HDTenEightyP/NetNews huggingface dataset:
From: ahaley@eoe.co.uk (Andrew Haley)
Newsgroups: sci.electronics,rec.audio,alt.folklore.computers
Subject: Re: Life after CDs
Date: 24 Jul 92 18:51:23 GMT
Organization: EO Europe Limited, Cambridge, UK
X-Newsreader: Tin 1.1 PL3

smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC) writes:
: In article <1992Jul23.041115.20377@bilver.uucp>, bill@bilver.uucp (Bill Vermillion) writes:
: 
: 	> 
: 	> They [Sony] couldn't break themselves of thinking 12" - ala LP's or
: 	> LDs.  I took Philips to come up with an under 5" disk.  And
: 	> then Sony and Philips got together and standardized on the
: 	> current 12cm disk that sped'ed out at 74 minutes.
: 	> 
: 	> 
: There is a story (probably apocryphal, anyone know?) that the 74 minutes
: time was chosen because it was just long enough to hold the Sony MD's wife's favourite piece of classical music...
: 
: Steve 

No, it's not apocryphal, but you've got a slightly distorted version.
The person was Akio Morita, not his wife, and one of his favourite
pieces is Beethoven's Ninth, which, if played fairly slowly, can be 74
minutes long. The Dutch engineers at Phlips supposedly wanted an
hour, which sounded like a nice round figure.

Incidentally, one of Morita's best friends was Leonard Bernstein.  I
wonder how long his recorded performances of the Ninth are.  Anyone
know?

Andrew.
From: jimc@tau-ceti.isc-br.com (Jim Cathey)
Newsgroups: sci.electronics
Subject: Re: RS-422A and RS-423.  Whats the diff?
Date: 22 Jul 92 22:32:00 GMT
Organization: ISC - Bunker Ramo, Spokane, WA

In article <Brsw0q.FKD@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>>What exactly is the difference between an RS-422A and an RS-423
>>standard?
>...
>If it's talking to Macs, it is *not* using RS-422, because the Macs
>don't speak RS-422.  They speak RS-423 (despite some misconceptions
>in some early Apple documentation).

So far as I know, RS-422 implies differential signals (2 wires per
signal) and RS-423 implies single-ended (1 wire per signal, plus a
global ground).  There may be some requirements for voltage swing above
and below 'ground', but true RS-422 shouldn't care one bit until you get
outside whatever the specified common-mode voltage range is for RS-422
(I seem to remember around +/- 10V).  I know that our RS-422 devices
used +5V only on the drivers, and I seem to remember that this is
allowed by the spec.  RS-423 uses the same voltage swing as RS-422, but
only on one line.  It is much less noise-immune, and is not good for the
thousands of feet of wire that RS-422 can drive (depending on the
signalling rate).  We routinely used 3000 feet RS-422 at 9600 baud over
shielded twisted-pair wiring in one of our older products.  Many RS-422
driver chips have a mode pin by which you can get twice as many RS-423
transmitters by strapping it so. 

I used to have the spec around, and I know I read it once, but I
can't find it anymore.

That said, both the Mac and the 68030 NeXT's use RS-422 for Rx and
Tx signals, and RS-423 for any others (DTR).  The 68040 NeXT's dropped
the Rx+ and Tx+ lines in favor of DCD and CTS (both RS-423).  So, the
new NeXT's are all RS-423 and all Macs use _both_, but do use RS-422
for the interesting ones.  None of these systems can multiplex, though,
because the Tx drivers are not enabled with RTS, they are strapped on
all the time (I think).

I don't remember if the Mac used +/- 5V for the drivers or +5V only.
Certainly -5V is available on the circuit card.

-- 
+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC-Bunker Ramo
! II      CC     !  TAF-C8;  Spokane, WA  99220
! IISSSS  CC     !  UUCP: uunet!isc-br!jimc (jimc@isc-br.isc-br.com)
! II      CCCCCC !  (509) 927-5757
+----------------+
			"PC's --- the junk bonds of the computer industry"
From: Chris_F_Chiesa@cup.portal.com
Newsgroups: sci.electronics
Subject: Re: Caller ID
Date: Sat, 25 Jul 92 07:00:51 PDT
Organization: The Portal System (TM)
Distribution: na
  <1992Jul20.170049.3206@krfiny.uucp>
  <1992Jul23.004400.9386@kd4dts.dixie.com>

Clarification of the Rochester Tel setup for "call trace," such as it is:
when I say you "pay extra," I don't mean that "it's there all the time and
you get a per-use charge."  No, here you have to SUBSCRIBE to the feature,
in advance, and pay for it whether you use it or not...

Chris
  Chris_F_Chiesa@cup.portal.com
From: babb@rapnet.sanders.lockheed.com (Scott Babb)
Newsgroups: sci.electronics
Subject: Re: SHOCKING STORIES
Date: 31 Jul 92 15:47:18 GMT
Organization: Sanders Associates
X-Newsreader: Tin 1.1 PL4

feliccia@rodan.acs.syr.edu (Nicholas J Feliccia) writes:
: .
: 
: Ok. I want to know from the net people. What is the largest voltage shock
: you have ever received (and survived.) I am not talking about rewiring
: a light switch. I am talking about kissing the flyback transformer.

Big volts sure can be fun, can't they?  How about big amps?  I find
that I have to come close to killing myself every 10 years or so,
just so that I won't do it again for another 10 years.

My last time was when I was fixing my grandmother's washing machine.
Several of her knee-high nylons had tried to escape over the wall, and
they wound up stuck in the impeller and drain line.  I was manually
pulling these goodies out of the drain line, while the machine was
running to help push them out, and catching the water in an aluminum
pie pan (not one of those wimpy things you buy at the supermarket,
this thing was 1/8 inch thick aluminum.)  I was holding onto the pump
motor with my right hand as I threw the water out of the back door of
her trailer with my left hand.  The pie pan hit the trailer door frame
just as the pump cleared another nylon.  I took the inductive kick
from the motor across the arms/chest.  Since I was sitting down, it
didn't knock me anywhere, it just blwe a hole through the pie pan,
burned my left hand, numbed me up, and made me feel stupid.

The previous time was when I was in high-school physics and I hooked
up a test lead to the +250V/50ma terminal on a power supply and grabbed
hold of it to connect it to my experiment.  This had no effect on me
until I also (how stupid can you get?) hooked a lead up to the -250V/50ma
terminal and grabbed it.  500V at 50ma(max) across the chest.  It knocked
my ass across the room.

I guess that I have a high tolerance for amps.  I've heard that 20ma
across the chest should cause heart fibrillation/stoppage.  I know that
when I was receiving electrical interference diathermy therapy from
my chiropractor for a very stiff neck, he let me control the intensity
of the therapy.  The idea was to keep the amperage just below the level
of pain so that I would get maximum muscle stimulation/exhaustion.  I
hit the stop on the control knob before I hit anything painful.  The
meter read 35ma across the back of my neck.  I could certainly feel it,
but it wasn't uncomfortable.  The chiropractor almost dropped a load
when he came to check on me.  He said that most people max out at
2 or 3ma.  Go figure!

--
   Lockheed Sanders may disagree so these are solely the opinions of:
             Scott L. Babb - babb@rapnet.sanders.lockheed.com
              "We didn't inherit the Earth from our parents,
                   we are borrowing it from our children."
Newsgroups: sci.electronics
From: markt@cup.hp.com (Mark E. Thompson)
Subject: Photographic Strobe Construction
Date: Thu, 30 Jul 1992 21:26:52 GMT
Organization: Hewlett-Packard
X-Newsreader: Tin 1.1scd1 PL4

I remember an article in Radio Electronics about a year or two ago about
constructing zenon tube studio strobe.  Does anyone remember when this was.

Mark
Xref: sparky sci.electronics:13190 sci.chem:2753
From: wdlee@ccwf.cc.utexas.edu (david lee)
Newsgroups: sci.electronics,sci.chem
Subject: Thermally Conductive Glue?
Keywords: glue, thermal glue, thermally conductive glue
Date: 23 Jul 92 17:41:09 GMT
Reply-To: wdlee@ccwf.cc.utexas.edu (david lee)
Followup-To: sci.electronics
Organization: The University of Texas at Austin

Netones:
 Do you know of any adhesives that are good thermal conductors?
I have been using some thermally conductive epoxy, that comes in
a pre-measured baggie (remove a barrier and you can mix
part A and part B). This is Sooooo *WASTEFUL*. I must use the entire
package even if I only need a tiny drop (that's about how much I
need at each use.) So, do you know of any reasonable solution to such
predicament?
Thanks!
David Lee
PS: Please reply directly to:
wdlee@ccwf.cc.utexas.edu
Subject: Blue Lasers 
Distribution: world
Organization: null
Date: Tue, 28 Jul 1992 23:04:51 +0000

> >I heard a brief tidbit in one of the popular media about (IBM?)
> >inventing a blue laser, making extremely high resolution laser
> >..
> 
> Hmm...I doubt it.  A couple of friends and I built a laser-sourced
> ..

Sony showed a blue solid state laser.

This was banner waving -- operates at liquid nitrogen temperatures.

Stated as at least 5 yrs from production.

Selenium doping or ?

(all taken from a news item so take as of iffy reliability)

  TC. 
    E-mail: tchannon@black.demon.co.uk or tchannon@cix.compulink.co.uk
                                
Newsgroups: sci.electronics
From: smithj@hpsad.sad.hp.com (Jim Smith)
Newsgroups: sci.electronics
Subject: Re: White noise generator.....
Date: 28 Jul 92 18:09:15 GMT
Organization: HP Signal Analysis Division - Rohnert Park, CA

This month's (I think) Radio Electronics magazine has a construction project
for a "Surf" generator that may suit your needs.  Paia Electronics in
Oklahoma (last I knew) sells kits for this sort of thing, ie, "The Wind,"
"The Surf," etc.
Organization: Queen's University at Kingston
Date: Thursday, 23 Jul 1992 21:13:43 EDT
From: <LEEK@QUCDN.QueensU.CA>
Newsgroups: sci.electronics
Subject: Re: 20 Bit Counter?
 <ERIC.92Jul22201943@iceland.telebit.com>

In article <ERIC.92Jul22201943@iceland.telebit.com>, eric@telebit.com (Eric
Smith) says:

Original post was about needing a 20-bit address generator for RAM.

>You could use a CMOS counter 14-bit counter like the 4040.  Remember that
>it needs CMOS input levels on the clock and reset lines.  Two of these would
>get you 28 bits.  These are really slow, and since you would need two of
>them anyhow, I think you're probably better of with 74xx parts.

There is the HC remix of the 4020, 4040 chip.  They are now 74HC4020 and
74HC4040.  These are faster chip and blessed with 74HC drive capabilities
and speed.  Do use them carefully.  Due to the rippling nature (each bit
has an accumulated delay from the last one in the chain) and CMOS
switching current, pretty bad ring on the output is possible.  I have
witnessed  2V ringing on a badly done wire wrap board with these chips.
I 'fixed' the problem by terminating the outputs to ground via 220 ohms
resistors.  The ringing is reduced to below TTL thresholds.

I pretty much use synchronous counters on all my designs - a side effect
of doing VLSI course and working with PLD's.

I would highly recommend using a series of synchronous counter described
below or at the very least use latches on the outputs clocked by a
different phase of the clock (ie hold the previous address until the
new one settles down).  This reduces the chip count and optionally allows
one to tristates the address generator for access from CPU side.

>
>If you need the counter to be fast enough to be able to read or write
>the memory "instantly" after incrementing, you need to use synchronous
>counters, like the 74xx163.  For a fully synchronous 20 bit counter, you
>would need to have four gates to generate the *ET (or was it *EP) inputs
>to each '163 after the first.  In practice you can tie the ripple carry
>output of each counter to the *ET and *EP inputs of the next counter up.

>There are probably some 8 bit synchronous counters also, in the 74xx500-699
>range, but I don't know them offhand.

74LS469 is a 8-bit up/down counter.  I don't know whether it is
synchronous or not.  It is missing from my really old TTL databook.

Alternative is to implement the counter in a PAL/GAL chip if you know
what you are doing and have the equipment to program it.  PLD's
are kind of slow, but they allow a much more complex designs.

>Eric

K. C. Lee
Elec. Eng. Grad. Student
From: cmtst9+@pitt.edu (Cynthia M Thaler)
Newsgroups: sci.electronics
Subject: Info wanted on HeathKit Dipswitch settings wanted
Summary: heathkit dipswitches?
Date: 23 Jul 92 20:34:29 GMT
Organization: University of Pittsburgh

I recently gained a HeathKit h-19, and need to re-configure it's
operating speed and such...Any one out have a listing of the
dipswitches and what each one is used to set?

Thanx in advance

Cindy Thaler
Newsgroups: sci.electronics,rec.audio,alt.folklore.computers
From: spc@pineal.sci.fau.edu (Sean 'Captain Napalm' Conner)
Subject: Re: Life after CDs
Organization: Florida Atlantic University, but who cares?
Date: Mon, 27 Jul 1992 19:47:30 GMT

In article <27JUL199209444686@erin.caltech.edu> shoppa@erin.caltech.edu (TIM SHOPPA) writes:
>	Also, I believe the same article pointed out that music *could* be
>recorded on both sides!  Has anyone actually seen this done?  It would mean
>that program information (and the trendy art designs) we are used to would
>be non-existent or in the very center circle of the CD.
>
  I don't know about that.  I've found that if I hold up a CD to a bright light,
I can actually SEE through it!  Although I'm sure that two layers could probably
be packed into the CD.

  Also, if the music is on both sides, then there goes all the information that
is currently printed on the CD's top side.

  -spc (And when we do get DSCD's (Double Sided Compac Disks), does that mean
	we have to flip the CD over, or buy a Double Sided CD player?)

Newsgroups: sci.electronics
From: cab@col.hp.com (Chris Best)
Subject: Re: PC masks from a laser printer??
Date: Mon, 27 Jul 1992 15:27:51 GMT
Organization: your service

>  . . . . . . . . I need to produce masks from a laser printer.
> I tried the obvious (direct print on transparency), but the result
> was sufficiently porous that the copper looked like a 1/2 tone printers plate

---------

This was a big topic here not long ago, so you'll get better responses soon.
Until then, here's an idea or two:

   run the transparency through the laser printer a few times.  The slop in
   the paper feed mechanism should be enough that the dots overlap.

   or, print the pattern several times, each on its own transparency, and
   stack them - this should also be enough to overlap the dots.
From: jmorriso@ee.ubc.ca (John Paul Morrison)
Newsgroups: sci.electronics
Subject: Any LOW power PAL/GALs?
Date: 27 Jul 92 02:59:31 GMT
Organization: University of BC, Electrical Engineering


I want to use a PAL or equivalent in a low power application.
So far, the best I've done is a NS GAL20V8, quarter power.

Allegedly this part is CMOS (EEPROM), but I measured about 30 mA
sucked in, when nothing was clocking it. Doesn't sound like
CMOS to me (ie  uA standby current).

I also want to use AMD's Palasm software (it's all I have),
and some of the fancier GALs claim to be logically compatible,
but they don't burn in the same way (if I try to substitute a PAL20L8
for example)

Just for reference: 30 mA isn't low power for a PAL/GAL, when
a 6811, RAM, ROM, Serial line driver, LCD display, keyboard scanner & latch
etc all TOGETHER take about 35 mA! (running even)

jpm



-- 
__________________________________________________________________________
 John Paul Morrison                     |
 University of British Columbia, Canada |
 Electrical Engineering                 |   .sig closed for repairs 
                                        |             
 jmorriso@ee.ubc.ca                     |
________________________________________|_________________________________
Hi! I'm a .signature dung-beetle. Add me to the rest of the crap in your .sig
Newsgroups: sci.electronics,rec.audio,alt.folklore.computers
From: felix@crowfix.com (Felix Finch)
Subject: Re: Life after CDs
Organization: Scarecrow Repair, Dutch Flat.
Date: Sun, 26 Jul 1992 15:29:47 GMT
	<1992Jul24.203724.22543@rchland.ibm.com> <19340@plains.NoDak.edu>

I've several CDs with 79 minutes and change.  I think the limit is 80
minutes, altho I've heard stories about companies with 2 hour CD
formats, who are bought out, etc.  Like the miracle carburetours
bought up by the oil companies, I suppose.
-- 

            ... _._. ._ ._. . _._. ._. ___ .__ ._. . .__. ._ .. ._.
   Felix Finch, scarecrow repairer / felix@crowfix.com / uunet!crowfix!felix
Newsgroups: sci.electronics
From: strong@tc.fluke.COM (Norm Strong)
Subject: Re: What is an IGBT?
Organization: John Fluke Mfg. Co., Inc., Everett, WA
Distribution: usa,sci
Date: Thu, 23 Jul 1992 14:37:02 GMT

In article <MOTOYAMA.92Jul20140840@harlgw92.harl.hitachi> motoyama@harl.hitachi (Hiroshi Motoyama) writes:
}In article <1992Jul14.094518.13698@vax5.cit.cornell.edu> cpyy@vax5.cit.cornell.edu writes:
}
}   >In article <1992Jul12.200132.8632@csus.edu>,
}   >tching@target.water.ca.gov (Tracy Ching) writes: 
}   >> 
}   >> 	What is an IGBT?
}   >
}   >It's an insulated gate bipolar resistor.  International Rectifier
}   >makes some nice ones.  I have a few IRGPC50U's.  They have the on
}   >characteristics (voltage drop, etc) of a BJT, but require a drive
}   >signal comparable to a MOSFET (just a gate charge).  Essentially,
}   >they combine the good parts of both.  The miller effect capacitance
}   >problem encountered in MOSFETs is typically less in a comparable
}   >IGBT.
}
}Can IGBT's amplify audio signal well?  Can they be used for Hi-Fi
}audio power amplifiers?

They can and are.  The justly admired Alexander configuration, espoused
by Analog Devices, uses complementary IGBTs as output devices.  

-- 

Norm Strong  (strong@tc.fluke.com)
2528 31st S.   Seattle WA 98144   USA
Xref: sparky sci.electronics:13430 rec.audio:10911 alt.folklore.computers:11257
From: francis@cs.adelaide.edu.au (Francis Vaughan)
Newsgroups: sci.electronics,rec.audio,alt.folklore.computers
Subject: Length of CDs (was Re: Life after CDs)
Date: 28 Jul 92 01:50:40 GMT
Reply-To: francis@cs.adelaide.edu.au
Followup-To: sci.electronics
Organization: Adelaide Univerity, Computer Science


The subject of the variation in length of CDs seems to
crop up with regularity.

CDs are played using a focussed laser beam with an effective
beam spot diameter of 2um.  Effective because at these sizes
there is no edge, rather the intensity drops to a level at
which energy outside the defined spot diameter is low enough
that the signal to noise is good enough to recover the data.
There are diffraction rings of significant amplitude outside
the spot.

The standard track pitch for a CD is 1.6um.  The tracks
themselves are 0.5um in width.  This gives the laser beam spot a
reasonable margin between tracks.

The tracks themselves are made of pits and bumps, the pit 
being one quarter of a wavelegth of of the light used in height.
The lasers used are 780 or 790 nm, and with a refractive index
of 1.55 for polycarbonate this yeilds a wavelength of ~500nm
and a pit depth of 125nm.

The pits encode the data by their length.  The coding is a 8/14
modulation that is encoded onto the CD with a non return to zero
inverted modulation that results in pits with a minimum length
of 3 times the base clock rate (T) and a maximum size of 11 time
T.  The actual physical length of the pits is limited by the
optical system, which must be able to detect the length of a pit
or bump reliably.

CDs play with a constant data recovery rate.  To make the best
use of the storage the CD the data is encoded with a constant
density, requiring that the CD be rotatated at a different rate
depending upon where on its surface it is being played.  Disks
are in general encoded so that the effective velocity of the
track is 1.4 metres/second.  Thus they vary in rotation speed
from 200 to 500 RPM.

CDs may be encoded with a linear velocity of anything between
1.2 and 1.4 meters/second.  This results in pits with a minimum
length of 0.833um if a velocity of 1.2 M/s is used.  CDs may be
recorded with a playing time of up to 74 minutes and 33 seconds
with the slower velocity.

However it is also possible to drop the inter track gap.
Dropping the spacing puts greater strain upon the tracking
system (which must be able to keep the beam on the same track)
and also increases the noise.  However by doing this CDs with
playing times in the vicinity of 82 minutes can be made.  Older
and poorer quality players can have problems with these CDs as
they are really not quite within spec.

Finally, CDs play from the inside to the outside because the
optical system needs to get a lock onto the track so it can
focus the beam.  The CD surface is the most stable in the inside
(where it is supported) so the system stands a better chance of
getting its initial lock.


					Francis Vaughan
Newsgroups: sci.electronics
From: sysrick@orion.spd.louisville.edu (Rick McTeague)
Subject: Easy-to-use SCSI interface chips. Do they exist?
Organization: University of Louisville
Date: Wed, 29 Jul 1992 22:05:31 GMT

I'm interested in building a device to hang off a SCSI interface. Is there
such a thing as an easy-to-use SCSI interface chipset? If anyone has any
experience here, and could give me some pointers to a good chipset, I'd
appreciate it...

Thanks in advance,
Rick
-- 

Rick McTeague
Electrical Engineering Department, Speed Scientific School
University of Louisville, Louisville, KY 40292
(502) 588-7020

Internet: sysrick@starbase.spd.louisville.edu

Disclaimer: I'm a stand-up comedian; if anyone takes me seriously, I'm
            doing something wrong!
Newsgroups: sci.electronics
From: medin@catbyte.b30.ingr.com (Dave Medin)
Subject: Correction...
Reply-To: medin@catbyte.b30.ingr.com
Organization: Intergraph Corporation, Huntsville AL
Date: Tue, 28 Jul 1992 16:53:52 GMT

It was brought to my attention something I needed to correct...

In my reply to radar detector-detectors, I used "IF" (intermediate
frequency) in place of what should have been "LO" (local
oscillator) twice. At the leakage level I mentioned, the
source would have to be the LO and not the desired mixdown
product, or the IF. The remainder is correct. I think I was
typing quickly to race a compile finishing on my machine...

IF detection, although at a lower power, is desireable
however, because in most cases the modulation on the carrier
is preserved in the IF. So, if you want to determine whether
a particular receiver is receiving YOU, look for a copy of your
modulation in its IF leakage. This principle is used, at least, in
military gear and has been used once (to my knowledge) to
back up an unauthorized signal reception case in court.

-- 
 --------------------------------------------------------------------
       Dave Medin			Phone:	(205) 730-3169 (w)
    Intergraph Corp.				(205) 837-1174 (h)
       M/S GD3004
  Huntsville, AL 35894 		Internet: medin@catbyte.b30.ingr.com
				UUCP:  ...uunet!ingr!b30!catbyte!medin

   ******* Everywhere You Look (at least around my office) *******

 * The opinions expressed here are mine (or those of my machine)
Newsgroups: sci.electronics
From: bovine@engin.umich.edu (Mitchell Rohde)
Subject: Re: Underground CD copying
Date: Wed, 22 Jul 92 01:16:50 EDT
Organization: University of Michigan Engineering, Ann Arbor

  Yes, there are bootleg CD's.... I accidently bought one.
  I know it is a bootleg because I called the company that 
 handles this particular alternative group ( very popular
 among this crowd ) and they said there was no such 
 "greatest hits" type compilation....
                               
.
  It sounds great though, and the group wanted me to tape it for them...
  ( which I did... )


Newsgroups: sci.electronics
From: tls@solbourne.com (Tom Schreur)
Subject: Re: Help me identify this!
Organization: Solbourne Computer, Inc.
Date: Fri, 24 Jul 1992 13:56:11 GMT

Being an ex-HP employee I believe that is an HP part number below
the Motorola symbol.  Exactly what it is though is beyond me.

Any curremt HPers out there who car to look it up?

tls

Newsgroups: sci.electronics