On 12/8/12 9:30 AM, johncr...@aol.com wrote:
Instead the discussion has centered on what microprocessor (of a hundred
that would work)
and how to eliminate glue logic and and a few analog parts to save
money. This is silly - silicon is
CHEAP.
Silicon is cheap, but for one-off fabrication by
On 12/6/12 1:56 PM, Bob Camp wrote:
Hi
The single best thing about a TBolt is Lady Heather.
Consider how many years it's taken to get it to where it is today. Consider
how many people have worked extensively on it. It's a wonderful thing to
have available.
Could you make a homebrew gizmo look
On 12/6/12 11:12 PM, Hal Murray wrote:
Suppose you just implement a simple bang-bang control.
Suppose the EFC is 1 volt and the frequency is correct but the GPSDO
phase is a bit early relative to the GPS PPS. So the FF says early
and the software says go-faster. That keeps happening for
On 12/6/12 5:01 PM, Bob Camp wrote:
Hi
The solution to the problem is well known in several forms. Cost is below $5
for pretty much all of them. No need to re-invent the wheel. The gotcha is that
you can't do it 100% with internal CPU peripherals. You will need *some* glue.
I think that's
On 12/6/12 11:20 PM, Don Latham wrote:
Good thought, Bob. AD9548 $27, eval board a whopping $250, get a
thunderbolt :-). The eval board has a lot of SMA's on it...
This is a general problem with eval boards these days.. They provide a
lot of functionality on the board to make it easy to
On 12/6/12 1:06 AM, Chris Albertson wrote:
Yes. The idea was the simplest GPSDO that can be build with no PCB around
an Arduino. We already know how to build compllelx and expensive GPSDO.
That is too easy.
I think you can use the PWM DAC on the Aruino to drive the OCXO. The
bandwidth of
On 12/6/12 4:42 AM, Bob Smither wrote:
On 12/05/2012 02:32 PM, M. Simon wrote:
Do you have a link for the nifty site?
This one is not just for the west coast, but has good reporting of grid
conditions:
http://fnetpublic.utk.edu/index.html
They have several real time graphic and table
On 12/6/12 9:45 AM, Dale J. Robertson wrote:
Arduino is Dirt Cheap!
And available over the counter retail at hundreds of Radio Shacks..
You get an idea during the day, and you can run out and buy one right
then.. (yes, you can mail order, but the fastest turnaround is a few
days, unless you
On 12/5/12 12:06 AM, Bruce Griffiths wrote:
Hal Murray wrote:
albertson.ch...@gmail.com said:
What is the simplest phase detecter that could work? I think only
that, and
then a duouble oven crystal from eBay, a GPS and and Arduido.
You also need a good D2A to drive the EFC on the osc.
A
On 12/5/12 2:45 PM, Marek Peca wrote:
This last idea is interesting... could be simulated by Matlab or similar.
It is known to work in ordinary non-linear transistor-based mixers. It
will produce more messy spectrum than double-balanced mixer, however,
for this purpose and completely within
oscillators, all
with their own stiffness coupled by a complex network of transmission
lines with propagation delays and mismatch.
On 12/3/2012 8:12 PM, Jim Lux wrote:
On 12/3/12 6:34 PM, Hal Murray wrote:
li...@lazygranch.com said:
I have one of those key fobs. Does the code somehow inform
On 12/4/12 4:28 PM, Bill Hawkins wrote:
Sorry about this, Tom, but there's some misinformation here.
I wasn't reading this until I saw your posting.
-Original Message-
From: Jim Lux
Sent: Tuesday, December 04, 2012 7:58 AM
On 12/3/12 9:59 PM, gary wrote:
I was meditating a bit
On 12/3/12 9:32 AM, dlewis6767 wrote:
I agree, Bob.
Like the billboard on the side of the highway says: - Does Advertising
Work? JUST DID -
The bad guys can read this list same as the good guys.
Security through obscurity never works in the long run. Much better to
discuss
On 12/3/12 6:34 PM, Hal Murray wrote:
li...@lazygranch.com said:
I have one of those key fobs. Does the code somehow inform the power the be
about the drift in the built in clock? Or is the time element of the code so
sloppy that the drift is acceptable?
The magic number changes every second
On 11/30/12 4:58 PM, John Ackermann N8UR wrote:
On Nov 30, 2012, at 7:42 PM, John Ackermann N8UR j...@febo.com wrote:
In this case, you're not looking for the RTC but rather the clock that drives
the COU
Read CPU. Stupid iPad keyboard.
I was wondering.. Clock Oscillator Unit? Cryptic
On 11/26/12 10:11 AM, Demian Martin wrote:
I asked Wenzel about mixers for phase noise measurement and they directed me
to Marki Microwave as what they use:
http://www.markimicrowave.com/2770/Mixers.aspx I have not obtained or
tested any myself but it's a pretty solid recommendation I think.
On 11/25/12 4:30 PM, Hal Murray wrote:
Suppose I have an A/D running at 1 MHz. The standard simple minded approach
is that it will work for any input signal with a bandwidth up to 1/2 MHz. We
usually think of that in the baseband, but it also works for, say 1.25 to
1.5 MHz. The input signal
On 11/25/12 5:19 PM, Said Jackson wrote:
Hal,
Check out the Analog Devices website. Good info on DDS Dacs there.
You want to stay a bit away from the 1/2fs Nyquist limit in your DA. The reason
is the image coming down from your 1MHz clock.
If you output say 0.45MHz, you have an image at 0.55
On 11/24/12 8:28 AM, Alan Melia wrote:
Joe the reason why its not so uncommon may not be obvious in the US :-))
12.8MHz is used as a reference for commercial and amateur PLLs in Europe
where the common channel spacing is 12.5kHz (/1024) or 6.25kHz (/2048).
This may mean that 12.8MHz oscillators
On 11/22/12 12:12 PM, Larry McDavid wrote:
I realize this modulation scheme change is perceived as a sensitive
subject. But, really, since the full scheme is fully disclosed no
company has a monopoly on its use.
Actually, I think the developing company does have patents on some of
the
On 11/15/12 4:30 AM, David J Taylor wrote:
i just used this to with a raspberry pi with good success.
https://www.adafruit.com/products/746
james
===
It looks idea, James, but ... with the 15 mm square patch antenna it
seems deaf compared to similar
On 11/15/12 5:33 AM, David wrote:
On Thu, 15 Nov 2012 05:02:54 -0800, Jim Lux jim...@earthlink.net
wrote:
On 11/15/12 4:30 AM, David J Taylor wrote:
i just used this to with a raspberry pi with good success.
https://www.adafruit.com/products/746
james
On 11/15/12 4:10 PM, Bob Camp wrote:
Hi
Not much of a market for that sort of stuff.
Bob
Big enough that Synergy Garmin have pricing for anywhere from 1 to
1000 units
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
Looking for a non-surplus ( e.g. A current catalog item) gps module, with
serial ( ttl or rs232) and 1 pps. Doesn't need high performance(100ns is
fine), but should be $100 ish. Something with an integrated antenna would
be great.
___
On 11/7/12 5:42 PM, shali...@gmail.com wrote:
That sounds odd, as most radios take tens of millisecond, if not hundreds to
switch from transmit to receive and back in any mode other than break-in CW.
Further JT65 is used with propagation modes that typically do not have a stable
or
On 11/3/12 8:50 AM, Chris Albertson wrote:
On Fri, Nov 2, 2012 at 10:32 PM, Sarah White kuze...@gmail.com wrote:
So, at or around 1981 (the year I was born) there was a cool concept.
IBM was selling personal computers (IBM-PC compatible later became a
thing) and by the time I was old enough to
Hello Said,
I'm familiar with your postings on the Time Nuts list, so I thought I'd
ask your advice. I searched the Time Nuts archive, but didn't come up with
what I was looking for (reference to a good GPS tutotial).
We have a GPS project in-house that requires us to characterize
On 10/31/12 6:17 PM, Tom Van Baak wrote:
Please read John Plumb's paper:
http://tycho.usno.navy.mil/ptti/ptti2002/paper29.pdf
and Rick Hambly's paper:
http://tycho.usno.navy.mil/ptti/ptti2002/paper9.pdf
At JPL, most of the calibration and performance testing and such is done
using an
On 10/25/12 11:02 AM, li...@lazygranch.com wrote:
The GPS seeing the horizon isn't required. Those satellites are filtered out by
software. The timing GPSs are designed to be less sensitive to the horizon.
when tracking a satellite above the cutoff, you still want the antenna
to not
On 8/21/12 9:53 AM, Sarah White wrote:
Wow. Okay. The user manual actual considers this cable delay to be worth
mention?
I can see why the trimble thunderbolt is a favorite among time nuts 3
I'm sold.
Cable time offset is in basically all GPSes. An awful lot of GPS
receivers (for timing)
On 1/14/12 9:18 PM, Chris Albertson wrote:
Not over kill at all. It is worth paying a few $$ not to have to
design a PCB. Worse then that is that most will take shortcuts and
design it so that you need a sppepcial IC programmer to program the
PIC. Thee $20 development boards allow you to
I just found an old 8720C at work, and I was thinking of pressing it
into service to do some experiments with measuring changes in receiver
filters and antenna match over temperature. (Since I don't have to pay
rental on it, it can just sit in the corner with the temp chamber and I
can slap
On 10/17/12 12:59 PM, gandal...@aol.com wrote:
Not exactly the programming manual but would it help?.
_http://na.tm.agilent.com/8720/programm/xrefhpib.htm_
(http://na.tm.agilent.com/8720/programm/xrefhpib.htm)
Ah, wait.try this:-)
On 10/17/12 3:35 PM, David Kirkby wrote:
On 17 October 2012 20:35, Jim Lux jim...@earthlink.net wrote:
Someone found the manual I needed (see the other posts).. it was on that
general website but not linked from anywhere...
Another place to get information, is asking on the Agilent VNA
On 10/17/12 4:48 PM, Sarah White wrote:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 10/17/2012 6:04 PM, Chris Albertson wrote:
((...snip...)) -- 1
Indoor antennas can work. It depands on the details. Hopefully
the skylight looks to the south. BTW that thin sheet of plastic
that makes
On 10/10/12 8:10 AM, bro...@pacific.net wrote:
Hi:
The reason for the GPS orbits is so that the ground track repeats.
Have Fun,
Brooke
and that makes it easy to predict visibility. Tomorrow will be the same
as today, shifted by 4 minutes.
___
I'm looking for an off the shelf commercial time display (or combination
of displays)..
Needs to display at least 3 zones, in 24 hr form (UTC, Pacific,
Eastern), and should display Day of Year, as well.
I can feed timecode to it, or even better, if it can ingest NTP. 1
second precision is
to each clock -no
separate power.
-Bob
On Tue, Oct 9, 2012 at 9:02 AM, Jim Lux jim...@earthlink.net wrote:
I'm looking for an off the shelf commercial time display (or combination of
displays)..
___
time-nuts mailing list -- time-nuts@febo.com
On 10/9/12 10:09 AM, Chris Albertson wrote:
For wall displays, I've noticed more and more people simply mounting a
large HD TVs to the wall and driving it with a computer. Even the
menu board in back of Starbucks and the directory near the elevator
that lists who is in what room on that floor.
On 10/2/12 10:35 PM, b...@lysator.liu.se wrote:
On 10/2/12 2:36 PM, saidj...@aol.com wrote:
Hello Paul,
thanks much for the feedback!
Yes, we think we have identified a nice combination of oscillators, GPS,
and firmware that seems to work pretty well. The GPSTCXO units cannot be
compared to a
On 10/2/12 5:08 AM, Azelio Boriani wrote:
Yes, I agree.
On Tue, Oct 2, 2012 at 1:29 PM, Bob Camp li...@rtty.us wrote:
Hi
The OCXO probably isn't going to do very well with the outdoor temperature
swings…
Bob
Why not.. granted it's easier with large mass and large insulation, but
On 10/2/12 3:39 PM, johncr...@aol.com wrote:
Hello All -
Here is a link that describes the GPS modulation. You do not need the
1 pps to lock the 10 MHz oscillator to the atomic clock in the satellites.
http://www.kowoma.de/en/gps/signals.htm
If you look at the block diagram you see PN code
On 10/2/12 4:48 PM, Charles P. Steinmetz wrote:
The Power Output is 0.5 Watts and it claims a jamming range of 1-10
Meters.
Anybody think there is something wrong?
I'd expect a much greater range with a 0.5 W jammer. But note that 0.5
W is the total output power -- the transmit power is
On 10/2/12 7:00 PM, shali...@gmail.com wrote:
The Thunderbolt is a special case that does not provide sawtooth correction
because it does not need it.
It uses the OCXO as the clock for the processor while disciplining it to GPS so
there is no nominal timing error between where the 1PPS is
On 10/2/12 7:33 PM, johncr...@aol.com wrote:
In considering the effect of a simple jammer on a GPS receiver, a simple
link analysis
is insufficient.
What must also be considered is the anti-jam capability of the receiver
which due to spread spectrum processing gain will reject any simple
On 9/30/12 10:51 PM, Thomas Valerio wrote:
Actually, it was in Nuts Volts as well, and I was thinking about posting
a similar query to the list, but my incentive and my interest pretty much
went negative when my cursory investigation revealed that price
information appeared to be non-existent.
On 9/28/12 8:31 PM, Chris Albertson wrote:
On Fri, Sep 28, 2012 at 5:29 PM, Bob Camp li...@rtty.us wrote:
HI
Sort of an open ended question, but there is a fairly simple couple answers:
SInce it's close in phase noise and not far removed, things like PLL's are
going to transfer it directly
On 9/27/12 10:41 PM, Majdi S. Abbas wrote:
On Fri, Sep 28, 2012 at 07:38:03AM +0200, b...@lysator.liu.se wrote:
Dont you have GPS/Cs locked cell networks anymore in the US?
http://www.endruntechnologies.com/cdma.htm
Björn,
Past experience with CDMA TOD references here is
On 9/26/12 10:15 PM, Peter Monta wrote:
I'm not sure about residual carrier aiding the tracking process. A Costas
loop recovers the carrier pretty well, and a symbol aided loop (where the I
channel has a hard limiter, for instance) does even better.
Yes, these work (and a soft tanh() limiter
On 9/27/12 7:23 AM, J. Forster wrote:
Jim,
What you are suggesting is essentially a spread spectrum system where the
chip pattern is time varient.
IMO, this is an incredible kludge. And, there is no gurantee that the
algorythm for generating the chip pattern will not change down the road.
On 9/27/12 2:58 PM, Bob Camp wrote:
Hi
It would be interesting to hear what the patent lawyers on the list think about
the patents. Given a quick read, they appear to cover any use of the specific
transmitted format for receiving time information.
IANAL, but..
reading Claim 1..
a key
On 9/27/12 10:02 AM, Bob Camp wrote:
Hi
Right here in PA for one. You essentially can not buy a new house without
there being various conditions written into the title. One universal one is
no antennas. The only exception is for one 19 sat dish for TV, since
that's a federal mandate.
On 9/26/12 7:11 PM, J. Forster wrote:
But if someone here designed and built a $100 receiver and offered it to
the group, that could well violate some of their IP.
As to building a home brew receiver and certifying a onsie so your lab's
cal is traceable, I'd certainly not trust a cal done that
On 9/27/12 3:10 PM, Charles P. Steinmetz wrote:
Chris wrote:
In another post you mentioned $0.21/kWH (you must be in California?), so
adjust all of these by a factor of 2.625 for your location -- but I
think the service rates in most of the US are closer to ours than to
yours).
A lot of
On 9/27/12 4:34 PM, Bob Camp wrote:
Hi
A PLL locks to phase. If the phase switches by 180 degrees, the phase tracking
switches signs. There's no way to track that. You either need to double the
frequency (and thus eliminate the modulation) or demodulate the signal and lock
to the result. If
On 9/26/12 9:46 AM, J. Forster wrote:
I just received this in reply to a query ablot the availability of
receiver designs for the new WWVB format:
No sir, the government does not have a receiver design. The design has
been created by Xtendwave under an SBIR grant. Their design is
What would annoy me is less-than-full disclosure of the transmitted
signal and its properties. For example, there's a claim in the paper
that the (31 26) Hamming code used can detect double-bit errors in the
encoded time.
You are right. The standard Hamming code: detect and correct 1
(3,1)
On 9/26/12 4:26 PM, J. Forster wrote:
And would anybody accept the results as accurate?
why not.. the transmit signal specification is published, you could
analytically prove what the receiver performance should be and verify
your implementation against it
We do this all the time with
On 9/26/12 5:15 PM, Bob Camp wrote:
Hi
Last time I checked, you can build one for your own use and are allowed to use
what ever you want, regardless of it's patent status.
not precisely true..there's some restrictions on that process (e.g. you
can practise an invention in the course of
On 9/26/12 9:11 PM, Peter Monta wrote:
Have you actually tried it and gotten it working, except possibly in a
very strong signal area?
This is precisely the issue. Squaring the WWVB signal results in a
significant SNR penalty. At high SNR it doesn't matter that much; at
low SNR you are in a
On 9/19/12 1:08 AM, Azelio Boriani wrote:
In my opinion you fall in the case of disciplining with holdover... this is
more like a disciplined oscillator (like a GPSDO) problem than a PLL.
Good point... it's like what happens when we come out of holdover.
On 9/19/12 4:38 AM, Bob Camp wrote:
Hi
Commonly this sort of thing is done with a sample and hold in the loop. No
reference in / put the loop voltage in hold. You still have a phase drift and
need to cope with the phase offset when the reference comes back.
or, in our case, we run the
I'm looking for info on behavior of a PLL (with VCXO) when the reference
comes and goes periodically. When the reference is gone, the PLL will
flywheel according to whatever the loop filter does. (we can turn off
the input to the filter, so we're not trying to track noise)..
What I'm
On 9/18/12 8:39 AM, Don Latham wrote:
won't it depend almost entirely on the charge pump filter?
Classic PLL with a mixer, not with a Phase Frequency Detector and charge
pump..
But yes, it depends in large part on the loop filter, but also on the
behavior of the oscillator.. (i.e. where
On 9/18/12 6:54 AM, Bob Camp wrote:
Hi
The shutter on a conventional movie projector is very much an on / off
device. They run well below 120Hz.
Actually, the typical movie projector uses a rotary shutter which runs
at twice the frame rate (e.g. 48 flashes/second) and is hardly a fast
On 9/18/12 1:49 PM, Magnus Danielson wrote:
On 09/18/2012 05:28 PM, Jim Lux wrote:
I'm looking for info on behavior of a PLL (with VCXO) when the reference
comes and goes periodically. When the reference is gone, the PLL will
flywheel according to whatever the loop filter does. (we can turn off
On 9/18/12 10:57 AM, Tom Knox wrote:
I remember reading that Hollywood played with faster frame rates and found a
substantial number of people experience motion sickness.
Not so much the frame rate, but generating imagery that isn't realistic..
your eye expects motion blur (particularly
On 9/18/12 9:48 AM, Raj wrote:
If you break the DC control chain of the PLL with a A2D and a controller and
back with a D2A .. you would program the control with any kind of behavior you
want. Just a thought!
That is exactly what we do... the PLL is actually implemented digitally
(DAC
On 9/17/12 3:00 PM, Azelio Boriani wrote:
OK, you can test a VP Oncore GPS receiver alone if you have a mean to
translate the TTL serial port to a regular RS232 for the PC. This can be
done with a MAX232 chip (or equivalent).
There are a ton of these (serial TTL ports) available inexpensively
.
What I'd also like to find is a cheap current loop interface (for
running low speed serial connections long distances using cat 5 wire)
On Mon, Sep 17, 2012 at 3:22 PM, Jim Lux jim...@earthlink.net wrote:
On 9/17/12 3:00 PM, Azelio Boriani wrote:
OK, you can test a VP Oncore GPS receiver
On 9/16/12 10:20 AM, Magnus Danielson wrote:
On 09/16/2012 05:47 PM, Poul-Henning Kamp wrote:
Dave Mills coined the term allan intercept as the cross over of
the two sources allan variances and it's a good google search for
his relevant papers.
I'm not entirely sure his rule of thumb for
On 9/10/12 11:03 PM, Chris Albertson wrote:
On Mon, Sep 10, 2012 at 4:11 PM, David Kirkby david.kir...@onetel.netwrote:
I've also had to pay inport duties and VAT on this, which comes to a
US equivalent of around $220. I doubt I will be able to recover that.
Talk to your customs people.
On 9/11/12 3:58 PM, Magnus Danielson wrote:
On 09/12/2012 12:00 AM, Richard (Rick) Karlquist wrote:
There is plenty of documentation at the IEEE web
site in the UFFC society's section. EerNisse
gave a paper at the Frequency Control Symposium
on it at the time. Kusters followed up a year
later
On 9/11/12 6:45 PM, Geoffrey Smith wrote:
Folks,
Following the Peter Gottlieb post, it seems that a number of list members
have been victims of carriers that mishandled badly packed gear. I now
too often the heart ache of a broken handles and the handle through the box
wall, not to mention
On 9/10/12 6:57 AM, David McGaw wrote:
He's making a joke - If you are traveling across time zones, why not
just set it to UTC and be done with it? :-)
David
This is a bigger deal than one might think. Especially since calendaring
software tries to be helpful and adjust things. So while
On 9/9/12 7:05 AM, Stan, W1LE wrote:
Hello The Net:
I need to consider getting a new wrist watch, but I need a second hand
and a digital display is unacceptable.
What would you consider in the 150$ price range ?
Thunderbolt driving a stepper motor?
Would be nice to have state of the art
On 9/9/12 9:37 PM, li...@lazygranch.com wrote:
What am I missing here? Vce = Vbe, so the diode connected transistor isn't
saturated.
I think it's where the diode is fully conducting, and into the linear
part of the V/I curve, not in the square law part any more.
In normal use the LO port
Consulting the hive-mind here on the list..
If one were looking for small/cheap/mass produced oscillators which have
decent phase noise.. what kind has the most repeatable frequency vs
temperature curve.
The usual 1ppm TCXO has about 0.1 ppm hysteresis, while other less
stable
On 9/7/12 12:20 PM, Bob Camp wrote:
Hi
I'm guessing that power is also an issue, so cheap OCXO's are out. If that's
true, I believe you are already at the cheap vs good inflection point with
the cell phone TCXO. At $2 they are pretty tough to beat. Just the fancy
crystal in something better is
A retired coworker of mine (Pogo) just published a book through JPL's
DESCANSO series
Coupled-Oscillator Based Active-Array Antennas: Ronald J. Pogorzelski
and Apostolos Georgiadis
http://descanso.jpl.nasa.gov/Monograph/series11_chapter.cfm?force_external=0
Why is this interesting to
On 8/31/12 11:35 PM, Hal Murray wrote:
The context is using the 60 Hz line for timing.
I'm feeding 60 Hz from a wall wart transformer into a modem control signal
that the kernel PPS stuff watches. Mostly, it works as expected, but
occasionally, it picks or drops a cycle.
In order to
On 9/1/12 6:56 AM, Arthur Dent wrote:
IMO, you have an instrumentation issue. I don't think the power grid can
do anything like that.
YMMV,
-John
I agree. If this was happening on the grid by the time this blip had
traveled down the line to you it would have been so filtered through
On 9/1/12 8:32 AM, Bob Camp wrote:
Hi
Observing a curve and being able to compensate it are often two different
things. Hysteresis is one very obvious example. Another is simple sensor lag. A
some what less obvious one is that the temperature performance is also
influenced by the rate of
On 9/1/12 11:00 AM, Bob Camp wrote:
Hi
I suspect that a good IT cut would probably do better than an SC in either
application. In the deep space situation, a copper slug in a dewar sounds like
a reasonable addition to the design.
If you're going to do dewars, then you're talking USOs for
On 8/31/12 7:06 AM, Bob Camp wrote:
Hi
An SC is going to have it's temperature curve centered up around 95C
or so. If it's been cut as an OCXO crystal the turns will be up there
as well. By the time it gets to room temp, the delta F / delta T is
moving mighty fast. Think in terms of multiple
On 8/31/12 7:16 PM, Bob Camp wrote:
Hi
Ok, that gets you back to the basics of really major delta F / delta T slopes.
Bob
yeah.. but as long as you know what the curve is.. the NCO has a huge
range (after all, we already have to tune over 500 kHz...a few hundred
Hz isn't a big deal.
A
On 8/29/12 8:45 PM, Richard (Rick) Karlquist wrote:
On 8/27/2012 11:45 PM, WB6BNQ wrote:
A microprocessor controlled XO is a non oven crystal oscillator system
that has
additional computational control providing a bit more than just mere
passive
temperature compensation. The additional
On 8/29/12 9:22 PM, Hal Murray wrote:
rich...@karlquist.com said:
No it doesn't use a cheap crystal. It uses a *special* SC cut crystal. This
crystal could very easily cost more than an OCXO crystal.
http://www.q-tech.com/mcxo.html
What's special about it?
Has to support the overtones
On 8/30/12 9:33 AM, Bob Camp wrote:
Hi
The fundamental / third approach is one of several possible ways to go. You
can also run an SC on the B and C modes to get thermometer data. Early
implementations used a pair of independent blanks, one cut to be a good
thermometer. Some have even gone as
On 8/30/12 12:37 PM, Bob Camp wrote:
Hi
The original patents on the MCXO are government property. One of the Ft.
Monmouth guys came up with the fundamental / third overtone idea back in the
80's. Several (at least three) companies were licensed by the government to
make the part.
Gotta be
On 8/30/12 6:12 PM, Bob Camp wrote:
Hi
If the temperature is varying slowly *and* there are no gradients you may get
your order of magnitude over some range. You might be surprised at your TCXO. A
lot of them are pretty darn good in the vicinity of room temp. You may already
be an order of
On 8/30/12 6:29 PM, Magnus Danielson wrote:
On 08/31/2012 03:12 AM, Bob Camp wrote:
Hi
If the temperature is varying slowly *and* there are no gradients you
may get your order of magnitude over some range. You might be
surprised at your TCXO. A lot of them are pretty darn good in the
vicinity
, Jim Lux jim...@earthlink.net wrote:
On 8/30/12 6:12 PM, Bob Camp wrote:
Hi
If the temperature is varying slowly *and* there are no gradients you may get
your order of magnitude over some range. You might be surprised at your TCXO. A
lot of them are pretty darn good in the vicinity of room temp
On 8/27/12 10:45 PM, Chris Albertson wrote:
On Mon, Aug 27, 2012 at 7:33 PM, Jim Lux jim...@earthlink.net wrote:
On 8/27/12 4:15 PM, Rick Karlquist wrote:
Several decades ago, the concept of the smart clock arose
at what was then HP. The idea was as discussed here to
characterize past aging
On 8/27/12 4:15 PM, Rick Karlquist wrote:
Several decades ago, the concept of the smart clock arose
at what was then HP. The idea was as discussed here to
characterize past aging, predict future aging, and
then correct the aging. The goal wasn't to turn a quartz
oscillator into an atomic clock
On 8/19/12 7:26 PM, Chuck Harris wrote:
Residential power is traditionally measured in watts, not V-A. Commercial
power is typically measured in V-A, with an additional fee for power factor
problems.
residential meters measure watts (active power) not VA...
What you want is the
On 8/17/12 10:41 PM, Mark Spencer wrote:
Regarding the NTP server another option is to buy a stand alone NTP server that
can accept a 1pps and or 10 Mhz input, and feed it the GPS or other reference
of your chosing. I picked up a Datum unit from ebay which is currently fed
1pps from a
On 8/18/12 6:23 PM, J. L. Trantham wrote:
I use one like this (theBay item 270881742870) and it works well in NW
Florida under some trees. I could get better performance if I had it up
higher but it serves my purposes. There are also ones with higher gain out
there as well, up to about 40 dB
On 8/14/12 1:42 PM, Ron Ward wrote:
HI Robert:
WOW! Thanks.
I need to build a double oven for my thunderbolt and set it to about 50
Degrees C.
I am really just trying to reduce the 24 hour temperature range.
I am looking at an application note from National Semiconductor, AN 266,
for a
On 8/8/12 5:19 AM, Sylvain Munaut wrote:
Hi,
SVG is uncompressed text. PNG compresses well, at least for simple cases.
Decently configured web servers will compress SVG on the fly during
transport, wich yields a 9k transfer size.
(and your server is definitely not properly configured for
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