Ran across the following; has 16 counter-timers and USB interface.
http://accesio.com/go.cgi?p=../usb-oem/usb-ctr-15.html
Might do the job.
Don
--
Neither the voice of authority nor the weight of reason and argument
are as significant as experiment, for thence comes quiet to the mind.
R. Bacon
Some time ago we initiated thoughts about development of a FPGA setup to
replace the HP stuff. Here it is, I think:
http://vigo.com.pl/index.php/en/english_menu/products/measurement_instruments/time_frequency_counters
I'm trying to get a price.
Don
--
Neither the voice of authority nor the
I have been playing with one of these units, and noticed that there
has been some discussion on them before on this list, so I wondered if
anyone might have any suggestions.
Basically, the unit powers up correctly, but the No GPS LED never
goes off - this obviously could be because it's broken or
Just finished rebuilding the digital clock, and all is well. The
original clock IC was still good, so the display board stayed with
minimal rework - only new interface and power system needed. Made a
number of improvements:
1. Eliminated original power/interface board and clock setting
Hi
The basic answer is:
1) Power them off of something stable around 18 to 19 volts. Anything higher
just heats them up without doing anything useful.
2) Put a heat sink on them. You want to get the base plate to below 50C.
Without a heat sink they get warm enough to significantly shorten their
Eric,
the power supply quality is not critical. The LPRO (like most other
Rb's) has an internal switching power supply, so the wide tolerance
in the primary power source voltage.
I found other Rb's to be quite sensitive to vibrations, but when they
are in a box, with a decent PS (I use an
You do realize that around that same time of some time ago the T3000 goodies
were already there, just waiting for you to buy them. ;) I just checked, and
the T3100 datasheet I have from last year even has the same md5sum as the one
currently on their website.
It would be interesting to know
There are lots of ways you can unintentionally affect a device
like an LPRO. For instance, suppose the internal power supply
dissipates a different amount of heat depending on the input
supply voltage. This could cause the oven to momentarily shift
its internal temperature a small amount...
On 07/10/11 19:01, Chuck Harris wrote:
There are lots of ways you can unintentionally affect a device
like an LPRO. For instance, suppose the internal power supply
dissipates a different amount of heat depending on the input
supply voltage. This could cause the oven to momentarily shift
its
No, I haven't done this, but I realized this after fiddling around with
supplies and verified the ideas with a friend of mine designing supplies
all the time. He also pointed out that many switch supplies tend to run
better when the supply voltage is on the low side of things.
Better?
Lower
fortunately, everything in the lab(basement) is on UPSs so in theory
the input voltages to the equipment should be pretty constant and I
was already planning on using a linear supply.
as far as magnetic disturbances go, what is a reasonable precaution
short of making a muMetal box?
On Fri, Oct
fortunately, everything in the lab(basement) is on UPSs so in theory
the input voltages to the equipment should be pretty constant and I
was already planning on using a linear supply.
Be careful, there. Most consumer type UPSs are not line regulators. When
there is sufficiently high line
On 07/10/11 19:00, WarrenS wrote:
Use the (J J) command to rezero the Phase plot (plus the cable delay if
desired)
and then read or adjust the Osc freq on the ppt plot.
With LadyHeather's filter off (F D 0) useful resolution is about 1e-10
in one second,
With the filter set to 10 sec (F D 10)
On 07/10/11 20:30, John Lofgren wrote:
fortunately, everything in the lab(basement) is on UPSs so in theory
the input voltages to the equipment should be pretty constant and I
was already planning on using a linear supply.
Be careful, there. Most consumer type UPSs are not line regulators.
I know that few of the GPS constellation satellites carry a Cs clock instead
of the Rb one: is it possible to take advantage from this? I think not
because Cs and Rb satellites are equally well steered but using the masking
options of GPS receivers maybe that Cs clocks can help.
On Fri, Oct 7,
Magnus Danielson wrote:
We're time-nuts. We are trying to get more from these devices
than the manufacturer ever intended.
So you let in normal mains into you lab? :-)
Me personally? I don't worry much about little stuff like that,
so I am more of a time-nut heretic. I did wire my house
On 10/7/11 11:16 AM, Eric Garner wrote:
fortunately, everything in the lab(basement) is on UPSs so in theory
the input voltages to the equipment should be pretty constant and I
was already planning on using a linear supply.
What kind of UPS? A static inverter? Most UPSes just feed the line
Very Important note, The above is NOT available directly from
LadyHeather's
ADEV plots (at least not yet - Mark is a revision coming?),
What one needs to do is to log the Tbolt's Freq and Phase data at the 1
sec
rate and then use that data with an external ADEV program such as Ulrich's
I run my pcs on a double conversion true sine wave UPS. It is designed to run
continuously. It converts to DC, which is easy to filter, then creates a
voltage and frequency regulated sine wave.
Modified sine is just a square wave. Complete junk.
Magnus
I probable was not very clear in my posting. (what else is new?)
There where TWO completely different subjects, goals and techniques in the
same Posting.
#1 was how to Log data for valid ADEV plots. That takes setting the filter
OFF for the reasons you state.
The ADEV tau axes provides
You would first have to answer which are better to use for short term, Cs or
Rb?
(the answer is: a good OCXO)
My guess is it does not mater, all are so much better than what is received
by a Tbolt.
And for long term where a Cs wins, they are disiplined/corrected in some
way so it don't mater.
On Oct 7, 2011, at 3:32 PM, John Miles jmi...@pop.net wrote:
Intuitively, I don't believe a GPSDO can outperform an HP 5071A-era clock
over periods greater than a few hours. But it may be reasonable to
benchmark 5061A-class standards with a good GPSDO setup. We really need
some more data
Hi,
As for the CS vs RB on orbit, the Elmer Perkins RBs on IIR are better out
to a few days than CS on the older satellites. Anybody knows which clocks
are in the new IIF-satellite on orbit? Any performance data published?
--
Björn
You would first have to answer which are better to use for
John
It would be great to have a direct Tbolt driver on TimeLab.
Right now it is so much trouble and time to use it, it takes away of the
great real time capabilities of TimeLab.
According to Tom his really good Cs has an Flicker noise floor of almost 10
days using 4 ns rms for phase noise.
On 07/10/11 20:59, Azelio Boriani wrote:
I know that few of the GPS constellation satellites carry a Cs clock instead
of the Rb one: is it possible to take advantage from this? I think not
because Cs and Rb satellites are equally well steered but using the masking
options of GPS receivers maybe
John
What was the RMS and PP phase noise for your 8e-14 test?
Something to keep in mind is that although the Z3801 has a better Osc than
the typical Tbolt.
Long term, really low noise is all about the quality of the GPS signal and
engine.
The Z3801's GPS engine is far inferior and not even
They are APC double conversion(online) UPSs. I ended up buying them
because my washing machine makes the lights in the basement flicker
when it runs so I didn't want that feeding through into my equipment.
I've looked into the ferroresonant regulators like the Sola MCR series
but they are pretty
I'm using Opti-UPS, but the same idea. They have software such that you can
monitor the power being delivered, frequency, voltage, etc.
The only real drawback to double conversion is the fan noise. The Opti-UPS is
slightly quieter than the APC, but not by much. The fan noise is quite
Long term, really low noise is all about the quality of the GPS signal and
engine.
And the antenna, and the multi-path, and ionosphere, etc. ...
With a Z3801A or TBolt (or any cheap single channel GPS) receiver
you should expect maybe a 5 to 10 to 15 ns variation over a 12 or 24
hour period.
On 10/7/2011 8:26 AM, shali...@gmail.com wrote:
I bought two HP 5334B on ebay for under $100 each (that was a couple of years
ago).
Nice counter, with GPIB.
Didier KO4BB
And no fans in the 5334, so quiet.
___
time-nuts mailing list --
In that test I was just capturing the ADEV table from the TSC-5120 so don't
have raw phase data.
I'm curious where you got the noise data for the TBolt gps engine -- that's far
better than I've seen quoted before. The Trimble data sheet that I found specs
the system PPS accuracy at 20
Hi Tom and Warren,
With a Z3801A or TBolt (or any cheap single channel GPS) receiver
you should expect maybe a 5 to 10 to 15 ns variation over a 12 or 24
hour period. You should be able to see this with a 5065A or a good
Cs reference.
Hope to get a working 5065A in a month or two... ;-)
The noise data is my measured values which I do several different ways. Some
of which are:
The GPS engine value was calculated from measuring the UNFILTERED RMS noise
of the freq plot data using LadyHeather, backed up by the independent way of
looking at the UNFILTERED 1 sec ADEV values
readings
using an external Osc that is known quieter than the Tbolt's Nose floor
(such as a low noise 10811)
and one that is nosier than the Tbolt's freq noise floor (like a LPRO).
For a plot of the Tbolt's noise floor I got see:
http://www.febo.com/pipermail/time-nuts/attachments/20111007
I want to measure the short term stability of a source
with substantial linear drift. I would like some measure
of stability along the lines of Allan deviation, but I
only want to measure the noise and ignore the drift.
AFAIK, ADEV treats linear drift like a form of noise.
Has this problem been
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-
boun...@febo.com] On Behalf Of Rick Karlquist
Sent: Friday, October 07, 2011 9:32 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Measuring short term stability minus linear drift
I want to measure the short term stability of a source
with substantial linear drift. I would like some measure
of stability along the lines of Allan deviation, but I
only want to measure the noise and ignore the drift.
AFAIK, ADEV treats linear drift like a form of noise.
Has this problem been
37 matches
Mail list logo
