Thanks all for the replies to my initial query as to whether anyone had any
firsthand experience with this device. The replies have been helpful.
It is also clear that what some see as an apple, others see as an orange. A
simple common truth perhaps which becomes very obvious when comparing the
Sorry but I disagree. Having done extensive work with the M7 and M6 in
connection with the with GPSDO work we are doing we have characterized the
units extensively. First from what we can see the difference between a SSR-6T
and a $ 16 M6 is that one has a TCXO and outputs sawtooth
Said,
On 20/08/2014 15:42, saidj...@aol.com wrote:
Hi Tony,
that's consistent with what I remember. Do you have the capability to count
the number of 10MHz pulses per second to see if it is phase-coherent with
the UTC 1PPS pulse?
I don't have any means to do that at the moment - when I
From: Tony
As I said, I measured the pulses at either 104ns (9.6MHz), with some
being shorter at 84ns. I've just repeated the measurements on a Reyax
RYN25AI (UBLOX MAX-7C) with the same results. Actually the scope
measures the longer pulses at either 104.3ns or 105.2ns and the shorter
pulses at
FYI. It is still available. Don't have it in hand yet, but one was
ordered just a few days ago...
Dan
On 8/21/2014 6:34 AM, time-nuts-requ...@febo.com wrote:
One example
is Synergy Systems' SSR-6Tr if it's still available. It was announced,
and discussed on this list, in 2012 but it still
Hi Bert,
I don't think we have any fundamental disagreement here. Maybe just a
difference in emphasis.
On 8/21/2014 4:34 AM, ewkeh...@aol.com wrote:
Sorry but I disagree. Having done extensive work with the M7 and M6 in
connection with the with GPSDO work we are doing we have characterized
David,
No problem, its still set-up. As you'd expect its rock solid at 8MHz
with no visible jitter.
Can you point me to the datasheet you're referring to? The MAX-7 and
NEO-7 datasheets don't provide any information on clocking.
In the 'u-blox 7 Receiver Description Including Protocol
On 21/08/2014 08:13, Ed Palmer wrote:
But, timing receivers do have features that can improve performance
over navigation receivers. Some that come to mind are position hold
mode, TRAIM, maintaining performance with only one satellite locked,
sawtooth correction, and precision survey. I
On Thu, Aug 21, 2014 at 9:45 PM, Tony tn...@toneh.demon.co.uk wrote:
I just tried sending various TMODE and TMODE2 configuration messages to the
NEO-7M. These allow you to select 'Disabled' 'Survey In' and 'Fixed Mode'
where you can specify the receiver's lattitude and longitude. Not
/divdivFrån: Tony
tn...@toneh.demon.co.uk /divdivDatum:2014-08-22 03:45 (GMT+01:00)
/divdivTill: Discussion of precise time and frequency measurement
time-nuts@febo.com /divdivRubrik: Re: [time-nuts] Ublox neo-7M GPS
/divdiv
/divOn 21/08/2014 08:13, Ed Palmer wrote:
But, timing receivers do
Paul,
How far from the equator are you? The farther you are, the more trouble
GPS has measuring your latitude due to worsening geometry.
By the way, does anyone know what the timing effects of that will be?
Is it documented anywhere? I noticed that the GLONASS satellites have a
higher
On 21 Aug, 2014, at 16:27 , Tony tn...@toneh.demon.co.uk wrote:
David,
No problem, its still set-up. As you'd expect its rock solid at 8MHz with no
visible jitter.
Can you point me to the datasheet you're referring to? The MAX-7 and NEO-7
datasheets don't provide any information on
tn...@toneh.demon.co.uk said:
Tony, any chance you could do a quick measurement at 8 MHz -
I think that should be a more constant period. ...
No problem, its still set-up. As you'd expect its rock solid at 8MHz with
no visible jitter.
I don't think you have fixed the problem, just made
Hal,
Except for a few magic target frequencies, the output will have
occasional (or frequent) missing or extra
cycles. The output will be clean if you are dividing by a power of 2.
(By switching from 10 MHz to 8
MHz, you have changed from frequent to occasional.)
Not true that
Quoting Tony tn...@toneh.demon.co.uk:
I don't have any means to do that at the moment - when I get time
I'll try programming my STM32F4 discovery board (168MHz ARM Cortex
M4) to take some measurements. However as I haven't used the timers
on that yet it'll take a bit of time to get it
On Thu, Aug 21, 2014 at 4:03 PM, Ed Palmer ed_pal...@sasktel.net wrote:
How far from the equator are you?
I believe 43.235262699 N (my median position) is about 4,809,051
meters from the equator.
___
time-nuts mailing list -- time-nuts@febo.com
To
Ed
We may be talking past each other I had problems with the statement that
the basic M6 and M7 are not suitable for GPSDO's. They are not GPSDO's in
them self but great GPS engines even without saw tooth correction which is an
impossibility since the data is not available. But as you
Hi
I would bet that they drop / add a cycle whenever the output gets ahead or
behind GPS by the appropriate (TCXO period) amount. The output stays “in phase”
with GPS (sort of). The output spectrum looks messy ….
Why would I guess this - it’s the cheap / low computation way to do it. Playing
I'm at about 50 N. I used a Navsync CW-12 connected to a VIC-100
antenna to do a long site survey and got the following results:
Latitude: 1.32 meters Std Dev., -1 to +4 meters total range
Longitude: 1.18 meters Std Dev., -3 to +1 meters total range
Height:3.90 meters Std Dev., +6.6 to
On Thu, Aug 21, 2014 at 11:09 PM, Ed Palmer ed_pal...@sasktel.net wrote:
Since you're closer to the equator your results should be somewhat better
than mine. You could use these numbers to help decide if you've got a
problem or not.
I was unclear. My point was (since I'm really an absolute
David,
No problem, its still set-up. As you'd expect its rock solid at 8MHz
with no visible jitter.
Can you point me to the datasheet you're referring to? The MAX-7 and
NEO-7 datasheets don't provide any information on clocking.
In the 'u-blox 7 Receiver Description Including Protocol
Be patient as soon as we have finished rollout of the FE 5680A and FE 405 B
GPSDO I will be off the list.
Bert Kehren
In a message dated 8/19/2014 9:31:50 P.M. Eastern Daylight Time,
csteinm...@yandex.com writes:
Bert wrote:
I guess time nuts like to talk about it but not fix it.
On 19/08/2014 16:11, Ed Palmer wrote:
Does anyone have a neo-7M and an HP 5371A or a 5372A Analyzer? Use
the Histogram Time Interval function to measure a block of samples.
That will show the length of the samples with a resolution of 200 ps.
That's what I did a couple of years ago when I
Hi Tony,
that's consistent with what I remember. Do you have the capability to count
the number of 10MHz pulses per second to see if it is phase-coherent with
the UTC 1PPS pulse?
I am thinking that the software may be using statistics to approximate 10
million cycles per second, which
Thanks, Tony. That's good info.
So now we've confirmed that the neo-7M has an NCO and it appears that
it's resolution is 20 ns. The data sheet shows the 'Accuracy of time
pulse signal' is 30 ns RMS and 60 ns for 99%, but it isn't clear whether
they're referring to jitter or error with
Good day all,
On another list to which I subscribe, there has been chatter about the Ublox
neo-7M GPS receiver. It seems that the device's configurable timepulse output
is configurable from 0.25hz to 10 MHz as well as it's duty cycle and can also
be set to be one condition when the GPS is not
Good day all,
On another list to which I subscribe, there has been chatter about the Ublox
neo-7M GPS receiver. It seems that the device's configurable timepulse
output is configurable from 0.25hz to 10 MHz as well as it's duty cycle and
can also be set to be one condition when the GPS is not
Graham,
Those are not GPSDO's by definition.
They are based on NCO technology.
The difference being many orders of magnitude higher phase noise and ADEV noise.
We tried to measure their phase noise and our TSC5125A could not even lock on
to the 10MHz - they were so noisy.
You can make a
ve3gtc
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
Of Said Jackson
Sent: August-19-14 12:44 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ublox neo-7M GPS
Graham,
Those are not GPSDO's by definition
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ublox neo-7M GPS
Graham,
Those are not GPSDO's by definition.
They are based on NCO technology.
The difference being many orders of magnitude higher phase noise and ADEV
noise.
We tried to measure their phase
saidj...@aol.com said:
its not a GPSDO though, not even a simple one :)
It does not discipline an oscillator. It generates the output by
mathematically calculating how many phases it has to add/drop in a second,
then digitally adds/drops/extends/retards the phase of the output clock to
Hal,
I guess that depends on your definition of disciplined.
The products that I am familiar with don't consider adjusting phase length
of an asynchronously running oscillator on a cycle-to-cycle basis thousands
of times per second to try to fit 10 million of them (or whatever your
Hal, as long as you maintain long-term phase lock it's a disciplined
oscillator. So, yes, a carrier tracking WWVB receiver with sufficiently stable
flywheel LO is a WWVBDO.
Said, too-short or too-long 100 ns cycles is one thing. Still ok for many
applications. But tell me more about extra or
Knowing a litle bit about semiconductor production it is safe to assume
that all 7M series divvices have the same chip and during production at ublox
some features are disabled or enabled. The result is one mask set one chip
run and one inventory.
I did see a recent announcement where a 7M
Hi Tom,
last time I looked at these I tried figuring out what they were doing. It
is very hard to get measurement data, our TSC did not converge on their
signal, and looking at the output on a scope revealed only a bunch of crazy
random phase jumps. I guess one could use a counter to
Hi
They are constrained by the same basic TCXO issues that give you sawtooth
correction. They do not use EFC to get the TCXO on frequency. With sawtooth
they give you a word that lets you know what’s going on. With the NCO’s they
often are doing very crude synthesis. They don’t put a $48 DDS
I recall when the LEA-M8F was announced that they mentioned a VCTCXO and
maybe I wrongly assumed that they used it for sawtooth correction they also
mention ability to control in addition an external OCXO. I previously
suggested using saw tooth correction information to tune a TCXO but that
Does anyone have a neo-7M and an HP 5371A or a 5372A Analyzer? Use the
Histogram Time Interval function to measure a block of samples. That
will show the length of the samples with a resolution of 200 ps. That's
what I did a couple of years ago when I analyzed the Navsync CW-12 with
the old
Hi
There are only two things they can be doing (since it’s not a tuned oscillator).
1) It’s a true DDS with a D/A on the output and you need to put a filter on it
before you can do anything at all with it.
2) It’s a pulse drop / add NCO that drops or adds at the 20 to 30 ns level (28
to 50
Hi
If you have to womp up a MCU anyway, there is no reason to put in a delay chip.
It’s easier / faster / more accurate to just do it all in the MCU. You have to
write and maintain custom code either way.
Bob
On Aug 19, 2014, at 7:53 PM, ewkeh...@aol.com wrote:
I recall when the LEA-M8F
I have a dozen ublox max-7's on hand and should have suitable PCB's
for the analysis in a couple of days. Unfortunately I don't have the
analyser, the test kit is currently limited to a HP5834A recently
calibrated to Rb and a 100MHz DSO so probably not what your looking
for.
Let me know if I
Bert wrote:
I guess time nuts like to talk about it but not fix it.
Will you PLEASE quit beating this tired old drum? All of us know
this is your opinion, although many of us have other explanations for
the phenomena you think it explains. We do not need you to repeat it
every time you
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