HDTenEightyP/NetNews huggingface dataset:
From: kly@sci.ccny.cuny.edu (Gregory Kozlovsky)
Subject: Seminar in Scientific Computing at City College
Reply-To: kly@sci.ccny.cuny.edu (Gregory Kozlovsky)
Organization: City College of New York - Science Computing Facility
Distribution: na
Date: Wed, 9 Sep 1992 00:48:16 GMT

		   City College of New York
		Department of Computer Science
		Seminar in Scientific Computing

	Hybrid solutions to semiconductor device models
	-----------------------------------------------
			  Ilan Efrat
		IBM T.J. Watson Research Center


The numerical solution of boundary value problems arising in
semiconductor modelling often requires very large discretization
grids, which result in lengthy computations. The main reason is
sharp boundary and internal layers which exist in these devices.
In many important cases it is possible to derive analytic expressions
for the leading layer terms. These approximations can be embedded
in a hybrid analytic-numerical schemes which lead to robust and
efficient procedures. A hybrid solution to a MOSFET model, based
on the drift diffusion equations will be presented.


			   Speaker
			   -------

Ilan Efrat received his B.S from Tel Aviv University, M.S. from MIT,
and his Ph.D in Applied Mathematics from the Technion in Haifa. He
works for IBM Science & Technology Center in Haifa, and is presently
visiting IBM T.J. Watson research center at Yorktown Heights.
Dr. Efrat's interests include iterative linear solvers and
numerical modeling of physical phenomena.


DATE:	 Tuesday, September 22, 1992
TIME:	 3:00 PM
PLACE:	 NAC Building, room 8/206

For information call Dr. Gregory Kozlovsky at 650-6149.
From: kly@sci.ccny.cuny.edu (Gregory Kozlovsky)
Newsgroups: nyc.seminars
Subject: Seminar in scientific computing
Date: 13 Sep 92 04:46:29 GMT
Reply-To: kly@sci.ccny.cuny.edu (Gregory Kozlovsky)
Distribution: nyc
Organization: City College of New York - Science Computing Facility


		   City College of New York
		Department of Computer Science
		Seminar in Scientific Computing

	Hybrid solutions to semiconductor device models
	-----------------------------------------------
			  Ilan Efrat
		IBM T.J. Watson Research Center


The numerical solution of boundary value problems arising in
semiconductor modelling often requires very large discretization
grids, which result in lengthy computations. The main reason is
sharp boundary and internal layers which exist in these devices.
In many important cases it is possible to derive analytic expressions
for the leading layer terms. These approximations can be embedded
in a hybrid analytic-numerical schemes which lead to robust and
efficient procedures. A hybrid solution to a MOSFET model, based
on the drift diffusion equations will be presented.


			   Speaker
			   -------

Ilan Efrat received his B.S from Tel Aviv University, M.S. from MIT,
and his Ph.D in Applied Mathematics from the Technion in Haifa. He
works for IBM Science & Technology Center in Haifa, and is presently
visiting IBM T.J. Watson research center at Yorktown Heights.
Dr. Efrat's interests include iterative linear solvers and
numerical modeling of physical phenomena.


DATE:	 Tuesday, September 22, 1992
TIME:	 3:00 PM
PLACE:	 NAC Building, room 8/206

For information call Dr. Gregory Kozlovsky at 650-6149.
Newsgroups: nyc.announce,nyc.general,nj.events,ny.general
From: scoter@ntmtv.UUCP (Patrick Thompson)
Subject: Shri Mataji to visit New York City
Originator: scoter@nmtvs12
Keywords: Sahaja Yoga, Meditation, Kundalini, Self-realization, Safe, Free
Reply-To: scoter@ntmtv.UUCP (Patrick Thompson)
Organization: Northern Telecom Inc, Mountain View, CA
Distribution: na
Date: Sat, 5 Sep 1992 00:22:13 GMT



Shri Mataji Nirmala Devi, founder of Sahaja Yoga, will visit
New York City on Tuesday and Wednesday, September 8th and 9th, 
to give free lectures on self-realization and the "Sahaja 
Yoga experience."

Her itinerary on this, her first tour of North America since
April 1991, includes visits to New York, Cincinnati, Toronto, 
Vancouver, Seattle, and Los Angeles.

Shri Mataji believes that world peace and collective consciousness 
can be achieved only through the inner transformation of human 
beings. Her system of meditation, Sahaja Yoga, manifests a subtle 
energy. This is experienced as vibrations which are felt on the 
central nervous system and lead to greater awareness and deeper 
intuition. Rather than requiring a "leap of faith," it is an actual 
experience of the integration of our physical, mental, emotional, 
and spiritual being. It thus brings about complete balance and inner 
peace. By bringing together people of all religious, ethnic, and 
social backgrounds, she has proven that the human bond is more than 
skin deep and that all ideologies are encompassed by the same 
universal values and truths.


		=======================================
		New York Public Program
		Tuesday, September 8th, 7 pm.
		Terrace on the Park
		5211 Flushing Meadow Park
		Queens
		Info: (914) 636-4406
		Free of charge
		=======================================


An additional program will be held at the United Nations on 
Wednesday, September 9th for U.N. personnel.

		=======================================
		United Nations Program
		Wednesday, September 9th
		United Nations
		U.N. Personnel only
		Info: (914) 636-4406
		=======================================



For more information about these upcoming programs or Sahaja Yoga 
in general, call the local information number given above or 
1-800-745-YOGA.




------------------------------
Patrick Thompson
ntmtv!scoter@ames.arc.nasa.gov
From: scs8@cunixb.cc.columbia.edu (Sebastian C Sears)
Subject: fsadfs
Reply-To: scs8@cunixb.cc.columbia.edu (Sebastian C Sears)
Organization: Columbia University
Distribution: nyc
Date: Tue, 8 Sep 1992 23:56:23 GMT



-------
Bored of my old .sig and lacking enough bikes to make an impressive list...
          scs8@cunixb.cc.columbia.edu --> Sea-Bass Sears --> DoD#0516
Newsgroups: nyc.test
From: scs8@cunixb.cc.columbia.edu (Sebastian C Sears)
Subject: test
Reply-To: scs8@cunixb.cc.columbia.edu (Sebastian C Sears)
Organization: Columbia University
Distribution: ny
Date: Tue, 8 Sep 1992 23:53:25 GMT



Newsgroups: nyc.test
From: scs8@cunixb.cc.columbia.edu (Sebastian C Sears)
Subject: testing
Reply-To: scs8@cunixb.cc.columbia.edu (Sebastian C Sears)
Organization: Columbia University
Distribution: nyc
Date: Tue, 8 Sep 1992 23:54:20 GMT


Blah, blah, blah....
Newsgroups: nyc.test
From: scs8@cunixb.cc.columbia.edu (Sebastian C Sears)
Subject: sf
Reply-To: scs8@cunixb.cc.columbia.edu (Sebastian C Sears)
Organization: Columbia University
Distribution: nyc
Date: Tue, 8 Sep 1992 23:57:29 GMT

blech....

-------
Bored of my old .sig and lacking enough bikes to make an impressive list...
          scs8@cunixb.cc.columbia.edu --> Sea-Bass Sears --> DoD#0516
   '79 Yamaha XS750F -- '85 Toyota 4Runner -- '92 Perception Corisca
Newsgroups: sci.electronics
From: qbarnes@urbana.mcd.mot.com (Quentin Barnes)
Subject: Re: Need encoding scheme for TV remote infrared controller
Organization: Motorola Computer Group, Urbana Design Center
Date: Fri, 4 Sep 1992 23:18:28 GMT

In <1992Sep2.003540.24065@aio.jsc.nasa.gov> mancus@roger.jsc.nasa.gov (Keith Mancus) writes:

>  We're in the process of building a small robot, and we'd like it
>to respond to a TV remote control.  Can anyone tell us:

>  (1) Is there a standard carrier frequency?  The IR sensor we're using
>detects 40 MHz.

>  (2) Is the encoding scheme standardized?  If so, what is it?
> 
>  (3) Are there any other pitfalls we should know about?

I spent a lot of time investigating IR remotes because I wanted to build
an IR repeater for my house.

I got an IR phototransistor, as many varied remotes as I could find
(Sony, RCA, Mitsubishi, NEC, and some off-brands for stereos, TVs, VCRs,
CDs, etc).  I found that all of them used a digital pulse system
based on a 40Khz IR carrier.  An individual command is constructed
of 6 to 14 "clock" pulses spaced every 8ms.  The number of clocks
depended on manufacturer and type of device being controlled.  The
information portion is encoded as a "data" pulse which appears
(or not) 1ms behind each clock pulse.  Each command was repeated
as long as the key was held down.  There was a timing gap between
command repeats.  I think it was 64ms, but I don't recall for sure.

I'm not saying this analysis will hold true for all remotes, but 
it did for the 10 or 12 I tried.

The circuitry for detecting the 40Khz IR carrier, demodulating it,
amplifying it, and cleaning it up would be a lot.  However, don't
bother.  Radio Shack sells a little silver cube a little bigger
than a sugar cube that does all the work!

This little cube is great, but there are a few caveats.  The spec
sheet that comes with it has several mistakes and ommisions.  (Big
surprise!)  The output signal is inverted from the input signal, not
positive logic like the diagram has.  Also there is no indication of
output voltage swings or the amount of current the output can drive.

I used a simple 2N2222 to reinvert the signal, give it a good voltage
swing, and drive the line.  (Ya, I know, if I do it again, I'll use a
FET, but I had a pile of the 2N2222's lying about.)

Important Tip: connect the shielding of the cube to ground!  Without
the connection, the cube is very sensitive to any and all electical
noise.  I found this out the hard way during prototyping my device. 

For my application, this drives a 555 which remodulates the signal
at the other end.

Feel free to send me mail if you have any further questions.

>| Keith Mancus    <mancus@sweetpea.jsc.nasa.gov>                         |
>|                 N5WVR                                                  |
>|  "If I owned Texas and I owned Hell, I'd rent out Texas and live       |
>|  in Hell." -General Sheridan                                           |
-- 
Quentin Barnes
qbarnes@urbana.mcd.mot.com | ..!uiucuxc!udc!qbarnes
From: dougm@pnet51.orb.mn.org (Doug Mcintyre)
Newsgroups: sci.electronics
Subject: Protection against electrical storms..
Date: 5 Sep 92 21:45:22 GMT
Organization: People-Net [pnet51], Minneapolis, MN.

Well, the lightning season is here again in Minnesota. What more can I do to 
protect my equipment against lightning strikes on the power lines? (This time
it took out a keyboard, fried the 8052AH controller, and the TV for the 2nd
time in 1 year). I have both the computer and TV on surge supressors (well,
the cheapo things with the 3 MOVs in them), and the computer system is totally
grounded as well with heavy duty copper cable to the water pipe. 

Should I move up to more expensive surge supressors? Or what more can be done
with the wiring in the house? The wiring is well grounded...

INET: dougm@pnet51.orb.mn.org                                GENIE: D.MCINTYRE1
Newsgroups: sci.electronics
From: mjohnson@netcom.Netcom.COM (Mark Johnson)
Subject: Re: "Typical" propogation delays
Date: Wed, 16 Sep 92 03:04:01 GMT
Organization: Netcom Online Communications Service

In article <1992Sep15.213750.3593@zip.eecs.umich.edu> johnwitt@cdrom.engin.umich.edu (John P Wittkoski ) writes:
  > I have a single specific part (say a 74ls04) and say it runs at the same 
  > temperature and humidity all the time. Will the propogation delay for that
  > specific single chip almost always be the same?

Add a couple more restrictions and the answer is Yes:
   the power supply voltage is constant
   the pattern of input stimuli is constant
   the output loading is constant


Prop delay is a strong function of
    1  output load
    2  supply voltage
    3  temperature
    4  input risetime / falltime
    5  input pattern
    6  manufacturing variances


Probably these are self evident except maybe number 5.
It just refers to the fact that not all input pins of an IC
give equally fast delays to the output.  For example many
TTL chips' datasheets give different specs for their
various pins.  What is often left unsaid, though, is that
in several logic families the three inputs of a NOR3 gate
are different speeds to the output (same with NANDs,
AOIs, muxes, etc).
Xref: sparky sci.electronics:15584 alt.guitar:7988
Organization: University of Illinois at Chicago
Date: Sunday, 13 Sep 1992 16:06:22 CDT
From: <U58402@uicvm.uic.edu>
Newsgroups: sci.electronics,alt.guitar
Subject: Re: Building effects units for guitars
Distribution: na
 <1992Sep3.222723.11105@ringer.cs.utsa.edu>  <Bu1318.2B8@comp.vuw.ac.nz>
 <1882d2INNov1@matt.ksu.ksu.edu>  <1992Sep4.164544.1779@pony.Ingres.COM>
 <TJS.92Sep4144545@godzilla.eecs.umich.edu>
 <TILL.92Sep8132433@acid-rain.lucid.com>
 <1992Sep9.021513.23393@u.washington.edu>

In article <1992Sep9.021513.23393@u.washington.edu>,
insomnia@carson.u.washington.edu (Ryan Klemmer) says:
>
>Moving on to effect devices.  Why analog?  Same reason.  Just off hand,
>a recent Guitar Player interview with The Cure asked why analog pedals.
>The answer was that they were just too mechanical, and not very good
>when going live.  They just didn't have the same feel, tonality, etc.

The main problem I find with the digital multieffect units is the crappy
user interface. I really hate having to go through several pages of
menus to change the depth of my chorus when I can just bend down and
twiddle the knob a little on my chorus stomp box.

I read an interview with Bob Bradshaw  where he was asked if anyone had
been dissatisfied with one of his rack systems. He said he built one for
Prince, who sent it back. Apparently Prince preferred to use his Boss
pedal chain, just so he could twiddle the knobs.

Actually, there is one technical difference between analog and digital
effects that I have found. Analog effects tend to be quieter (!) than
digital effects. I have used an analog chorus, a digital
delay/chorus/flanger pedal, and a rackmount digital multieffects unit. I
found the analog pedal to be the quitetest of the three.

Wilbur Pan
(aka u58402@uicvm.uic.edu
 at the ever so friendly and personal univ. of ill. at chicago)
From: Ted_Eugene_Viens@cup.portal.com
Newsgroups: sci.electronics
Subject: Re: Re: Impedance match 50 to 75 ohms
Date: Sun, 13 Sep 92 08:55:59 PDT
Organization: The Portal System (TM)
Distribution: na
  <1992Sep11.101819.58812@cc.usu.edu>

Hello, Brian.

Both HP and Tek sell a minimum loss pad specifically made to match 75 ohm
lines to the 50 ohm N-type input.  The pad is constructed with only three
precision resistors in a T-pad circuit.  Unfortunately, I don't know the
value of the resistors.  The use of non-inductive precision resistors makes
the pad fairly frequency independent.  The commercially available minimum
loss pads come with a calibrated loss value on them and usually a BNC input
connector.  If you are not prepared to pay the couple of hundred dollars
for the commercial pads, I am sure that a considerate tech rep would give
you the resistor values from their pad's schematics.

Good luck

Ted Viens
Newsgroups: sci.electronics
From: aslt@acad2.alaska.edu
Subject: AC power inverter questions?
Organization: University of Alaska
Date: Tue, 15 Sep 1992 01:09:00 GMT

This is probably a stupid... *ahem*, well, a question that reveals how just how
much I have forgotten, but it is one that I have thought about frequently
over the years, and the discussions about power supplies and dynamotors
and whatnot resurrected it in my mind...

Many inverters use square waveforms rather than sinusiodal waveforms. 
Intuitively, though, it seems that significantly less energy will be 
transferred from the primary to the secondary of the transformer using 
square waves (input changes at discrete places in the waveform) than 
would be transferred using sinusoidal waveforms (input continuously changing)
What am I missing?

Along the same lines, presumably the outputs of inverters are square waves
rather than sinusoids (I'm speculating, I don't know).  It seems you could 
do some serious damage to the motors in some devices, drills, margarita 
blenders, refrigerators, freezers, and such.  Any comments?

Thanks a bunch.  E-mail replies welcome.

Lee
From: jfw@ksr.com (John F. Woods)
Newsgroups: sci.electronics
Subject: Re: NEED: TTL controlled 115V 5A Switching
Date: 10 Sep 92 11:48:42 EDT

jg3o+@andrew.cmu.edu (Jason Ari Goldstein) writes:
>The subject pretty much says it all.  I need to switch some light
>switches with TTL signals (I am building a controller for my
>fraternities dance floor lights).
>BTW, I have looked into solid state relays but $17-$25 each is way too
>much.  So, if someone could send me a circuit diagram or point me to a
>good book (especially for triacs) it would make me very happy.

They're cheaper surplus; Hosfelt Electronics (1-800-524-6464) has a 10A
opto-isolated solid state relay for $9.95, and an optoisolated 2.5A relay
for $2.59 (which could be used to switch individual lights).  They have no
minimum order.  These aren't "logic gate" relays, however, and probably
need more input current than LS TTL can supply:  a 7407 or 7417 open-collector
TTL hex buffer with a 200 ohm collector resistor ought to be an adequate
translator; on the other hand, my Digikey catalog has some SSRs with 3-30V
inputs that claim to require "1-18mA"; since that presumably means 1mA at
3V, that's a little more reasonable.  LS TTL still won't cut it, but a
74LS125A quad bus buffer will just abut handle it, and a 74LS245 octal bus
transceiver will be loafing (and only costs $.75 from Digikey).

Someone else mentioned that Radio Shack has a Forrest Mims III book that has
a circuit (they even still carry enough parts to build it, too :-).  Note that
if you don't know what you're doing wiring it up, you are better off buying
a commercially prepared unit (unless your fraternity doesn't care about it's
fire insurance -- if a hand-made unit causes a fire, or even looks to the
insurance inspector like it might have, you can forget about the insurance).
If you *do* know what you're doing, it's not too hard to wire it up properly;
just remember to be very respectful of what 10A at 110V can do...
Xref: sparky sci.electronics:15646 alt.guitar:8036
From: jgray@balboa.eng.uci.edu (Jeff Gray)
Subject: Re: Building effects units for guitars
Newsgroups: sci.electronics,alt.guitar
Organization: University of California, Irvine
Date: 15 Sep 92 05:14:14 GMT
Distribution: na

>   Ask any guitar player what kind of amplifier they would use and most would
>   say tube.  Why?  Because they have a certain sound that semiconductor
>   devices just can't produce.
>
>Not true; tube amplifiers sound like they do because of the specific
>circuit topology used, the overdrive characteristics, and the low use of
>feedback -- not because they use tubes.  (I described this more completely
>in an earlier post.)
>
>On the market however, you'll find that all the available tube amps are
>subtle variations variations on one design and all transistor amps are
>subtle variations on maybe three designs, so yeah, the generalization holds
>in that respect. But note the distinction between what's available on the
>market and what's technically possible!  

On that note, I can give the example of the MosValve amp, which I own and
love.  More because of the price and power than the ability to say "I
tested against tube amps and it was as good or better."  I can't say that
because I didn't do it, and even if I had I wouldn't bother pretending my
opinion meant anything.  But in the manual that came with the amp, the
designer and founder of Tube Works explained that he designed the amp
to use a MOSFET like tube amps use tubes, not like every other amp 
on the maker uses a transistor, which is why it sounds like a tube amp.

(This is a perfect example of why I became a digital designer instead of an
analog guy -- a truly outstanding analog design is rare and can last
for decades before (if ever) becoming obsolete, making it very difficult to be
an outstanding analog designer.)

>
>   Moving on to effect devices.  Why analog?  Same reason.  
>
>In case it wasn't clear, my comments about the musical quality of analog
>vs. digital effects were specifically about what's available on the market,
>not what's technically possible.
>
>  -- Don

I have a Peavey Pro-Fex and I think that Peavey must have put a hell of a lot
of effort into developing natural-sounding DSP algorithms for distortion and
reverb and other very analog-y effects.  To me the all-digital distortion
sounds much better than that available in the Digitech Twin-Tube preamp.
And certainly a hell of a lot better than the transistory crap that comes
out of a Quadraverb GT.
--
Jeff Gray               
Dept of ECE, University of California, Irvine
jgray@balboa.eng.uci.edu                             "Is logic just a synonym
                                                           for this savagery?"
Newsgroups: sci.electronics
Subject: MODIFYING VGA cards for PCs
From: geoffrey@cosc.canterbury.ac.nz (Geoff Thomas)
Date: 11 Sep 92 20:26:16 +1200
Distribution: world
Organization: Computer Science,University of Canterbury,New Zealand


A few questions about modifying VGA cards:


1) How can I cram 2 VGA cards into a PC, and have them independently
addressable? Because of the way DOS handles it's video address space,
only one card can reside in the video address space, but what if, on a
3/486 the other card could be given a different address space that
doesn't clash with the first, and could be addressed via protected mode
on the 3/486.


2) Any ideas on how to give the VGA card a flat video memory, rather
than a paged one?

3) Lastly, is it possible to speed up writes to the video address space?
Currently its quite slow, and I want to speed it up.


Any thanks much appreciated.
Geoff Thomas.
From: cyberman@toz.buffalo.ny.us (Cyberman)
Newsgroups: sci.electronics
Subject: internet adress for Texas Instruments
Date: 10 Sep 92 01:37:08 GMT
Organization: The Tower of Zot - (716)691-3865

Mispelled Title says it all!

I would like to know of TI's internet adress and how to use it to find out 
about thier products.
Cyberman  
 


************************************************************
* Cyberman@TOZ.BUFFALO.NY.US                               *
*   "Life is what you put into it" - Cyberman              *
* Optimistic - running through a barn of manure looking    *
* for the horse!  /\ [] ( )                                *
Xref: sparky sci.electronics:15653 comp.sys.intel:1710
From: roy@alfrat.uucp (Roy Phillips)
Newsgroups: sci.electronics,comp.sys.intel
Subject: Re: Info needed on 16MByte SIMMs for PC
Date: 14 Sep 92 18:41:41 GMT
Reply-To: roy@alfrat.UUCP (Roy Phillips)
Organization: A+F System-Entwicklung, W-Germany

In article <1992Sep11.024131.5679@mintaka.lcs.mit.edu> drosera@hal.gnu.ai.mit.edu (Donald Burden) writes:
>In article <BuDJsw.8t1@unx.sas.com> sasbge@ant.unx.sas.com writes:
>>
>>2.  I have turned and read *every* page in this months issue of 
>>_Computer Shopper_.  I only saw one advertisement for 16MByte SIMMs.  Is
>>this beast so very new to the PC world that they are not yet available?
>>I'm trying to determine if it would be possible to purchase the 16MB
>
>From what I've read TI (Texas Instruments) is the only source for 16 megabit
>DRAMs.  They are currently only making them for military uses now, with 
>commercial production starting this winter.  I wouldn't expect 16 MB SIMMS
>to be released, and commercially viable (costing less than four times the
>price of 4 MB SIMMS) before next summer at least.  Out now though are 
>8 MB SIMMS, but these just contain twice as many chips as 4 MB SIMMS.

  NEC manufacture a 16MB SIMM with the following part no.:

     MC-4216000A9BA-70 (16Mx9 70ns)

  The price here in Germany is in the region of DM 1800,- (don't ask me 
  what that is in dollars), as 4MB SIMMS from the same source cost
  DM 150,-, it's no bargain, but if you *need* 64MB then you're gonna
  have to pay for it.

  Apparently, Hitachi also market a 16MB SIMM, with the part no.:

     HB-I6056A169B8

  which is probably a 80ns device, so a 70ns *B7 may exist. 

  Roy
--
Roy Phillips
A+F SystemEntwicklung
DW-4030 Ratingen
Germany
roy@alfrat.de
{uunet}!mcsun!unido!alfrat!roy
Newsgroups: sci.electronics