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Today's Topics:
1. BNC Question (brucekar...@aol.com)
2. Re: BNC Question (Rick Karlquist)
3. Re: BNC Question (Chuck Harris)
4. Re: Datronn Wavetek 4910 (Oz-in-DFW)
5. Re: PIC processor CTMU module used for sub-ns TIC
applications? (cook michael)
6. Re: PIC processor CTMU module used for sub-ns TIC
applications? (Bruce Griffiths)
7. Re: PIC processor CTMU module used for sub-ns TIC
applications? (Poul-Henning Kamp)
8. Re: LightSquared gets at least some political attention
(Magnus Danielson)
9. Vectron Oscillator Model 217-5604 Info search (Arnold Tibus)
----------------------------------------------------------------------
Message: 1
Date: Sat, 16 Apr 2011 21:02:20 EDT
From: brucekar...@aol.com
To: time-nuts@febo.com
Subject: [time-nuts] BNC Question
Message-ID: <13449.219ed47.3adb9...@aol.com>
Content-Type: text/plain; charset="US-ASCII"
An Amphenol document discussing the mating compatibility of their 50-ohm
and 75-ohm BNC connectors can be found here
_http://www.amphenolrf.com/products/bnc.asp?N=0&sid=46B11E806D75617F_
(http://www.amphenolrf.com/products/bnc.asp?N=0&sid=46B11E806D75617F) .
Bruce, KG6OJI
------------------------------
Message: 2
Date: Sat, 16 Apr 2011 18:55:34 -0700
From: "Rick Karlquist" <rich...@karlquist.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Subject: Re: [time-nuts] BNC Question
Message-ID:
<01ec8a7b0e22e9d28beeb4002ef88181.squir...@webmail.sonic.net>
Content-Type: text/plain;charset=iso-8859-1
Oz-in-DFW wrote:
BNCs can be as good as TNCs when properly applied, but the bayonet
mechanism allows too much mechanical alignment play for reasonable
reliability past a GHz or so. If they are properly installed and the
cable is not allowed to put a radial or significant tensile load they
perform as well as a TNC and close to an N. For all that, I won't use
FWIW:
The guts of a BNC/TNC is very similar if not identical to a type N,
which is good for at least 12.4 GHz. The Agilent 13 GHz scopes
have "precision" (IE tight fitting) BNC connectors on the probes.
All of which of course doesn't mean the Asian BNC's you bought
at the hamfest are any good.
Rick N6RK
------------------------------
Message: 3
Date: Sun, 17 Apr 2011 00:04:48 -0400
From: Chuck Harris <cfhar...@erols.com>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] BNC Question
Message-ID: <4daa66e0.6070...@erols.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Rick Karlquist wrote:
FWIW:
The guts of a BNC/TNC is very similar if not identical to a type N,
which is good for at least 12.4 GHz. The Agilent 13 GHz scopes
have "precision" (IE tight fitting) BNC connectors on the probes.
All of which of course doesn't mean the Asian BNC's you bought
at the hamfest are any good.
Rick N6RK
There is a very significant difference between the N and the BNC
construction with regards to what is the insulator in the transition
section between the male and female connector: With the BNC (and TNC)
connector(s), the space is filled with an interdigitated plastic
dielectric. With the N, the space is filled with air.
-Chuck Harris
------------------------------
Message: 4
Date: Sat, 16 Apr 2011 23:18:56 -0500
From: Oz-in-DFW <li...@ozindfw.net>
To: Discussion of precise voltage measurement <volt-n...@febo.com>
Cc: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] Datronn Wavetek 4910
Message-ID: <4daa6a30.8010...@ozindfw.net>
Content-Type: text/plain; charset=ISO-8859-1
I suspect this was an inadvertent mis-post to time-nuts intended for
volt-nuts
On 4/16/2011 4:01 PM, WB6BNQ wrote:
JF,
Not meaning to be unfriendly, BUT this list * * IS NOT * * a "general"
test equipment repair faculty.
The unit in question is a series of regulated voltage sources that are
adjustable. Being adjustable means it is not absolute. Equally so, your
3458A is, likewise, adjustable and is totally dependent upon the
references it was adjusted against. Besides the type of wires and
corresponding thermals in your connection arrangement, you have the
ambient
temperature in the mix.
As you state you just bought it used, how do you expect it to be perfect
? It has most likely been kicked around for a while and with no known
calibration history, those values do not surprise me at all. Do you
really think your 3458A is perfect ? Is your "cal lab" really up to the
job ? If so, then send your new BOX to them and compare after you
get it back.
Your question "What is the reference of the replacement batteries ?" is
ambiguous. If you meant the part number, then open it up and do the
research. As for the batteries, except for mounting issues, they are
just a power source for all the different regulated supplies that feed
those front panel connectors.
Bill....WB6BNQ
JF PICARD wrote:
I am looking for the service manual of the Datron Wavetek 4910. I have
just got this reference standard from Ebay : is it normal to see 3
cells at 2 or 3 ?v under 10V and one at + 13?v (23?C with 3458A just
calibrated yesterday) or it is an obvious problem with the cell (the
third one) ? What is the reference of the replacement batteries ?
Thanks.
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--
mailto:o...@ozindfw.net
Oz
POB 93167
Southlake, TX 76092 (Near DFW Airport)
------------------------------
Message: 5
Date: Sun, 17 Apr 2011 07:34:29 +0200
From: cook michael <michael.c...@sfr.fr>
To: beale <be...@bealecorner.com>, Discussion of precise time and
frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] PIC processor CTMU module used for sub-ns TIC
applications?
Message-ID: <4daa7be5.5060...@sfr.fr>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Le 17/04/2011 00:20, beale a ?crit :
The application note merely asserts the possibility, but neglects to
present a specific design. Has anyone here attempted to use a PIC CTMU in
that way?
The app note doesn't give a complete design, but the principle of
precision time measurement is explained with a corresponding block
design under "Precision Time Measurement". It relies on A/D sample and
hold capacitor charging between 2 edge detections. Worth looking into
though. I expect the data sheets will show how to implement it and
define its limitations.
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------------------------------
Message: 6
Date: Sun, 17 Apr 2011 17:37:54 +1200
From: Bruce Griffiths <bruce.griffi...@xtra.co.nz>
To: beale <be...@bealecorner.com>, Discussion of precise time and
frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] PIC processor CTMU module used for sub-ns TIC
applications?
Message-ID: <4daa7cb2.8060...@xtra.co.nz>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
beale wrote:
I see Microchip application note AN1375 at
http://ww1.microchip.com/downloads/en/AppNotes/01375a.pdf suggests that
the CTMU module included in some recent PIC parts, for example
PIC18F46J11 can be used as a TIC building block for interpolating time
intervals with sub-ns resolution. I gather this module was originally
designed for touch sensing applications; they also mention measurement of
absolute and relative capacitance.
The application note merely asserts the possibility, but neglects to
present a specific design. Has anyone here attempted to use a PIC CTMU in
that way?
I've been studying Richard McCorkle's PICTIC-II design (1) with an eye to
implementing the digital parts in a CPLD, and so far have a start/stop
counter working (2). I haven't yet started on the analog part of the
circuit, but now I'm wondering if Microchip has already done the work for
me, in a $4 part ? (3)
(1) http://www.ko4bb.com/dokuwiki/doku.php?id=precision_timing:pictic
(2) http://bealecorner.org/best/measure/time/CPLD-TIC/
(3)
http://parts.digikey.com/1/parts/1671850-ic-pic-mcu-flash-64kb-44-tqfp-pic18f46j11-i-pt.html
Spotted that feature several months ago.
It should work well to within the limits of the CTMU module design.
IIRC the external capacitance needs to be kept low for sub ns resolution.
Crosstalk from within the PIC chip as well as ground and Vcc bounce may
be an issue.
A statistical fill the buckets linearity test will allow evaluation the
integral and differential nonlinearities in such a TDC.
In this case a relatively unstable source is required to enable such
testing.
One of the resistance tuned silicon oscillators available from LTC and
elsewhere should work well.
Bruce
------------------------------
Message: 7
Date: Sun, 17 Apr 2011 05:42:29 +0000
From: "Poul-Henning Kamp" <p...@phk.freebsd.dk>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Cc: beale <be...@bealecorner.com>
Subject: Re: [time-nuts] PIC processor CTMU module used for sub-ns TIC
applications?
Message-ID: <21853.1303018...@critter.freebsd.dk>
Content-Type: text/plain; charset=ISO-8859-1
In message <4daa7be5.5060...@sfr.fr>, cook michael writes:
Le 17/04/2011 00:20, beale a =E9crit :
The application note merely asserts the possibility, but neglects to
present a specific design. Has anyone here attempted to use a PIC CTMU
in that way?
I tried it when I had a pic18f25j50 in my breadboard anyway, but
failed to get reliable results. If you want to play with it, I
suggest you make an actual PCB and clean/coat it very carefully
to avoid leaking current or electrostatic fields.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by
incompetence.
------------------------------
Message: 8
Date: Sun, 17 Apr 2011 09:29:12 +0200
From: Magnus Danielson <mag...@rubidium.dyndns.org>
To: time-nuts@febo.com
Subject: Re: [time-nuts] LightSquared gets at least some political
attention
Message-ID: <4daa96c8.7020...@rubidium.dyndns.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 04/17/2011 12:45 AM, Charles P. Steinmetz wrote:
John wrote:
IMO, your crack about NTSC is unjustified.
IMO, NTSC color was a very elegant engineering solution to backwards
compatability. Without that, we could well be still watching B&W.
The other contemporary backward-compatible solutions -- PAL and SECAM --
did not suffer from the color drift that plagued color NTSC. So, there
were superior methods of backward-compatible color insertion available
and the FCC still chose the NTSC method. Bad decision, which saddled the
US with inferior broadcast video for 60 years -- just as choosing 8VSB
has done for digital video in the US.
This is why "Never Twice Same Colour" became an alternative expansion of
NTSC. If you look at PAL you will see that it was made more resistive to
multipath phase errors by alternating the polarity of one of the colour
difference signals on every other field, which by interlacing will cause
the opposite turn in the colour spectrum on the next line so on average
they will cancel.
As I recall it, the original choice of colours for the NTSC caused greif
over time and was in practice changed later. A quick check on the NTSC
wikipedia article verifies this.
So NTSC didn't get it all quite right.
Also, stepping from 60 fields per second to 60/1,001 fields per second
still haunts us when PAL stayed at 50 fields per second. For SD-SDI they
where able to match them up to a common 270 MBd, but for HD-SDI we have
1,485 MBd and 1,485/1,001 MBd. This had to be solved with dual
oscillators in the first products, then with a re-synthesis chip and now
there is oscillators with dual frequencies which is good enough. This
1,001 factor also comes into play with some audio production... so this
factor remains with changed underlying TV system.
So some of their particular technology choices isn't a good long term
solution.
NTSC did manage to get a colour solution out of the door, but it wasn't
the best technological solution for its day.
Cheers,
Magnus
------------------------------
Message: 9
Date: Sun, 17 Apr 2011 10:22:09 +0200
From: Arnold Tibus <arnold.ti...@gmx.de>
To: Time-Nuts <time-nuts@febo.com>
Subject: [time-nuts] Vectron Oscillator Model 217-5604 Info search
Message-ID: <4daaa331.3010...@gmx.de>
Content-Type: text/plain; charset=ISO-8859-15
Hi,
is there anybody in the group who could give me informations of the
Vectron Crystal Oscillator Model 217-5604?
I got two of this type with 9.995985 MHz and 9.99597 MHz and I think
these would be good for mixing 10 MHz units down to 4 kHz Audio for
measurement purpose.
Can dim. is 2" x 2" x 3" with 4 1/4" studs. Electrical connection is
provided by 7 solder studs and the output connector is an F-SMA.
It looks like that only 2 contacts were used, so maybe these are not
OCXOs and not voltage contollable.
Unfortunately I cannot find anything about this Model in the WWW.
It would be great if anybody could give me some data.
Many thanks in advance,
regards
Arnold
------------------------------
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End of time-nuts Digest, Vol 81, Issue 57
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