J.D. Bakker wrote:
At 08:30 +1200 14-08-2010, Bruce Griffiths wrote:
J.D. Bakker wrote:
4) If the ADC(s) have a sufficiently wide full power bandwidth then
one could just sample a pair of quadrature phased 250kHz sinewaves.
As someone who's used to thinking in I/Q I must say I've always
Hi guys,
My project is over and I'll be home on Sunday. The chips that were ordered
and paid for will go out tomorrow and you should see them this coming week.
I know some of you are itchy to get chips ordered and I apologize for
dropping off the grid these past three weeks. I've been on travel
At 19:01 +1200 14-08-2010, Bruce Griffiths wrote:
J.D. Bakker wrote:
At 08:30 +1200 14-08-2010, Bruce Griffiths wrote:
Using a synchroniser allows the TAC output range to be combined
with the coarse timestamp derived by sampling a counter clocked by
the same clock as the synchroniser.
I
J.D. Bakker wrote:
At 19:01 +1200 14-08-2010, Bruce Griffiths wrote:
J.D. Bakker wrote:
At 08:30 +1200 14-08-2010, Bruce Griffiths wrote:
Using a synchroniser allows the TAC output range to be combined
with the coarse timestamp derived by sampling a counter clocked by
the same clock as the
Hi
This isn't my design originally. The 620 ohm resistor in question sources
current into a diode stack. The initial current will vary more from the
tolerance of the diodes than it will from the 1 ohm change ( or 6 ohm = 1%).
The other resistor sets the range on two pots. The pot's tolerance
Hi
Simply a few stories I thought I would share.
Simulate design. Use manufacturer's published models. Build design. Note
differences. Call manufacturer. Answer - switched die three years ago, Ft is
now much better ( now 3x old parts ).
Odd they never mentioned that to people who work for
I have ALWAYS distrusted simulation and computer modeling. And I used to
teach the stuff. GIGO.
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
-John
===
Hi
Simply a few
From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sat, August 14, 2010 7:05:35 AM
Subject: Re: [time-nuts] What's the latest correct PICTIC II Mouser project?-
Heathkid
Hi
This isn't my design
Bob Camp wrote:
Hi
Simply a few stories I thought I would share.
Simulate design. Use manufacturer's published models. Build design. Note differences.
Call manufacturer. Answer - switched die three years ago, Ft is now much better
( now 3x old parts ).
Odd they never mentioned that to
FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or
instructions in a production design is a fool.
If you are that silly, you must fully specify the selection criteria.
-John
===
Bob Camp wrote:
Hi
Simply a few stories I thought I would share.
Simulate
Actually this is a good argument FOR modeling well applied because you can
simulate parts that you cannot buy today but that your vendor will ship under
the same part number a few years down the road. Try doing that in the lab...
I have experienced it so many times it's not even funny. And that
(in production yes I agree)
In research things are different.
You wouldn't mind to make an selection of fets or else
to obtain the very top specs of a certain unique instrument
design as the real final product are the results you
may obtain with that instrument and not at all it's design...
So
Okay Stanley... I've got a Tektronix 370A curve tracer at work. So the
diodes need to be matched? No problem.
So I match the diodes and the resistors to within 0.001%. Are there any
other components that need matched? Also, you mentioned using hemostats as
heatsinks on the diodes while
J. Forster wrote:
FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or
instructions in a production design is a fool.
If you are that silly, you must fully specify the selection criteria.
-John
Or, has their back against the wall and can't do it any other way.
How is
Simulation has some value in determining things like allowable component
tolerances and Worst Case analysis, but those are really production
engineering rather than design.
As to working at brassboard but not in production, it is prudent to check
that your parts are within the production part
I think you missinterpret what I meant. Two examples:
I've seen programmers who use instructions that are not part of a uP
instruction set and are undocumented, just to be clever. If a different
brand of chip, or even a different rev., the chip does something
completely different. These guys
Hi
The PDP-8 had so much code that depended on un-documented instructions that
they had to include them in later versions of the machine
Bob
On Aug 14, 2010, at 12:01 PM, J. Forster j...@quik.com wrote:
I think you missinterpret what I meant. Two examples:
I've seen programmers who
DEC code was a nightmare. Any DG Nova line code would run on any machine.
-John
=
Hi
The PDP-8 had so much code that depended on un-documented instructions
that they had to include them in later versions of the machine
Bob
On Aug 14, 2010, at 12:01 PM, J. Forster
On 08/14/2010 05:48 PM, J. Forster wrote:
Simulation has some value in determining things like allowable component
tolerances and Worst Case analysis, but those are really production
engineering rather than design.
As to working at brassboard but not in production, it is prudent to check
that
On 08/14/2010 06:15 PM, J. Forster wrote:
DEC code was a nightmare. Any DG Nova line code would run on any machine.
This is how we have learned what is a bad idea... and it is now
documented in the guidelines.
Use of the top 8 bits in pointers caused headaches for the 68k machines
when
Hello,
I've read at least two similar stories in Troubleshooting Analog
Circuits by Bob Pease.
One is that it seems that some time ago, National Semiconductor started
shipping LF411s marked as LF351s as an improvement... and as Bob says,
most of the customers probably were happy with that
1) I have no previous experience building precision anything, I'm not an expert.
2) My guess is the design expects quality components and depends on the auto
calibration to correct any component drift.
Short term stability between calibrations is what we want. The absolute value
of
C16 and
On 08/14/2010 06:39 PM, Javier Herrero wrote:
Hello,
I've read at least two similar stories in Troubleshooting Analog
Circuits by Bob Pease.
One is that it seems that some time ago, National Semiconductor started
shipping LF411s marked as LF351s as an improvement... and as Bob says,
most of
Duplicate message without in-line picture.
- Forwarded Message
From: Stanley Reynolds stanley_reyno...@yahoo.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sat, August 14, 2010 11:41:36 AM
Subject: Re: [time-nuts] What's the latest correct PICTIC
One side-effect is that you run into possibilities of oscillation.
This have happend and was the cause of a GPS outage in a US Harbour a
few years back. What was a wise design became an enemy due to a subtle
change in part. Don't recall if the part was replaced by an
equivalent or same
I think this is pretty common with transistors.
A company is making a particular part, then a new, better part comes
along that exceeds the spec of an existing part. So they start putting the
new die into the old package as well as making the new part. Fewer dice to
make likely means cheaper and
I think it was a one-off failure:
http://www.gpsworld.com/gnss-system/signal-processing/the-hunt-rfi-776
-John
===
One side-effect is that you run into possibilities of oscillation.
This have happend and was the cause of a GPS outage in a US Harbour a
few years back. What was a
Line got moved to other side of big ocean. Process got tweaked beta is
now 4x what it was.
I'm pretty sure that military grade parts have paperwork and processes to
cover that case. I expect it costs a lot.
I think the same sort of service is available to high volume customers at a
less
On 08/14/2010 07:10 PM, J. Forster wrote:
I think it was a one-off failure:
http://www.gpsworld.com/gnss-system/signal-processing/the-hunt-rfi-776
This is the incident I described, but notice that there where three
sources, two of which was different antennas with the same amplifier...
both
El 14/08/2010 19:17, Hal Murray escribió:
So maybe it doesn't take a high volume, you just have to get plugged into the
right paperwork flow and then read all the fine print to see if the change is
interesting.
Yes. I'm not a high volume customer, only mid-to-low :) But I receive
the PCNs
Hi
Not so much.
Mil grade just makes sure they qualify a change.
At the time we had the issues the volume on the transistors was quite high. The
cost os screening was still prohibitive. They write the specs with very few
limits for a reason
Bob
On Aug 14, 2010, at 1:17 PM, Hal Murray
Hi
I seem to get weekly notices about a resin changing or a new date code format.
Silicon changes don't seem to be on the same system. That's still better than
it was 30 years back.
Bob
On Aug 14, 2010, at 1:38 PM, Javier Herrero jherr...@hvsistemas.es wrote:
El 14/08/2010 19:17, Hal
I sometimes get some PCNs about process changes on silicon (new process
or new masks). I suppose that depends on manufacturers :)
Regards,
Javier
El 14/08/2010 19:49, Bob Camp escribió:
Hi
I seem to get weekly notices about a resin changing or a new date code format. Silicon
changes don't
Mil specs cover a number of things that are not always in the commercial specs,
but not always, and mil spec parts are going the way of the dodo. Nobody wants
to make them, except the local garage shop which does not mind selling you
$0.02 parts for $60 (quite common) and the worst is that
My last two posts made it to the Archives at febo.com and I guess other members
mail boxes, but not my in box or spam folder. Just wonder why as this doesn't
seem to happen with time-nuts posts by others ? Is this a yahoo mail problem ?
Stanley
___
When I was building spacecraft payloads for the USAF, there was a lot of
resistance to using commercial parts. If something failed, you had to
right back to square one with the acceptance tests, and that took months.
Often we just used stuff from the Apollo QPL.
-John
=
Mil specs
It's being tracked ok by our FireFly-1A right now, see here:
http://www.jackson-labs.com/images/gpsstat.htm
Bye, Said
Sent From iPhone
On Aug 13, 2010, at 14:46, Magnus Danielson mag...@rubidium.dyndns.org wrote:
On 08/13/2010 09:41 PM, Henry Hallam wrote:
Is anyone else having issues with
On 8/14/2010 10:08 AM, J. Forster wrote:
FWIW, IMO any engineer who uses undocumented or uncontrolled parameters or
instructions in a production design is a fool.
If you are that silly, you must fully specify the selection criteria.
-John
This is, easily said, a wonderful goal, and absolute
Right, but that was over days ago. I think my problem was just some
unusually strong multipath.
Thanks
H
On Aug 13, 2010 2:46 PM, Magnus Danielson mag...@rubidium.dyndns.org
wrote:
On 08/13/2010 09:41 PM, Henry Hallam wrote:
Is anyone else having issues with satellite 26 at the moment?
There
On 8/14/2010 12:10 PM, J. Forster wrote:
I think it was a one-off failure:
http://www.gpsworld.com/gnss-system/signal-processing/the-hunt-rfi-776
-John
I wish it were a one off. I and friends at cell ops chase these things
all of the time in the cellular and public safety bands. This one
I can't recall hearing of other wide-area jamming of GPS, but they may not
have reached the media.
Certainly, that incident alone demonstrates the vulnerability of GPS and
argues against the shutdown of LORAN.
-Jo0hn
===
On 8/14/2010 12:10 PM, J. Forster wrote:
I think it was a
On 8/14/2010 10:08 AM, J. Forster wrote:
FWIW, IMO any engineer who uses undocumented or uncontrolled parameters
or
instructions in a production design is a fool.
If you are that silly, you must fully specify the selection criteria.
-John
This is, easily said, a wonderful goal, and
Hi
It's a very rare thing to see jelly bean parts screened for RF parameters. Much
more common to catch and fix an issue at the board level. Pretty rare to see
discrete RF anymore anyway.
Bob
On Aug 14, 2010, at 3:56 PM, J. Forster j...@quik.com wrote:
On 8/14/2010 10:08 AM, J. Forster
I've seen audio range power amps that will oscillate on a part of a cycle
because an output device with a higher fT was installed. Older vintage
parts with the same type JEDEC number never did that.
-John
Hi
It's a very rare thing to see jelly bean parts screened for RF
Hal Murray wrote:
Line got moved to other side of big ocean. Process got tweaked beta is
now 4x what it was.
I'm pretty sure that military grade parts have paperwork and processes to
cover that case. I expect it costs a lot.
I think the same sort of service is available to high volume
In my post below I didn't understand how a constant electromagnet on
the side of the pendulum could adjust the pendulum rate.
Well I've worked it out. Despite common misconceptions pendulum swing
rate is not independent of amplitude. It is to the first order but not
when calculated properly.
The
On Apollo they had file cabinets full of drawers for IBM punch cards,
except each had a microfilm insert.
They could trace a single #6-32 screw back to the mine the iron ore came
from.
-John
=
Hal Murray wrote:
Line got moved to other side of big ocean. Process got tweaked beta
Once I had a batch of JANTX 2NA (with all the paperwork) that were PNPs.
They actually were marked JANTX 2NA. This was for a mil job in the 80's. We
did not fool around with the mil specs back then.
I was a young engineer then and not all that involved in the process, so I was
kept
Attached is my first pictic ii data. It is the difference between the PPS
output
of a Trak 8820 and a Odetics Comsync. Turned on the counter display at the end
of the run to show that most of the data was the interpolars.
Stanley
001073
001075
001072
001072
001066
Not that it really matters for this thread, but, the 2NA was one of the
most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP
complement. - regards - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
-Original Message-
From:
In a message dated 14/08/2010 23:39:20 GMT Daylight Time, mfe...@eozinc.com
writes:
Not that it really matters for this thread, but, the 2NA was one of the
most common NPNs and not PNPs. As I recall, the 2N2907A was its PNP
complement. - regards - Mike
--
Wasn't that
Surely all this is a case of an engineer being able to
read..specifications :-))
Manufactures specify to sell parts, most of the important parameter are
minimum values, and the range is as wide as it can be. If you want a
parameter bracketed then you must specify that when buying and pay the
A method that measures the phase of a damped LC circuit oscillatory
transient triggered by the event to be timestamped:
http://risorse.dei.polimi.it/digital/products/2010/High frequency,high
time resolution time-to-digital converter employing passive resonating
circuits.pdf
http://risorse.dei.polimi.it/digital/pubblications.html
then scroll down
Stanley
- Original Message
From: Bruce Griffiths bruce.griffi...@xtra.co.nz
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sat, August 14, 2010 7:05:03 PM
Subject: [time-nuts]
Hi
Simulation might or might not have helped.
1) Was Vbe breakdown even included in the Spice model
2) If so did it ring bells (rare) or did it just clip without error ( common )
3) Would the same designer who didn't understand it in the first place have
seen it clipping at -5 and concluded
Scroll to the bottom of the first list, or search for 'LC tanks'
Don't know why Bruce's link doesn't work, but I get 404 - file not found.
Bill Hawkins
-Original Message-
From: Stanley Reynolds
http://risorse.dei.polimi.it/digital/pubblications.html
then scroll down
Stanley
-
Yes, I guess it was. I have been in the military business since 1967, and,
certainly seen my share. Besides all of the screw ups, there was one that
really took the cake. I once worked for a company that had to build a radio
that was strictly build-to-print. The original drawing had a mil-spec
When they receive the request for the pdf they check to see what page referred
the request if it wasn't their site then they assume some other web site
leaching bandwidth. This other site pretends to serve the file but in fact it
is
still served by them. This pretend site doesn't pay for the
stanley_reyno...@yahoo.com said:
When they receive the request for the pdf they check to see what page
referred the request if it wasn't their site then they assume some other
web site leaching bandwidth. This other site pretends to serve the file but
in fact it is still served by them.
?? The yellow banded R means established reliability. I see no reason why
the NF should be any different then one w/o the yellow band. They are the
same part, only one is tested more.
Not white band perchance?
-John
===
Yes, I guess it was. I have been in the military business since
oh well no credit for me, but what happened to the missing space when so many
other spaces made it thru as %20 ?
- Original Message
From: Hal Murray hmur...@megapathdsl.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sat, August 14, 2010 8:27:09
I only mentioned the yellow band because of reliability. Seems like the
original resistor was 220 ohms and the one that actually met the required NF
was 330 (or the other way around). So, it was not the yellow band that had
to be changed. - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ,
Hi
I think it was the value that changed. Somebody typo'd 10k at 10 ohms
Bob
On Aug 14, 2010, at 9:42 PM, J. Forster j...@quik.com wrote:
?? The yellow banded R means established reliability. I see no reason why
the NF should be any different then one w/o the yellow band. They are
Somebody read the resistor code backwards then? Easy enough if you don't
know what you're doing w/ Established Reliability parts.
-John
=
I only mentioned the yellow band because of reliability. Seems like the
original resistor was 220 ohms and the one that actually met the
My guess as to what the data may indicate is performance of the 10 Mhz 20PPM
PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto
calibrate off. Fatness of the line/width maybe PICTIC error. Note graph seems
to
show me leaving the room and returning via the outside
Hi
Is it shielded from drafts?
Bob
On Aug 14, 2010, at 10:12 PM, Stanley Reynolds stanley_reyno...@yahoo.com
wrote:
My guess as to what the data may indicate is performance of the 10 Mhz 20PPM
PICTIC internal oscillator, need to repeat test with precision 10Mhz and auto
calibrate
One problem is the door opens don't move in the same direction, a rain storm
did
cool things off outside during the test but it was still warmer outside both
times.
I will place a box over the Pictic and rerun the test.
Stanley
- Original Message
From: Stanley Reynolds
Mea Culpa.
Below is a link to the paper using SAW filters to achieve a sub ps time
interval interpolator noise:
http://cddis.gsfc.nasa.gov/lw16/docs/papers/las_4_Prochazka_p.pdf
And the associated presentation:
http://cddis.gsfc.nasa.gov/lw16/docs/presentations/las_4_Prochazka.pdf
Bruce
A few preliminary measurements here (I'm working on getting some software
support together):
http://www.ke5fx.com/pictic.htm
-- john, KE5FX
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Stanley Reynolds
Sent: Saturday, August 14,
John glad you are getting good results and have something to
compare to. Back to
me who doesn't have any knowns but lots of guessing. Attached is
a run with a
box cover over the pictic, run is shorter ~ 800 seconds but the
box does look
like it helps.
I need to do a lot more testing but
Here's your first run in red, compared to your second one in green...
-- john, KE5FX
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Stanley Reynolds
Sent: Saturday, August 14, 2010 3:28 PM
To: time-nuts@febo.com
Subject:
Thanks for looking at my data that was what I was fishing for all along :-)
I was looking at the article:
A Small Dual Mixer Time Difference (DMTD) Clock Measuring System W.J. Riley
Richard posted
And thinking it would be nice to do the DSS and Mixer boards to go with the
pictic II.
Or
Yes don't think the box did do much. I do have two different dividers here I
just need too finish the projects I have.
Thanks again,
Stanley
- Original Message
From: John Miles jmi...@pop.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sat, August
Thanks for looking at my data that was what I was fishing for all
along :-)
You can import it the same way, actually -- install the TimeLab beta at
www.ke5fx.com/timelab/setup.exe and use File-Import ASCII Phase Data to
read your file. Set Nominal Frequency to 1, Numeric Field # to whichever
An ACAM GP2 evaluation board is available here:
http://shop.omegacs.net/
However an ACAM GP1 would probably be a better fit in a DMTD with a beat
frequency of 10Hz or more as the GP1 has a measurement range of 200ms.
Bruce
Stanley Reynolds wrote:
Thanks for looking at my data that was what
Bruce Griffiths wrote:
An ACAM GP2 evaluation board is available here:
http://shop.omegacs.net/
Ignore this link as I omitted to read the fine print
However an ACAM GP1 would probably be a better fit in a DMTD with a
beat frequency of 10Hz or more as the GP1 has a measurement range of
76 matches
Mail list logo
