Will agree I would hack something in. The same for the synthesiser. I could
swear someone on time-nuts already has. The phase detection circuit is
audio and it would take some experimentation. I think Corby supplied an
alternative approach on the A7 opamp so a lot of good work.
But the charcoal
In the past few months I've noticed problems on multiple US-based public
NTP stratum 1 servers that use CDMA as their stratum 0 clock.. EndRun
Technologies Tempus LX (
https://endruntechnologies.com/pdf/USM3014--000.pdf) is an example.
This is not a surprise. In the US Verizon has announced
Hi,
I would also like to update the 5065A but so far there are no kits or pcb
available. I think that the first things to update are also the "simplest ones"
like the voltage regulation, the C field generator but first, the integrator
board, because there are many old HP5065A that keep
Hi,
I found this little text that may be an amusing read on how ADEV and
MDEV came to be among other things.
https://ethw.org/w/images/5/5f/Allan_OH_-_MVAR_TVAR_and_OptimumPrediction.pdf
The Lighthill book is very important little thing, which few seems to
know. It works on Fourier transform
Hello Time-Nuts,
Just wondering if anyone has run into the following with TimeLab, and
has a solution.
I have been running TimeLab on a Windows 7 laptop for some time now
and it has been working great. A while back, I installed on a Windows
All-In-One (HP) and had display issues. The display
On 9/30/2020 12:47 PM, Magnus Danielson wrote:
This is all true, except for the last part, since you really need to
consider the duo of Jim Barnes and David Allan. If you look at the early
work, their work and contribution overlap. Some of the important math
was actually discovered by Jim
On 10/7/20 6:00 AM, Tom Van Baak wrote:
"Dave's Story on how GPS helped NASA/JPL synchronize their Deep Space
Network tracking stations"
https://ethw.org/w/images/a/ac/Allan_OH_-_GPSandtheDeepSpaceNetwork.pdf
"they flew me out to Goldstone in their
corporate jet to look at that facility, "
Hi
With the advent of cheap PCB houses that also do cheap assembly, the ability to
cobble
up this or that has moved from the “nutty” into the “pretty easy” category.
Indeed with very
specific parts (integrator cap, fancy op-amp) you might have to hand solder one
or two
leaded parts on the
Hi
People have successfully mounted eBay synthesizers in 5065’s. They work
and it is one way to take care of that.
Bob
> On Oct 6, 2020, at 10:49 PM, paul swed wrote:
>
> Will agree I would hack something in. The same for the synthesiser. I could
> swear someone on time-nuts already has.
Regarding the quest to keep a 5065A running...
The 5065 in my hobby corner was equipped with the firstversion of the
AC-Amplifier (A7) that did not have a frequency
selective 2nd harmonic detector. So I copied the later
design but made possible the use of selected polyester
precision audio
FYI: The main interview (about 50 pages) with David Allan is a really
good read:
https://ethw.org/Oral-History:David_W._Allan
The set of 5 PDF addenda (~2 pages each) to the main interview are:
"Technical Background on the Fundamental Noise Problem"
Hi Bob like the DDS pcboards?
On Wed, Oct 7, 2020 at 10:40 AM Bob kb8tq wrote:
> Hi
>
> People have successfully mounted eBay synthesizers in 5065’s. They work
> and it is one way to take care of that.
>
> Bob
>
> > On Oct 6, 2020, at 10:49 PM, paul swed wrote:
> >
> > Will agree I would hack
On Sat, 03 Oct 2020 10:37:59 +0200
Matthias Welwarsky wrote:
> When I started to look more into the software side of the TICC and especially
> the ominous "time dilation" parameter, I set up an experiment where I feed
> the
> same event into both channels of the TICC, for evaluating the
Hi John,
the noise is likely not white, but it really depends on what is the dominant
noise source in the system. I guess there is some correlation but still enough
entropy to make a difference. I'll try with different cable lengths next to
see if it makes a measureable difference, but ideally
Just curious Bob. What do you mean by higher resolution? Would that be a longer
accumulator and more bits in the D/A? 73 - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115
-Original Message-
From: time-nuts On Behalf Of Bob kb8tq
Sent: Wednesday, October 7, 2020
Hi
The “normal” 32 bit DDS chips only get you just so far in terms of tuning
resolution.
If you want to run a fixed / well regulated C Field, a DDS with (say) 48 bits
would allow
you to tune the device well past parts in 10^-15. There are several DDS chips
out
there that will do this. Some of
So, you are increasing the length of the accumulator. What about the D/A then?
73 - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115
-Original Message-
From: time-nuts On Behalf Of Bob kb8tq
Sent: Wednesday, October 7, 2020 1:55 PM
To: Discussion of precise time
Hi
Well….. the existing synth in the 5065 is no champion spur wise. Coming up with
a
DDS that is “as good as” is not all that crazy.
The 5 MHz reference is multiplied to 6.x GHz and then mixed with the synth. The
close in
phase noise of the multiplied signal is mixed with the synth. The
It seems to me that now since the register so much longer, yet the D/A is the
same, updates to the D/A will take longer and therefore creating more close in
spurs. That 20logN does suck, but is real. I may suggest running the output of
the DDS through a 5 MHz crystal, or better yet a very
Hi,
The existing syntesizer is rich on spurs. Very rich in fact. Fairly strong.
However these spurs is far enough not to cause much of a problem for the
clock, but they will help to demodulate some noise.
The noise being problematic is too far in for the spurs of the synthesis
to generate any
Hi Attila --
Just a couple of corrections -- the "coarse clock" in the TICC runs at
10 kHz (100 us), not 1 kHz, and therefore the TDC never sees a
measurement interval longer than 100 us, not 1 ms.
More importantly, the chart in Figure 17 of the datasheet is for
operation in "Mode 1" of the
Hi
> On Oct 7, 2020, at 4:25 PM, John Ackermann N8UR wrote:
>
> Hi Attila --
>
> Just a couple of corrections -- the "coarse clock" in the TICC runs at 10 kHz
> (100 us), not 1 kHz, and therefore the TDC never sees a measurement interval
> longer than 100 us, not 1 ms.
>
> More importantly,
Matthias,
Thanks for posting the raw data. You mention that both channels get the
same signal and so you expect a sqrt(2) improvement in noise
measurement. But consider...
1) sqrt(2) is only valid if both channels are equal to begin with. Plot
the ADEV of chA and chB and you'll see this
On Mittwoch, 7. Oktober 2020 22:25:40 CEST John Ackermann N8UR wrote:
> It would be possible to lower the noise slightly by using a 16 MHz clock
> rather than 10 MHz (but if you look at Figure 15, the improvement
> wouldn't be very great). That would require reprogramming the PIC
> divider chip,
kb...@n1k.org said:
> If you want to run a fixed / well regulated C Field, a DDS with (say) 48 bits
> would allow you to tune the device well past parts in 10^-15.
I don't know how to think about a DDS in this context.
I remember years ago thinking that a DDS was the greatest thing since
Hi
If you look at the standard chips that do this, they expand the accumulator.
The D/A is limited to the “normal” number of bits based on the max clock
frequency. ( = no free lunch …).
Bob
> On Oct 7, 2020, at 5:37 PM, Mike Feher wrote:
>
> So, you are increasing the length of the
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