Hi
> On Jul 11, 2019, at 9:37 AM, Leo Bodnar wrote:
>
>> Well part of it comes from designing, testing, and manufacturing a few
>> thousand OCXO designs over the years. We likely built 10’s of millions of
>> OCXO’s over the time I was doing / managing that.
> It might be just my personal
> Well part of it comes from designing, testing, and manufacturing a few
> thousand OCXO designs over the years. We likely built 10’s of millions of
> OCXO’s over the time I was doing / managing that.
It might be just my personal opinion but credential swinging is better left out
of technical
Hi
Well part of it comes from designing, testing, and manufacturing a few
thousand OCXO designs over the years. We likely built 10’s of millions of
OCXO’s over the time I was doing / managing that.
> On Jul 11, 2019, at 3:56 AM, Leo Bodnar wrote:
>
> Hello, /
>
> Why would you not want
Hello,
Why would you not want high drive level for best close-in noise? This is at
odds with general thinking in the industry.
Close-in in this context means from 0.1Hz to 1/f knee which is 1-100kHz
depending on the design of the sustaining amplifier.
There are few reasons why low phase noise
Hi
It depends a lot on the offset you are looking at. For close in phase noise,
you probably don’t
want high drive. If you are only after phase noise past 10KHz, you may not want
/ need
an OCXO in the first place. Selecting crystals (like one in a hundred) for very
high drive /
low phase
I did, sorry, - it was a finger slip.
Now, what I find kind of funny is that one of the meanings of "monotonous" is
"repetitious or periodic" which is almost exactly the opposite of monotonic.
Leo
> From: "David G. McGaw"
> Leo -
> I do believe you mean non-monotonic, rather than
> From: Bob kb8tq
> Drive power on an OCXO will pretty much always be below a milli-watt. A
> typical design will be in
> the range of 1/10 to 1/100 of that power level.
It depends whether OCXO is designed for long term stability and low ageing or
low phase noise.
Low ageing requires low
Hi
TCXO’s are very different beasts than OCXO’s. In an OCXO, the crystal is not
exposed
to any significant temperature change.
Bob
> On Jul 9, 2019, at 8:05 PM, Mark Goldberg wrote:
>
> That is the dirty little secret of crystals. Manufacturers will test the
> temperature response in one
That is the dirty little secret of crystals. Manufacturers will test the
temperature response in one direction, but if you heat and then cool
crystals and measure the frequency, they do exhibit significant hysteresis.
I've not been able to get a supplier of TCXOs for me to characterize this
as I
Hi
Well, if you ever get back into it:
You play games with varicap diodes to straighten out the curve. You may bias
them, you might
put them in parallel, you might put a coil or a cap across them. You can get
the curve plenty flat
enough for a control loop.
Hopping / discrete steps
and non monitonicity in the device is the death of a control loops.
My attempts at building good OCXOs using cheap AT crystals in the 90s
was thwarted by non monotonic bending crystals !
And everytime they would wake up, the monitonicity would be in a
different part of the control
HI
Actually a monotonous ( = un-exciting) GPSDO is a *really* good thing :) Having
one that
does exciting stuff from time to time is *not* at all what you are after :)
Now we get to find out what auto spell check did to all of that …...
Bob
> On Jul 9, 2019, at 3:57 PM, David G. McGaw
>
Leo -
I do believe you mean non-monotonic, rather than non-monotonous. Not
being monotonous is a good thing. :-)
David N1HAC
On 7/9/19 1:20 PM, Leo Bodnar wrote:
> It's not very good, it is highly non-linear and even worse - nonmonotonous.
> It sometimes produces runt pulse glitches when you
It's not very good, it is highly non-linear and even worse - nonmonotonous.
It sometimes produces runt pulse glitches when you roll time backwards.
I have used them in GPS clocks for many years but never enabled them for end
user mode.
It's really a very primitive delay line series and I don't
offended by your post.
respectfully,
Robert LaJeunesse
> Sent: Tuesday, July 09, 2019 at 6:26 AM
> From: "ew via time-nuts"
> To: time-nuts@lists.febo.com
> Cc: ew
> Subject: Re: [time-nuts] Advantages of GNSS ???
>
> Dana
> This was in response to Mark Sins " I
In message <8e74832c-58e6-c2ef-f68c-48e116718...@leapsecond.com>, Tom Van Baak
writes:
>The plot is beautiful. The reason this delay line technique isn't used
>much anymore is that AFAIK the Dallas chips are no longer produced. So
>almost every uses s/w sawtooth correction now.
So...
On Tue, July 9, 2019 10:50 am, Tom Van Baak wrote:
> chip. Look carefully and see the DS1023-50, which is an 8-bit
> programmable delay line (~0 to ~127 ns in 0.5 ns steps).
...
> The reason this delay line technique isn't used
> much anymore is that AFAIK the Dallas chips are no longer produced.
Let's put the Bert vs. Dana misunderstanding aside.
To me the key feature in Bert's photo is the Dallas/Maxim digital delay
chip. Look carefully and see the DS1023-50, which is an 8-bit
programmable delay line (~0 to ~127 ns in 0.5 ns steps). This is a
technique used to remove sawtooth error
offended by your post.
respectfully,
Robert LaJeunesse
> Sent: Tuesday, July 09, 2019 at 6:26 AM
> From: "ew via time-nuts"
> To: time-nuts@lists.febo.com
> Cc: ew
> Subject: Re: [time-nuts] Advantages of GNSS ???
>
> Dana
> This was in response to Mark Sins " I
Dana
This was in response to Mark Sins " I don't think that I have ever seen what to
do with the sawtooth value
documented in any receiver documentation"I did this 4 years ago it, is a
sawtooth corrected ublox. First pass. Always do a follow on board but never
did any thing with it since
One what? I see that it is a Ublox unit, but see no reference to the
interesting
modern units like the 9 series. Also, I note that the only reference on
the board
to "ant" is on the lower right corner, while what I suppose to be the
actual antenna
connector appears to be an SMA near the upper
Well now you can see one
Bert Kehren
In a message dated 7/8/2019 7:02:07 PM Eastern Standard Time,
hol...@hotmail.com writes:
A big issue with using the sawtooth correction message from a GPS receivers is
the issue of just what that sawtooth value is related to and how to apply it to
the
A big issue with using the sawtooth correction message from a GPS receivers is
the issue of just what that sawtooth value is related to and how to apply it to
the measured PPS value / phase.
I added the ability to Lady Heather to calculate a sawtooth corrected "paper
clock" by applying the
avigation rate - up to 20Hz on F9P.
> F9P's rate of TP can be set from 0.25Hz to 10MHz according to the datasheet
> but in reality is usually wider.
>
> TP edge quantisation is a separate issue to TP base rate adjustment and it is
> done at TP rate.
>
> Leo
>
>
&g
can be set from 0.25Hz to 10MHz according to the datasheet but
in reality is usually wider.
TP edge quantisation is a separate issue to TP base rate adjustment and it is
done at TP rate.
Leo
> Subject: Re: [time-nuts] Advantages of GNSS ???
> They go absolutely crazy updating nav?.. bu
Leo Bodnar writes:
> Correction on all Ublox receivers including F9P is done at navigation
> rate which can be set as high as 20Hz.
If you are thinking of the sawtooth correction, then I think you'll find
that this is only available for the full second. There is some mumbling
in the manual that
Hi
They go absolutely crazy updating nav….. but they only come up with the timing
correction once a second.
From the latest version of the F9T Manual UBX-19005590 - R02 on page 43:
The recommended configuration when using the UBX-TIM-TP message is to set both
the measurement rate
Correction on all Ublox receivers including F9P is done at navigation rate
which can be set as high as 20Hz.
Leo
> From: Bob kb8tq
> Frequency of any GNSS output on the F9P is limited by the accuracy of the
> time pulse.
> Correction is only done once a second.
Here is screen grab of an F9T tracking GPS/GLONASS/GALILEO/BEIDOU. In the max
sig level display the sats that the F9T says do L2 ionospheric corrections are
shown in GREEN.
Note that the F9T thinks that it is seeing signals from PRNs 192..202 These
are the Japanese QZSS sat PRNs.
Hello Luiz,
(Did we meet at IFCS-EFTF in Orlando? If so, my apologies for not
remembering your name, and for repeating here what you know). I presented
some preliminary time-transfer data for the F9P at IFCS and wrote a short
paper for the proceedings; if you’d like a copy, I am happy to send you
On Fri, 5 Jul 2019 19:49:59 -0500
"Graham / KE9H" wrote:
> Does using the signals from GPS (USA), plus GLONASS (Russia), plus Beidou
> (China), and plus Galileo (Europe), actually provide any improvement in
> time/frequency accuracy?
There are multiple angles to this:
1) Galileo offers the
Hi
On the F9P you have the specific issue of L1 / L2 with older GPS satellites.
The device
only does L2C. That cuts the “population” roughly in half. This is not a great
thing for a
“GPS only” setup with that device.
BIPM does not directly control or feed timing into the various GNSS
Hey Graham,
I'm gonna start a project soon to evaluate a F9P as a Time Transfer GNSS
receiver. For now i haven't too much answers for you but only i know is:
the BIPM uses all labs that participate from UTC to make corrections of
GNSS satellites frequency, also for the TAI use. I think GNNS T is
I have several questions for the group, since there are several members
that have been able to start evaluating the uBlox F9P and perhaps the F9T
GNSS receivers.
For the purposes of time and frequency determination, is there an advantage
to using the GNSS receivers, relative to just the US GPS?
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