Hi Don,
Hardly. As long as you do GPS L1 C/A code only, chanses you get any
useful improvement isn't all that great. SBAS may help you some thought.
Cheers,
Magnus
On 11/13/2017 05:35 AM, Don wrote:
I read where the first GPS III satellite had finally been approved for
flight.
The report
On Sun, Nov 12, 2017 at 6:38 PM, John Miles wrote:
>
> Most of the 100 and 200 MHz bricks I've seen work with either 5 or 10 MHz
> . I don't know if I've seen any 80 MHz units that do. All of the ones
> I've bought on eBay have been from the customer-proprietary 500- series
> with unusual input
I read where the first GPS III satellite had finally been approved for
flight.
The report said they will provide three times better location accuracy
than current GPS.
Will "better" onboard clocks help contribute to this improvement? How
are they "better"?
Can we expect enhanced timing accu
> Yes, exactly those. With no input, would they be expected to be 4 kHz off?
> The spec for the standard part wants the input to be within 1e-7. I would
> not expect them to be so far off free running.
That does seem like a lot. I'd expect a few hundred Hz of error at the most.
> I saw 13 MHz o
Hi
If it is a OCVCXO and it pulls > 50 ppm at 80 MHz, it’s got terrible phase
noise close in.
That’s true with or without the PLL engaged.
Bob
> On Nov 12, 2017, at 7:46 PM, Mark Goldberg wrote:
>
> Yes, exactly those. With no input, would they be expected to be 4 kHz off?
> The spec for the
Yes, exactly those. With no input, would they be expected to be 4 kHz off?
The spec for the standard part wants the input to be within 1e-7. I would
not expect them to be so far off free running.
I saw 13 MHz on the 500-14273 and stayed away from those.
Do you know of any part numbers that use 10
apollo...@gmail.com said:
> prior to my senior project most geodetic surveyors used a Wooden boxed,
> marine chronometer, to get sub second UT1 time, or back then, GMT
How did you get the data out of the wooden box?
--
These are my opinions. I hate spam.
_
Sounds like he's talking about the small 'bricks' that Wenzel sells with
internal PLL-disciplined OCXOs. Some of these expect oddball input
frequencies. Just looking at the 80 MHz parts on the shelf around here,
500-14273 wants a 13 MHz input, 500-25010 uses 24.576 MHz, and 500-25009 uses
19
Hello fellow Time nuts,
I am a newbie here, just joined, first post. But back in college dabbled in
"precise time" recording in the field, for
Geodetic Surveying field measurements, Star Shots. transiting the
meridian. Very crude by today standards, but effective for
field measurements that had t
> But be aware, that measurements close to the limit of thermal noise
> will make your measurement go sour. There the noise of your splitter
> will cause an anti-correlation effect and the measured noise will
> suddenly drop way below thermal noise. Craig Nelson and Archita Hati
> from NIST, Enrico
Hi
I guess my point was more that there is not a VCO / PLL combo in an OCXO.
If dropping the supply gets you on frequency, then you have moved things a lot
with that voltage change. 50 PPM is a lot of delta T on any normal OCXO
crystal.
That strongly suggests there is something wrong in the co
The standard oscillator, 501-14057 (
www.wenzel.com/wp-content/parts/501-14057.pdf) will lock to an external 10
MHz reference and this one is marked "80 MHz" and "15V on the label. Maybe
someone swapped the labels. I did try lowering the supply voltage. It got
to 80 MHz at about 11V and still did n
Hi
It’s pretty certain that there is no PLL inside an 80 MHz low phase noise OCXO.
If it is 4 KHz off frequency at 80 MHz, that gets you into the 50 ppm range.
Either
it is running on a really odd crystal spur or it’s not at the right
temperature. Drifting
around by 100’s of Hz ( = ppm’s at 8
The 6-7us of latency in this discussion does not involve the network path. In
this regard network latency is fairly well addressed with hardware
timestamping, although trying to get readings across the clock domains looses
dozens of nanos of precision. In this discussion, the 6-7us of latency
o
The seller has replaced it with one that does the exact same thing, which
is weird to have two fail in the same way. They are getting hot and the
frequency varies with the input voltage, so I tended to guess not the
heater as I don't think it could pull that far over temp, and it always is
high. If
This beast may have some interesting uses:
http://www.analog.com/en/products/clock-and-timing/clock-generation-distribution/clock-synchronization/ad9544.html
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer |
That reminds me, should anyone have a schematic for an SR 830 walking
amplifier, can you please get in touch with me. I have one that keeps eating
voltage regulators.
> On Nov 12, 2017, at 12:12, Dr. David Kirkby (Kirkby Microwave Ltd)
> wrote:
>
>> On 10 November 2017 at 16:37, Bob Camp wro
On 10 November 2017 at 16:37, Bob Camp wrote:
> Hi
>
> There is no perfect answer. I’d go with the 53230 simply because it
> *might* be supported
> the longest.
>
> Bob
>
If I had to take a bet, I would say the SR620 will be supported longer.
Stanford Research seem to be selling the same produc
Hi
I would say there are *very* few companies out there that will
sell you high grade precision OCXO crystals in single piece quantities.
I think you would get one much quicker and cheaper by pulling it out
of an eBay OCXO. You can do good far removed phase noise with
a lot of crystals. Onc
Hi
As a guess - the oven circuit has stopped working. Next step
would be to tear it open and trace out the schematic. After that
make reasonable guesses for any parts that are poorly labeled.
Much of what shows up on eBay has been through the ringer in
China. A high percentage the OCXO's I get o
On Sun, 12 Nov 2017 16:34:35 +0100
Magnus Danielson wrote:
> > That said, it is probably worth trying what actually happens when
> > using a 16bit ADC instead of 14bit. If there are any students here
> > looking for a bachelor or master thesis project doing noise measurement,
> > feel free to con
On Sat, 11 Nov 2017 04:44:53 -0800
"Tom Van Baak" wrote:
> That said, I want to point out that the latest GPSDO / counter from Stanford
> Research continues their tradition of relatively open design. If you have an
> hour, go through the very detailed user manual, which includes theory of
> op
On Wed, 8 Nov 2017 14:24:08 -0600
"Chris Caudle" wrote:
> On Wed, November 8, 2017 12:55 pm, Gary E. Miller wrote:
> > I knew about the errata, I left out that detail to see when someone
> > actually read my citation.
>
> OK, I don't want to quibble about versions, and whether the "latest
> vers
I have obtained a couple 80 MHz Wenzel Oscillators P/N 500-16423A. They are
proprietary but similar to the VHF PLO and 501-14057 Oscillators. I want to
use this to replace the internal oscillator in my Perseus SDR, for better
accuracy and maybe better phase noise. Both of these are way off in
frequ
On Tue, 7 Nov 2017 22:07:43 +
Leo Bodnar wrote:
> Coincidentally, I have been testing relative phase difference of two GPS
> clocks
> http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301
> since Friday.
> They are completely independent, including separ
Hoi Leo,
On Thu, 2 Nov 2017 21:45:56 +
Leo Bodnar wrote:
> I suspect delta-sigma body of knowledge can be applied almost wholesale to
> this seemingly silly oscillator concept.
> Did I just repeat something trivial that has been discussed to death here
> before?
Trivial? Yes. Well known
On 11/12/2017 03:57 PM, Attila Kinali wrote:
On Fri, 27 Oct 2017 09:35:08 +0800
"Li Ang" <379...@qq.com> wrote:
I just found Andrew recently post a phase noise measruement page on
www.aholme.co.uk/PhaseNoise/Main.htm .
Indeed a nice post, as usual for Andrew.
He uses 4-channel 14bit ADC
On Wed, 1 Nov 2017 10:15:43 -0700
Denny Page wrote:
> > 6-10µs is the interrupt latency of linux on ARM SoC. I guess, to get
> > below that you'd have to tweak the kernel a bit. Which should not
> > be that difficult. Definitly simpler than writing your own IP and NTP
> > stack from scratch.
>
>
Hi Jim,
On Wed, 1 Nov 2017 11:39:32 -0700
jimlux wrote:
> So, it would be nice to have a *cheap* lowish power packaged part that
> has the Q of an OCXO, but without the power consumption of the oven
> (typically measured in watts).
>
> yeah, I'd be operating it *way* far from the optimum turn
On Wed, 1 Nov 2017 13:11:00 -0400
wrote:
> I am trying to beat existing products like the Dallas DS3231 and Micro
> Crystal RV-8803-C7-32.768kHz-3PPM-TA-QC, which use (I think) a similar
> strategy. I’m hoping I can beat them by using more accurate temp tensing,
> longer and more exhaustive ca
On Fri, 27 Oct 2017 09:35:08 +0800
"Li Ang" <379...@qq.com> wrote:
> I just found Andrew recently post a phase noise measruement page on
> www.aholme.co.uk/PhaseNoise/Main.htm .
Indeed a nice post, as usual for Andrew.
> He uses 4-channel 14bit ADC to do the sampling work. -170dBc noise floor
The first one was a real prove what was possible for the first time, the second
paper shows the physics based limitations, 73 de Ulrich
Sent from my iPhone
> On Nov 12, 2017, at 9:36 AM, Attila Kinali wrote:
>
> Hi,
>
> I received two papers by Ulrich:
>
> "Accurate Noise Simulation of Micro
Hi,
I received two papers by Ulrich:
"Accurate Noise Simulation of Microwave Amplifiers Using CAD",
by Rohde, Pavio, Pucel, 1988
http://time.kinali.ch/rohde/noise/accurate_noise_simulation_of_microwave_amplifiers_using_cad-1988-rohde_pavio_pucel.pdf
This is the paper Ulrich mentioned a few days
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