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ABC of electronics terms

(To find chips for distinct functions, see the functional pages.)

D

DAA

Data Access Arrangement

This is a telephone line interface
Try Cermetek, TK or Xecom
Or ask Kerry Berland <kberland@ix.netcom.com>
Or see the telecom section of the latest reference quide of Compliance Engineering.

DAC

Digital to Analog Converter

• users.desupernet.net/sokos/ad.txt

DAQ board

Where	Manufacturer
www.natinst.com/	National Instruments

Data communications

Handbook of Data Communications

John D. Lenk

Prentice-Hall, 1984

Data translation

Where	Manufacturer
www.telebyteusa.com/	Telebyte Technology

Datacomm IC

Where	Manufacturer
www.metalink.co.il/	Metalink Transmission Products

Date calculations

www.ap.columbia.edu/courses/cs1005x/HW03.html

home.capecod.net/~pbaum/date/rata.htm

home.capecod.net/~pbaum/date/week.htm

book: Almanac for Computers by the Nautical Almanac Office, United States Naval Observatory, Washington, D.C. and the Royal Navy

DC-DC Convertor

Where	Manufacturer
www.lambdaaa.com/	(Lambda) Advanced Analog
www.powertrends.com/	Power Trends
www.vicr.com/	Vicor

DCF-77

This is German/European system for broadcasting the time (on the long wave radio frequency band, if I remember correctly...)
Time info transmitter in Germany (Mainflingen).

local	More
www.linux-magazin.de/ausgabe.1996.11/Funkuhr/dcf77.html
www.prog-link.com/DCF77/DCF-11.html
www.prog-link.com/DCF77/DCF-17.html

Debugger

See Monitor and Debugger

Decoder

In general a decoder decodes something that has been coded. Coding is normally done for protection but sometimes also for compression.
In case of a TV signal decoder, there are several methods to decode it. A very simple on is reversing the horizontal and/or vertical sync signals. TV's don't like this. It's also possible to change these syncs using a quasi-random sequence. The processor in the decoder must know the right pattern to be able to restore the original signal.
Usually cable companies start with a simple decoding algorithm and check how many people will start selling illegal decoders.
Once they know how big this market is and when it's serously threatening their income, they start using a more difficult alogorithm in the decoder...
Opening up the decoder sometimes erases the processor's memory.
What I said above is based on analogue TV signals of course. With digital TV signals it can be done much more sophisticatedly.

Decompiler

www.cs.utwente.nl/~faase/Ha/decompile.html	Frans F.J. Faase <faase@cs.utwente.nl>
www.dur.ac.uk/~dcs0mpw/	Martin Ward <Martin.Ward@durham.ac.uk>
www.dur.ac.uk/~dcs1tmb/home.html	Tim Bull [Gone?]

Desolder

Remove IC*'s from PCB again.

When you have a load of PCB's with possibly valuable chips on them, don't do the desoldering yourself. There are specialized companies that can do it much better. When you do it yourself the IC*'s will have to be checked and straightened anyway which is quite expensive. Mail me instead.

For small amounts: Tricks.

Development tools

www.techonline.com/ - Technical catalog of EDN

Diac

www.americanmicrosemi.com/tutorials/diac.htm

Die

Or 'bare die'
It's the stuff IC*'s are made of and should be handled under special conditions. Don't ever open a box with bare die to look what's inside. It doesn't like this just like photopaper...

See also Chip Supply and Sierra Components and:
www.bgmicro.com/ - B.G. Micro

Digital design

nyquist.ee.ualberta.ca/pub/cookbook/digital/

Circuit examples

Book:

title	order at Amazon USA	price indication
Engineering Digital Design	ISBN: 0126912955	$80

DIN

Deutsche Industry NormGerman industry standard.

www.din.de/

See also ANSI, CCITT, CEN, IEEE, ISO, NEN

Diode

ftp.psyber.com/tcj/faqs/udiode.faq	FAQ in text
www.avtechpulse.com/faq.html/	FAQ in HTML
www.americanmicrosemi.com/tutorials/diode.htm	Tutorial
www.americanmicrosemi.com/tutorials/diodearrays.htm	Tutorial

Where	Manufacturer
www.cdi-diodes.com/	Compensated Devices
www.diodes.com/	Diodes Inc
www.deetee.com/	DT	high performance silicon photodiodes
www.microsemi.com/	Microsemi Corp
www.unitrode.com/	Unitrode

A Schottky diode is a metal-semiconductor junction (rather than a junction between two semiconductor materials), but you don't need to know that. It has a smaller voltage drop when forward-biased, than a regular silicon diode. About half as much, maybe less maybe more. Used when you need a diode with a very low voltage drop. Germanium diodes are another option, but they have their own limitations.Andy

Dioden Datenbuch 1980/81

(in German)

Siemens AG, Bereich Bauelemente, Produkt-Informationen,

Balanstraße 73

8000 München 80

Bestell-Nr. B/2239

Disassembler

ftp.cdrom.com/pub/simtelnet/msdos/disasm/

Disassemblers from the Simtel archives

See also the IDE section.

Discrete components

www.americanmicrosemi.com/faq.htm - FAQ about discrete components

Disk size limitations

Will the problems never stop?

BIOS limitations previously occurred at 528-Mbyte and 2.1-Gbyte capacities.
The next BIOS frontier is the 8.4-Gbyte barrier.

See:
www.seagate.com/support/disc/faq/8point4.shtml

Display

See:

local

Optoelectronics

Distributor

Where	Manufacturer
www.cir.com/	Circuit Specialists
www.compdist.com/	Component Distributors, Inc
www.digikey.com/	DigiKey
www.elexp.com/	Electronix Express
www.jameco.com/	Jameco Electronics
www.marshall.com/	Marshall Electronics
www.mouser.com/	Mouser Electronics
www.nuhorizons.com/	Nu Horizons
www.pios.com/	Pioneer Standard-Electronics
www.potterpower.com/	Potter Production
www.powell.com/	Powell Electronics, Inc
www.tsc.hh.avnet.com/	Hamilton-Hallmark

More

Divide

Dividing is a mathematical operation that is quite expensive in terms of hardware or software time usage, therefore dividing techniques are heavily discussed on embedded software mailing lists.

Here a couple of emails that a lot of people have enjoyed reading in the mean time...
And although you mustn't take everything in it too seriously, it contains a lot of very basic information!

Division techniques for embedded processors.

DOS

Disk Operating System(The OS's before the DOS's were TOS's (Tape Operating Systems)The term was in general use before it became short for MS-DOS or PC-DOS

www.gensw.com/ - Embedded DOS from General Software

DNA computers

Computers that will use DNA strings to do slow but very massively parallel processing.

www.eecis.udel.edu/~dna3/
www.cis.udel.edu/~dna3/
www.sfn.saskatoon.sk.ca/~ae916/
www.informatik.uni-trier.de/~bern/B+W/GI/Announce/1996/DBC96.CFP.html

DRAM

Dynamic Random Access Memory is:

Dynamic	It loses it's contents when not refreshed (SRAM* doesn't)
Random Access	You don't need to read/write all the bits/bytes in succession
Memory	It remembers things

DRAM needs about 4 times as much transistors as SRAM* so it's generally 4 times bigger or 4 times cheaper at any given moment. DRAM is also generally slower.

Succession of DRAM technologies:

DRAM	Dynamic Random Access Memory
FPDRAM*	Fast Page Mode DRAM
EDO	Extended Data Output
SDRAM*	Synchronous DRAM
SDRAM* II	Synchronous DRAM with double data rate (by Samsung, see also DDR)
D-RDRAM	Direct RAMBUS DRAM
SLDRAM	SyncLink DRAM (by Samsung, Hyundai)
DDR	Double Data Rate SDRAM* (by Samsung)
?	Advanced Rambus DRAM (by LG)

More

• users.supernet.com/sokos/dram.zip - Tim Olmstead
• www.siemens.de/Semiconductor/products/ICs/31/pdf/MOD_041.pdf (272 KByte) Brief explanations of currently available DRAM types.

See also:

• www.webopedia.com/

DRAM manufacturers:
Europe:

• Siemens

• Fujitsu
• Hitachi (merged it's DRAM operation with NEC in 199911..12)
• NEC (merged it's DRAM operation with Hitachi in 199911..12)
• Oki
• Toshiba

• IBM
• Micron
• TI (stopped about 199806, products went to Micron if I remember correctly)

• Goldstar/Lucky Goldstar
• Hyundai
• Samsung

DRAM sellers:

• www.kingston.com/
• www.pricewatch.com/
• www.thechipmerchant.com/

(Don't be fooled by others: They often just buy it from the manufacturers above and package it themselves. It's very expensive by now to produce DRAM of the newest generations...)

--Is Japan losing the DRAM race?--
"Japan Inc." is downsizing, causing a number of embattled semiconductor manufacturers to reluctantly concede that they are losing the DRAM production race. In a series of interviews last week, most top chip executives agreed that Micron Technology Inc. and the Big Three South Korean memory-IC suppliers will dominate the commodity DRAM global market that was once Japan's sole domain.
www.ebnonline.com/story/OEG19981105S0026
(This message came from The EDTN Network's "Electronics Alert!", Bulldog Edition: 19981109)

Driver

A driver is a piece of software that is dedicated to handling a certain hardware device. It's a kind of interface between the OS and the hardware. It's usually provided by the hardware maker and distributed on a CD-ROM or floppy together with the piece of hardware. Because it takes a while before the product reaches you after the CD-ROM or floppy has been made, so newer versions of the drivers can often be found on the Internet.

Check the sites in this order:

1. The site of the maker of the product.
2. The site of the maker of the chipset on the product.
3. General driver sites.

Also check:

• The OS maker's site (Microsoft for example.)
• The site of your retailer or their distributor/importer.

See also Operating System.

Driver sites:

www.driverguide.com/	Driver Guide (You need to register first!)
www.drivershq.com/	Drivers headquarter
www.driverupdate.com/	Driver Updates
www.mrdriver.com/	Mister Driver
www.windows95.com/	For Windows95 only?
www.tucows.com/	Ultimate Collection Of Windows Software (where have the drivers gone?)
www.winfiles.com/

DSP

See here.

DTMF

Dual* Tone Multi-Frequency

1	2	3	697
4	5	6	770
7	8	9	852
0	*	#	941
1209	1336	1477	Hz

When you press one of the telephone set's buttons two tones are produced: One signifying the row and the other the column. The frequencies are choosen thus that they don't contain harmonical frequencies of each other. Normal human speech doesn't contain mixed frequencies that are stable for a signifant duration.
Nice DTMF coders are the PCD3311 and PCD3312 by Philips and a nice decoder is the MT8870 by Mitel and Samsung.

local	DTMF and other telecom chips
www.repairfaq.org/ELE/HTML/FAQ/	It's probably here somewhere
nyquist.ee.ualberta.ca/pub/cookbook/faq/DTMF.doc	MS Word format
www.winternet.com/~genave/dtmf.html	More info, introduction
www.parallaxinc.com/downloads/Documentation/Application%20Kits/CM8880%20DTMF%20Transceiver/CM8880%20Transceiver.pdf	For the Basic Stamp by Parallax
www.parallaxinc.com/downloads/Source%20Code/Application%20Kits/CM8880%20DTMF%20Transceiver/CM8880src.zip	For the Basic Stamp by Parallax
www.interstice.com/~sdattalo/technical/theory/dtmf.html	DTMF Theory

DVD

Digital Video Disk, a standard for putting video on new 3.7+ Gb CD-ROM's.

www.tully.com/dvdsig/

DVD Special Interest Group (SIG)