Dear nuts,
Triggered by Ulrich's very interesting thread on nasty DDS features, I would
like to submit for comments an idea for an application of DDS technology
which hopefully does not suffer from them. We have a need at CERN to
distribute RF signals (those used for driving particle-accelerating
With the temperature stabilized, compared to just 1 degree swings in
temperature I see a 10 times improvement in the 1PPS standard deviation, and a
3 times improvement in the oscillator and dac control voltage.
-
Between that data and LH's EFC plot you should have som
Hi,
Is there a DDS spur prediction software around ?
I mean for an arbitrary DDS design, like I would
implement with logic or fpga etc.
A code where I can enter nr of bits adc bits etc.
(not a thing for a particular analog-devices chip or
other dds chip)
tks.
Luis Cupido
ct1dmk.
___
On 1/27/11 5:17 AM, Luis Cupido wrote:
Hi,
Is there a DDS spur prediction software around ?
Not generically..
There is a dissertation out there with some matlab code. I'll see if I
can find a link
Most of the time what I do is write a little program in matlab/octave,
run a bunch of sampl
Hi
There are a bunch of cheap little USB thermometers out there ($10 or
so).
[]
Bob
Thanks for that heads-up, Bob, I had missed those. I just ordered a
couple, although it will now be after the Chinese New Year when they
arrive!
Cheers,
David
--
SatSignal software - quality software wri
On 1/27/11 5:17 AM, Luis Cupido wrote:
Hi,
Is there a DDS spur prediction software around ?
I mean for an arbitrary DDS design, like I would
implement with logic or fpga etc.
A code where I can enter nr of bits adc bits etc.
(not a thing for a particular analog-devices chip or
other dds chip)
On 1/27/11 5:17 AM, Luis Cupido wrote:
Hi,
Is there a DDS spur prediction software around ?
I mean for an arbitrary DDS design, like I would
implement with logic or fpga etc.
A code where I can enter nr of bits adc bits etc.
here's a good start.. Martin Pechanec's work...
http://geociti.es
Hi
As a first order approximation for phase noise:
Feed them both into a mixer and look at the output on a sound card after
some amplification.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Lester Veenstra
Sent: Thursday, Janua
Hi
If anybody is doing PLL's and does not have a copy of that book - go out and
get it.
In the second edition, limiters are in section 6.4 starting on page 125. The
"good stuff" (complete with Bessel functions) is on pages 126 and 127.
Bob
-Original Message-
From: time-nuts-boun...@feb
Hi
There's some stuff in Matlab if you have the right package add-on's.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Luis Cupido
Sent: Thursday, January 27, 2011 8:18 AM
To: Discussion of precise time and frequency measurement
S
Even the original is a good classic on PLLs. I have an original photocopy of
the typed pre-publication volume, as well as the actual book. Regarding hard
limiters, we did a lot of study on their behavior on the resulting power
spectra. We use a one bit quantizer of ASW signals and then displayed th
Hi
With a "normal" TBolt running on the bench, it's very obvious that
temperature and EFC are directly related to each other. With a little
scaling (and possibly an inversion) the plot of one lays down on top of the
other. As long as you can eyeball that kind of relation, there's an issue.
Why w
Hi,
On 27/01/11 01:30, ehydra wrote:
Hm Magnus -
I heard of it as a standard text book but never looked inside. And not
known that it describes limiter behaviour.
Anyway. Now I have a version of 2004, 3rd edition, and cannot find the
mentioned chapter. Please post a little more info, so I can
Hi Mike,
On 27/01/11 18:25, Mike Feher wrote:
Even the original is a good classic on PLLs. I have an original photocopy of
the typed pre-publication volume, as well as the actual book. Regarding hard
limiters, we did a lot of study on their behavior on the resulting power
spectra. We use a one b
Bob wrote:
If all that's true, what you are watching on the EFC is the TBolt
correct out the OCXO TC.
Agreed (well, superimposed upon its correction of all other drift mechanisms).
By this (quite possibly imperfect) measure: When the EFC goes down
3:1, you have improved the thermals by 3X. I
I found chapter Appendix 7A "Analysis of interference in a hard limiter"
There is a half page with a couple of formulas. Not much, not
practically oriented. Only idealized hard-limiters.
I'm interested in SOFT-limiters!
Hm. Does the writer seen a real working system once upon in time?
- Henry
The best once I found is this:
http://www.holmea.demon.co.uk/FracN/Simulate.htm
- Henry
Luis Cupido schrieb:
Hi,
Is there a DDS spur prediction software around ?
I mean for an arbitrary DDS design, like I would
implement with logic or fpga etc.
A code where I can enter nr of bits adc bits e
I've just listed this item on EBay: 32064101.
Low starting bid of GBP0.99
A real blast from the past, but may be of interest to someone in the group.
Will be digging out some other stuff shortly as part of a move/downsize.
Cheers
Rob K
___
t
List,
The temperature numbers that members have published are very impressive.
My question is: What does the tbolt use for a temperature sensor and is there
or has anyone been able to independently verify that the stated numbers are
accurate? Of course if they are working extremely well it may
List,
Please help me with this physics question.
If one has a given cube, say 2 x 2 x 2 inches. And one has the choice of
aluminum, copper, or lead (just for an example). Will each store or hold the
same amount of BTUs or does the density make a difference?
IF the density makes a difference,
With the temperature stabilized, compared to just 1 degree
swings in temperature I see a 10 times improvement in the
1PPS standard deviation, and a 3 times improvement in the
oscillator and dac control voltage.
Mark,
Do you have any measurements of the actual 1PPS output
with and without tempe
The heat capacity of an object is the "Heat Capacity" = M * Cp
M = Mass
Cp = Specific Heat (at constant pressure)
M = Vol * SG
SG = Specific Gravity ( = density/density of water)
So, Heat Capacity = Vol * SG * Cp
If you want to know how much heat is required to change tempo:
Heat = Vol * SG *
Thermal energy in metals are measured in 'pro kg'. The rest is just
calculation.
From a practical standpoint I would use copper. You can solder and weld
it more easely.
Look for how head-fin spreaders work for CPUs.
- Henry
Perry Sandeen schrieb:
List,
Please help me with this physics que
List,
I was reading some of the history of mechanical clocks and was astonished to
see that one guaranteed its accuracy to 2 milliseconds per day! (And it was)
Now this same clock when tested with modern equipment tested to be accurate to
200 micro-seconds per day. Astonishing!
This got to wo
Hi Perrier:
When was this?
Do you have a URL?
Have Fun,
Brooke Clarke
http://www.PRC68.com
Perry Sandeen wrote:
List,
I was reading some of the history of mechanical clocks and was astonished to
see that one guaranteed its accuracy to 2 milliseconds per day! (And it was)
Now this same clo
Perrier-
"My question is: What does the tbolt use for a temperature sensor..."
The Thunderbolt uses the DS1620
http://pdfserv.maxim-ic.com/en/ds/DS1620.pdf
-Arthur
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go t
Hi Rob,
don't the worst typos always end up in the title!
cheers,
ian
> Date: Thu, 27 Jan 2011 20:08:10 -
> From: "Rob Kimberley"
> Subject: [time-nuts] SYSTRON-DONNER 3522 -IEEE 448 BUSSER II
> To: "'Discussion of precise time and frequency measurement'"
>
> Message-ID: <000301cbbe
Boy I sure don't know but.
I could make some assumptions especially if it were 100 years ago. I might
guess its either a sun or star track and the fact that exactly 24 hours
later it crossed. Granted the clock could be adjusted so that its tick would
exactly cross. Most likely a light/candle and a
At one time I took some data on a 5370A with a FTS4060 cesium as the reference.
Those numbers tracked the self-reported numbers. I can't find the raw data
anymore.
Warren also pointed out that with the temperature stabilized you can increase
the filter time constant 2-3 times over what a non
Most metals have a specific heat around .34, where water is 1.0. ( so .34 BTU
to raise a pound od aluminum by 1 deg F)
The have different densities, so on a per volume basis, you want dense.
Tungsten for instance or osmium
You also need to consider conductivity though. Gold is good
On Jan 27
If you are considering conductivity for dynamic reasons, the correct
figure of merit is "Thermal Diffusivity"
= (Specific Heat) / (Thermal Conductivity)
-John
=
> Most metals have a specific heat around .34, where water is 1.0. ( so .34
> BTU to raise a pound od aluminum by 1 deg F
By this (quite possibly imperfect) measure: When the EFC goes down
3:1, you have improved the thermals by 3X. If you started at 1 C
swings, the OCXO is now seeing 1/3 C swings.
Agreed (re: the EFC component that correlates to changes in Tbolt
ambient temperature).
A number of posts have ment
Well spotted that man!!
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of gonzo .
Sent: 27 January 2011 9:02 PM
To: time-nuts
Subject: Re: [time-nuts] SYSTRON-DONNER 3522 -IEEE 448 BUSSER II
Hi Rob,
don't the worst typos always end up in
Hi
If you go by Wikipedia, 10 ms per day was considered pretty good in 1909.
Shortt clocks came along in 1929 and are mentioned as 1 second per year. I
suspect the 2 ms / day and 1 sec per year numbers are both referring to a
Shortt.
Simple answer is that all of this came along after you had ele
Hi
The assumption is that other than OCXO short term and aging - all the bumps
and dips in the road have been eliminated. As I mentioned earlier that is
indeed an assumption that has a lot of sub assumptions that go into it.
It also assumes that GPS is correct over the time period involved.
To
The temperature numbers that members have published
are very impressive.
My question is: What does the tbolt use for a temperature
sensor and is there or has anyone been able to independently
verify that the stated numbers are accurate? Of course if
they are working extremely well it may be a mo
At 04:18 PM 1/27/2011, J. Forster wrote...
If you are considering conductivity for dynamic reasons, the correct
figure of merit is "Thermal Diffusivity"
= (Specific Heat) / (Thermal Conductivity)
If you want a thermal mass to help control temperature swings, the more
heat capacity is good. Is
If you want the thermal mass to behave close to an isothermal body,
diffusivity is very important.
For example, a large mass of still water has high heat capacity, but poor
diffusivity. Much of the heat capacity is useless.
-John
==
> At 04:18 PM 1/27/2011, J. Forster wrote...
>>If
> If you want a thermal mass to help control temperature swings, the more
> heat capacity is good. Isn't more thermal conductivity also desired? It
> seems like a substance with low conductivity wouldn't gather/release heat
> well.
It depends on the time constant (frequency) of the thermal chan
Lady Heather calculates the statistics over the data that is shown on the
screen. You can change the view window into the captured data buffer and see
how the statistics change over various time intervals. It can calculate
average, rms (the default), standard deviation, or variance. Plus
On Thu, Jan 27, 2011 at 12:38 PM, Perry Sandeen wrote:
> List,
>
> Please help me with this physics question.
>
> If one has a given cube, say 2 x 2 x 2 inches. And one has the choice of
> aluminum, copper, or lead (just for an example). Will each store or hold the
> same amount of BTUs or doe
jim...@earthlink.net said:
> Most metals have a specific heat around .34, where water is 1.0. ( so .34
> BTU to raise a pound od aluminum by 1 deg F)
Where did you get that?
This table says:
Aluminum 0.215
Copper 0.092
Iron0.107
Lead0.031
http://phoenix.phys.clemson.edu/labs/2
At 05:33 PM 1/27/2011, J. Forster wrote...
If you want the thermal mass to behave close to an isothermal body,
diffusivity is very important.
For example, a large mass of still water has high heat capacity, but
poor
diffusivity. Much of the heat capacity is useless.
If the equation given ["T
I got the Thermal Diffusivity definition upside down.
-John
=
> At 05:33 PM 1/27/2011, J. Forster wrote...
>>If you want the thermal mass to behave close to an isothermal body,
>>diffusivity is very important.
>>
>>For example, a large mass of still water has high heat capacity, b
Hi This is an interesting concept of measuring or comparing without
electronics. Dont forget the scientists of former eras has some quite
inovative bits of kit. the CRT dated from the 1920 but Victorians used a
sooted glass slide carried on a small trolley that was moved by a falling
weight
On Thu, Jan 27, 2011 at 12:55 PM, Perry Sandeen wrote:
> ...how the heck they were able to calibrate a clock to milliseconds per day
> back then?
Let it run for 1,000 days, then you only need to be able to measure to
the nearest second to get to ms per day. Or maybe you can measure to
0.1 seco
I'm getting ready to scrap a bunch of the Odetics GPStar's I have for
the cool 5x7 HP LED displays
Of the 11 antenna/down converters I've found one works.
http://petelancashire.com/gallery/main.php?g2_itemId=19820
I'd like the lists opinion if saving the OCXO is worth puling of the board
http:/
Luis Cupido wrote:
Is there a DDS spur prediction software around ?
I mean for an arbitrary DDS design, like I would
implement with logic or fpga etc.
That file I linked to yesterday has a
couple references on page 4:
- Martin Pechanec’s MATLAB scripts ( mentioned earlier by Jim L. ),
- Zs
On Thu, Jan 27, 2011 at 3:54 PM, Pete Lancashire
wrote:
>
> I'd like the lists opinion if saving the OCXO is worth puling of the board
You mean is the OCXO worth your time to salvage it? I don't know but
from those photos I see 100 parts that are worth my time to salvage.
I look at those photos
On 27/01/11 22:37, Tom Van Baak wrote:
By this (quite possibly imperfect) measure: When the EFC goes down
3:1, you have improved the thermals by 3X. If you started at 1 C
swings, the OCXO is now seeing 1/3 C swings.
Agreed (re: the EFC component that correlates to changes in Tbolt
ambient tempe
On 1/27/11 11:19 AM, ehydra wrote:
I found chapter Appendix 7A "Analysis of interference in a hard limiter"
There is a half page with a couple of formulas. Not much, not
practically oriented. Only idealized hard-limiters.
I'm interested in SOFT-limiters!
Soft limiters are even more complex to
On 1/27/11 3:20 PM, Hal Murray wrote:
jim...@earthlink.net said:
Most metals have a specific heat around .34, where water is 1.0. ( so .34
BTU to raise a pound od aluminum by 1 deg F)
Where did you get that?
probably misremembering.. Standing in an airport terminal trying to
figure out whe
Hi all,
I'm building a frequency master unit based on the Tbolt with associated
buffers and dividers to give multiple frequencies and outputs plus
utilising the PPS to provide the ref for an embedded linux box to
provide NTP. This will provide the 10Mhz and others as the master lock
for my l
Peter a couple of comments.
Great pictures you can really see the technology and if the net connection
wasn't so slow I would look at the eprom dates and such.
I know Odetics, the company well. I think they are long gone or the
goverment div survived so that suggests these are circa 1990-1994.
I ha
At 07:53 PM 1/27/2011, jimlux wrote...
I did do some googling and found this interesting statement in
Wikipedia
Another way of stating this, is that the volume-specific heat capacity
(volumetric heat capacity) of solid elements is roughly a constant.
I'll admit that I'm prone to citing Wikiped
On 27/01/11 20:19, ehydra wrote:
I found chapter Appendix 7A "Analysis of interference in a hard limiter"
There is a half page with a couple of formulas. Not much, not
practically oriented. Only idealized hard-limiters.
I'm interested in SOFT-limiters!
Jim's problem was with a hard-limiter so
On Thu, Jan 27, 2011 at 4:56 PM, Tim Tuck wrote:
> PPS to provide the ref for an embedded linux box to provide
> NTP. This will provide the 10Mhz and others as the master lock for my lab.
>
> A small chunk of linux based code might do, but a PIC or AVR would be
> better.
Seems that you alre
Magnus Danielson schrieb:
On 27/01/11 20:19, ehydra wrote:
I found chapter Appendix 7A "Analysis of interference in a hard limiter"
There is a half page with a couple of formulas. Not much, not
practically oriented. Only idealized hard-limiters.
I'm interested in SOFT-limiters!
Jim's problem
Heather started out as a AVR application on a MegaDonkey touch screen
controller (http://www.mega-donkey.com) but I quickly came to the conclusion
that it was much better suited to a dedicated $20 surplus laptop.
You can rather easily extract the temperature controller code from the source
co
On 28/01/11 03:33, ehydra wrote:
Magnus Danielson schrieb:
On 27/01/11 20:19, ehydra wrote:
I found chapter Appendix 7A "Analysis of interference in a hard limiter"
There is a half page with a couple of formulas. Not much, not
practically oriented. Only idealized hard-limiters.
I'm interested
60 matches
Mail list logo
