Holmes thol...@woh.rr.com
To: 'Discussion of precise time and frequency measurement'
time-nuts@febo.com
Sent: Tuesday, March 4, 2014 12:07 PM
Subject: Re: [time-nuts] Another atomic clock question
Hanging bridge? What is it; where is it found; and how does it form?
My guess
thol...@woh.rr.com said:
Hanging bridge? What is it; where is it found; and how does it form?
Tom Clark and Rick Hambly: Timing for VLBI
http://gpstime.com/files/tow-time2009.pdf
tvb: Motorola GPS M12+ Sawtooth
http://www.leapsecond.com/pages/m12/sawtooth.htm
--
These are my opinions.
Of Hal Murray
Sent: Tuesday, March 04, 2014 1:23 PM
To: Discussion of precise time and frequency measurement
Cc: hmur...@megapathdsl.net
Subject: Re: [time-nuts] Another atomic clock question
thol...@woh.rr.com said:
Hanging bridge? What is it; where is it found; and how does it form?
Tom Clark
Hi
Be careful of what you wish for.
One way to “eliminate” the hanging bridge is to have the oscillator exactly on
frequency. That sounds fine. The problem is that you are always in the middle
of a bridge. The other way is to put the oscillator well off frequency. That
way you have lots of
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
albertson.ch...@gmail.com said:
So does this mean I can epoxy a sandstone power resister to a junk crystal
and keep the frequency exactly perfect by varying the power in the resister?
Sure, for some values of perfect and such.
Hi
The simple approach is to use an op amp, a thermistor, and a couple of
resistors. No need for anything digital. You can easily get all the gain
possible (before oscillation) out of a very simple circuit.
The net result will be about a 1C stability when you run it over temperature
(say 0
On 3/3/14 2:18 AM, Hal Murray wrote:
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
albertson.ch...@gmail.com said:
So does this mean I can epoxy a sandstone power resister to a junk crystal
and keep the frequency exactly perfect by varying the power in the resister?
Hal,
For science-fair level accuracy try a $2 PTC-60 thermistor heater
one component oven for minimal complexity. I tried this with a
small box and insulating foam and it gives surprisingly good
results. Leave it to the ham radio guys to come up with a low
cost solution.
Hi
If you are measuring temperature in a room who’s temperature does not change,
then yes you can hold 0.1 C. That of course is based on the “room does
not change temperature” and that equates to absolutely no change at all.
The only rational way to discus temperature stability is as a
On Mon, Mar 3, 2014 at 2:18 AM, Hal Murray hmur...@megapathdsl.net wrote:
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
albertson.ch...@gmail.com said:
So does this mean I can epoxy a sandstone power resister to a junk crystal
and keep the frequency exactly perfect by
In message ab202da8-82bd-4861-af15-abbf92779...@rtty.us, Bob Camp writes:
If you are measuring temperature in a room who's temperature does not
change, then yes you can hold 0.1 C.
That would make you quite famous, since the current best measurement
of Bolzmans constant has a relative
The OCXO maker is forced to use a temperature sensor because he does
not have access to a frequency reference. If do have an external
frequency reference then the crystal itself makes a good thermometer.
So why not use THAT thermometer to control the heat added by the
resister.Such a system
Hi
The crystal as normally cut makes a very poor thermometer compared to a
thermistor.
Bob
On Mar 3, 2014, at 6:46 PM, Chris Albertson albertson.ch...@gmail.com wrote:
The OCXO maker is forced to use a temperature sensor because he does
not have access to a frequency reference. If do have
So does this mean I can epoxy a sandstone power resister to a junk
crystal and keep the frequency exactly perfect by varying the power in
the resister?
Sure. In fact you can loosely phase lock it to GPS that way. Your xtal doesn't
need to have an EFC pin. You are using external temperature as
of precise time and frequency measurement time-nuts@febo.com
Sent: Monday, March 3, 2014 6:40 PM
Subject: Re: [time-nuts] Another atomic clock question
Sure. In fact you can loosely phase lock it to GPS that way. Your xtal doesn't
need to have an EFC pin. You are using external temperature
On Mon, Mar 3, 2014 at 4:51 PM, Charles Steinmetz csteinm...@yandex.com wrote:
What you are proposing is a disciplined oscillator using the oven setpoint
as the control input.
What I want to try is building a GPSDO for say $25 for everything
except the GPS.
A fun contest would be to adopt
Hi
So I can use the scrap (zero value) 5 MHz 3rd OT HC-40 package SC’s that are
sitting in a pile in the basement right ?
Bob
On Mar 3, 2014, at 8:47 PM, Chris Albertson albertson.ch...@gmail.com wrote:
On Mon, Mar 3, 2014 at 4:51 PM, Charles Steinmetz csteinm...@yandex.com
wrote:
What
Yes, there is some satisfaction is measuring to fine tolerances. Of
all the physical measurements we can take, frequency can be measured
with the most accuracy.You say 1ppb is enough.Let's see a
billion is 1E9. A 10Mhz signal is 1E7 cycles per second 9-7 is 2.
You can get to 1ppm
In a message dated 02/03/2014 02:07:05 GMT Standard Time,
bob91...@yahoo.com writes:
All this is very interesting. However, my interest is frequency. In
other words, I want to know that my standard oscillators are as close to
desired frequency as possible, and how close that turns out to
My opinion: For 1ppm you will need any reasonable GPS receiver that
has a 1PPS output. You can find them that are really good and put the
Chris,
I agree investing in a cheap GPS receiver is a good step for anyone playing
with time frequency. I would recommend the same.
But I'd like to
Hi
When you say “adjust crystals close” do you mean:
1) Grinding / plating crystal blanks? (as in fabricating crystals from scratch)
2) Setting uncompensated crystal oscillators on frequency? (as in some radios)
3) Calibrating the OCXO that is the master reference for an instrument?
That all
Hi
Assuming you are after a reference at 10 ppb accuracy:
10 ppb would be a 10 second beat note on WWV at 10 MHz. (I *hope* I got the
decimal point right that time).
Fire up your radio and start listening to the various frequencies. You want a
time when it’s crystal clear with absolutely no
I'm not ready to delve into temperature measurement. But I thought
conventional wisdom is that most crystals are AT cut and an attempt at zero
average coefficient is made, causing a nonlinear characteristic. But perhaps
over a limited range it's linear. The problem of course is calibration.
Yes Nigel, it's a waste of time but so are computer games and going to
Disneyland and such. We do it because we get pleasure, and nobody can
criticize that.
I am a bit confused over your mention of Trimble units. I'm not familiar with
them or what they are supposed to do. I better do some
Hi
On Mar 2, 2014, at 10:58 AM, Bob Albert bob91...@yahoo.com wrote:
I'm not ready to delve into temperature measurement. But I thought
conventional wisdom is that most crystals are AT cut and an attempt at zero
average coefficient is made, causing a nonlinear characteristic. But perhaps
Hi
Trimble is one of many companies in the GPSDO business. A GPSDO is an
oscillator that is locked up to the GPS signal. In many cases the oscillator is
a pretty good OCXO. Trimble made a lot of these for the cell tower people. They
now show up pretty regularly on the surplus market.
A GPSDO
BA I am a bit confused over your mention of Trimble units. I'm not
familiar with them or what they are supposed to do.
BA I better do some homework.
The best thing said so far ...
Scan the archives and Google for GPSDO, do some research and reading
Then the archives for Trimble then for
li...@rtty.us said:
A number of them have sold recently on eBay for about $130.
Don't forget the antenna and power supply.
--
These are my opinions. I hate spam.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
In a message dated 02/03/2014 16:06:49 GMT Standard Time,
bob91...@yahoo.com writes:
Yes Nigel, it's a waste of time but so are computer games and going to
Disneyland and such. We do it because we get pleasure, and nobody can
criticize that.
-
Hi Bob,
I'm not
bob91...@yahoo.com said:
But I thought conventional wisdom is that most crystals are AT cut and an
attempt at zero average coefficient is made, causing a nonlinear
characteristic. But perhaps over a limited range it's linear. The problem
of course is calibration.
Most crystals are low
Hi
Depending on which auction you find and what they include you may indeed have
some other bits and pieces to dig up as well. The prices run in cycles, so you
will always pay a bit more if you “want it right now” than if you are willing
to sit back and shop for a few months.
Bob
On Mar 2,
Hi
These days, you can get some *very* low cost crystals. They sell by the pound
rather than by the piece. The tolerance as delivered may be 0.1% for
temperature plus calibration. Aging is likely to be “who knows”. The
temperature characteristic could be a third order curve. More likely it’s a
- Original Message -
From: Hal Murray hmur...@megapathdsl.net
To: Bob Albert bob91...@yahoo.com; Discussion of precise time and
frequency measurement time-nuts@febo.com
Cc: hmur...@megapathdsl.net
Sent: Sunday, March 02, 2014 2:45 AM
Subject: Re: [time-nuts] Another atomic clock
To: Bob Albert bob91...@yahoo.com; Discussion of precise time and
frequency measurement time-nuts@febo.com
Cc: hmur...@megapathdsl.net
Sent: Sunday, March 02, 2014 2:45 AM
Subject: Re: [time-nuts] Another atomic clock question
bob91...@yahoo.com said:
Okay you want numbers. Well, I think 10
: hmur...@megapathdsl.net
Sent: Sunday, March 02, 2014 2:45 AM
Subject: Re: [time-nuts] Another atomic clock question
bob91...@yahoo.com said:
Okay you want numbers. Well, I think 10 ppb or thereabouts should do it.
Somewhere there is a discontinuity in accuracy plotted against cost and I
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
So does this mean I can epoxy a sandstone power resister to a junk
crystal and keep the frequency exactly perfect by varying the power in
the resister?
--
Chris Albertson
Redondo Beach, California
Hi
As long as your resistor keeps the temperature to within a micro degree it will
do pretty well.
Bob
On Mar 2, 2014, at 2:09 PM, Chris Albertson albertson.ch...@gmail.com wrote:
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
So does this mean I can epoxy a sandstone
On 3/2/14 11:09 AM, Chris Albertson wrote:
Junk crystals are good thermometers. Ballpark is 1 ppm/degree-C
So does this mean I can epoxy a sandstone power resister to a junk
crystal and keep the frequency exactly perfect by varying the power in
the resister?
Yes.. but you have to hold
On 3/2/14 12:21 PM, Bob Camp wrote:
Hi
As long as your resistor keeps the temperature to within a micro degree it will
do pretty well.
Oh, you were looking for 1E-12.. I was thinking 1E-9 would be good enough.
The other issue is that the phase noise might be pretty bad with a cheap
Hi
The gotcha is that there are second order temperature effects. If you are going
to run the crystal very far off turn, you need to keep it more stable than you
might think.
Bob
On Mar 2, 2014, at 3:40 PM, Jim Lux jim...@earthlink.net wrote:
On 3/2/14 12:21 PM, Bob Camp wrote:
Hi
As
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second order temperature effects. If you are going
to run the crystal very far off turn, you need to keep it more stable than you
might think.
hysteresis, memory effect, restart of frequency drift
Yeah, it puts a limit on
On 3/2/14 1:00 PM, Magnus Danielson wrote:
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second order temperature effects. If you
are going to run the crystal very far off turn, you need to keep it
more stable than you might think.
hysteresis, memory effect, restart of
HI
On Mar 2, 2014, at 4:00 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote:
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second order temperature effects. If you are
going to run the crystal very far off turn, you need to keep it more stable
than you might
Hi Bob,
On 02/03/14 23:16, Bob Camp wrote:
HI
On Mar 2, 2014, at 4:00 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote:
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second order temperature effects. If you are going
to run the crystal very far off turn, you
On Mar 2, 2014, at 5:29 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote:
Hi Bob,
On 02/03/14 23:16, Bob Camp wrote:
HI
On Mar 2, 2014, at 4:00 PM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
On 02/03/14 21:45, Bob Camp wrote:
Hi
The gotcha is that there are second
tmiller11...@verizon.net said:
Is that 3 MHz OCXO one from Ridge? If so, I opened one up and was surprised
to find it did not have any foam insulation.
RDR Electronics
There were 2 per board, from some old telco/cell gear.
http://w9fz.com/ham/s3mhz2.jpg
http://w9fz.com/ham/3mhzocxo.txt
As Jim mentions in another post, you can run on the fundamental and the third
(or 5th or 7th) and get a thermometer out of the delta between the two modes.
The gotcha is that a change in load impedance will shift the frequencies
unequally. That will give you an apparent temperature change.
I
Hi
I believe the paper was by Stan Shadowski. I’m *certain* I’ve mis-spelled his
last name, which is indeed a very poor move on my part. I would not be
surprised if there are several co-authors.
I don’t have the UFC indexes here at home so I have no quick way to look it up.
Bob
On Mar 2,
There are WWVB clocks with serial output. Arcron made one that I added
linux ntp support for some years back.
http://www.atomictimeclock.com/radsynarcron.htm
http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver27.html
As I recall, it was under $100, quite nicely styled, and is sitting here
All this is very interesting. However, my interest is frequency. In other
words, I want to know that my standard oscillators are as close to desired
frequency as possible, and how close that turns out to be.
Yes, the Internet gives me time of day as close as I care to know. I have an
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