Tobias Pluess writes:
> I once tried to use the internal PLL of the microcontroller to boost
> the OCXO frequency to the max. 72 MHz which my microcontroller
> accepts. While this would greatly increase the frequency measurement
> resolution, it decreased stability because it appeared that the PLL
Subject: Re: [time-nuts] Yet another GPSDO project.
Hi
How much impact your distribution setup has on the OCXO phase noise depends a
*lot* on how quiet the
OCXO is. If it is in the -170 dbc/ Hz range, then pretty much anything can mess
up the phase noise ….
Bob
> On Mar 27, 2019, at 5:05
_
> From: time-nuts [time-nuts-boun...@lists.febo.com] on behalf of Leo Bodnar
> [l...@leobodnar.com]
> Sent: Thursday, March 21, 2019 09:14
> To: time-nuts@lists.febo.com
> Subject: Re: [time-nuts] Yet another GPSDO project.
>
> Tobias,
> Have you
-boun...@lists.febo.com] on behalf of Leo Bodnar
[l...@leobodnar.com]
Sent: Thursday, March 21, 2019 09:14
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] Yet another GPSDO project.
Tobias,
Have you measured resulting phase noise of the finished unit?
Thanks
Leo
> From: Tobias Pluess
>
...@lists.febo.com] on behalf of Leo Bodnar
[l...@leobodnar.com]
Sent: Thursday, March 21, 2019 09:14
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] Yet another GPSDO project.
Tobias,
Have you measured resulting phase noise of the finished unit?
Thanks
Leo
> From: Tobias Pluess
> s
Hi
Good point. We tend to *assume* ADEV-ish concerns when there may
be other parameters that take precedence. You most certainly can mess
up phase noise (and spurs) in a GPSDO.
Bob
> On Mar 21, 2019, at 4:14 AM, Leo Bodnar wrote:
>
> Tobias,
> Have you measured resulting phase noise of the
Tobias,
Have you measured resulting phase noise of the finished unit?
Thanks
Leo
> From: Tobias Pluess
> sure, I believe you since my primary requirement was phase noise. This is
> because I'd like to use the OCXO as reference for my spectrum analyzer and
> also for my HP 8663 signal generator
tq
> [kb...@n1k.org]
> Sent: Wednesday, March 20, 2019 14:27
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Yet another GPSDO project.
>
> Hi
>
> Indeed you want a digital “phase detector” of some sort. Your counter on the
> mi
Tobias,
If your controller has a 10 bit ADC available, I would suggest using the
TIC circuit in Lars's GPSDO. For a 10 MHz input, it needs only a 74HC390
divide by 10, a 74HC4046 phase detector, plus 1 diode, 1 capacitor, and 2
resistors to produce a 1 nsec resolution TIC. You get a fresh TIC
do.
Best
Tobias
From: time-nuts [time-nuts-boun...@lists.febo.com] on behalf of Bob kb8tq
[kb...@n1k.org]
Sent: Wednesday, March 20, 2019 14:27
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Yet another GPSDO project.
Hi
perhaps. What I have now is just an FLL, I think.
Best
Tobias
From: time-nuts [time-nuts-boun...@lists.febo.com] on behalf of Achim Gratz
[strom...@nexgo.de]
Sent: Wednesday, March 20, 2019 19:14
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] Y
n device, unfortunately... perhaps I should look for an
> Oscilloquartz 8663 or so?
>
>
> Tobias
> HB9FSX
>
>
>
> From: time-nuts [time-nuts-boun...@lists.febo.com] on behalf of Bob kb8tq
> [kb...@n1k.org]
> Sent: Tuesday, March 19, 2019 23:35
> To: Discussi
Discussion of precise time and frequency measurement'
Cc: bneu...@axtal.com
Subject: Re: [time-nuts] Yet another GPSDO project.
Hi Tobias,
Indeed the OCXO which you got from us (AXTAL) was an item from stock, which
was not particularly designed for low ADEV. As it is from an older
production lot, the
and frequency measurement
Betreff: Re: [time-nuts] Yet another GPSDO project.
Hi,
no, I don't want the OCXO to closely follow the 1PPS - this would make no
sense. Instead I thought the "right way" of doing it is perhaps:
a) measure the phase difference between the GPS PPS and the PPS derived fro
Tobias Pluess writes:
> By the way, this is the unit I built:
>
> https://hb9fsx.ch/wordpress/index.php/2018/11/14/my-own-gpsdo-part-i/
Nice build. Minor nit: Whatever foam you used to isolate your OCXO
further is probably not SAGEX, but looks to be either cross-linked PE
foam or (more likely)
device, unfortunately... perhaps I should look for an
> Oscilloquartz 8663 or so?
>
>
> Tobias
> HB9FSX
>
>
>
> From: time-nuts [time-nuts-boun...@lists.febo.com] on behalf of Bob kb8tq
> [kb...@n1k.org]
> Sent: Tuesday, March 19, 2019 23:35
> To: Discussion of precise
frequency measurement
Subject: Re: [time-nuts] Yet another GPSDO project.
Hi
Ok, *if* you phase lock the OCXO to closely follow the GPS PPPS, the OCXO will
be every bit as noisy
as the GPS. Actually it will be worse since you now have 1Hz noise running
around that needs to be
taken care of ( =
Tobias asked,
@Jim Harman
Indeed I know Lars' GPSDO. Can you tell what performance you achieved with
one of those?
It is hard for me to quantify the performance because I don't have anything
better to compare it to. The TIC resolution is 1 nsec.
I can say that it will stay phase locked to the 1
Also Nick Sayers's GPSDO described here
https://www.tindie.com/products/nsayer/gps-disciplined-ocxo/
is based on the same design and he has performance data.
On Tue, Mar 19, 2019 at 8:32 PM Jim Harman wrote:
> Tobias asked,
> @Jim Harman
> Indeed I know Lars' GPSDO. Can you tell what
Hi
Ok, *if* you phase lock the OCXO to closely follow the GPS PPPS, the OCXO will
be every bit as noisy
as the GPS. Actually it will be worse since you now have 1Hz noise running
around that needs to be
taken care of ( = the output of the phase detector is a series of pulses at a 1
Hz rate).
Thanks for the replies so far.
Unfortunately I used digest mode for this mailing list, so perhaps my answers
are not well-formed - please excuse; I have changed my settings to non-digest
(even though this is perhaps a bit less convenient).
@Jim Harman
Indeed I know Lars' GPSDO. Can you tell
Tobias Pluess writes:
> I was reading on this list for quite a while, but still have some
> questions I'd like to ask. Please forgive me my perhaps silly
> questions since I am a newbie to the timenuts world :-)
>
> So I have built my own GPSDO. I used a low phase noise OCXO from
> AXTAL, a
Hi
Sounds like you are having fun :)
Indeed GPSDO’s are an interesting thing to play with. The further you dig, the
more nasty …. errr ….
fun …. things you find.
Some real quick pointers:
The output of the GPS module (any GPS module) is womping around a *lot*
compared to an OCXO. Your
5335
You might want to study the design by Lars Walenius posted on this list in
2014 and updated here
https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/
Lars has unfortunately passed away, but his design lives on. I have built a
couple of GPSDOs based on his
I was reading on this list for quite a while, but still have some questions I'd
like to ask. Please forgive me my perhaps silly questions since I am a newbie
to the timenuts world :-)
So I have built my own GPSDO. I used a low phase noise OCXO from AXTAL, a
LEA-M8T module and a small STM32F303
25 matches
Mail list logo
