On Thu, 23 Nov 2017 13:18:35 -0500
Bert Kehren via time-nuts wrote:
> There was recently discussion of the use of the LTC1655 which
> is still my # 1 choice. What was not mentioned on the 1650 is that in needs
> a external reference discontinued and double ling the cost.
There is just a tad
Hi
On 11/26/2017 02:26 PM, Attila Kinali wrote:
Though, if you have a decent 16bit DAC and want to get to 18bit,
that's fairly simple using delta-sigma modulation... if you can live
with a low pass fillter after the DAC. But the DNL will be the limiting
factor here (unless you use some special t
I guess everyone has seen this, but Linear has a nice appnote «A Standards Lab
Grade 20-Bit DAC with 0.1ppm/°C Drift»
http://cds.linear.com/docs/en/application-note/an86f.pdf
Ole
> 26. nov. 2017 kl. 13:50 skrev Magnus Danielson :
>
> Hi
>
>> On 11/26/2017 02:26 PM, Attila Kinali wrote:
>> Tho
Hi All,
I've a question for all the group. Ho can I obtain a Rinex Data Stream from
a GPS receiver? I need to convert NMEA data?
Thank you so much.
Marco
*Best Regards,*
*Marco Cardelli - IZ5IOW*
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Depending on the receiver, the manufacturer usually provides a conversion
utility.
No such thing as a RINEX «stream» though, as far as I know. The observations
are usually collected in a vendor specific (or sometimes neutral, like BINEX)
format, and then converted to RINEX in batch.
Ole
> 26.
Hi
Each time I’ve tried the method in the app note, there has been a tone in the
output
spectrum at the sample rate of the ADC. I’ve never found a way to do the
grounding
that eliminates it. The tone is large enough to show up as a spur on a
“typical” OCXO
when it goes into the EFC port.
Bob
Is summing a "fine tune" 16bit DAC and a "coarse tune" 16bit (or less)
DAC with an op-amp not good enough?
On Sun, Nov 26, 2017 at 5:53 PM, Bob kb8tq wrote:
> Hi
>
> Each time I’ve tried the method in the app note, there has been a tone in the
> output
> spectrum at the sample rate of the ADC. I
Hi
If you sum two DAC’s without any sort of feedback, you get problems when the
“coarse” dac is changed. You have no way to know the step size of the coarse
dac to (say) 20 bit precision.
As an example : If you are after 20 “good” bits, you might overlap
them at the 10 bit point on the coarse d
...and what about shrinking the 16bit over the fraction of the EFC
range that, for example, the OCXO will be using for the next 5 years?
16bit over 10V are as 20 (a little less, OK) over 1V, if I can use my
16bit over 1V for the next 5 years, when the DAC will be near full
scale I can "trim" the ag
Hi,
You can't get RINEX from NMEA, Rinex can be gotten from the raw steam.
Regards.
Thierry MUSEUX
Directeur Technique Electronique, Informatique & Télécom
Port. : +33 (0)6 15 22 09 62
thierry.mus...@geoflex.fr
Géoflex - Attention, nouvelles coordonnées :
4 grande rue du 8 mai 1945 – 91430 VAUHAL
Hi Marco,
What receiver? What do you mean with stream?
Besides the software of the manufacturer, the tools in RTKLIB could help
you as well.
I am not aware of NMEA sentences that contain raw data, you need to
parse the proprietary protocol of your receiver.
Best,
Thomas, SA6CID
On Sun, Nov 2
We tried coarse and fine using a LTC 24 bit ADC for characterization but
test time is prohibitive and all the data has to be stored, or do it
dynamically like Tbolt does, I suspect SRS does something like that on the
OCXO
they can afford it since it looks like the do that through out the uni
As I said in my original post from our point of view there are only two
reasons for a Rb time and 16 bits will do the job. I would not do an OCXO
with less than 22 bits if analog at all.
Bert Kehren
In a message dated 11/26/2017 8:56:51 A.M. Eastern Standard Time,
opronnin...@gmail.com w
Hi
If you only run over 10% of the EFC range, you only gain 3 bits. If the
objective is
in the 22 bit vicinity, (maybe 20 maybe 22 …) you really don’t get enough bits
at a 10%
span. From a lot of years of playing with control loops, if you need 20 *good*
bits, you better
have a few more than
Hi,
NMEA are produced by all the GSP/GNSS receiver. From low cost to hight end.
There are no raw data in the NMEA sentences.
U-Box chip , low cost give raw stream in a proprietary format.
Raw data are given by the most of the case high end receiver, when the option
is enable.
Some time there are
About to start repairing a second 5065A. Gathering parts.
1.
Looking for a replacement for the still available but very expenceive OPA111
used in later versions A9 Integrator of the HP5065A.
There are indeed some candidates at Digi-Key, but when the selection of max
Input current, offset volta
BTW, that is the temp sensitivity of the X72 rubidiums that I have tested...
--
Your OCXO may be happy at 1x10^-11 / C
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Hi
The “gotcha” with compensated devices is that there can be interesting
breakpoints or decoupling to the sensor. Those show up more if the compensation
is working very hard to get the job done. Put another way - if you start at
1x10^-9/C
and compensate to 1x10^-11/C that is very different tha
Here's a short reply to the comments of Bob, Attila, Magnus, and others.
Thanks for reading the paper carefully. I appreciate it. Some of the
comments are quite interesting, other seem off the mark. Let's start with
an interesting one:
The issue I intended to raise, but which I'm not sure I stated
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