...@febo.com] On
Behalf Of Magnus Danielson
Sent: Wednesday, May 16, 2012 10:57 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
On 05/16/2012 02:21 PM, shali...@gmail.com wrote:
It would be very easy to use a constant current to drive the LED and
simply
short
On 05/17/2012 05:38 AM, Tom Holmes wrote:
The LED current could also be switched with a very long rise/fall time so
that there isn't any transient, in the abrupt sense of the word. Who's gonna
see the difference?
In a group that has GPS synchronized clock hands?
HERESY!
:)
Tom Holmes,
May 2012 20:44:04
To:time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
On 5/14/2012 8:21 PM, Tom Van Baak wrote:
one day during an experiment where I was
comparing a large set
On 05/16/2012 05:25 AM, Hal Murray wrote:
rich...@karlquist.com said:
FWIW, the E1938A oscillator control board had a happy light LED that
flashed 1 time per second, and sure enough this corrupted the power supply
and affected some applications. We added a command to turn it off.
Why should
@febo.com
Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
On 05/16/2012 05:25 AM, Hal Murray wrote:
rich...@karlquist.com said:
FWIW, the E1938A oscillator control board had a happy light LED that
flashed 1 time per second, and sure enough this corrupted the power supply
and affected some
But if the LED transition was offset any significant amount of time from
the PPS, you wouldn't be able to use it to set your watch!
Dave :-)
On Wed, May 16, 2012 at 10:57 AM, Magnus Danielson
mag...@rubidium.dyndns.org wrote:
Then, to reduce the impact on the PPS signals, the LED on/off
On 05/16/2012 07:42 PM, Dave Martindale wrote:
But if the LED transition was offset any significant amount of time from
the PPS, you wouldn't be able to use it to set your watch!
Dave :-)
Well, the offset compensates for the protein computer delay.
Cheers,
Magnus
On Wed, May 16, 2012
I always thought it was nice to have the pretty LEDs showing the power
supplies are working, but then you have to find the one that's not lit.
I've seen others that have a 'fail' indicator, but if the power supply
is dead, what powers the fail LED.
The B-1B test stations have an interface
Message-
From: Mike S mi...@flatsurface.com
Sender: time-nuts-boun...@febo.com
Date: Mon, 14 May 2012 20:44:04
To: time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
On 5/14/2012 8
@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Cc: Discussion of precise time and frequency measurementtime-nuts@febo.com
Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
These types of pulses should be routed as open-ended source-terminated
: Discussion of precise time and frequency
measurementtime-nuts@febo.com
Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
These types of pulses should be routed as open-ended source-terminated
reflected wave switched transmission lines. Power will only flow for
nanoseconds as the pulse travels
: [time-nuts] Why are 1PPS signals so skinny?
These types of pulses should be routed as open-ended source-terminated
reflected wave switched transmission lines. Power will only flow for
nanoseconds as the pulse travels over the line. There won't be a drop of
50% of the voltage at the target
On 5/15/2012 2:45 PM, shali...@gmail.com wrote:
The narrow pulses are easily filtered by the power supply because the
frequency distribution of the power consumption has a much smaller
component at 1Hz.
But, since PPS is the leading edge, if the power draw for a longer pulse
width causes
seeing into the future for doing? Equalize the amplitude?
Injecting/reducing the current to adjust the dV/dt? Can you explain?
On Tue, May 15, 2012 at 9:47 PM, Mike S mi...@flatsurface.com wrote:
On 5/15/2012 2:45 PM, shali...@gmail.com wrote:
The narrow pulses are easily filtered by the
Yes, but the point is to not use end-termination for all the reasons
mentioned by others in this thread, such as massive spike in power consumption
once per second, over-voltage spikes if the termination is faulty or
missing, higher ADEV due to power supply modulation, etc etc..
Your test
On 5/15/2012 3:59 PM, Azelio Boriani wrote:
seeing into the future for doing? Equalize the amplitude?
Injecting/reducing the current to adjust the dV/dt? Can you explain?
Once the leading edge has occurred, the only information of significance
has been transmitted. What happens after doesn't
On Tue, 15 May 2012 15:47:46 -0400
Mike S mi...@flatsurface.com wrote:
On 5/15/2012 2:45 PM, shali...@gmail.com wrote:
The narrow pulses are easily filtered by the power supply because the
frequency distribution of the power consumption has a much smaller
component at 1Hz.
But, since
It is worth noting that skipping the end termination is probably a bad idea
when daisy-chaining a signal from one output to more than one device input.
The input at the end of the cable will see a clean rise from zero to 5 V
(or whatever the driver's open-circuit voltage is), but the other inputs
On 5/15/2012 4:19 PM, Attila Kinali wrote:
If the
PPS pulse is short, it contains very little energy, which means
the energy can be supplied by the small capacitors at the output
driver. The longer the pulse gets, the more energy it needs.
The pulse is meaningless. It's only the leading edge
Not really, your setup requires all inputs except the very last one to be
high-impedance to work, and to have a trigger point of 1.25V as well to work
properly (when used with a proper 50 Ohms source). So no difference there.
So it doesn't make any difference, since the same exact inputs
Mike,
Attila is trying to explain that the leading edge is not what we are
concerned about in this thread (its subject to discussion in other email
threads), it is the effect of what follows after that leading edge, and
propagates
down the power supplies to cause side effects that is
On 5/15/2012 5:14 PM, saidj...@aol.com wrote:
it is the effect of what follows after that leading edge, and propagates
down the power supplies to cause side effects that is being discussed here.
I'm asking What side effects? I haven't seen any mentioned. And
really, if an increase in power
QED: here is a phase noise plot of a 200ms 1PPS pulse showing up in the
phase noise spectrum of a 10MHz source (at 1Hz to 10Hz offsets) because the
unit was providing a 100mA current pulses into the cable, and power supply
modulation of the 10MHz output happened inside the unit.
The pulses
Easy, in a precision lab you NEVER turn off the lights. That causes too big a
temperature shift. In fact, a warm body is a 100 watt heat source. That
extra heat load can easily affect precision equipment. And that's why zombie
technicians are in such high demand... the undead are always
Forgot to mention,
on this list we are often concerned with noise floors of -170dBc or lower,
and stabilities of 1E-013 or lower.
At that level, your scenario of stepping into the room and turning on the
light will likely cause a measurable effect just because of the mechanical
vibration
saidj...@aol.com said:
Also, the Thunderbolt has less than 5 Ohms output impedance, so you get a
reflection going back from the 50 Ohms end-termination anyway because the
impedance is mismatched!
I think that's a different problem.
If the far end termination matches the cable there won't
Yes, you are right of course. My bad. This should have been written as:
The Thunderbolt has less than 5 Ohms output impedance, so if you get a
reflection coming from the cable stubs or non-end-terminated cable back into
the Thunderbolt, then you get ringing on the cable because the
On Tue, 15 May 2012 16:51:13 -0400
Mike S mi...@flatsurface.com wrote:
On 5/15/2012 4:19 PM, Attila Kinali wrote:
If the
PPS pulse is short, it contains very little energy, which means
the energy can be supplied by the small capacitors at the output
driver. The longer the pulse gets, the
On Wed, 16 May 2012 00:40:07 +0200
Attila Kinali att...@kinali.ch wrote:
Just have a look at [3]. The spurs you see there are most likely
* 60Hz mains
* 120Hz mains (first harmonic)
* a nearby radio station (according to TVB)
Err.. sorry, this should read John Ackermann, not TVB.
On May 14, 2012, at 09:33 , b...@lysator.liu.se wrote:
More modern 3-5.5V into 50ohm, 20us.
http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf
Is a similar standard available for the older PLGR devices?
--
Mark J. Blair, NF6X n...@nf6x.net
Jenny Craig?
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saidj...@aol.com wrote:
Yes, but the point is to not use end-termination for all the reasons
mentioned by others in this thread, such as massive spike in power
consumption
once per second, over-voltage spikes if the termination is faulty or
FWIW, the E1938A oscillator control board had a
On Tue, 15 May 2012 16:43:50 -0700, Rick Karlquist
rich...@karlquist.com wrote:
saidj...@aol.com wrote:
Yes, but the point is to not use end-termination for all the reasons
mentioned by others in this thread, such as massive spike in power
consumption
once per second, over-voltage spikes if
On 05/16/2012 01:43 AM, Rick Karlquist wrote:
saidj...@aol.com wrote:
Yes, but the point is to not use end-termination for all the reasons
mentioned by others in this thread, such as massive spike in power
consumption
once per second, over-voltage spikes if the termination is faulty or
FWIW,
Date: Tue, 15 May 2012 15:47:46
To: time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
On 5/15/2012 2:45 PM, shali...@gmail.com wrote:
The narrow pulses are easily filtered
do other things...
-Original Message-
From: Mike S mi...@flatsurface.com
Sender: time-nuts-boun...@febo.com
Date: Tue, 15 May 2012 17:23:41
To: time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Why are 1PPS
Hi Rick,
one reason why we happy blink at 1/2Hz :)
There are other offendors as well, such as the processor and GPS going
through the hoops once per second, but the 100mA surge from the 1PPS output
driver trumps all else.
bye,
Said
In a message dated 5/15/2012 16:44:08 Pacific
I met Jenny in 1987 - not that skinny at the time :) That was after she
sold the company already.
In a message dated 5/15/2012 16:41:34 Pacific Daylight Time, b...@iaxs.net
writes:
Jenny Craig?
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-nuts] Why are 1PPS signals so skinny?
saidj...@aol.com said:
Also, the Thunderbolt has less than 5 Ohms output impedance, so you get a
reflection going back from the 50 Ohms end-termination anyway because the
impedance is mismatched!
I think that's a different problem.
If the far end
On 5/15/2012 8:58 PM, shali...@gmail.com wrote:
Mike, here is the effect of the A/C cycling on and off during a warm
spring day on the delay through a piece of RG-8 cable maybe 3 feet
long:
You're comparing the effect of voltage droop due to a 10W load on a 120V
(or 240V, for Euros) AC feed
For what it's worth, that seems to be the standard way to distribute analog
video (composite or component). A low-impedance voltage source with a gain
of 2 drives a bunch of outputs with an individual 75 ohm series resistor
for each output. Each cable that is connected to an output has a
rich...@karlquist.com said:
FWIW, the E1938A oscillator control board had a happy light LED that
flashed 1 time per second, and sure enough this corrupted the power supply
and affected some applications. We added a command to turn it off.
Why should lights blink when they are happy?
Your
My first inclination, if I were building a timing receiver, would be to make
the PPS output a nice, symmetrical square wave. But pretty much all GPS
timing receivers output an anorexic, dinky little heroin addicted supermodel
sized pulse (from 1 to 150uS wide is typical).
Feed a 5V 1Hz square wave into a 50OHM load and look at the power drain. Do
the same with a 100uS pulse and smile at the difference.
On Mon, May 14, 2012 at 5:23 PM, Mark Sims hol...@hotmail.com wrote:
My first inclination, if I were building a timing receiver, would be to
make the PPS
Le 14/05/2012 17:23, Mark Sims a écrit :
My first inclination, if I were building a timing receiver, would be to make
the PPS output a nice, symmetrical square wave. But pretty much all GPS
timing receivers output an anorexic, dinky little heroin addicted supermodel
sized pulse (from 1
Mark Azelio,
Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.
http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf
More modern 3-5.5V into 50ohm, 20us.
http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf
Above are two standards
I thought it was only standard practice, now I see that there are standards
and requirements too.
On Mon, May 14, 2012 at 6:33 PM, b...@lysator.liu.se wrote:
Mark Azelio,
Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.
http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf
You don't want it symmetric. If it were then you'd not be able to
notice if it was inverted. You need the asymmetry but the next
question is how asymmetric? In theory all the information is on
the raising edge of the pulse so you cam make it as short as you like
and not loose any information.
Mark Sims wrote:
My first inclination, if I were building a timing receiver, would be to
make the PPS output a nice, symmetrical square wave. But pretty much
all GPS timing receivers output an anorexic, dinky little heroin addicted
supermodel sized pulse (from 1 to 150uS wide is
Mark, Azelio and Björn,
On 05/14/2012 06:33 PM, b...@lysator.liu.se wrote:
Mark Azelio,
Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.
http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf
More modern 3-5.5V into 50ohm, 20us.
OK, thank you for the references.
On Mon, May 14, 2012 at 9:20 PM, Magnus Danielson
mag...@rubidium.dyndns.org wrote:
Mark, Azelio and Björn,
On 05/14/2012 06:33 PM, b...@lysator.liu.se wrote:
Mark Azelio,
Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.
Magnus,
https://assist.daps.dla.mil/quicksearch/ is the search site for
military standards. MIL-188-155 is not found. Could it be another dash
number?
Mike
On 5/14/2012 2:20 PM, Magnus Danielson wrote:
Mark, Azelio and Björn,
On 05/14/2012 06:33 PM, b...@lysator.liu.se wrote:
Mark
On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
https://assist.daps.dla.mil/quicksearch/ is the search site for military
standards.
Hmm. Doesn't find MIL-TGDBP-41. I got this from my (now late) great uncle, Bob
Sedgwick -- who was to hydraulics what I am to computers, only he has a
Maybe the correct number is MIL-STD-188-115?
On Tue, May 15, 2012 at 1:18 AM, Jim Hickstein j...@jxh.com wrote:
On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
https://assist.daps.dla.mil/quicksearch/ is the search site for
military standards.
Hmm. Doesn't find MIL-TGDBP-41. I
I haven't heard that one before. I try to slip in the TLAR check in all
the test procedures I write. When 'they' ask, I look at it and say:
That Looks About Right.
Mike
On 5/14/2012 6:18 PM, Jim Hickstein wrote:
On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
Hi
I would bet that the basic electrical definition of the skinny PPS dates at
least to the mid 50's if not earlier.
Bob
On May 14, 2012, at 3:20 PM, Magnus Danielson wrote:
Mark, Azelio and Björn,
On 05/14/2012 06:33 PM, b...@lysator.liu.se wrote:
Mark Azelio,
Or even 10V into
Mark,
I too once preferred 50% duty cycle 1 Hz signals because they seemed more
natural. But one day during an experiment where I was comparing a large set
of clocks I noticed my lab's digital AC power meter was jumping by tens of
watts every second.
When a dozen DUT generate 1PPS along with
On 5/14/2012 8:21 PM, Tom Van Baak wrote:
one day during an experiment where I was
comparing a large set of clocks I noticed my lab's digital AC power
meter was jumping by tens of watts every second.
The last thing you want
in a precision timing lab is to load your AC line down exactly once a
Hi
If you want to avoid a crazy power supply, you decouple the power to the output
amplifier on the PPS driver. Nice big caps, droop a little during the pulse.
Charge up while there's no pulse.
Bob
On May 14, 2012, at 8:44 PM, Mike S wrote:
On 5/14/2012 8:21 PM, Tom Van Baak wrote:
one day
Tom,
Send me your masers/cesiums and it'll save you the horrendous grief that those
pesky pulsey signals are causing you...
I still like 50:50 duty cycles. It makes das blinkenlights so much easier to
see.
These types of pulses should be routed as open-ended source-terminated
reflected wave switched transmission lines. Power will only flow for
nanoseconds as the pulse travels over the line. There won't be a drop of 50% of
the voltage at the target and no large power spikes in the unit or
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