HDTenEightyP/NetNews huggingface dataset:
From: jeh@cmkrnl.com
Newsgroups: sci.electronics
Subject: Re: FM stereo in TIME domain. (Was Re: How does stereo FM radio work?)
Date: 4 Oct 92 22:05:23 PDT
Distribution: na
Organization: Kernel Mode Consulting, San Diego, CA

In article <1992Oct03.042813.15261@ssc.com>, markz@ssc.com (Mark Zenier) writes:
> In article <1992Oct1.165659.8131@bnr.ca> mwandel@bnr.ca (Markus Wandel) writes:
>>Say that everything was based on square waves, and that you started out
>>with a 38KHz clock waveform.  Based on this clock, you alternately select
>>the left or the right channel for transmission, transmitting a sequence
>>of samples L, R, L, R, L, R, etc.  You also add a 19KHz pilot tone at
>>half the clock frequency.
> 
> Well, damn.  If you plot it out on paper, it does work.  You end
> up the L+R, added with the L-R (or R-L) times the 38 kHz subcarrier.
> 
> Getting the 19 kHz phase just right could be a problem, as would getting
> the lowpass filter needed to round off the sharp edges without messing
> up the phase response.
> 
> Did any commercial gear work this way?

Someone else mentioned that at least one of Heath's top-of-the-line receivers
did.  And many (most?  all?) recent color tvs demodulate the 3.58 MHz chroma
subcarrier this way. 

	--- Jamie Hanrahan, Kernel Mode Consulting, San Diego CA
Internet:  jeh@cmkrnl.com, hanrahan@eisner.decus.org, or jeh@crash.cts.com
Uucp:  ...{crash,eisner,uunet}!cmkrnl!jeh
Newsgroups: sci.electronics
From: kim@ee.ualberta.ca (Kim Adams)
Subject: Need advice on PCB packages for PC
Reply-To: kim@ee.ualberta.ca (Kim Adams)
Organization: University of Alberta Electrical Engineering
Date: Mon, 5 Oct 1992 15:03:57 GMT

Hi!

We would like to purchase packages for schematic diagrams and PC 
board layouts.

We have a 486 with OS/2, $2500 Canadian. Windows is coming soon.

Autorouting would be nice, but, could do without it.  For now all we
need is for the two programs to talk to each other and have an easy user
interface.

Thanks in advance for your advice on the best bang for the buck.

Kim
Newsgroups: sci.electronics
From: rob@dexter.psych.umn.edu (Robert Stephens)
Subject: IBM Keyboard Info
Organization: University of Minnesota
Date: Mon, 28 Sep 1992 21:19:31 GMT


I need some technical info on the circuitry,
and pinouts for a standard IBM keyboard.\

Could someone please E-mail some info to me?

Thanks in advance.
 
---------------------------------------------
Robert C. Stephens   rob@dexter.psych.umn.edu
---------------------------------------------
Human Factors Research Laboratory
University of Minnesota
60 Norris Hall
172 Pillsbury Dr. SE
Minneapolis, MN  55455
---------------------------------------------
Phone: (612) 626-7521
---------------------------------------------

Newsgroups: sci.electronics
From: neal@cmptrc.lonestar.org (Neal Howard)
Subject: Re: Russian tubes
Date: Mon, 5 Oct 1992 16:09:09 GMT
Distribution: usa
Organization: CompuTrac Inc., Richardson TX

In article <1992Oct2.151028.29255@b30.ingr.com> medin@catbyte.b30.ingr.com writes:
>In article <1992Oct1.165047.3239@cs.ucf.edu>, crochet@next3.acme.ucf.edu (Larry Crochet) writes:
>|> Can anyone recommend importers of Russian made tubes?  I'm particularly  
>|> interested in type 6550 tubes.Someone had told me that the former Soviets  
>|> can export and sell tubes at a very low price.
>|> 
>|> Thanks,
>|> 
>|> Larry 
>
>I don't have the issue here, but the most recent Radio Electronics
>mag I received had a one page ad for a tube importer in the middle
>ad section... Soviet tubes were included.
>
>-- 

Also look in "Nuts and Volts" mag. (kinda like the "Auto Trader" but for
electronic goodies instead of cars). If you need small quantities fast,
try a music store that sells electric guitars & amps. Peavey markets the
"SOVTEK" brand of 6550's for replacements for tube-type guitar amps and
they are significantly cheaper than the GrooveTubes brand. Peavey also
sells in bulk if you go to a store than has a repair shop that is a Peavey
warranty service center and talk the technicians into selling them by the
case for a discount. I worked for one for a few years while in college and
used to get them for about $12 each. The SOVTEK 6L6 (5881's actually) were
pretty good for guitar amps also and used to cost me about $9 each.
<--------------------------------------------------------------------->
< Neal Howard    DoD #686             | '91 Harley Sportster XLH-1200 >
< email: neal@cmptrc.lonestar.org     | '70 Kawasaki G4-100cc dirtbike>
< CompuTrac, Inc. (Richardson, TX)    | '69 Cougar XR7-GT390          >
<--------------------------------------------------------------------->
From: pandey+@cs.cmu.edu (Manish Pandey)
Newsgroups: sci.electronics
Subject: Suppliers of Signetics / National Semiconductor parts
Date: 5 Oct 92 20:36:53 GMT
Article-I.D.: cs.Bvo19K.oM.2
Distribution: usa
Organization: School of Computer Science, Carnegie Mellon


 I am looking for suppliers of Signetics / National Semiconductor
parts ( other than Digi-Key ). Do you know of any ? 

 I will post a summary on this newsgroup.

Thanks a lot,

Manish Pandey
************************
School of Computer Science
Carnegie Mellon University
(412) 268-3054 / (412) 421-8403 (home)
pandey@cs.cmu.edu
-- 

Manish Pandey
SCS-CMU 412-268-3054(w) 412-421-8403(h)
pandey@cs.cmu.edu
From: Jeff.Dairiki@mailbox.bison.mb.ca (Jeff Dairiki)
Newsgroups: sci.electronics
Subject: 02/Followup: Help! My CD player sk-sk-sk-sk-skips
Date: 25 Sep 92 05:52:05 GMT

till quite a few people who believe that a well-designed
(high linearity) multibit DAC sounds better than a fast 1-bit or low-bit
DAC.  In general, I believe that there's no general answer to the
question... there are good-sounding and bad-sounding CD players of both
types.

In effect, a 1-bit or low-bit converter takes this [the oversampling]
process to an extreme...  it does almost all of the filtering using
digital mathematics, uses a _very_ fast converter (the equivalent of
256x oversampling, or even more) and then uses a simple one- or
two-stage analog filter.


(End of quoted materials)


So it seems to me that the new 'one-bit' CD player technology is just a
cost cutting measure and provides no increase (though probably no
decrease in audio quality.)

It has also been clarified that neither oversampling or one-bit A/D's
have anything to do with error correction schemes, or (of course) the
quality of the transport and optical stuff.  Therefore this information
is of no use in selecting a new CD player which is less prone to slip.

Evidently, Sony has a new portable (D-515, I think?) out which has
enough RAM inside to buffer about three seconds worth of music.  Thus it
should be able to skip for three seconds before the listenters pleasure
begins to suffer.  This new unit is obviously the most expensive that
money can buy...


Thanks Again to all past and future respondents...

Jeff
dairiki@u.washington.edu
-- 
-----
==>{ Jeff Dairiki   (KI6MO/7)  } University of Washington           
   { dairiki@u.washington.edu  } Applied Physics Laboratory        
   { (206)543-6262 / 543-1399  } 1013 NE 40th St; Seattle, WA 98105

 * Origin: The Electronic Mailbox (1:348/7.0)
Newsgroups: sci.electronics
From: gsulliva@enuxha.eas.asu.edu (Glenn A Sullivan)
Subject: Re: Infra Red Data Link: Need Help building one
Summary: Computing NOISE FLOOR for IR links
Organization: Arizona State University
Date: Sun, 4 Oct 1992 06:35:47 GMT

 pandey+@cs.cmu.edu (Manish Pandey) writes:
.....[lots deleted]....
>  I need suggestions on how to design and build such a system. Any ideas
> you have may be useful to me. So please send them to me. My main difficulty
> is with the actual analog/optoelectronics portions of the link. ....
......
Assume your LEDs output 10milliwatts, spread uniformly over a hemisphere.
[Actually, it ain't uniform at all.] Assume your pickup is 20 feet away. And
that your pickup area is 1/16 X 1/16 inch. The "path loss" is the ratio
of the pickup area, divided by the hemispherical area, at a 20 foot radius.
So, [(1/16 inch) X (1/16 inch)]                           1/256
---------------------------------------------------- = -----------------
[ (1/2 == hemi) * 4 * PI * (20 feet * 12 inch/foot)^2 ]   2*PI*240^2

or about 2*PI*256^3. For ease, use logarithms (and soon, decibels)
   about 0.65 + 3*2.3 = 7.4, or about 25 million. Or, using binary powers,
   1.5*2^26, giving (more exactly) about 50 million. Or, 77dB loss.

Our available OPTICAL power was +10dBmilliwatt. Our received power was
+10 - 77 , or -67dBm; for those wanting "watts", this is -97dBWatts, or
2 * 10e-10 watts.

A typical phototransistor (not Darlington) gives 1 milliamp collector
current per microwatt of optical energy (remembered from various system
designs of laser rangers and IR beacons). We have not 1 uW of optical energy,
(which would be -30dBm) but 2*10e-4 uW. 

Assume 100 picofarads collector capacitance for your phototransistor.
To provide 10 microseconds risetime, we could use a 100Kohm resistor.
This would, of course, easily lead to saturation (and greatly slowed response)
for strong signals, for daylight, for incandescent and flourscent lights.
So use a collector resistor of 1K ohm. And figure how to keep the transistor
in its linear region, despite daylight, and also servoing out the 60Hz.

Our voltage is Current * resistance. 
The current is 2*10e-4 microwatt * 1mA/uW, or 0.2microAmps.
Our voltage is 0.2millivolts.

What is the thermal noise?
4*K*T*B*R, assuming NO NOISE CONTRIBUTED by phototransistor (seriously wrong).
K is Boltsmann's COnstant
T is room temperature (though John Nagle uses thermoelectric coolers here)
B is bandwidth of your pulse processor; try 1/(3*risetime)
R is the collector resistor.

But you are ignoring 10 or 20 or 30dB noise contribution by phototransistor.

Allen Sullivan
Designer of RF/video circuits for GO-Video
CS PhD student Arizona State Univ
From: jg3o+@andrew.cmu.edu (Jason Ari Goldstein)
Newsgroups: sci.electronics
Subject: 8259 PIC --> 8051
Date: 28 Sep 92 11:52:44 GMT
Article-I.D.: andrew.Qelq_Ai00WBKM61nAd
Organization: Senior, Physics, Carnegie Mellon, Pittsburgh, PA

Hey now,

Has any one ever connected up an 8259 Programmable Interrupt Controller
to an 8051?  I happened to stuble across the 8259 and it seems to do
what I need (that is - monitor 8 sources).  Is there any other PIC out
there that might be simpler to interface? Etc. Etc.

Thanks a lot in advance.

Later...

Jason A. Goldstein
___________________________________________
I'm a peripheral visionary...
I can see the future but only off to the sides.

Over, Finished, Gone, Done, Out.  (Finally)
Xref: sparky sci.electronics:16437 sci.engr.mech:372
From: flip@tbd2.brl.mil (Philip J. Peregino )
Newsgroups: sci.electronics,sci.engr.mech
Subject: Re: Endevco address/ph no.
Date: 1 Oct 92 17:58:58 GMT
Followup-To: sci.electronics
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.

In article <vc_p==m@dixie.com> jgd@dixie.com (John De Armond) writes:
>I've misplaced my Endevco (the accelerometer people) catalog.  I'd appreciate 
>someone sending me the address and phone number of them.

30700 Rancho Viejo Road
San Juan Capistrano, CA 92675
714-493-8181
Newsgroups: sci.electronics
From: cshort@nmsu.edu (Spmg*d, Lord of Potted Meat Product)
Subject: Re: Are HeNe lasers polarised?
Organization: Computing Research Lab
Date: Wed, 30 Sep 1992 07:02:55 GMT

>>>>> On 29 Sep 92 06:16:38 GMT, rxtajp@minyos.xx.rmit.oz.au (Andrew Pettifer) said:

> NNTP-Posting-Host: minyos.xx.rmit.oz.au
> I would REALLY LIKE to have an answer to this question, i suspect that they
> usually are, but i hope otherwise.
> If someone could let me know i would be eternally grateful........

it is certinally possible to get non-polarised HeNe's. they tend to
run a little cheaper then their polarised brothers.

i picked up a nonpolarised 5.3mw HeNe head for $125. they're not hard
to find.

c.
--

                                                                      |S
  |------------------------|                                          |P
  |don't fear the hippie   |-------------------------------           |L
  |he's got mind control-dm|    spamgod is: cshort@crl.nmsu.edu       |E     
  |------P|-----i was driving at the speed of light and turned on my  |E
         E|   headlights. the light piled up on my windshield like----|N ----|
         A|   wet toilet paper.            ----------------|Yak Cheese Abuser|
	 C|				                   |-----------------|
         E|
Newsgroups: sci.electronics
From: rky57514@uxa.cso.uiuc.edu (Tall Cool One )
Subject: How do those chaser lights move back and forth??
Organization: University of Illinois at Urbana
Date: Thu, 1 Oct 1992 04:18:20 GMT

Hi,

	I've been wondering for a long time - How do those moving lights work?
Specifically, those lights arranged linearly that seem to move from one end
to the other, and then reverse direction and move toward the other end.  
Kinda like the lights mounted on K.I.T.T., that car from Knight Rider..
(Remember that TV series??).  Can I somehow do it with 4017 decade counters??
Any ideas would be greatly appreciated.  Thanks.


 _I_______________________________________________________________________I_
(_@_)                                                                   (_@_)
|   |   Raymond Yeung                   Internet: Nimbus@uiuc.edu       |   |
|   |                                  NeXT mail: rky57514@             |   |
|   |   EE student at the                         sumter.cso.uiuc.edu   |   |
|   |   University of Illinois                                          |   |
|   |   at Urbana-Champaign           CompuServe: 70700,1011            |   |
(___)-------------------------------------------------------------------(___)
  I                                                                       I
From: princecr@mala.bc.ca
Newsgroups: sci.electronics
Subject: DC to AC help
Date: 28 Sep 92 09:56:40 -0700
Organization: Malaspina College

	If I have a DC current how can I go back to an AC current???  This has
confused me greatly.  Can anyone help?
						chris.
From: wjm@utrcv1 (Bill)
Newsgroups: sci.electronics
Subject: TTY Deaf Service?
Date: 30 Sep 92 16:32:00 GMT
Organization: United Technologies Research Center
News-Software: VAX/VMS VNEWS 1.41

Before I ask my question, I must give some background info:

I have what is referred to as a 'TTY' device.  Basically it is a small 
computer terminal type device used for communicating over the phone lines 
with some friends who are deaf.

It consists of a keyboard, single line flourescent display, and an 
accoustic coupler for a phone's handset.

As I understand things, the TTY service for the deaf runs at some 
non-standard (per today's modern computer equipment), settings.  I think it 
is something like 75 baudot, which defines its binary character set 
and transmission speed.  (Suppossedly this is still used because the TTY 
service was originally set up by the phone company using old mechanical
teletype devices, and newer TTY units must adhere to the standard for 
compatibility.)

Now for my question:

Is there a product available (or plans for a kit), that would allow me to 
use my PC as a TTY device?

Besides the luxury of a nice keyboard and monitor, it would be convenient 
for storing messages or sending pre-written messages.  (With appropriate 
software.)  And a direct phone connection via my modem would be nicer.

Any help would be greatly appreciated,

+ ><> + ><> + ><> + ><> + ><> + ><> + ><> + ><> + ><> + ><> +
+   __          United Technologies Research Center         +
+  /__)  . / /  Silver Lane MS 74, East Hartford, CT 06108  +
+ /___/_/_/_/_  (203) 727-7484  Internet = WJM@UTRC.UTC.COM +
+   Mazeika                                                 +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+ God's got an army, not afraid to fight.                   +
+ Soldiers of the cross, and children of the light.         +
+ Warriors of righteousness, with healing in their hands.   +
+ God's got an army, marchin through the land.     -Carman  +
+ <>< + <>< + <>< + <>< + <>< + <>< + <>< + <>< + <>< + <>< +
Newsgroups: sci.electronics
From: davesum@wam.umd.edu (David Andrew Sumner)
Subject: Hitachi IC's
Originator: davesum@rac1.wam.umd.edu
Organization: University of Maryland at College Park
Distribution: usa
Date: Mon, 28 Sep 1992 03:37:47 GMT

Does anyone know where I can find a Hitachi HD440072.  I've got a
schematic for a VGA to NTSC converter, but I can't find the Hitachi
IC that it requires.  correction.  I can't find anyone willing to
sell it in lots of less than 100.  
Newsgroups: sci.electronics
From: medin@catbyte.b30.ingr.com (Dave Medin)
Subject: Re: Soil Humidity Sensors
Reply-To: medin@catbyte.b30.ingr.com
Organization: Intergraph Corporation, Huntsville AL
Date: Thu, 1 Oct 1992 15:06:03 GMT

For soil moisture detection with a set trip point, try using a National
LM1830 (from Digi-Key, 1-800-344-4539). The chip uses an AC excitation
signal so it won't cause electrolytic corrosion of your sensors, and works
by detecting the level of its excitation signal. It is simple to apply
(the National Linear data book has some ap notes).

-- 
 --------------------------------------------------------------------
       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: sehari@iastate.edu (Babak Sehari)
Subject: Re: Ultra-stable FM transmitter?
Originator: sehari@vincent2.iastate.edu
Organization: Iowa State University of Science and Technology, Ames, Iowa.
Date: Sun, 27 Sep 1992 19:14:32 GMT

In <1992Sep22.222924.1@acad2.alaska.edu> aslt@acad2.alaska.edu writes:

>Hi all,

>I need a mono FM transmitter in the 88-95 MHz range.  Couple of hundred mW or
>so (part 15?).  The input will be line-level out of a mixing board.  
>We will be transmitting primarily voice, so hi-fi is not 
>really necessary (but would be nice 8^)).  What is important is broadcast 
>frequency stability over the long term (as in months if not years) with varying
>temperatures, humidity, supply voltages, phase'o'th'moon, etc.  At first guess,
>this means crystal-based design to me, but maybe there are other ways...

>Anyway, are there any (cheap-and-simple-and-using-readily-available-parts) 
>cookbook type circuits for this type of thing, and if so, where would I 
>find it?

>BTW, I've tried the BA1404, but it drifts all over the place.  Works
>wonderfully otherwise.  I also looked in the ARRL handbook, but all it
>gave was a block diagram.

>Thanks in advance.  E-mail replies welcome.

>Lee

Look it up in "The Encyclopedia of Electric Circuits", by R. F.  Graf.
Page: 681  It is stable for most practical purposes, unless you are looking
for narrow band FM transmitter and receiver.  Then you need a Crystal 
Oscillator.  Look it up in: Analysis and design of Integrated Electronic
Circuits, P.  M.  Chirlian, published by Harper & Row.
You could also look it up in:   Electronic Devices and Circuits:  Discrete
and Integrated, Mohammed S.  Ghausi; Pub. HRW.

                    With highest regards,
                         Babak   Sehari.
From: dino@inqmind.bison.mb.ca (Tony stewart)
Newsgroups: sci.electronics
Subject: Re: Which Diode?
Date: Tue, 29 Sep 92 19:37:52 CDT
Organization: The Inquiring Mind BBS  1 204 488-1607

gallant@oasys.dt.navy.mil (Robert Gallant) writes:

> Hi, I am trying to find the proper diode to combine the trigger signals
> from two ignition coils on my car.
> 
> This combined signal is used to trigger a new fuel injection computer
> (so there will be little to no current through the diodes).
> 
> Here is a diagram:
> 				D1
> 			  ------>|----------------------------|
> 			  |                              D2   |---OUT
> 	 (+)       (-)    |       (+)       (-)       --->|---|
> 	 ==        ==-----|       ==        ==--------|
>        ----------------   |     ----------------      |
>        -              -   |     -              -      |
>        -  Coil 1      -   |     -   Coil 2     -      |
>        -              -   |     -              -      |
>        ----------------   |     ----------------      |
> 			  |                           |
> 			 ---                         ---
> 			 --- Condensor 1             --- Condensor 2
> 			  |                           |
> 			  |                           |
> 			 GND                         GND
> 
> This is the stock setup except for the two diodes.
> 
> The voltage present at the (-) terminals should be alternating between
> 0 and +14.1 volts at 300 Hz maximum.
> 
> I have tried 1N4148 diodes with a 100K ohm resistor from OUT to GND.
> The diodes went bad immediately.
> 
> Any help would be appreciated.
> 
> Rob
> gallant@oasys.dt.navy.mil

1n4148's are low peak inverse voltage rated and your cct will generate 
large resonant peaks when the coils are switched off. When they are 
reverse biased and reach their rated voltage, then they can act as Zener 
diodes, thus you have a low impedance path between the 2 diodes an they 
carry enough current to self destruct.
Use 1N4005 rated for 600V and use a separate 100kohm res. for each diode 
rather than tying the diodes together.
THAT's ALL.!$$

dino@inqmind.bison.mb.ca
The Inquiring Mind BBS, Winnipeg, Manitoba  204 488-1607
From: rkarlqu@hpscit.sc.hp.com (Rick Karlquist)
Date: Tue, 6 Oct 1992 18:21:04 GMT
Subject: Re: 25 ohm coax cable
Organization: Hewlett-Packard, Santa Clara, CA
Newsgroups: sci.electronics

In sci.electronics, dhina@dxcern.cern.ch (Mourad Dhina) writes:

> Hello,
> i am trying to realize a circuit i found in an electronics magazine.
> one of the components it uses is a semi-rigid coax cable of
> 25 ohms impedance. this is the first time i hear of this (i only
> knew 50, 75 and 93 ohms cables, which are standard). anybody
> knows where to find this?
> Mourad

You used to be able to buy 25 ohm semi-rigid coax from Precision 
Tube in Pennsylvania, but I am not sure they still make it.
Most people just use two 50 ohm lines in parallel.

If you don't mind flexible coax, here's a trick I used.  I ordered
"Braid-shielded teflon-insulated wire" from Alpha wire.  By 
choosing #18 wire, and a very thin insulation (I think is was 
something like 10 mils thick), I ended up with 16 ohm "coax" which
worked quite well to at least 100 MHz.  If you ordered the
#20 or #22 gauge version (which they also make), you should be 
able to get up to 25 ohms.  Anyway, they're all standard catalog
items.

Rick Karlquist
rkarlqu@scd.hp.com
Newsgroups: sci.electronics
Subject: Need Spice Model for 2N4338
From: hhallika@zeus.calpoly.edu (Harold Hallikainen)
Date: Sat, 03 Oct 1992 07:09:08 GMT
Organization: California Polytechnic State University, San Luis Obispo


Hello!

	Wonder if someone could email me a pspice model for a 2N4338
JFET, or point me to an FTP site that may have such a model!
	Thanks!

Harold
From: w644171c@edinboro.edu
Newsgroups: sci.electronics
Subject: HELP! NEED A TRACKING DEVICE.
Date: 2 Oct 92 01:40:39 GMT
Organization: Edinboro University of Pennsylvania

I'm looking for a electronic tracking device, kit or assembled form.
A few ex-military friends and I were approached by the college R.O.T.C.'s
to have a friendly war game.  We intend to win ! ! !  
We hope to place tracking devices on them and take them prisoners without

firing a shot.
If anyone can help me out please reply here or by E-MAIL.


Thanks

Paul