In message [EMAIL PROTECTED], Steve
Rooke writes:
2008/10/2 Bruce Griffiths [EMAIL PROTECTED]:
Save yourself a counter and just divide the frequency down to about 1Hz
and time stamp the 1Hz transitions with the Linux box.
As long as you know the division factor its easy enough to calculate
I'd planned on a simple interface to the PC via using the parallel,
suitably strapped, as a basic output port. Now, I could use it as an
input but I'd probably have to poll the port which would be somewhat
inefficient but an option I guess. Think I could just record the
staring time of the
2008/10/2 Poul-Henning Kamp [EMAIL PROTECTED]:
In message [EMAIL PROTECTED], Steve
Rooke writes:
2008/10/2 Bruce Griffiths [EMAIL PROTECTED]:
Save yourself a counter and just divide the frequency down to about 1Hz
and time stamp the 1Hz transitions with the Linux box.
As long as you know the
Scuse me for top posting.
Guess I'm going to do something a bit like plan 3 but mostly in
hardware. My plan for the PC is just to use it to gate the oxco output
into the pre-scalier divider chain for a specific time period. The
output of the pre-scalier will be a series of pulses which can be
I'm not planning to use this oxco to sync the NTP on my PC, just using
NTP to check the frequency of my oxco so I can use it to calibrate my
counters, as a timebase and hence to allow me to lock amateur radio
transceivers to a precise frequency for QRP (very low power long
distance work). If
Steve,
Hmmm... If I measured a 10MHz oscillator for a 1/10 second, I
could achieve, at best, 1ppm accuracy. Now my measuring
system has a non accumulating error in the ms range, say 1s,
so this would be totally unworkable. If I sampled for 1s,
best would be .1ppm accuracy...
this is a
Ulrich Bangert wrote:
Steve,
Hmmm... If I measured a 10MHz oscillator for a 1/10 second, I
could achieve, at best, 1ppm accuracy. Now my measuring
system has a non accumulating error in the ms range, say 1s,
so this would be totally unworkable. If I sampled for 1s,
best would be
I recently acquired an HP 5061B (Options 3 and 4). The system came without an
AC cable.
I can easily make a replacement cable for the system. However, I need to know
the pin assignments. I can open the unit to look, but if someone has the
answer it would save me the hassle.
Each of the
By the way...I know that for single phase AC the assignment of hot and
neutral technically doesn't matter...but I'm a purist...
Thanks.
Jeff
Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402
--- On Thu, 10/2/08, Jeffrey Okamitsu [EMAIL PROTECTED] wrote:
From: Jeffrey Okamitsu [EMAIL PROTECTED]
On 10/1/08 10:18 PM, Steve Rooke [EMAIL PROTECTED] wrote:
2008/10/2 Bruce Griffiths [EMAIL PROTECTED]:
Save yourself a counter and just divide the frequency down to about 1Hz
and time stamp the 1Hz transitions with the Linux box.
As long as you know the division factor its easy enough to
Was this the pretty one on Ebay? - you really, really need to open it
up at least to ensure nothing came adrift in shipping, I'll second Tom
on the sheer coolness of the 5061B but also remember most of the
components in a Cesium beam fall under the category of Unobtainium
so you will want to
Scott, Tom. Thanks for your input. I am sure the unit was working before
hand. I will probably pop the top cover off and have a look.
The schematic helps. Thanks.
Yes, this was the one on e-bay. Was I bidding against you?
Jeff
Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402
--- On Thu,
That critically depends what country you are in.
In the UK you can normally safely connect yourself between neutral and
earth, as neutral is always bonded to earth at the sub-station. There
may be a few volts on neutral due to phase imbalance in the three phase
supply and how far you are from
US is similar regarding the lashing together of earth and ground for single
phase power. However, current US electric code is very specific about which
terminal of the AC plug is wired to hot and which is wired to neutral.
Jeff
Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402
--- On Thu,
US is similar regarding the lashing together of earth and ground for
single phase power. However, current US electric code is very specific
about which terminal of the AC plug is wired to hot and which is
wired to neutral.
It used to matter back in the tube days when cheap radios/TVs didn't
No I bought a 5061A a few weeks before unfortunately it has issues
some of which are traceable to improper packing. I'm surprised you
did not buy the power cord (i did) on ebay. The Cannon connectors
are expensive but they can be had from Powell Electronics here in
Massachusetts.
I think
Basically, we get ours from a 230 Volt,
center-tapped transformer secondary.
The center tap is also earthed. We can
connect 115 Volt appliances between either
end of the transformer and center-tap neutral.
Higher-current appliances connect to both
ends to get the full 230 Volts.
The neutral is
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of David C. Partridge
Sent: Thursday, October 02, 2008 9:31 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] AC Connector On HP 5061B
That critically depends what
Hi Mike:
The reason for the center tapped transformer on the pole pig is to protect the
house occupants from a primary to secondary short in the pole pig transformer.
That would put 4KV into your house.
It's not clear to me how 230 VAC countries handle that problem? If they also
use the
2008/10/3 Brooke Clarke [EMAIL PROTECTED]:
It's not clear to me how 230 VAC countries handle that problem? If they also
use the same transformer but only bring in the 230 VAC then neither side of
the
line is near ground potential.
In 230/240 VAC the neutral side of the transformer output is
Scott. Thanks for the information. Tsuchiya-san provided the part number for
the connector and I have already ordered one from Powell.
I am looking forward to getting the unit up and running and providing a stable
10 MHz from which I will lock all of my frequency sensitive test equipment.
Similar to what another poster suggested, but more direct -
assuming the schematic shows that only the live side is fuse protected
inside the HP, then if you take out the fuse
on the rear panel, and see which prong on the connector connects to it, that
should tell you.
- unless both sides are
What happens to a 5061 if I swap the power wires? I can imagine some second
order considerations that would depend on how the power transformer is
constructed.
The transformer is symmetrical so no worries there. The only
difference is the fuse. Black (hot) is fused, white (neutral) isn't.
I'm wondering about the possibility of checking the frequency of my
oscillator by using a NTP synced RT Linux system. What I'm thinking of
An all-PC frequency counter is a great idea. True, the
performance is limited compared to GPS time sources and
hardware frequency counters, but there's
According to the circuit diagram, only one side is fused and it is identified
on the schematic as the hot side.
Jeff
Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402
--- On Thu, 10/2/08, Ian Sheffield [EMAIL PROTECTED] wrote:
From: Ian Sheffield [EMAIL PROTECTED]
Subject: Re: [time-nuts] AC
Mike Monett wrote:
Hello Bruce,
This is my first attempt to post so I'm not sure if it will work.
I have been researching the forum archive and find it is by far the
best resource on time and frequency available anywhere. Also, your
posts are extremely helpful to a newcomer.
Tom Van Baak wrote:
I'm wondering about the possibility of checking the frequency of my
oscillator by using a NTP synced RT Linux system. What I'm thinking of
An all-PC frequency counter is a great idea. True, the
performance is limited compared to GPS time sources and
hardware
When using a sound card for frequency comparisons the zero crossing time
stamp resolution is improved if the slew rate of the input signal is
slow enough that several (3 or more) samples are taken in the vicinity
of the zero crossing. One can then make use of WKS (Whittaker,
Kotelnikov,
Lux, James P wrote:
In the U.S., depending on where the installation is (residential vs
industrial), the neutral (groundED conductor)
is bonded (code-speak for permanently connected) to the earth ground at the
service entrance panel. The safety ground
(groundING conductor aka green-wire
Tom Van Baak wrote:
When using a sound card for frequency comparisons the zero crossing time
stamp resolution is improved if the slew rate of the input signal is
slow enough that several (3 or more) samples are taken in the vicinity
of the zero crossing. One can then make use of WKS
In message [EMAIL PROTECTED], Tom Van Baak writes:
I'm wondering about the possibility of checking the frequency of my
oscillator by using a NTP synced RT Linux system. What I'm thinking of
An all-PC frequency counter is a great idea.
Actually, the best hardware for the job is the Soekris
Tom Van Baak wrote:
The instability of the sound card LO isnt completely cancelled if the
zero crossings of the the 2 signals aren't coincident.
That seems right for absolute event timing with a stereo sound card
but I think for a frequency measurement the delay, if any, between
And this is another reason you should pay attention to hot and neutral.
The hot side is usually where the fuse is, as is the case in the 5061.
If you swap them, you no longer have any protection against an internal
hot-to-ground AC fault.
Bill Ezell
--
They said 'Windows or
Lux, James P wrote:
In the U.S., depending on where the installation is (residential vs
industrial), the neutral (groundED conductor) is bonded
(code-speak
for permanently connected) to the earth ground at the
service entrance panel. The safety ground (groundING
conductor aka
Tom
The short term phase instabilities of the sound card LO that occur
during the finite interval between the zero crossing times for one
channel and the zero crossing time for the other channel can be
significant.
...
Bruce,
I'm all ears for details about the phase stability of
Call me crazy but I wonder if my accurate relative period of time
could be derived from the 230VAC 50Hz mains supply over here. Now,
before you yell at me, consider this, I have a couple of mains driven
clocks in the house and only seem to need to change the time on them
when we go from Standard
Call me crazy but I wonder if my accurate relative period of time
could be derived from the 230VAC 50Hz mains supply over here. Now,
before you yell at me, consider this, I have a couple of mains driven
clocks in the house and only seem to need to change the time on them
when we go from
At 5:32 PM -0700 10/2/08, Tom Van Baak wrote:
Tom
The short term phase instabilities of the sound card LO that occur
during the finite interval between the zero crossing times for one
channel and the zero crossing time for the other channel can be
significant.
...
Bruce,
I'm all
Tom Van Baak wrote:
Tom
The short term phase instabilities of the sound card LO that occur
during the finite interval between the zero crossing times for one
channel and the zero crossing time for the other channel can be
significant.
...
Bruce,
I'm all ears for details about
Good point.
BTW. I confirmed the schematic - B is hot, A is neutral.
Jeff
Jeffrey K. Okamitsu, PhD, MBA
+1-609-638-5402
--- On Thu, 10/2/08, wje [EMAIL PROTECTED] wrote:
From: wje [EMAIL PROTECTED]
Subject: Re: [time-nuts] AC Connector On HP 5061B
To: Discussion of precise time and
Tom
The major source of interchannel phase shift instability will be the
phase shift instabilities of the sound card input RC coupling network
particularly if electrolytic capacitors are used and the input
frequencies are too close to the high pass RC filter 3dB frequency.
Amplifier
Bruce Griffiths wrote:
Tom
The major source of interchannel phase shift instability will be the
phase shift instabilities of the sound card input RC coupling network
particularly if electrolytic capacitors are used and the input
frequencies are too close to the high pass RC filter 3dB
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Steve Rooke
Sent: Thursday, October 02, 2008 2:02 PM
To: [EMAIL PROTECTED]; Discussion of precise time and
frequency measurement
Subject: Re: [time-nuts] AC Connector On HP 5061B
2008/10/3 Brooke
The time constant should have been 22ms and the phase shift 1.16us with
a tempco of 580ps/C.
Since both channels have the same nominal low frequency cutoff the
differential phase shift tempco will be somewhat smaller.
Thanks for the calculations. So it's probably safe to say the
Hi Tom,
2008/10/3 Tom Van Baak [EMAIL PROTECTED]:
For standard (or Allan) deviation of mains frequencies, see:
Accuracy and stability of the 50 Hz mains frequency
http://wwwhome.cs.utwente.nl/~ptdeboer/misc/mains.html
60 Hz AC Mains Frequency Accuracy Measurement
Tom Van Baak wrote:
Anyway, I think it would make a fun project to see how well a
typical PC sound card actually does as a 1PPS or LF phase
comparator and frequency counter. I wouldn't expect better
results than a $50 surplus eBay time interval counter, but it
would be interesting to see just
Many thanks for these pointers, very interesting and useful work. This
does show that for a long sampling time, quite a high degree of
accuracy could be obtained. The downsides are that the sampling period
would have to be very long and could easily be affected by power cuts
causing failure
Tom Van Baak wrote:
measure to 1 ppm within ten seconds.
/tvb
http://www.LeapSecond.com
p.s. For extra credit, tee your UUT into both channels, do twice
the math, and see if you can measure both differential phase,
and differential phase drift between them.
Tom
A better way may be
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