Dear Tom, Luciano, all,
Thank you for your comments. The Sulzer is not intended to be used as a
high accuracy standard. The oscillator fits nicely to some old radio's
;-) However, I think (not measured) that stability of the oscillator is
better then the average stability of a modern low budge
In message <5058061f.6040...@clanbaker.org>, Michael Baker writes:
>I was wondering, after seeing some 100 watt LED series
>wired assemblies that were listed at 30-34 VDC @ 2.9A if a
>number of LEDs could be wired in series and powered directly
>from a rectified 110 VAC power source.
You wouldn't
Hi Jeroen,
I have a paper copy of the SULZER 5A (the 5 MHz version) and of the
Racal. If you want I can make a paper copy and send you it by postal
service. I do not know if Tom have a pdf copy of the manuals. Me too
have these OCXO for passion. I suggest you to buy e ceep GPSDO and use
it as
> Hm Maybe if an 1:1 isolation transformer is used
>except that it would be too heavy and large
>
>Mike Baker
Mike,
As long as one is spending on a transformer.. might as well use a
step down transformer and use lower voltage lights!
Raj
___
Dear Luciano,
Thank you for your offer to make copies of the manuals. If it is OK with
you, I can make a PDF-scan of the manuals and send them to KO4BB to be
put on his website. I will contact you offlist for my address details.
Luckily enough I have a GPSDO, but... the GPSDO is at home and t
Hi
I suspect those same 120Hz sensitive people would not be able to watch TV or
a movie :)
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chris Albertson
Sent: Tuesday, September 18, 2012 1:35 AM
To: Discussion of precise time
On 9/17/2012 6:03 PM, time-nuts-requ...@febo.com wrote:
OK, you can test a VP Oncore GPS receiver alone if you have a mean to
translate the TTL serial port to a regular RS232 for the PC. This can be
done with a MAX232 chip (or equivalent). Then the pinout (refer to the
FYI, I've had really goo
Time-Nutters--
OK-- So flicker would be objectionable running off a
rectified 110VAC line.My thinking was to find
a way around needing a current limiter that would
waste energy as heat. Rectifying (and some filtering)
of the 110AC line seemed to be one approach.
I am thinking of building
Shouldn't be a problem with the standard UV -> phosphor style white
LED's that are on the market today. The phosphor has a hang time that
runs into the minutes, if all of the glowing LED bits in my lamps are
an indication. They glow softly for several minutes after turn off.
-Chuck Harris
Chri
In message , "Bob Camp" writes:
>I suspect those same 120Hz sensitive people would not be able to watch TV or
>a movie :)
I suggest you either carry out a couple of experiments yourself, or
go a little easy on the irony.
CRTs, and LCDs go out of their way to avoid flickering using physical
o
Boy I have been staying clear of this discussion.
Pretty sure they make drop in led tubes now at $$$
Its funny we speak to a 100 watt lamp. But for a led that would be
something like 24 watts.
It makes no sense to speak in watts. Instead Lumens. I think we want the
luminisity of a 100 watt incandes
Hi
The shutter on a conventional movie projector is very much an on / off
device. They run well below 120Hz. The phosphors in a white LED are at least
as long persistence as those in a TV set. There are a *lot* of TV's out
there that refresh at 60 Hz or less.
Bob
-Original Message-
From:
I'm looking for info on behavior of a PLL (with VCXO) when the reference
comes and goes periodically. When the reference is gone, the PLL will
"flywheel" according to whatever the loop filter does. (we can turn off
the "input" to the filter, so we're not trying to track noise)..
What I'm parti
Hi Paul;
I started thinking about this project because we are installing a new EMC room
at work and thought we could use totally eliminate lighting as a noise source
with LED lighting. Allowing lighting during even the most precise measurements.
While researching I ran across some amazing items
TTL to USB serial adapters on ebay for very reasonable.
Don
Dan Kemppainen
>
> On 9/17/2012 6:03 PM, time-nuts-requ...@febo.com wrote:
>> OK, you can test a VP Oncore GPS receiver alone if you have a mean to
>> translate the TTL serial port to a regular RS232 for the PC. This can
>> be
>> done wit
won't it depend almost entirely on the charge pump filter?
Don
Jim Lux
> I'm looking for info on behavior of a PLL (with VCXO) when the reference
> comes and goes periodically. When the reference is gone, the PLL will
> "flywheel" according to whatever the loop filter does. (we can turn off
> the
On Tue, Sep 18, 2012 at 5:56 AM, Michael Baker wrote:
> Time-Nutters--
>
> OK-- So flicker would be objectionable running off a
> rectified 110VAC line.My thinking was to find
> a way around needing a current limiter that would
> waste energy as heat.
Even if flicker were not a problem what h
Hi
Gardner in "Phaselock Techniques" has figure 4.8 that is a pretty good
starting point.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Jim Lux
Sent: Tuesday, September 18, 2012 11:29 AM
To: Discussion of precise time and frequen
Usually in a regular PLL the missing reference should pull the output at
the lowest voltage: as if the input frequency is too high. It helps if the
charge pump output can be disabled when the reference stops: in this case
the output voltage will go down following the droop of the
integrator/filter.
Hi
A LED is indeed a diode. It's current changes pretty fast as voltage
changes. It's voltage drop also highly temperature dependant. Driving one
with a constant voltage and no current limiting is a very tough proposition.
You would need to feedback the temperature of the device and adjust the
sup
Hi
If you go the eBay route, the FTDI chip set (as mentioned in the links
below) is very much the one you want to get. There are several other chip
sets out there. I have yet to see one that's as solid as the FTDI's.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nu
You really want to drive the LEDs with switcher designs typical in battery
chargers, basically hysteretic current output. Prior to LIon batteries (which
are voltage sensitive), the old nicad/NiMH chargers used the hysteretic scheme.
If you want a simpler switcher, you can take the garden vari
On Tue, Sep 18, 2012 at 5:21 AM, Bob Camp wrote:
> Hi
>
> I suspect those same 120Hz sensitive people would not be able to watch TV or
> a movie :)
In the old CRT type TV sets, the phosphor has some persistence.
Movies are modulated with a square waves, the frame blinks off and
goes dark then
If you break the DC control chain of the PLL with a A2D and a controller and
back with a D2A .. you would program the control with any kind of behavior you
want. Just a thought!
Raj, vu2zap
At 18-09-2012, you wrote:
>I'm looking for info on behavior of a PLL (with VCXO) when the reference comes
Dan Kemppainen wrote:
On 9/17/2012 6:03 PM, time-nuts-requ...@febo.com wrote:
OK, you can test a VP Oncore GPS receiver alone if you have a mean to
translate the TTL serial port to a regular RS232 for the PC. This
can be done with a MAX232 chip (or equivalent). Then the pinout
(refer to the
FY
Hi
A white LED is like a fluorescent bulb. The actual LED runs at UV and there
are phosphors in it to convert the UV to various colors of visible light.
The phosphor mix determines the color balance of the LED. It also adds
persistence to the output, just like a CRT.
I do very much agree that yo
li...@rtty.us said:
> There are a *lot* of TV's out there that refresh at 60 Hz or less.
Many years ago, we had a busted fluorescent light at work. I could see the
flicker out of the corner of my eye. I found it annoying, so I'm a firm
believer that some people can see flicker in some condit
If you all check, they are using LEDs in traffic signals now by the
thousands. These are variations of multiple LEDs used in these signals and
they
are all powered by 115vac thru the traffic controllers.
Joe k3wry
In a message dated 9/18/2012 1:28:18 A.M. Eastern Daylight Time,
mp...
Hi
... and if you take a hammer to one, they have a cheap little switcher built
right into the base of the bulb.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of k3...@aol.com
Sent: Tuesday, September 18, 2012 1:24 PM
To: time-nuts@
On 9/18/12 8:39 AM, Don Latham wrote:
won't it depend almost entirely on the charge pump filter?
Classic PLL with a mixer, not with a Phase Frequency Detector and charge
pump..
But yes, it depends in large part on the loop filter, but also on the
behavior of the oscillator.. (i.e. where do
I think that even flicker you cannot consciously see, subconsciously can have
effects of mental fatigue and eye strain. This is why most florescent fixtures
are in pairs firing at 180 degrees.
An optical sensor on a scope should allow the power supply to be tweaked for a
steady light.
Thomas
On 9/18/12 6:54 AM, Bob Camp wrote:
Hi
The shutter on a conventional movie projector is very much an on / off
device. They run well below 120Hz.
Actually, the typical movie projector uses a rotary shutter which runs
at twice the frame rate (e.g. 48 flashes/second) and is hardly a fast
transi
I remember reading that Hollywood played with faster frame rates and found a
substantial number of people experience motion sickness.
Thomas Knox
> Date: Tue, 18 Sep 2012 10:51:07 -0700
> From: jim...@earthlink.net
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Hi Power LED Light power s
The local sandwich shop that I frequent recently switched to LED lighting. When
I walk up to the counter I can see the flicker when people's hands are moving.
The same applies for LED taillights when a vehicle is moving as well as newer
LED tower lighting.
Bob
On Sep 18, 2012, at 13:15, Hal
If you take your garden variety boost converter and place a resistor as the
load, the current in the inductor is regulated. (Current is vreference over
this resistor value.) All these dedicated LED drive chips do is reduce the
voltage across the resistor to improve efficiency. In addition, they
On 18 Sep, 2012, at 12:42 , Chris Albertson wrote:
> On Tue, Sep 18, 2012 at 5:21 AM, Bob Camp wrote:
>> Hi
>>
>> I suspect those same 120Hz sensitive people would not be able to watch TV or
>> a movie :)
>
> In the old CRT type TV sets, the phosphor has some persistence.
> Movies are modul
You have apparently not tried any modern/quality LED bulbs. The Sylvania
Ultra series have a 95 CRI (color rendering index). Bridgelux makes some
arrays with a CRI over 98. I defy you to tell the difference between the
output of those bulbs (or any LED with a CRI over 85) and halogens. My
On 9/18/2012 1:48 PM, time-nuts-requ...@febo.com wrote:
In the old CRT type TV sets, the phosphor has some persistence.
Movies are modulated with a square waves, the frame blinks off and
goes dark then blinks on. But the LED's brightness is fast enough to
track the sine wave and would be brigh
I would hence believe that a 50 Hz flicker must be pretty close to the edge of
what can be perceived, so I'm having trouble believing that a flicker at more
than twice that rate would be perceptible at all by anyone.
Oh, but it is. A couple of years ago I bought one of the Chinese 30 LED spot
There are ways for the flicker to be more evident. Don't laugh, but
chewing something hard like a pretzel can bring out the flicker.
Basically you can get beat patterns between the vibration of your eye
and the light flicker.
There is a common problem with DLP projectors that use color wheels.
On 18 Sep, 2012, at 15:06 , John Lofgren wrote:
>
> I would hence believe that a 50 Hz flicker must be pretty close to the edge
> of what can be perceived, so I'm having trouble believing that a flicker at
> more than twice that rate would be perceptible at all by anyone.
>
>
> Oh, but it is
On Tue, Sep 18, 2012 at 2:27 PM, gary wrote:
>
> A similar problem occurs with matrixed LED displays mounted on machinery
> that has vibration. Very common in industrial controls since they like LEDs
> for readability.
>
This is very evident on the new L train cars in Chicago. They have a
multico
That's because the signs are scanned/multiplexed displays. It is not 60/120
Hz flicker.
Tom
- Original Message -
From: "Ryan Szekeres"
To: "Discussion of precise time and frequency measurement"
Sent: Tuesday, September 18, 2012 3:38 PM
Subject: Re: [time-nuts] Hi Power LED Light po
Hi
Oddly enough western New York State also had a 25 Hz grid. Something about
Niagara Falls / George Westinghouse comes to mind. If as a youngster you
rummaged around in the attic you could indeed find 25 Hz gear still sitting
up there. Wish I'd kept it rather than parted it out.
Bob
-Origin
On Tue, Sep 18, 2012 at 2:46 PM, Tom Miller wrote:
> That's because the signs are scanned/multiplexed displays. It is not 60/120
> Hz flicker.
>
> Tom
>
Something new to research. Thanks!
--
Ryan Szekeres
KB9TQN
___
time-nuts mailing list -- time-nuts
On 09/18/2012 05:28 PM, Jim Lux wrote:
I'm looking for info on behavior of a PLL (with VCXO) when the reference
comes and goes periodically. When the reference is gone, the PLL will
"flywheel" according to whatever the loop filter does. (we can turn off
the "input" to the filter, so we're not try
On 09/18/2012 06:15 PM, Bob Camp wrote:
Hi
Gardner in "Phaselock Techniques" has figure 4.8 that is a pretty good
starting point.
In general, it's a really good book to read. Gardner covers this field
well, and even if some of the stuff I needed wasn't in there, it was an
excellent startingp
That is a very fun prank to do.
Show someone an o'scope with a flat line on it and hand them a pretzel or
carrot.
Tell them that you have implanted several sensors into their brain and you
want to calibrate them starting with mandibular vibration.
I have seriously freaked some people out with
Only one LED per segment is on. They are arranged in a matrix -- keeps the
pin count down to a dull roar.
http://www.instructables.com/id/LED-Dot-Matrix-Display/
http://www.electronics-lab.com/projects/misc/013/index.html
DaveH
> -Original Message-
> From: time-nuts-boun...@febo.com
Has anyone tried the fluorescent replacement LED tubes? Apparently you remove
the ballast from the fixture and power the tube from the 120V AC line.
Any chance these would reduce the noise in a lab from conventional fluorescent
tubes?
Thanks.
<>___
time
dennis.c.fergu...@gmail.com said:
[context is flicker from light bulbs running on 25 Hz power]
> I would hence believe that a 50 Hz flicker must be pretty close to the edge
> of what can be perceived, so I'm having trouble believing that a flicker at
> more than twice that rate would be perceptib
The LED traffic signals around here are super noisy electrically. They
rip up my mobile gear from the AM broadcast band through 2 meters any time
we are close to a traffic light. Some are worse than others. If you can find
out who makes them then avoid that manufacture like the plague.
Al,
Fellow Time Nuts,
in the last week we had more than 50 emails concerning Fedex versus UPS
shipping and how to package something, now we have a similar number of emails
about LED lighting.
I hope we can end this thread soon, or move it to another discussion group.
I for one am getting real
I spent many years as an electrician/electronics technician in a
performing art center. Many artists would simply not practice or perform
under fluorescent light because of the supposed flicker issue. Many of those
who had no choice complained about it. Dancers were the worst.
Al, k9si
On 9/18/12 1:49 PM, Magnus Danielson wrote:
On 09/18/2012 05:28 PM, Jim Lux wrote:
I'm looking for info on behavior of a PLL (with VCXO) when the reference
comes and goes periodically. When the reference is gone, the PLL will
"flywheel" according to whatever the loop filter does. (we can turn of
On 9/18/12 10:57 AM, Tom Knox wrote:
I remember reading that Hollywood played with faster frame rates and found a
substantial number of people experience motion sickness.
Not so much the frame rate, but generating imagery that isn't "realistic"..
your eye expects motion blur (particularly
On 9/18/12 9:48 AM, Raj wrote:
If you break the DC control chain of the PLL with a A2D and a controller and
back with a D2A .. you would program the control with any kind of behavior you
want. Just a thought!
That is exactly what we do... the PLL is actually implemented digitally
(DAC driving
I've tried that with a replacement tube that worked with the original
ballast, all you had to do was remove the starter.
The results were horrible. The tube was about a metre above my scope and
waving the probe about showed horrible spikes and damped oscillatory
waveforms up to several volts in am
On Tue, Sep 18, 2012 at 7:49 PM, Morris Odell wrote:
> The discussion about LED flicker was interesting. As I understand it the
> human eye can act as a peak detector
Actually the rods and cones in the retina only respond the changes in
brightness. the eye constantly moves so that the image al
Hi:
Does anyone know who made the crystal for the HP-106 and / or Sulzer
oscillators?
Is Bliley Electric Company still in business? They use to sell a 5th
overtone precision quartz crystal for "frequency standard" use.
Where could you find the ultimate crystal today for a frequency standar
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