Symmetricom/Datum FTS-1050A Disciplined Frequency Standard
Ed,
You might look at the paper developed by Luciano Paramithiotti for a 10MHz to 5MHz regenerative divider. He has kindly shared his design, complete with circuit diagram. Might be what you're looking for.
[ http://www.timeok.it/wp-content/uploads/2015/08/low-noise-regenerative-divider1.pdf | http://www.timeok.it/wp-content/uploads/2015/08/low-noise-regenerative-divider1.pdf ]
He has lots of other time/frequency related stuff on his website as well.
http://www.timeok.it/time-and-frequency/
Cheers,
DaveM
From: "Time-Nuts" time-nuts@lists.febo.com
To: "Time-Nuts" time-nuts@lists.febo.com
Cc: "ed breya" eb@telight.com
Sent: Friday, July 29, 2022 8:30:14 PM
Subject: [time-nuts] Looking to build 10 MHz tp 5 MHz regenerative frequency divider
Been busy planning and rounding up parts and subsystems for my
multi-function box for looking at phase noise and stability etc mostly
on 10 and 5 MHz. The PN part will be kind of like Erik's recent project,
using those identical MTI 10 MHz OCXOs (the subject of my recent info
search) for initial experimenting. The baseband analyzer will be the
HP3561A (0-100 kHz).
The other part will be a fairly simple analog DMTD system, with fixed
100 Hz offset for 10 MHz, and 50 Hz for 5 MHz. I found I have a nice old
10 MHz OCXO that has mechanical tuning only, that will be committed
(built in) to this project. It's set now for 9.9999 MHz (10 MHz - 100
Hz). I have no suitable 5 MHz OCXOs for this, so figured on dividing the
9.9999 MHz by two when needed.
I recall many times over the years encountering talk about low noise
regenerative dividers, but now that I'm actually contemplating making
one, I can't seem to find much detail. I found a number of commercial
ones like at Wenzel et al, but not much in the way of design detail.
John M's ke5fx site has a good example for 80-40-20 MHz, but I can't
seem to find any of the linked papers and such that were the basis. What
I'm hoping is to find one or more examples of designs already figured
out for 10 MHz/2. I think there must be some out there.
Does anyone know of such?
Ed
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Hi
This is not a bad way to a feed ( via appropriate limiters) to counters for things
like ADEV. It’s not a very good way to do phase noise …. The floor will be a bit
high and the “folding’ process will make things a bit tough to sort out ….
Bob
On Jul 29, 2022, at 5:30 PM, ed breya via time-nuts time-nuts@lists.febo.com wrote:
Been busy planning and rounding up parts and subsystems for my multi-function box for looking at phase noise and stability etc mostly on 10 and 5 MHz. The PN part will be kind of like Erik's recent project, using those identical MTI 10 MHz OCXOs (the subject of my recent info search) for initial experimenting. The baseband analyzer will be the HP3561A (0-100 kHz).
The other part will be a fairly simple analog DMTD system, with fixed 100 Hz offset for 10 MHz, and 50 Hz for 5 MHz. I found I have a nice old 10 MHz OCXO that has mechanical tuning only, that will be committed (built in) to this project. It's set now for 9.9999 MHz (10 MHz - 100 Hz). I have no suitable 5 MHz OCXOs for this, so figured on dividing the 9.9999 MHz by two when needed.
I recall many times over the years encountering talk about low noise regenerative dividers, but now that I'm actually contemplating making one, I can't seem to find much detail. I found a number of commercial ones like at Wenzel et al, but not much in the way of design detail. John M's ke5fx site has a good example for 80-40-20 MHz, but I can't seem to find any of the linked papers and such that were the basis. What I'm hoping is to find one or more examples of designs already figured out for 10 MHz/2. I think there must be some out there.
Does anyone know of such?
BTW I finally pulled the trigger on acquiring an HP8663A, which I've been wanting to get for a very long time. I've had a fully loaded (all bands) HP11729C for many years, to go with it, and finally be of use. In the TIM department, I have a busted HP5370A, and a good HP5372A.
Ed
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See www.timeok.it
Il 31 lug 2022 04:34, Bob kb8tq via time-nuts
time-nuts@lists.febo.com ha scritto:
Hi
This is not a bad way to a feed ( via appropriate limiters) to
counters for things
like ADEV. It’s not a very good way to do phase noise …. The floor
will be a bit
high and the “folding’ process will make things a bit tough to sort
out ….
Bob
On Jul 29, 2022, at 5:30 PM, ed breya via time-nuts
<time-nuts@lists.febo.com> wrote:
Been busy planning and rounding up parts and subsystems for my
multi-function box for looking at phase noise and stability etc
mostly on 10 and 5 MHz. The PN part will be kind of like Erik's
recent project, using those identical MTI 10 MHz OCXOs (the subject
of my recent info search) for initial experimenting. The baseband
analyzer will be the HP3561A (0-100 kHz).
The other part will be a fairly simple analog DMTD system, with
fixed 100 Hz offset for 10 MHz, and 50 Hz for 5 MHz. I found I have
a nice old 10 MHz OCXO that has mechanical tuning only, that will be
committed (built in) to this project. It's set now for 9.9999 MHz
(10 MHz - 100 Hz). I have no suitable 5 MHz OCXOs for this, so
figured on dividing the 9.9999 MHz by two when needed.
I recall many times over the years encountering talk about low
noise regenerative dividers, but now that I'm actually contemplating
making one, I can't seem to find much detail. I found a number of
commercial ones like at Wenzel et al, but not much in the way of
design detail. John M's ke5fx site has a good example for 80-40-20
MHz, but I can't seem to find any of the linked papers and such that
were the basis. What I'm hoping is to find one or more examples of
designs already figured out for 10 MHz/2. I think there must be some
out there.
Does anyone know of such?
BTW I finally pulled the trigger on acquiring an HP8663A, which
I've been wanting to get for a very long time. I've had a fully
loaded (all bands) HP11729C for many years, to go with it, and
finally be of use. In the TIM department, I have a busted HP5370A,
and a good HP5372A.
Ed
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_______________________________________________
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Just wondering if anyone happens to know typical or an actual measured
phase noise instance of the 640 MHz reference in the HP8663A. It does
not seem to be specified (unless I missed it somehow), but there's an
"option 03" that specifies it. I don't think the option provides any
improvement, just results of an actual measurement on the particular unit.
Ed
if it is not to urgent I could measure it for you, I have the HP8663A
and one 8562E with the "special function" box
On 8/12/2022 10:37 AM, ed breya via time-nuts wrote:
Just wondering if anyone happens to know typical or an actual measured
phase noise instance of the 640 MHz reference in the HP8663A. It does
not seem to be specified (unless I missed it somehow), but there's an
"option 03" that specifies it. I don't think the option provides any
improvement, just results of an actual measurement on the particular
unit.
Ed
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The 8663 has a 10811 driving an X8 driving an 80 MHz
xtal filter. The cleaned up 80 MHz drives another
X8 to make 640 MHz, which is further cleaned up with
a 640 MHz SAW filter.
At least with the 8662, you have to purchase an option
to even have a 640 MHz output at all.
The SAW filter was made at HP in Santa Rosa originally,
but then they closed the fab for it. I designed the
SAW filter into the 5071A in the form of a phase locked
oscillator. A few 100 instruments were made, but then
I had to design it out.
Rick N6RK
On 8/12/2022 11:30 AM, Alex Pummer via time-nuts wrote:
if it is not to urgent I could measure it for you, I have the HP8663A
and one 8562E with the "special function" box
On 8/12/2022 10:37 AM, ed breya via time-nuts wrote:
Just wondering if anyone happens to know typical or an actual measured
phase noise instance of the 640 MHz reference in the HP8663A. It does
not seem to be specified (unless I missed it somehow), but there's an
"option 03" that specifies it. I don't think the option provides any
improvement, just results of an actual measurement on the particular
unit.Ed
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Hello Ed, and others.
I've been lurking here for a while. Quite the knowledge base
represented here!
I've got access to an 8663A with "specified" phase noise that come from
an HP 3048 system. I've got access to an E5505A PNTS as well as an
Aeroflex PN90000. I could measure it for you. The Aerofelx only goes
to 1MHz offsets. The E5505 will go to 40MHz.
I've got quite a few 8663As and a few 8662s. I could use the 640MHz
from the "specified" unit as the reference and then test the others.
Still learning the subtleties of the PN9000, but I bet the 640 from it's
synthesizer is not as good as the HP.
I'll just do it and post it here. I've been measuring allot of sources
around the lab while getting ready to go into the design of LOs for the
Next Generation very large array project. NRAO has allot of boat
anchors to maintain. Budget is tight right now on this new project so
I've got to keep these things going.
On 8/12/2022 4:30 PM, Richard (Rick) Karlquist via time-nuts wrote:
The 8663 has a 10811 driving an X8 driving an 80 MHz
xtal filter. The cleaned up 80 MHz drives another
X8 to make 640 MHz, which is further cleaned up with
a 640 MHz SAW filter.
At least with the 8662, you have to purchase an option
to even have a 640 MHz output at all.
The SAW filter was made at HP in Santa Rosa originally,
but then they closed the fab for it. I designed the
SAW filter into the 5071A in the form of a phase locked
oscillator. A few 100 instruments were made, but then
I had to design it out.
Rick N6RK
On 8/12/2022 11:30 AM, Alex Pummer via time-nuts wrote:
if it is not to urgent I could measure it for you, I have the HP8663A
and one 8562E with the "special function" box
On 8/12/2022 10:37 AM, ed breya via time-nuts wrote:
Just wondering if anyone happens to know typical or an actual
measured phase noise instance of the 640 MHz reference in the
HP8663A. It does not seem to be specified (unless I missed it
somehow), but there's an "option 03" that specifies it. I don't
think the option provides any improvement, just results of an actual
measurement on the particular unit.
Ed
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--
Jim Muehlberg
Senior Engineer
National Radio Astronomy Observatory
ngVLA Local Oscillator Lead
1180 Boxwood Estates Rd B-111
Charlottesville, VA 22903-4602
P 434.296.0270
F 434.296.0324
www.cv.nrao.edu/~jmuehlbe
Thanks all, for replies and possibly running some tests. The reason I'm
asking about this is that now that I finally have the HP8663A, I'd like
to rig it up with the HP11179C, and its documentation mentions all this
option 3 stuff on the 8663A. So I started wondering, just how good is
it, and if there's a "typical" or representative spec. Again, I believe
option 3 just means that the particular unit was tested at the factory
before delivery, and the results documented and included with the unit.
Over time, this info could be lost.
My unit has option 2 only, which is fancier phase modulation, that could
be handy for some things. Before it arrived, I studied up the design and
evolution in the manuals. It appears that the 8662A and earlier 8663A
models may have had the 10544 OCXO installed, while mine is one of the
later versions, officially sporting the 10811-60111. I found that this
is indeed what's in there, and the cal seal is marked ca 2014 - likely
the last time it was messed with. It seems to work so far, and it is
quite an impressive beast.
On the 11179C, I had a stroll down memory lane for a while. I kind of
forgot how much I had worked on it about a dozen years ago. Since I had
no prospect of getting a 8662A or 8663A back then, I had been collecting
and mounting parts to make a fairly high grade built-in 640 MHz source.
The scheme was based on a 80 MHz VTOCXO, to be doubled up and filtered
thrice to 640 MHz, and phase locked to 10 MHz if needed. I already had
all the major pieces fitted, and a bunch of notes on the design details.
I started yanking all this stuff out to restore it to stock, but then
started thinking "not so fast - maybe this could be pretty good after
all." Since I really don't know how good the 640 MHz from the 8663A is,
I'll keep all the pieces and info from the other scheme together, just
in case.
Ed
-----Original Message-----
From: ed breya via time-nuts [mailto:time-nuts@lists.febo.com]
Thanks all, for replies and possibly running some tests. The reason I'm
asking about this is that now that I finally have the HP8663A, I'd like
to rig it up with the HP11179C, and its documentation mentions all this
option 3 stuff on the 8663A. So I started wondering, just how good is
it, and if there's a "typical" or representative spec. Again, I believe
option 3 just means that the particular unit was tested at the factory
before delivery, and the results documented and included with the unit.
Over time, this info could be lost.
The 5953-8376 brochure from 2001 shows both specified and typical values for
the option-003 output. Here's what the 8663As around here do, vis-a-vis
those numbers:
Each one was measured by downconverting its rear-panel output to 11 MHz
using a pair of external mixers driven by the other two. This wasn't a
great test setup -- lots of cables running all over the place and the
generators were powered from different AC outlets -- so I didn't leave the
spur markers turned on. Still looked reasonably clean, though. Hard to
complain considering the oldest of the units is >35 years old.
I don't have an easy way to measure the 640 MHz output from the 11729C's SAW
oscillator (would have to pull it out of the rack and open it up), but
Product Note 11729C-2 says that it's quieter than the 8662/3 rear panel
output above 70 kHz and noisier below that. Sounds plausible enough.
-- john
Hi Ed,
could you share some info about your own 640 MHz source?
I would be very interested.
I do have an 8663A, but I have no idea about how good it actually is and
currently, I don't have a possibility to test it because I still lack an
11729C carrier noise test set (but I would like to make something similar
myself some day). Apparently my 8663A is one of the latest units, because
it is already labelled Agilent.
best
Tobias
On Sun, Aug 14, 2022 at 8:11 PM ed breya via time-nuts <
time-nuts@lists.febo.com> wrote:
Thanks all, for replies and possibly running some tests. The reason I'm
asking about this is that now that I finally have the HP8663A, I'd like
to rig it up with the HP11179C, and its documentation mentions all this
option 3 stuff on the 8663A. So I started wondering, just how good is
it, and if there's a "typical" or representative spec. Again, I believe
option 3 just means that the particular unit was tested at the factory
before delivery, and the results documented and included with the unit.
Over time, this info could be lost.
My unit has option 2 only, which is fancier phase modulation, that could
be handy for some things. Before it arrived, I studied up the design and
evolution in the manuals. It appears that the 8662A and earlier 8663A
models may have had the 10544 OCXO installed, while mine is one of the
later versions, officially sporting the 10811-60111. I found that this
is indeed what's in there, and the cal seal is marked ca 2014 - likely
the last time it was messed with. It seems to work so far, and it is
quite an impressive beast.
On the 11179C, I had a stroll down memory lane for a while. I kind of
forgot how much I had worked on it about a dozen years ago. Since I had
no prospect of getting a 8662A or 8663A back then, I had been collecting
and mounting parts to make a fairly high grade built-in 640 MHz source.
The scheme was based on a 80 MHz VTOCXO, to be doubled up and filtered
thrice to 640 MHz, and phase locked to 10 MHz if needed. I already had
all the major pieces fitted, and a bunch of notes on the design details.
I started yanking all this stuff out to restore it to stock, but then
started thinking "not so fast - maybe this could be pretty good after
all." Since I really don't know how good the 640 MHz from the 8663A is,
I'll keep all the pieces and info from the other scheme together, just
in case.
Ed
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