HDTenEightyP/NetNews huggingface dataset:
From: rcamama@ccwf.cc.utexas.edu (Robert Camama)
Newsgroups: sci.electronics
Subject: VERY small Sony Walkman design:  did this exist, any to be found?
Date: 13 Sep 92 08:31:04 GMT
Distribution: usa
Organization: The University of Texas at Austin, Austin TX




	Some years ago, a friend of mine told me of what sounded like a short lived (on the consumer market) Sony Walkman design.  It seems this Walkman was so small that it didn't 
completely enclose the tape it was being used on.  That's all I recall about
it (sorry for the lack of info) and I was just wondering:

	1) Was this Walkman available in the consumer electronics market at all?
	2) If it did, does anyone know of anyone/any organization that might
		have one of this design and be willing to part with it?



Thanx in advance,
R. Camama
From: sundeep@Caere.COM (Sundeep Gupta)
Newsgroups: sci.electronics
Subject: How to use 60 HZ AC for (cordless) extensions to a phone.
Date: 9 Sep 92 18:23:45 GMT
Organization: Caere Corp.


I'm wondering if anybody out here has built/knows details about
remote extensions using the AC home wiring. For eg, I have seen
ads for devices that can serve as an extension for the phone.
The base unit of this device plugs into the phone outlet. Then 
an extension unit plugs into any 110 V AC outlet and lets you plug
your phone into it, effectively letting you plug your phone into
any power outlet. 

I suppose that the base unit uses the 60 HZ Power line as a carrier, and modulates
( FM /AM ?) the phone signal. The remote unit then acts as a demodulator.

Doe anybody have any comments/ experience/ circuits/ sources /info for such a device ?


/sundeep

#############################***********************##############################
<sundeep@caere.com>
Caere corporation							"me worry ? who ? me !!? why do you ask Dr Freud ? Why?
Los Gatos, CA 95030.					 why ??. I demand an explaination. ha, worry !!
#############################***********************##############################
Newsgroups: sci.electronics,rec.video.cable-tv
From: David W. Hawkins <dwh@resumix.portal.com>
Subject: RE universal sync restorer trouble
Organization: Resumix Inc.
Date: Mon, 14 Sep 92 15:40:38 GMT

I have assembled the universal sync restorer described in the
May '90 issue of RE and it's not quite working. A friend of
mine has assembled one as well and his works fine. So we've
tried to compare what his is doing to what mine is doing.
We can't find any difference at all, yet his works.

Mine shows symptoms of the sync being off-frequency. Specifically,
with no input, good sync shows up. When we add input, we see the
picture torn horizontally (like the horizontal hold control is
way off) and the picture crawls vertically at about 2-3 seconds
per frame-height (however, the sync generated by IC9 is perfectly
stable).

We suspect the circuitry near IC5. If we remove IC5 from mine and
jumper from the collector of Q5 on his to the same spot on mine
(i.e. take the output of HIS IC5 and put it in my circuit),
it works. We have, however, compared waveforms on all pins
of IC5, substituted IC5, substituted crystals, substituted
a few of the capacitors... Nothing makes any difference. We still
cannot find any difference between his and mine, yet mine does not
work.

What am I missing?

Xref: sparky sci.electronics:15456 rec.radio.amateur.policy:1618 alt.folklore.urban:23245
From: ron@pilot.njin.net (Ron Natalie)
Newsgroups: sci.electronics,rec.radio.amateur.policy,alt.folklore.urban
Subject: Re: Is this legislation for real?
Date: 10 Sep 92 18:36:52 GMT
Followup-To: sci.electronics
Distribution: usa
Organization: Rutgers Univ., New Brunswick, N.J.

> How about for cellular phones?

You're under the mistaken impressoin that cellular phones are in fact
radios.  Congress and the Cellular Industry knows better.

-Ron

The privacy of a radio with the convenience of a phone.
Newsgroups: sci.electronics,alt.guitar
From: grey@bnr.ca (Bryan Miller)
Subject: Re: Building effects units for guitars
Reply-To: grey@bnr.ca (Bryan Miller)
Organization: Bell-Northern Research Ltd.
Date: Fri, 4 Sep 1992 20:41:27 GMT

One good thing to say for the practicality of DSP and
the home dabbler:

Effects programs can be distributed electronically.
It's a lot harder to email a legible schematic and
etch a board :)

If you program in a 'portable' language like C and
get a public domain compiler for your DSP, you're
flying for pretty cheap if you can get at least part-
time access to a computer.

It's a totally different type of guitar hacking,
to be sure :)

Grey
Newsgroups: sci.electronics
From: tadams@sbctri.sbc.com (Tom. Adams 529-7860)
Subject: CSMA/CD on RS232?
Organization: Southwestern Bell Technology Resources, St.Louis, MO
Date: Tue, 15 Sep 92 15:00:15 GMT

I was wasting time in a meeting, and came up with an idea that seems
interesting to me.  Consequently I'm sure it's been done, or more likely
been shown to be just incredibly stupid. :)

I'd like to connect multiple devices to an RS232 line, buswise.  All devices
would either be programable, (i.e. PC's) or be frontended by a (cheap)
microprocessor.  I'm wondering if CSMA/CD is a reasonable way to manage 
very low speed bus contention.  If so, it would seem reasonable to transmit 
address information, data, CRC's etc over the wire.  I'm not quite sure
how to manage the Collision detect part, since I can't just look at 
voltage levels on the wire.  Applications would be low volume data logging
and control systems, ridiculously overpriced burglar alarms, etc.

Perhaps it would be more reasonable to just look at some twisted pair
protocol that already has multi drop, like sdlc.

Opinions?
-- 
Tom Adams	tadams@sbctri.sbc.com adams@swbatl.sbc.com   314-529-7860
misology (mi-sohl'-ogee) Hatred of reason, argument, or enlightenment.
--  misologist n.	Not in any way connected to the word management.
Newsgroups: sci.electronics
From: gkm@cc.uow.edu.au (Glen K Moore)
Subject: Need company address - FILAC
Summary: I need a comapny address for FILAC so that I can get circuit diagrams t
Keywords: Blood pressure heart rate
Organization: University Of Wollongong
Date: Fri, 11 Sep 92 08:10:53 GMT

Do you know where FILAC is located?
They make heart rate monitors and blood pressure guages.

Either reply of fax direct
gkm@cc.uow.edu.au
fax 61-42-213151 (country-area-number)

Thanks!! I am desparate.
Newsgroups: sci.electronics
From: praetzel@marconi.uwaterloo.ca (Eric Praetzel)
Subject: O2 and CO2 sensors
Organization: University of Waterloo
Date: Wed, 9 Sep 1992 16:33:54 GMT

Does anyone know of some good O2 and CO2 sensors that are accurate and
repeatable (linearity is not a strong requirement)?  The application is
measuring the concentrations in air and human breath.
  - Eric 
Newsgroups: sci.electronics,rec.radio.amateur.policy,alt.folklore.urban
From: mem@mv.mv.com (Mark E. Mallett)
Subject: Re: Is this legislation for real?
Organization: MV Communications, Inc.
Distribution: usa
Date: Mon, 7 Sep 1992 05:28:52 GMT

In article <ERIC.92Sep6171003@iceland.telebit.com> eric@telebit.com (Eric Smith) writes:
>>>On 5 Sep 92 04:45:04 GMT, mcovingt@athena.cs.uga.edu (Michael A. Covington) said:
>> (2) A bill to ban receivers that can tune in cellular phones.
>> (Right now, eavesdropping is illegal but the equipment itself isn't.)
>
>Geez, you mean old televisions with UHF tuners will become illegal?  :-)

Only the ones with roman numerals.

-mm-
-- 
Mark E. Mallett  MV Communications, Inc./ PO Box 4963/ Manchester NH/ 03108
Bus. Phone: 603 429 2223    Home: 603 424 8129     BIX: mmallett
Internet: mem@mv.MV.COM  ( uucp: ...{decvax|harvard}!mv!mem )
Looking for news and mail in southern NH / northern MA?  Try MV!
Newsgroups: sci.electronics
From: kilian@cray.com (Alan Kilian)
Subject: Computer controlled bike load.
Organization: Cray Research, Inc.
Date: 8 Sep 92 16:02:51 CDT

How about using one of those fans that is turned by the back wheel.
Add an enclosure and have a variable door on the fan.
as the door closes the fan will get easier to turn.

-- 
 -Alan Kilian           kilian@cray.com 612.683.5499 (Work) 612.729.1652 (Home)
  Cray Research, Inc.   655 F Lone Oak Drive, Eagan  MN, 55121 
                        "It's based on actual math". -Dilbert
From: smckinty@sunicnc.France.Sun.COM (Steve McKinty - Sun ICNC)
Newsgroups: sci.electronics
Subject: Re: Where does snow come from?
Date: 8 Sep 1992 10:45:28 GMT
Organization: SunConnect
Distribution: world
NNTP-Posting-Host: hardy.france.sun.com

In article <etxansk.715946468@garbod20>, etxansk@garbo.ericsson.se writes:
> 
>  I'm wondering where the snowy screen information comes from, on a TV
> set that isn't receiving any real RF video signal.
> 
>  Is the snow "in the air" or does it only exist in the TV's tuner?
> 
>  If it's noise from earth and the rest of our universe, will this
> messy information fade away if I hide the tuner's receiving parts
> behind a shield that's good enough?
> 
>  I don't need the answer to solve a specific problem, I'm just 
> curious about how these things work.
> 
>  Anders Skelander
>  

Most of it is generated inside the tuner, in the mixer stage. Mixers
are notoriously noisy, about the only way to silence them is to run them
somewhere near absolute zero, which makes watching TV rather chilly :-)

There is some background noise 'in the air', especially if you live near
an industrial area, but its pretty low-level. The big radio telescopes
operate their circuitry close to 0degrees, because they want to see the
background noise from the universe.

If you remove the aerial, and completely screen the input socket, you'll
find that the snow hardly diminishes at all. Disconnect the power supply
from the mixer transistor and you get a calm grey screen.

The automatic gain circuitry inside a TV is designed to compensate for
mixer noise. Where possible it leaves the amplifier between Aerial and
Mixer at the highest gain possible, and reduces the gain after the mixer
if necessary (if you are receiving a strong signal). That way you get the
highest ration of signal-to-mixernoise. As a last resort it will reduce the
gain of that first amplifier (delayed AGC), at that point the signal is
likely to be so strong that the noise is undetectable. Its not just
a problem with TVs, all superhet recievers suffer from it.

Steve
Newsgroups: sci.electronics
From: kravitz@foxtail.com (Jody Kravitz)
Subject: Re: TESLA COIL
Organization: The Foxtail Group
Date: Wed, 9 Sep 1992 15:27:26 GMT

al@sys6626.bison.mb.ca (Haus Der Luge) writes:

> 
>I am interested in making myself a TESLA COIL.
> 
>I would REALLY appreciate some help if somebody could tell me where to 
>find a schematic, information etc.  (I've looked through about 7 years of 
>SCIENTIFIC AMERICAN "home scientist" articles to no avail.).
> 
>Thanks,
>Haus Der Luge
> 

I called my buddy, Mike Ames, who is co-author of a paper on building
Tesla Coils.  He has one at home thats about as tall as I am and throws
3 foot sparks.  He dictated the following additional information:

There is an organization called TCBA - Tesla Coil Builders Association.
Harry Goldman is in charge.  3 Amy Lane, Queensbury, NY, 12804 USA.
518-792-1003.  He publishes 4 times a year a bulliten of about 18 pages
cointaining a compilation of whats going on amongst the hobbiests building
these.  This quarter shows a 30' tall one built by a physicist at Stanford
whch was taken to Barcelona this summer.

Please use Mike Ames' name if you call Harry.  Harry is an ex college
professor who does this essentially as a non-profit thing.  Its about 20$/year
to join and you will save months or years of time in figuring out what
the right parts are back issues are available.

There is a group in Seattle that has video tapes of their member's projects.
Each tape as about 3 useful pieces of obscure information.  They are
about $20/each.  Harry can probably give you a pointer to them.

Enjoy.  You are not crazy to want to build one.

Jody

From: tonya@hpldsla.sid.hp.com (Tony Arnerich)
Date: Wed, 9 Sep 1992 19:30:39 GMT
Subject: Re: Try this with your DMM
Organization: HP Scientific Instruments Division - Palo Alto, CA
Newsgroups: sci.electronics

Mark-Tarbell@suite.com writes:

> Have you ever tried to get a DMM to measure its own battery voltage?

> It seems that one must decouple the input from the battery terminals,
> but there must be a trick to it (I'm using a .01mfd disc cap).

It won't pass DC in series configuration. Used in parallel, it might
help filter out any aliasing that might occur as the power demands
on the battery shift during the integration period.

> What happens is that the display cycles +/- 2 volts around the true
> value, but never settles down, seeming to indicate a ground loop.

> Any ideas?

I recently bought some low-voltage detector/warning chips from Digi-Key
(still waiting on them, back-ordered), that run off the voltage that
they are sensing. Until I got the data sheet, I wondered how they'd
deal with the very big problem of what to compare the voltage to. After
all, everything is shifting as the voltage drops.

It's very simple: there's an on-board regulator to run the chip, which
of course sets a lower limit of the voltage you want to monitor. There's
also a very stable 1.3V reference inside the chip, which is compared
to an external resistor divider that you design. Now the chip can run
accurately off a voltage lower than the sense setpoint.

If you use a divider and probe that point, you will be measuring a
voltage closer to the battery (-): previously, you tried to measure
battery (+). Your errors probably won't disappear, but they will be
different. It will be a trade-off between dividing the error and 
approaching the LSB of the display.

For better isolation, you might need to increase the input impedance of
the DMM, perhaps with an op-amp.

tonya@hpldsla.sid.hp.com
Newsgroups: sci.electronics
From: stettbac@isibee14 (Juerg Stettbacher)
Subject: Re: LCD applications wanted
Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
X-Newsreader: Tin 1.1 PL5
Distribution: usa
Date: Tue, 15 Sep 1992 16:43:30 GMT

John Schuch (hbg6@phx.mcd.mot.com) wrote:
: I developed a simple cable and driver system to connect a two line
: by 40 character LCD module to the parallel port of my PC. I needed
: it to test about 40 LCD modules I bought at a 'junk' store and it
: worked very well.
: 
: A couple of people suggested I publish the thing but I can not think
: of any good applications for driving an LCDM from a PC other than
: testing the module.
: 
: Can you think of any good uses for this thing?
: 
: Thanks, John


Hi John

Replace your screen by the LCD and save energy this way. Also it's
probably better for your eyes...


juerg at ethz switzerland
Newsgroups: sci.electronics
From: gude@uniwa.uwa.edu.au (David J W Emrich)
Subject: Circuit to multiply audio signals wanted.
Summary: Anyone out there remember op-amp multipliers?
Keywords: multiply modulate
Organization: University of Western Australia
Date: Sun, 6 Sep 1992 16:12:05 GMT

Hi Netland...

I have a little problem that I can't solve immediately, coz I havent'
got/can't find the relevant text book.

Here is the outlay... I have two (later maybe more) audio signals, that
are amplitude limited to 2V peak to peak, but no low-frequency
limitations.  (Eg DC to 20kHz).  I want to "multiply" the two signals
together, which, if I remember rightly, is the same as modulating one
signal with the other.  Since modulation is symmetric, if 100%
modulation is used, I figure that is the same as multiplying them
together.  I know there is an op-amp circuit somewhere to do exactly
what I want, but I can't remember, (it was 8 years since I started
Engineering, and I haven't used much of it since.  Poor old memory...)

The only tricky bits are:
1) if _either_ one of the inputs is 0v (i.e. no signal), then the output
must be as close to 0 as possible.  I seem to remember some modulation
circuits that still let one signal through at about 10% for zero
modulation input.

2) Ideally, I should be able to switch the inputs over (i.e. swap roles
from "carrier" to "modulation") with no discernible difference in
output.  This isn't totally necessary, I will probably end up with a
computer controlled soft-switcher to swap signals around later, but it
would be nice in the early stages.

3) If possible, it should be easily expanded to handle more than two
inputs, hopefully without cascading, coz I don't want too many booster
amplifiers to bring the signal back up to 2v after every stage.


Can anyone remember their op-amp theory, or alternatively suggest a
good, _current_ electronics text that covers this sort of thing?

Please respond to email address below, I don't think too many others
will want to wade through this stuff!

Thanks in advance.


[dav]    aka
David Emrich
gude@uniwa.uwa.edu.au
Newsgroups: sci.electronics
From: nagle@netcom.com (John Nagle)
Subject: Re: Filtering TV Commercials
Date: Tue, 08 Sep 92 05:35:24 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 

agodwin@acorn.co.uk (Adrian Godwin) writes:
>Note to the person writing an FAQ for this group .. can adkillers go
>in there please, along with ECM for police radar as discussed-to-death ?
>I nominate the 'most effective solution' for adkillers to be the 
>suggestion made last time around : that an adkiller service be supplied,
>via dialup line or pager channel, with kill signals generated by a team of 
>dedicated kids and a majority voting circuit.

     That's been tried.  Blair Neumann built and demonstrated such
a thing, calling it SmarTV.  The home unit contained several VCRs
and a control computer, and based on info transmitted by phone line,
would construct a commercial-free version of your selected programs
for later viewing.  Blair was a highly visible figure on the WELL,
and described his product in detail there.  He received some
press coverage when the prototype was demonstrated.

     Shortly before the scheduled launch date of the product, Blair
committed suicide.

					John Nagle
Newsgroups: sci.electronics
From: finneyk@seanews.akita.com (Ken Finney)
Subject: 120 HZ oscillator query
Organization: SEANEWS - Seattle Public Access News & Mail
Date: Fri, 11 Sep 1992 23:36:17 GMT


I'm in need of an oscillator that puts out two square waves, 
180 degrees out of phase, each one 60 Hz and 50% duty cycle.  
My original idea was to use a MM5369 17 stage divider (with a
7.15 MHz crystal it would generate a 120 Hz output) to drive
a flip-flop to generate the two 60 Hz wave forms.  Unfortunately,
the MM5369 doesn't produce a 50% duty cycle output.  So, does
anyone know of a IC (or simple (ie: cheap) circuit) that is 
designed to produce the signals I'm looking for?
 
Wave form A
      |------|      |------|      |------|      |------|
------|      |------|      |------|      |------|      |------
 
Wave form B
------|      |------|      |------|      |------|
      |------|      |------|      |------|      |------
 
Note: The "High" times of the two waveforms must not overlap,
and it would be even nicer if they have a "break before make"
characteristic.
From: prob@btmp24.be (Pascal Roobrouck SH53)
Newsgroups: sci.electronics
Subject: ST62XX MCU software wanted
Keywords: MCU
Date: 4 Sep 92 05:01:19 GMT
Reply-To: prob@btmp24.be (Pascal Roobrouck SH53)
Organization: Alcatel Bell Telephone, Antwerpen, Belgium



Hi, 

I currently started developing on the ST6210 ST6215 MCU from
SGS-THOMSON. Does anyone have a software library for that tiny MCU, or
maybe some higher (-than assembly-) language cross-compiler (for a PC or
Unix workstation ) ? 

If you happen to look for it, I have the INTROL C-compiler/assembler and
some Kilobytes of source for the Motorola 68HC11 (my previous playtoy)
so we can probably exchange something. For the ST621x I have the
St-Starter kit with simulator and m-assembler for PC.

I'm also interested in a PC-software simulator for the 68HC11, is there
one commercially available ? Is there a freeware simulator ???


Thanks,

       
   ~~..~~
     '`


Pascal Roobrouck
prob@sh.alcbel.be
From: olson@anchor.esd.sgi.com (Dave Olson)
Newsgroups: sci.electronics
Subject: Re: Need Help With SCSI Device
Date: 14 Sep 92 05:52:23 GMT
Organization: Silicon Graphics, Inc.  Mountain View, CA

In <1992Sep13.151356.1307@mccc.edu> pjh@mccc.edu (Pete Holsberg) writes:
| The Trantor MiniSCSI converter gets its power from pin 38 of the SCSI
| device it plugs into, in this case, a WangDAT 1300. However, the W'DAT
| poops out only 2V amd the M'SCSI wants 5.
| 
| Could someone tell me about pin 38 before I start futzing around with 5V
| power supplies and piggyback connectors? :-)

Pin 38 on the centronics connector is termpower, on ribbon cables
it is pin 26.  Only one device on the SCSI bus is required to
supply termpower, and not all devices can be jumpered to supply it
(many assume the host will supply it).  When present, it only
needs to exceed 4.25 volts under SCSI-2 (not 5), and I think it
was only 4 v required under SCSI-1.  Since a diode is also required
when termpower is supplied, you will seldom see 5 v on the termpower
line.  Presumably the Trantor is able to accept that, since from all
accounts it mostly works.

As I recall, the WangDAT units *can* be jumpered to supply term
power, but you'll have to check your manual to see if this is true,
and which jumper(s)/switches to change.
--
Let no one tell me that silence gives consent,  |   Dave Olson
because whoever is silent dissents.             |   Silicon Graphics, Inc.
    Maria Isabel Barreno                        |   olson@sgi.com
Newsgroups: sci.electronics
From: richard@newt.ee.byu.edu (Richard Christensen)
Subject: <<FOR SALE  68030 33MHz. - $150 OBO
Organization: Brigham Young University, Provo UT USA
Date: 14 Sep 92 17:05:00
Originator: richard@newt.ee.byu.edu
Keywords: 68030



I have a 68030 at 33 MHz chip.  I need to sell it
for $300 obo.  I'll pay shipping.  Nothing is wrong
with it, I just can't use it.  I know that the 
sample price is around this figure, I called Motorola,
so it should be a steel at this price.

Richard@remus.ee.byu.edu or 1-801-374-0941  5-10 pm mountain
                            1-801-378-3812  8-5  am-pm mountain
Newsgroups: sci.electronics
From: pnp3558@tamsun.tamu.edu (Paul Norman Packebush)
Subject: Pulse Transformers for use in MOSFET drivers *HELP*
Organization: Texas A&M University, College Station
Date: Wed, 16 Sep 1992 00:36:46 GMT


Newsgroups: sci.electronics
From: djk@world.std.com (Dan J Keldsen)
Subject: Phone circuit projects...
Summary: Looking to build circuits to provide hold and in-use functions
Keywords: HOLD IN-USE PHONE
Organization: The World @ Software Tool & Die
Date: Sun, 6 Sep 1992 01:50:29 GMT

I'm trying to find a book or books or just schematics from some kind soul,
that would enable to me to have a 2-line system (modifying a 1-line phone)
that would have a light for the ringer (on each line), and same light
would light (and stay lit) while that line was in use. So, I need plans
for a 2-line HOLD circuit, and plans to light da light of a line in-use. BTW,
the in-use light should work if an extension phone is in use also, not just
the attached phone to said circuit.

----------------------------------------------------------------------
Dan Keldsen			Working on a Brain-to-
djk@world.std.com		MIDI convertor...
Somerville, MA			Anybody willing to sport
BERKLEE College of Music	the necessary "elective surgery" ??
----------------------------------------------------------------------

Newsgroups: sci.electronics
From: markl@research.nj.nec.com (Mark Lee)
Subject: GPIB control via Macintosh
Originator: markl@research.nj.nec.com
Organization: NEC Research Institute
Distribution: usa
Date: Tue, 15 Sep 92 12:42:19 GMT

I am trying to convert my lab from MS-DOS based control to Macintosh
based control.  All my instruments communicate using the GP-IB (IEEE-
488) standard, which I like very much and want to keep.

Does anyone out there have any experience with or recommendations for
GP-IB control software and hardware that will run on, say, a Mac IIci or
a Mac IIfx?  Replies can be emailed to me at markl@research.nec.com.

Thanks in advance,
Mark

Newsgroups: sci.electronics