vergita...
This page, from the TechTarget website, defines
digital-to-analog conversion, and gives the
first example of a device which does this:
"Digital-to-analog conversion is a process in which
signals having a few (usually two) defined levels
or states (digital) are converted into signals
having a theoretically infinite number of states
(analog). A common example is the processing, by
a modem,of computer data into audio-frequency
(AF) tones that can be transmitted over a twisted
pair telephone line. The circuit that performs this
function is a digital-to-analog converter (DAC)"
"Binary digital impulses, all by themselves, appear
as long strings of ones and zeros, and have no
apparent meaning to a human observer. But when
a DAC is used to decode the binary digital signals,
meaningful output appears. This might be a voice,
a picture, a musical tune, or mechanical motion."
http://whatis.techtarget.com/definition/0,,sid9_gci213875,00.html
The audio output is the screaming stream of noise
you hear when you're dialing up to your ISP with
a standard 56K modem, or when you pick up the phone
when it's receiving a fax signal.
Other examples of digital signals, presented to the
user in analog form, would be the streaming audio
from an 'm3u' format playlist on MP3.com, or a
Flash video presentation.
http://www.MP3.com
http://www.macromedia.com/
Another would be your CD player, which uses a
Digital Audio Converter to translate the digitally
encoded music on the CD into analog audio output.
And, of course, the DVD converts the signals into
both music and video.
An excellent discussion of the electronic circuitry
involved, is on this page at Play-Hookey.com:
http://www.play-hookey.com/analog/d2a_converter.html
And this page, by Jim Thompson of the University of
Washington, details the technology behind the 1-bit
DAC commonly used in CD players:
http://www.ee.washington.edu/conselec/CE/kuhn/onebit/primer.htm
Yet another example of such a device is the cable modem
which I'm using to connect with the internet right now.
The following page, cached by Google, from the South
Western site (South-Western is a division of Thomson
Learning) outlines the differences between the standard
(56 Kbps) telephone modem, the DSL modem, and the cable
modem:
"...cable modems, using TV coaxial cable as the
transmission medium and advanced digital-to-analog
technology, achieve typical transmission speed of
2.5 Mbps."
http://216.239.53.100/search?q=cache:WsisWK5beysC:www.swcollege.com/acct/hall_01/comp_app_rev.doc+%22digital+to+analog+technology%22&hl=en&ie=UTF-8
or, in pdf file format, here:
http://www.swcollege.com/acct/hall_01/comp_app_rev.doc
Searches done, via Google:
"digital to analog"
://www.google.com/search?num=50&hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=%22digital+to+analog%22
"digital to analog technology"
://www.google.com/search?num=50&hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=off&q=%22digital+to+analog+technology%22
Please do not rate this answer until you are satisfied that
the answer cannot be improved upon by means of a dialog with
the researcher through the "Request for Clarification" process.
sublime1-ga |
Clarification of Answer by
sublime1-ga
on
08 Dec 2002 15:14 PST
vergita...
As indicated in my comment at your other post of this
question, I am adding references to resources with
diagrams of the conversion process.
Digital signals are often stored, as in the case the
CD or DVD, and are then retrieved and converted into
audio format, as illustrated in the diagram on this
page, by Mike Wozniewski, from the McGill University
School of Computer Science:
http://www.cs.mcgill.ca/~mwozni/DigAudio_reproduction.html
Another page which has diagrams which you may find useful
is this one, by Mihai Nadin, Head, Program in Computational
Design, University of Wuppertal, Germany; President,
MINDesign, USA/Germany:
http://www.code.uni-wuppertal.de/uk/computational_design/who/nadin/publications/articles_in_books/art&science/welcome.html
Scroll down to see the diagrams.
There are other diagrams which are available from the
search outlined below, however they are in pdf file
format. To view this files, you can download the free
Acrobat Reader from the Adobe website, here:
http://www.adobe.com/products/acrobat/readstep2.html
Searches done, via Google:
"digital to audio" diagram
://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=%22digital+to+audio%22+diagram
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