Also an interesting material when high thermal conductivity is considered
is boron nitride. It is around five times better than copper, comparable
to diamond and can be sintered to a ceramic material.
Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very
good electrical
nd he worked out this very nice
> circuit
> > using easy to find 2N3904 BJTs.
> >
> > I simulated the circuit using PSPICE. Here are the details.
> >
> > https://www.darksmile.net/ee/frequency_doubler_BJT.html
> >
> > George
> >
> > On 9/10/2020
he details.
>
> https://www.darksmile.net/ee/frequency_doubler_BJT.html
>
> George
>
> On 9/10/2020 19:11, Bruce Griffiths wrote:
> > You could use either the NIST CG JFET doubler or its bipolar CB
> equivalent.
> >
> > Bruce
> >> On 11 September 2020 at 0
Dear colleagues
I recently got a FTS1000 oscillator. (Not FTS1000A or B, but just FTS1000,
I assume it is the first version). It is a very nice unit, but I wanted to
know a bit more about its construction and opened it.
After I had replaced the foam which was already quite dissolved, I began
Hallo all
I've got a question concerning the DMTD methodology.
I want to compare different oscillators to each other in a 3-cornered hat
fashion such that I can work out (hopefully at least approximately) their
stability.
For this, I thought about the attached schematic.
I plan to connect my
Dear Colleagues
I have made some tests with my self-made GPSDO which we discussed on this
very list.
I was allowed to install it at my workplace and put the antenna on the
roof, with almost 360° free sky view.
(I will have to compare different oscillators anyways, so I could install
mine as well.
Dear colleagues
I am currently thinking about a concept for my own TIC. While I gathered
some knowledge during my GPSDO project about using the TDC7200 as
interpolator, I have not yet a good idea how I should design the input
stage of a TIC. It should be somewhat universal, i.e. it should be
I wonder why the only (or at least, most of the) GPSDOs one can find on
eBay are from China. Is there a reason for that?
I would like to buy used GPSDOs and OCXOs from other sources because the
stuff from China is often of doubtful pedigree and I would never 100% trust
one of those. They often
/an-op-amp-limiter-how-to-limit-the-amplitude-of-amplified-signals/
but I don't know whether this is a timenuts-grade circuit.
Tobias
On Mon., 13 Apr. 2020, 23:53 Bob kb8tq, wrote:
> Hi
>
> > On Apr 13, 2020, at 5:06 PM, Tobias Pluess wrote:
> >
> > Hi Bob
> &
; put in
> to get the job done. A home project may be even more lopsided since it
> likely
> is the first time you have done this or that.
>
> Lots of twists and turns. Lots of projects started and never fully
> completed.
> I have piles and piles of them ….
>
> Bob
>
>
n ….
>
>
> Bob
>
> > On Apr 14, 2020, at 8:11 AM, Tobias Pluess wrote:
> >
> > G'day
> >
> > OK I see I must do it with time tagging :-)
> > Is it correct that the time tagging just spits out the time (in ns, for
> > example) when the ris
14, 2020 at 1:54 PM Bob kb8tq wrote:
> Hi
>
> > On Apr 14, 2020, at 2:31 AM, Tobias Pluess wrote:
> >
> > Hi Taka
> > good to know you're working on the same stuff :-)
> > I also think that this is the goal, sort of. But apparently there are
> some
> &
> you could tune one to the high end of its range and the other to the low
> end.
> With most OCXO’s, there is plenty of tune range.
>
> Bob
>
> > On Apr 14, 2020, at 2:23 AM, Tobias Pluess wrote:
> >
> > Hey Bob
> >
> > ok now I see your point! you ta
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
> On Monday, April 13, 2020, 5:53:52 PM EDT, Bob kb8tq
> wrote:
>
> Hi
>
> > On Apr 13, 2020, at 5:06 PM, Tobias Pluess wrote:
> >
> > Hi Bob
> > awesome, thanks! of course it is 1
runs an internal time count, each edge gets “labeled” with a
> precise time
> stamp that is good to nanoseconds or picoseconds. A Time Interval Counter
> simply measures the time between edges. That sounds like the same thing,
> but
> it’s not quite ….)
>
>
> > On Apr 13,
Apr 13, 2020, at 5:06 PM, Tobias Pluess wrote:
> >
> > Hi Bob
> > awesome, thanks! of course it is 1e6, not 1e7, I got a mistake :-)
> >
> > Maybe I have some good OpAmps for this purpose in my box. I will try it!
> of
>
> You need something that is quiet (like t
o do it properly as a DMTD, then you set up two counters. One
> to measure mixer A and the other to measure mixer B. Set them both up to
> measure frequency. Time tag the data files so you know which reading
> matches up with which.
>
> Fun !!!
>
> Bob
>
> > On Apr 13, 20
Hi again Bob
I tried to do some measurements with a DMTD!
In my junk box I found a little PCB from earlier experiments on that topic,
with a power splitter and two SRA-3H mixers, it was even already wired for
the DMTD configuration. So I gave it a try!
As "transfer oscillator" I used my HP 8663A
Hi Perrier
I try to explain phase noise in a simple way.
Assume you have a perfect oscillator which outputs a perfectly pure sine
wave. How would that oscillator's signal look like on a perfect spectrum
analyzer? it would be zero everywhere, except at the carrier frequency,
there would be an
> new in TO-92!!!)
>
> Tim N3QE
>
> On Fri, Apr 3, 2020 at 7:55 PM Tobias Pluess wrote:
>
> > Hi Taka
> >
> > what are those discrete amp designs you mention? I have seen some, but
> not
> > those you mention. These which I have seen seem to be quite date
1.
> For the ultimate performance at low offset frequencies one can build a
> mixer using diode connected BJTs as NIST have done.
>
> Bruce
> > On 04 April 2020 at 12:38 Tobias Pluess wrote:
> >
> >
> > Hi Bruce
> >
> > I have some TUF-1 mixers in my junk
pen across first ….
>
> Bob
>
> > On Apr 3, 2020, at 7:38 PM, Tobias Pluess wrote:
> >
> > Hi Bruce
> >
> > I have some TUF-1 mixers in my junk box as well as some JFET OpAmps
> AD8626.
> > So, if I connect the OpAmps appropriately with some diode li
Hi Taka
what are those discrete amp designs you mention? I have seen some, but not
those you mention. These which I have seen seem to be quite dated, use
strange or old parts (selected 2SC... transistors which are not so easy to
obtain here) or have other issues.
There is also the Wenzel amp, but
range for which the opamp
> is well behaved whilst maintaining the increase in slew rate for the output.
>
> Has anybody here ever tried the OPA698 / OPA699 limiting op amps?
>
> http://www.ti.com/lit/ds/symlink/opa698.pdf
>
> A lower 1/f corner would be appreciated, and slightly less
r multiplier.
>
> John
>
>
> On 4/3/20 11:25 AM, Tobias Pluess wrote:
> > Hi again Bob,
> >
> > yes you describe a simple DMTD measurement. But could you tell me what
> the
> > difference is between that and comparing the 1PPS pulses?
> > I mean,
ap or two as a high pass
> > and low pass filter ( DC offsets can be a problem ….) and you have a
> > working
> > device that gets into the parts in 10^-13 with your 5335.
> >
> > It all can be done with point to point wiring. No need for a PCB layout.
> > Be
>
the 5335 can “see”. Indeed, even when you get
> close to those numbers, things may get a bit weird due to the fact
> that you are measuring counter “noise” plus device noise.
>
> Bob
>
> > On Apr 2, 2020, at 3:13 PM, Tobias Pluess wrote:
> >
> > Hello all
> &
hi John
yes I know the DMTD method, and indeed I am planing to build my own DMTD
system, something similar to the "Small DMTD system" published by Riley (
https://www.wriley.com/A Small DMTD System.pdf).
However I am unsure whether that will help much in this case, because all
what the DMTD does
Hello all
in the meantime I figured out most of my problems and my GPSDO is working
now with some very ugly prototype code. Today, I wanted to do some ADEV
measurements.
My plan was to compare the 1PPS generated from my GPSDO to the 1PPS of my
Oscilloquartz STAR4; unfortunately I have nothing
Dear colleagues,
as you may remember I am still working on my own GPSDO project.
So far I have populated all the components on the PCBs I made, and I have
written some very basic software to test everything. Currently, I am
running following simple test:
I set my DAC to a constant value (5 Volts
Hi,
I am sure it is theoretically possible to find an optimal control loop
design if you have accurate models of the OCXO and for the behaviour of the
1PPS pulse.
TvB has written a GPSDO simulator which allows to code different PLL and
control algorithms. I have implemented something similar in
Hi Matthias,
jup, I agree but this "problem" will be easily fixed using the internal
pullup resistors of the STM32.
Best
Tobias
HB9FSX
On Thu, Feb 27, 2020 at 2:43 PM Matthias Welwarsky
wrote:
> On Mittwoch, 19. Februar 2020 14:50:57 CET wrote:
> > Hoi Tobias,
> >
> > Sorry for the late
nswers below:
Quoting Tobias Pluess :
> a) is it acceptable to route some signals under the GPS module? As
> one can see, the signals I have routed under the GPS module go to
> the front panel interface, i.e. they are not highspeed signals or
> so, but I still wonder whether you expert
Hi colleagues
In parallel to my GPSDO project I am also thinking about a DMTD measurement
system which should also be capable of doing phase noise measurements. This
will be necessary to measure the stability and phase noise of my own GPSDO.
There is the paper from W. J. Riley, "A small DMTD
Dear colleagues
I was a bit lazy in the past, so it took way too long to finish the schematics
for my new GPSDO.
I am currently making some first trials on the PCB layout; however, I still
would like to show you guys my schematics and ask what you think about it. See
the attachment.
Page 1
>> I would advice against using a CMOS switch. They are relatively slow and
>> their timing is not well defined.
> There are many variants of these tailored to different applications.
> You will need to check some more characteristics like charge injection
> if you go that route.
I also don't
nt
Subject: Re: [time-nuts] Question for my new GPSDO
Hoi Tobias,
On Wed, 16 Oct 2019 16:30:19 +
Tobias Pluess wrote:
> I attached my own schematics of the EFC control circuit. I think with this
> circuit, it should be possible to achieve a similar resolution as you
> mentioned in yo
Hi Jan-Derk
this is maybe a bit offtopic, but if you don't mind I would like to ask anyway:
is this a DMTD system you have built yourself? I saw a lot of messages on this
topic in the archive, but didn't find where it started.
Since I would also like to do some clock stability measurements but
Hi colleagues
thanks to your inputs I could design the EFC circuit for my new GPSDO and I
think its quite clear how that will work.
So in the past days, I spent my spare time on thinking about the control
algorithm. I used FLL previously, which gave unsatisfactory results, so I think
PLL is
Hi Attila,
I have read all your messages, but for the sake of simplicity, I only reply to
your last one.
First, thanks for sending the schematics. I have a look at them. To see the
components you selected is indeed very helpful.
I attached my own schematics of the EFC control circuit. I think
ut open source, GPSDO and that would be useful
background reading for you.
/tvb
On 10/14/2019 4:49 AM, Tobias Pluess wrote:
> Hello all together
>
> thanks for your replies so far and hints for my new GPSDO design.
> I have now designed the EFC circuit such that it is easily possib
indeed their reaction normally was “no can
do”.
Bob
> On Oct 9, 2019, at 2:28 AM, Tobias Pluess wrote:
>
> Hi Bob
>
> thanks for your explanation with the Telecom Rb. I am going to make the same
> calculations for my OCXOs I plan to use.
> The ground pin current modulating the
Well, temperature measurement is anyways not the key point of my project, so I
will use any ordinary digital temperature sensor. The BME is very nice, but
perhaps overkill for this application.
I want to have a temperature sensor mainly because I plan to send the
temperature and OCXO current
nd
current is handled the same in your test as in your final circuit …..
Bob
> On Oct 8, 2019, at 2:21 AM, Tobias Pluess wrote:
>
> Hi Bruce,
>
> oh yes I know, for sure no special resistor will be used for the oven heater!
> By the way, many GPSDOs I have tested (e.g. Trimble Thun
to be
monotonic. If you want to stick with a hardware DAC you might consider the
18 bit AD5680, which is a 16 bit DAC that interpolates 2 additional bits.
On Mon, Oct 7, 2019 at 6:02 PM Tobias Pluess
wrote:
> Hi Guys,
>
> I am planning to make a new version of my own GPSDO. I have attached the
&g
> On 08 October 2019 at 10:06 Tobias Pluess mailto:tobias.plu...@xwmail.ch > wrote:
>
>
> Hi Guys,
>
> I am planning to make a new version of my own GPSDO. I have attached the
> schematic of the OCXO and DAC. Because the stability of my previous design
> was n
Hi Guys,
I am planning to make a new version of my own GPSDO. I have attached the
schematic of the OCXO and DAC. Because the stability of my previous design was
not yet optimal, I now chose better components; my main criteria was the lowest
tempco I found.
As one can see, I plan to use the
PM, Tobias Pluess wrote:
>
> Hi Leo,
>
> sorry for my late reply.
> I have not yet measured the phase noise of my finished unit, since I am still
> waiting to complete my phase noise measurement equipment.
> However, I have a decent test report for my OCXO, where the phase n
-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,
if it is of interest for someone:
I have made my own distribution amplifier for this exact purpose. Since I want
sine waves, not square, I used some OpAmps. Hamilton Technical Services has
published a design for a distributor here
of alternatives …
Bob
> On Mar 20, 2019, at 3:53 AM, Tobias Pluess wrote:
>
> 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 differen
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
roll over. There are lots of alternatives …
Bob
> On Mar 20, 2019, at 3:53 AM, Tobias Pluess wrote:
>
> 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:
>
&g
bo.com] Im Auftrag von
Tobias Pluess
Gesendet: Mittwoch, 20. März 2019 08:54
An: Discussion of precise time 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
ou would want your detector drift to be < 20% of this (or about
1 nV) to get the job done
…. yikes ….
Lots of fun !!
Bob
> On Mar 19, 2019, at 4:43 PM, Tobias Pluess wrote:
>
> Thanks for the replies so far.
> Unfortunately I used digest mode for this mailing list, so perhaps my answer
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
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
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