http://www.bbc.co.uk/news/science-environment-15830844
Rob Kimberley
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Gentlemen,
i would like to draw your attention to this site:
http://pstca.com/spice/ripple/ripple.htm
The author of this site thank-worthy not only presents circuits for power
supply finesse but also simulates them with SPICE. It seems to turn out as if
the well known Wenzel suggestions for
On 11/21/11 9:05 PM, Chris Albertson wrote:
You guys missed my point. I did not mean that survey and timing errors are
so large What I meant was that even if you assume unreasonably large
errors (like a surveyor being off by a full meter) you still don't get
60nS.
If I were to bet money,
On Nov 21, 2011, at 10:57 PM, Jim Lux wrote:
On 11/21/11 5:15 PM, Bob Camp wrote:
Hi
You can have a surveyor come out and locate your gizmo to sub one inch
accuracy for a lot less than a clock trip costs. A one meter ( or 3 ns)
error would be pretty large these days. Both have been
Hi
Interesting site - Thanks!
A couple of observations:
There are a couple of circuits (low noise op-amp based) that can generate lower
noise than what he's shown.
You need to be careful looking at his results. A lot of what he shows is the
result of changing the model used for the output
In imaging systems, where the noise on the pixel supply was critical, I had
good luck using a buck switcher followed by an LDO, whose maximum PSRR point
determined the operating frequency of the switcher. All normal techniques for
removing SMPS noise still apply.
I used the ISL9000
Hi
With modern high frequency switchers, often a LC filter between the switcher
and the LDO does the trick. The gotcha is that not all the energy is conducted.
Radiated energy quickly becomes the issue….
Depending on what you are timing that may be more or less of an issue. 10 MHz
Omitting the output bypass cap in the single transistor Wenzel
cancellation circuit is somewhat misleading in that it reduces the high
frequency attenuation,
All his other circuits include such caps.
A simple tweak (adjusting a resistor ratio) which makes the shunt
transistor collector current
On Tue, Nov 22, 2011 at 11:54 AM, Robin Kimberley
robkimber...@btinternet.com wrote:
http://www.bbc.co.uk/news/science-environment-15830844
You don't refute an experimental result by saying you can't explain it
with current Physics. You refute it with another experimental result,
or by pointing
Another potential problem is that the cascaded emitter follower circuit
shown is likely to oscillate in the VHF region.
An unbypassed resistor in series with the base of each emitter follower
should be used.
Bruce
Bruce Griffiths wrote:
Omitting the output bypass cap in the single transistor
On Tue, Nov 22, 2011 at 3:17 PM, Bob Camp li...@rtty.us wrote:
in the first paper, the distance uncertainty was given as 20cm
Of which the survey likely contributed next to nothing and stuff like earth
tides contributed the majority of the error ….
See
Hi
Earth tides and even more un-stoppable events like politics …
Bob
On Nov 22, 2011, at 1:28 PM, Javier Serrano wrote:
On Tue, Nov 22, 2011 at 3:17 PM, Bob Camp li...@rtty.us wrote:
in the first paper, the distance uncertainty was given as 20cm
Of which the survey likely contributed
In message 6f9e458f-b701-49c1-8d83-ebda35784...@ulrich-bangert.de, Ulrich Ban
gert writes:
It seems to turn out as if the well known Wenzel suggestions for voltage
regulator finesse were not state of the art [...]
I've played a bit with the Wenzel circuits and they can provide truly
outstanding
As Bob Pease used to say: Spice plots are good for padding bird cages, not
much else :)
Hittite has a fantastic new ultra low noise LDO for VCO's. Haven't had a
chance to check that out, but it looks very promising. Has anyone tried that
part here?
Also, remember that those caps are
The Hittite parts (there are two versions, one with 1 output and one with
4 outputs, HMC860 and HMC976) unfortunately have a foot note
on the data sheet that indicates
that the noise numbers are good in the application circuit, which
happens to include large capacitors. The capacitors are really
If you want low noise voltage regulation, use a shunt regulator. If the load is
low current, feed it with a floating current source such as a depletion mode
jfet (or several in parallel). These are also sold as current regulating
diodes.
I've used this scheme in IC designs. You also find it
On Nov 21, 2011, at 10:33 PM, Charles P. Steinmetz wrote:
The TS2500 was a very similar unit that received its timing signals from GPS.
I assume they were built on the same case, hence the spare chassis hole (and
perhaps also some features in BTMon that are not used by the TS2700).
I
Why is the shunt regulator push-pull? Because of the series regulator first
and the shunt regulator then?
On Tue, Nov 22, 2011 at 8:59 PM, li...@lazygranch.com wrote:
If you want low noise voltage regulation, use a shunt regulator. If the
load is low current, feed it with a floating current
You are pushing on the load plus shunt with a current source, though
traditionally a resistor is used. You are pulling on the source (current source
or resistor) with the shunt, which takes any current the load isn't using. The
LDO depends on the load to sink current.
I have used this scheme
Under roms/IOtech 488a and other roms.
This includes copies of the various peripheral controllers also.
Simple how to to convert to a full controller.
I do not have a iotech 488a full pdf that contains the commands section 3.
So if someone finds that it would be good to add.
Regards
Paul.
The shunt regulator also serves to isolate load current fluctuations
from the main supply, since it makes it appear as a constant
resistance, current, or power load, depending on the design. This can
eliminate cross-talk between various circuitry.
For example, I just made one for my new 5065A
Yes, load isolation is a valuable feature I left out. Perhaps the key feature.
The audio designers like it for channel separation.
--Original Message--
From: ed breya
Sender: time-nuts-boun...@febo.com
To: time-nuts@febo.com
ReplyTo: Discussion of precise time and frequency measurement
The frequency accuracy is measured based on the EFC variation. I have
recently received my TBolts, not yet fired up, actually preparing the power
supply. Where is the DAC? I can't find... the LT1014 is not a DAC, the SO8
2105 is not an LT2105 nor an LTC2105. The DAC is 20bit as I can read in the
The sensitivity of that EFC input is so low on my LPRO unit, that the PS and
DAC noises are not a problem at all.
Should add a 1K resistor in series with the Dac out before connecting it to
anything outside of the TBolt.
Attached is an expanded 4 day plot showing part of the same LPRO run
On 11/22/2011 03:17 PM, Bob Camp wrote:
On Nov 21, 2011, at 10:57 PM, Jim Lux wrote:
On 11/21/11 5:15 PM, Bob Camp wrote:
Hi
You can have a surveyor come out and locate your gizmo to sub one inch accuracy
for a lot less than a clock trip costs. A one meter ( or 3 ns) error would be
pretty
li...@lazygranch.com schrieb:
The bozos at Broadcom have actually patented using shunt regulation in their chips. Good luck enforcing that patent.
Must be a joke or misunderstanding.
Look for example in the datasheet of TCA440. A really old IC. In the
internal circuit displayed is a diode
On 11/16/2011 10:03 AM, David J Taylor wrote:
I own a Mac Mini and a MacBook. Their NTP implementation is simply a
joke.
Even with a local stratum 1 I can't get decent accuracy. :-(
David, weren't you interested in a LED clock I was going to build?
Cheers,
Miguel
A pity that there isn't
On 11/16/2011 12:28 PM, David J Taylor wrote:
Apple run their own NTP servers and ship their Macs configured to use
them
to sync time.
Last time I looked those servers were either not working, or very
broken! Apple should use the pool rather than create single poinst of
failure.
Their
On 11/16/2011 11:14 AM, Mike S wrote:
At 10:03 AM 11/16/2011, David J Taylor wrote...
A pity that there isn't a port of the reference NTP for the Mac, such
as we have on Windows.
macmini-2:~ mikes# ntpd --version
ntpd - NTP daemon program - Ver. 4.2.4p4
Seems to be the standard
MB asked (off line):
I have wanted to find out how to marry one of my Tbolts to one of my LPRO
Rb oscillators for a long time.
Some say doing this is a waste of time.
All depends what you plan to do with it.
Changing the Tbolt's internal Osc to an external LPRO Rb Osc will increase
the
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