Empathy List Archives

FV

Folkert van Heusden

Sun, Nov 24, 2024 5:20 PM

Hi,

A while ago I bought the following GPSDO: https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301
I wanted to let it produce a 1 Hz pulse but if I feed its output to a
PICDIV or a PICODIV, then nothing comes out. I verified with a scope
that a 10 MHz pulse train comes out of the GPSDO. Now I had an other
GPSDO by Leo (the
https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234

it got lost during relocation :-/) and with that one, it all worked
just fine.
What also works fine is the current GPSDO -> reference clock input of
a DG1022Z and then use that function generator as a divider. Not
ideal though (the rigol has loud fans, a picdiv doesn't).
Any ideas what it could be?

regards

Hi, A while ago I bought the following GPSDO: https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301 I wanted to let it produce a 1 Hz pulse but if I feed its output to a PICDIV or a PICODIV, then nothing comes out. I verified with a scope that a 10 MHz pulse train comes out of the GPSDO. Now I had an other GPSDO by Leo (the https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234 - it got lost during relocation :-/) and with that one, it all worked just fine. What also works fine is the current GPSDO -> reference clock input of a DG1022Z and then use that function generator as a divider. Not ideal though (the rigol has loud fans, a picdiv doesn't). Any ideas what it could be? regards

BL

Brian Lloyd

Mon, Nov 25, 2024 2:47 PM

I have the units you mention, plus the newer one, which is what you really want. Neither of your devices will produce a 1pps output. They are strictly frequency references, not time references, and have a minimum frequency of about 400Hz.

If you want a unit that will produce a 1pps time signal, you need one of the newer 1420 or 1421 units. Warning, the 1pps is the raw 1pps from the internal GNSS module. It is fairly noisy (lots of jitter) so it is great for long-term timing, not so good for short-term. You need a clean-up oscillator with a very long PLL loop time constant to clean up the short-term 1pps.

Best regards.

On 11/24/24 11:20, Folkert van Heusden via time-nuts wrote:

Hi,

A while ago I bought the following GPSDO:
https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301
I wanted to let it produce a 1 Hz pulse but if I feed its output to a
PICDIV or a PICODIV, then nothing comes out. I verified with a scope
that a 10 MHz pulse train comes out of the GPSDO. Now I had an other
GPSDO by Leo (the
https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234

it got lost during relocation :-/) and with that one, it all worked
just fine.
What also works fine is the current GPSDO -> reference clock input of
a DG1022Z and then use that function generator as a divider. Not
ideal though (the rigol has loud fans, a picdiv doesn't).
Any ideas what it could be?

regards

time-nuts mailing list --
time-nuts@lists.febo.com
To unsubscribe send an email to
time-nuts-leave@lists.febo.com

--

Brian Lloyd
WB5BL - J79BL - NNA6BL
706 Flightline
Spring Branch, TX 78070
brian@heaviside-hf.com
+1.210.620.0011

I have the units you mention, plus the newer one, which is what you really want. Neither of your devices will produce a 1pps output. They are strictly frequency references, not time references, and have a minimum frequency of about 400Hz. If you want a unit that will produce a 1pps time signal, you need one of the newer 1420 or 1421 units. Warning, the 1pps is the raw 1pps from the internal GNSS module. It is fairly noisy (lots of jitter) so it is great for long-term timing, not so good for short-term. You need a clean-up oscillator with a very long PLL loop time constant to clean up the short-term 1pps. Best regards. On 11/24/24 11:20, Folkert van Heusden via time-nuts wrote: > Hi, > > A while ago I bought the following GPSDO: > https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301 > I wanted to let it produce a 1 Hz pulse but if I feed its output to a > PICDIV or a PICODIV, then nothing comes out. I verified with a scope > that a 10 MHz pulse train comes out of the GPSDO. Now I had an other > GPSDO by Leo (the > https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234 > - it got lost during relocation :-/) and with that one, it all worked > just fine. > What also works fine is the current GPSDO -> reference clock input of > a DG1022Z and then use that function generator as a divider. Not > ideal though (the rigol has loud fans, a picdiv doesn't). > Any ideas what it could be? > > regards > _______________________________________________ > time-nuts mailing list -- > time-nuts@lists.febo.com > To unsubscribe send an email to > time-nuts-leave@lists.febo.com -- Brian Lloyd WB5BL - J79BL - NNA6BL 706 Flightline Spring Branch, TX 78070 [brian@heaviside-hf.com](mailto://brian@heaviside-hf.com) +1.210.620.0011

FV

Folkert van Heusden

Mon, Nov 25, 2024 4:44 PM

Hi Brian,

Indeed the minimum frequency is around 400 Hz if I remember correctly.
That's why I wanted to introduce the PICDIV. Together with the
'ARM/TRIG' pins it works pretty well.
Note that today I succeeded to get it to work. Unfortunately I'm not
100% sure what it was that it did not work before, but most likely I
"burned" the PIC-uC-s incorrectly before.

On Mon, Nov 25, 2024 at 02:47:14PM +0000, Brian Lloyd via time-nuts wrote:

I have the units you mention, plus the newer one, which is what you really want. Neither of your devices will produce a 1pps output. They are strictly frequency references, not time references, and have a minimum frequency of about 400Hz.

If you want a unit that will produce a 1pps time signal, you need one of the newer 1420 or 1421 units. Warning, the 1pps is the raw 1pps from the internal GNSS module. It is fairly noisy (lots of jitter) so it is great for long-term timing, not so good for short-term. You need a clean-up oscillator with a very long PLL loop time constant to clean up the short-term 1pps.

Best regards.

On 11/24/24 11:20, Folkert van Heusden via time-nuts wrote:

Hi,

A while ago I bought the following GPSDO:
https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301
I wanted to let it produce a 1 Hz pulse but if I feed its output to a
PICDIV or a PICODIV, then nothing comes out. I verified with a scope
that a 10 MHz pulse train comes out of the GPSDO. Now I had an other
GPSDO by Leo (the
https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234

it got lost during relocation :-/) and with that one, it all worked
just fine.
What also works fine is the current GPSDO -> reference clock input of
a DG1022Z and then use that function generator as a divider. Not
ideal though (the rigol has loud fans, a picdiv doesn't).
Any ideas what it could be?

regards

time-nuts mailing list --
time-nuts@lists.febo.com
To unsubscribe send an email to
time-nuts-leave@lists.febo.com

--

Brian Lloyd
WB5BL - J79BL - NNA6BL
706 Flightline
Spring Branch, TX 78070
brian@heaviside-hf.com
+1.210.620.0011

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hi Brian, Indeed the minimum frequency is around 400 Hz if I remember correctly. That's why I wanted to introduce the PICDIV. Together with the 'ARM/TRIG' pins it works pretty well. Note that today I succeeded to get it to work. Unfortunately I'm not 100% sure what it was that it did not work before, but most likely I "burned" the PIC-uC-s incorrectly before. On Mon, Nov 25, 2024 at 02:47:14PM +0000, Brian Lloyd via time-nuts wrote: > I have the units you mention, plus the newer one, which is what you really want. Neither of your devices will produce a 1pps output. They are strictly frequency references, not time references, and have a minimum frequency of about 400Hz. > > If you want a unit that will produce a 1pps time signal, you need one of the newer 1420 or 1421 units. Warning, the 1pps is the raw 1pps from the internal GNSS module. It is fairly noisy (lots of jitter) so it is great for long-term timing, not so good for short-term. You need a clean-up oscillator with a very long PLL loop time constant to clean up the short-term 1pps. > > Best regards. > > On 11/24/24 11:20, Folkert van Heusden via time-nuts wrote: > > > Hi, > > > > A while ago I bought the following GPSDO: > > https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301 > > I wanted to let it produce a 1 Hz pulse but if I feed its output to a > > PICDIV or a PICODIV, then nothing comes out. I verified with a scope > > that a 10 MHz pulse train comes out of the GPSDO. Now I had an other > > GPSDO by Leo (the > > https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234 > > - it got lost during relocation :-/) and with that one, it all worked > > just fine. > > What also works fine is the current GPSDO -> reference clock input of > > a DG1022Z and then use that function generator as a divider. Not > > ideal though (the rigol has loud fans, a picdiv doesn't). > > Any ideas what it could be? > > > > regards > > _______________________________________________ > > time-nuts mailing list -- > > time-nuts@lists.febo.com > > To unsubscribe send an email to > > time-nuts-leave@lists.febo.com > > -- > > Brian Lloyd > WB5BL - J79BL - NNA6BL > 706 Flightline > Spring Branch, TX 78070 > [brian@heaviside-hf.com](mailto://brian@heaviside-hf.com) > +1.210.620.0011 > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

MD

Marek Dorsic

Mon, Nov 25, 2024 5:50 PM

Hello,

 I replicated your scenario with LeoBodnar and PicoDIV and it worked without problems.

Note, that the PicoDIV starts to output PPS on GPIO17 only after SYNC signal is received. If no sync required, just short the GPIO19 and GPIO20 pins, or use the signal on GPIO21.

Kind regards,
.md

On 25 Nov 2024, at 15:47, Brian Lloyd via time-nuts time-nuts@lists.febo.com wrote:

I have the units you mention, plus the newer one, which is what you really want. Neither of your devices will produce a 1pps output. They are strictly frequency references, not time references, and have a minimum frequency of about 400Hz.

If you want a unit that will produce a 1pps time signal, you need one of the newer 1420 or 1421 units. Warning, the 1pps is the raw 1pps from the internal GNSS module. It is fairly noisy (lots of jitter) so it is great for long-term timing, not so good for short-term. You need a clean-up oscillator with a very long PLL loop time constant to clean up the short-term 1pps.

Best regards.

On 11/24/24 11:20, Folkert van Heusden via time-nuts wrote:

Hi,

A while ago I bought the following GPSDO:
https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301
I wanted to let it produce a 1 Hz pulse but if I feed its output to a
PICDIV or a PICODIV, then nothing comes out. I verified with a scope
that a 10 MHz pulse train comes out of the GPSDO. Now I had an other
GPSDO by Leo (the
https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234

it got lost during relocation :-/) and with that one, it all worked
just fine.
What also works fine is the current GPSDO -> reference clock input of
a DG1022Z and then use that function generator as a divider. Not
ideal though (the rigol has loud fans, a picdiv doesn't).
Any ideas what it could be?

regards

time-nuts mailing list --
time-nuts@lists.febo.com
To unsubscribe send an email to
time-nuts-leave@lists.febo.com

--

Brian Lloyd
WB5BL - J79BL - NNA6BL
706 Flightline
Spring Branch, TX 78070
brian@heaviside-hf.com
+1.210.620.0011

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hello, I replicated your scenario with LeoBodnar and PicoDIV and it worked without problems. Note, that the PicoDIV starts to output PPS on GPIO17 only after SYNC signal is received. If no sync required, just short the GPIO19 and GPIO20 pins, or use the signal on GPIO21. Kind regards, .md > On 25 Nov 2024, at 15:47, Brian Lloyd via time-nuts <time-nuts@lists.febo.com> wrote: > > I have the units you mention, plus the newer one, which is what you really want. Neither of your devices will produce a 1pps output. They are strictly frequency references, not time references, and have a minimum frequency of about 400Hz. > > If you want a unit that will produce a 1pps time signal, you need one of the newer 1420 or 1421 units. Warning, the 1pps is the raw 1pps from the internal GNSS module. It is fairly noisy (lots of jitter) so it is great for long-term timing, not so good for short-term. You need a clean-up oscillator with a very long PLL loop time constant to clean up the short-term 1pps. > > Best regards. > > On 11/24/24 11:20, Folkert van Heusden via time-nuts wrote: > >> Hi, >> >> A while ago I bought the following GPSDO: >> https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301 >> I wanted to let it produce a 1 Hz pulse but if I feed its output to a >> PICDIV or a PICODIV, then nothing comes out. I verified with a scope >> that a 10 MHz pulse train comes out of the GPSDO. Now I had an other >> GPSDO by Leo (the >> https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234 >> - it got lost during relocation :-/) and with that one, it all worked >> just fine. >> What also works fine is the current GPSDO -> reference clock input of >> a DG1022Z and then use that function generator as a divider. Not >> ideal though (the rigol has loud fans, a picdiv doesn't). >> Any ideas what it could be? >> >> regards >> _______________________________________________ >> time-nuts mailing list -- >> time-nuts@lists.febo.com >> To unsubscribe send an email to >> time-nuts-leave@lists.febo.com > > -- > > Brian Lloyd > WB5BL - J79BL - NNA6BL > 706 Flightline > Spring Branch, TX 78070 > [brian@heaviside-hf.com](mailto://brian@heaviside-hf.com) > +1.210.620.0011 > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

DG

David G. McGaw

Mon, Nov 25, 2024 6:59 PM

What is the voltage level you are measuring out of the Mini Precision
GPS Reference Clock? The PICDIV is looking for a clock from <0.3Vdd to

0.7Vdd. If the PICDIV is running from 5V, The GPSDO may not be

driving the input high enough.

73,

David N1HAC

On 11/24/24 12:20 PM, Folkert van Heusden via time-nuts wrote:

Hi,

A while ago I bought the following GPSDO: https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301
I wanted to let it produce a 1 Hz pulse but if I feed its output to a
PICDIV or a PICODIV, then nothing comes out. I verified with a scope
that a 10 MHz pulse train comes out of the GPSDO. Now I had an other
GPSDO by Leo (the
https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234

it got lost during relocation :-/) and with that one, it all worked
just fine.
What also works fine is the current GPSDO -> reference clock input of
a DG1022Z and then use that function generator as a divider. Not
ideal though (the rigol has loud fans, a picdiv doesn't).
Any ideas what it could be?

regards

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com

What is the voltage level you are measuring out of the Mini Precision GPS Reference Clock? The PICDIV is looking for a clock from <0.3Vdd to >0.7Vdd. If the PICDIV is running from 5V, The GPSDO may not be driving the input high enough. 73, David N1HAC On 11/24/24 12:20 PM, Folkert van Heusden via time-nuts wrote: > Hi, > > A while ago I bought the following GPSDO: https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301 > I wanted to let it produce a 1 Hz pulse but if I feed its output to a > PICDIV or a PICODIV, then nothing comes out. I verified with a scope > that a 10 MHz pulse train comes out of the GPSDO. Now I had an other > GPSDO by Leo (the > https://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=234 > - it got lost during relocation :-/) and with that one, it all worked > just fine. > What also works fine is the current GPSDO -> reference clock input of > a DG1022Z and then use that function generator as a divider. Not > ideal though (the rigol has loud fans, a picdiv doesn't). > Any ideas what it could be? > > > regards > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

JA

Jürgen Appel

Wed, Nov 27, 2024 12:23 PM

Hej,

On Monday, 25 November 2024 15:47:14 Central European Standard Time Brian
Lloyd via time-nuts wrote:

I have the units you mention, plus the newer one, which is what you really
want. Neither of your devices will produce a 1pps output. They are strictly
frequency references, not time references, and have a minimum frequency of
about 400Hz.

I'd like to underline this. The phase of the generated frequency is not locked
to the 1pps from the internal GPS module, i.e. although they deliver an output
frequency with an accuracy within their specs, there is a remaining frequency
offset that does not average out to zero, and any clock you build with them
will drift, even with GPS lock.

I contacted the manufacturer and got a modified firmware, such that that is
solved at the expense of additional noise from 1s to 2000s avering times.
Using the output with this modified firmware to generate your own 1 pps will
keep time on a long timescale - although you still would need a way to find
the correct offset from UTC to make it a usable clock.

Cheers,
Jürgen

--
Jürgen Appel
Senior Scientist
Denmark's National Metrology Institute
Dansk Fundamental Metrologi, DFM A/S (dfm.dk)
Kogle Allé 5
DK-2970 Hørsholm
Denmark

Mobile: +45 25459049
Email: jap@dfm.dk
VAT: DK-29217939

Hej, On Monday, 25 November 2024 15:47:14 Central European Standard Time Brian Lloyd via time-nuts wrote: > I have the units you mention, plus the newer one, which is what you really > want. Neither of your devices will produce a 1pps output. They are strictly > frequency references, not time references, and have a minimum frequency of > about 400Hz. I'd like to underline this. The phase of the generated frequency is not locked to the 1pps from the internal GPS module, i.e. although they deliver an output frequency with an accuracy within their specs, there is a remaining frequency offset that does not average out to zero, and any clock you build with them will drift, even with GPS lock. I contacted the manufacturer and got a modified firmware, such that that is solved at the expense of additional noise from 1s to 2000s avering times. Using the output with this modified firmware to generate your own 1 pps will keep time on a long timescale - although you still would need a way to find the correct offset from UTC to make it a usable clock. Cheers, Jürgen -- Jürgen Appel Senior Scientist Denmark's National Metrology Institute Dansk Fundamental Metrologi, DFM A/S (dfm.dk) Kogle Allé 5 DK-2970 Hørsholm Denmark Mobile: +45 25459049 Email: jap@dfm.dk VAT: DK-29217939

time-nuts@lists.febo.com

gpsdo by leo bodnar & picdiv