Here are some details on the gravity measurements:
http://projects.npl.co.uk/itoc/project-structure/reg/gravity-observations/
AFAIK this campaign is done with GPS-PPP and TWSTFT for frequency
comparison. The troposphere makes it hard to reach 1e-17 level for the
satellite links - even with a week
Hi all,
On Friday I toured the METAS Time Frequency lab with two others:
Patrick, a colleague from work and Atilla, a fellow time-nut.
I'd like to report a bit about what we learned today that may be of
interest to other time-nuts.
[]
If anyone has any questions or comments, let me know and
rich...@karlquist.com said:
I used a CPLD in a 900 GHz (that's right 900 GHz) optical sampling scope
timebase. It was great because you just write a 17 bit counter in VHDL and
there it is. You don't have to know anything about building digital
hardware any more (40 years of experience
rich...@karlquist.com said:
Can someone explain to me how this is going to work in light of the fact that
each clock is in a different gravitational field?
They just shift from measuring time to measuring gravity. :)
Time too good to be true
By Daniel Kleppner
March 2006
Can someone explain to me how this is going to work in
light of the fact that each clock is in a different
gravitational field? Or is accuracy not the measurement,
but rather stability? No, that can't be because any
lab that wants to measure stability merely needs to build
two or three
NIST already measured the shift as they jacked one lab-bench 3 dm up.
Already for the EAL to TAI conversion, the altitude correction is done.
So, they are aware of it and already compensate for it when needed.
Gravity shifts is definitely on the map of comparison issues they need
to deal with.
The counter only had to run at ~50 MHz, on account of our
mode locked laser ran at that frequency. I don't remember
what the CPLD was rated at.
Rick
On 6/5/2015 8:19 PM, Hal Murray wrote:
rich...@karlquist.com said:
I used a CPLD in a 900 GHz (that's right 900 GHz) optical sampling scope
Hi
On Jun 5, 2015, at 11:19 PM, Hal Murray hmur...@megapathdsl.net wrote:
rich...@karlquist.com said:
I used a CPLD in a 900 GHz (that's right 900 GHz) optical sampling scope
timebase. It was great because you just write a 17 bit counter in VHDL and
there it is. You don't have to know
Hi
Here’s an example:
http://parts.arrow.com/item/detail/arrow-development-tools/bemicromax10#pg2e
https://www.altera.com/products/fpga/max-series/max-10/overview.highResolutionDisplay.html
There are other outfits that make similar parts that are at least as good. This
is considered a
low end
On Sat, 6 Jun 2015 09:52:11 -0400
Bob Camp kb...@n1k.org wrote:
Was it a simple
counter or was there enable/up/down/load type gating involved?
What would you have done if you needed to run a bit faster?
Bought a faster FPGA or gone to an ASIC.
Could you buy a
faster chip?
Hoi Rick,
On Fri, 05 Jun 2015 17:19:05 -0700
Richard (Rick) Karlquist rich...@karlquist.com wrote:
Can someone explain to me how this is going to work in
light of the fact that each clock is in a different
gravitational field? Or is accuracy not the measurement,
but rather stability? No,
I completed the TCXO to OCXO (MTI 240-0530-D) upgrade yesterday with no
issues. TCXO is a bit troublesome to remove (Four through the hole
mounts. Can made stiff and difficult to move any corner much. Slowly
worked my way around the four mounts repeatedly until they came loose.) but
a bit of
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