Aiwa XR-MD95 What Is An Md Mini Disc?, Types Of Mds, The Limitations Of Md, Quick random access

WHAT IS AN MD (MINI DISC)?

An MD is only 64 mm (2 5/8 in.) in diameter, about half the size of a conventional CD. But an MD can be used to store and playback a full 74 minutes of data such as a CD. Unlike a CD, MD comes in a plastic cartridge, so that it can be handled with ease. The cartridge also protects the disc inside from shocks, dust and scratches. Unlike cassette tapes, which can become stretched or tangled, an MD is an excellent durable media.

TYPES OF MDS

There are two types of MDs: “Optical discs” and “Magneto-optical

discs”.	Both	types	use laser	beams	and optical pick-up
technology to		read	recorded	during	playback.
Optical	discs

These are playback only discs. Like CDs, they are used as

prerecorded	music	discs. You	record or edit them.
		data
			The	shutter	covers
		Label	the	opening	only on
		cannot	the	non-labeled
			side	of the	MD.
Recordable	MO*l	discs

These are recordable discs which can be recorded on again and again, like cassette tapes. The recording method called magneto-optical technology employs a laser and magnetism to record signals. Therefore, the quality of recorded sound does not deteriorate even after many playbacks and recordings,

4 m

El+LabelThe shutter covers the opening on both sides of the MD.

*’ MO: An abbreviation of Magneto Optical

Ultra compact size made possible by ATRAC*2 technology

A newly developed digital audio compression technology called the ATRAC system automatically extracts only the frequencies that are actually audible to the human ear and cuts the frequencies which are inaudible. This compresses the amount of data to be recorded to 1/5 of the normal amount. The ATRAC system is based upon studies carried out in the field of auditory psychology and does not impair the quality of the audible sound.

*2 ATRAC: An abbreviation of Adaptive TRansform Acoustic Coding

Quick random access

One of the great features of the MD is that you can search for desired tracks quickly. There are also quick and easy functions for random playback, in which the order of the tracks can be rearranged at random, and for renumbering tracks enabling them to be played in any order.

THE LIMITATIONS OF MD

Recording on the MD is performed differently from that of a cassette tape or a DAT. Therefore, the MD system is subject to the following restrictions.

“TOC* Full” is displayed even if the recording time

does not reach the maximum recordable time of the

disc (60-minute or 74-minute).

“TOC Full” is displayed when 254 tracks are already recorded on a disc, without respect of the recording time.

*TOC: An abbreviation of Table Of Contents,

“TOC Full” is displayed even if a disc is not fully recorded on.

If there are lots of emphasis data in a particular track, the unit handles the data as index codes, and tracks are counted, in addition, without respect of the time and number of tracks.

The remaining time on a disc is not increased even after some short tracks have been erased.

When the remaining time on a disc is displayed, which may not be increased even after erasing short tracks because the sections less than eight seconds are not counted.

Tracks cannot be joined (the COMBINE function does not function).

Tracks created by editing may not be joined.

The total of the recorded time and the remaining time on a disc does not match with the maximum recordable time of the disc (60-minute or 74-minute).

Recording is performed by the minimum unit of one cluster (two seconds). Even if the recorded section is shorter than two

seconds, a two-second space is needed in recording. Therefore,

M

the available time becomes shorter. If there are scratches on a disc, the available time becomes shorter as well, because the sections which are scratched are automatically erased.

Track numbers may not be registered properly.

When recording from a CD through digital inputs (using the CD

*MD button), small tracks may be created depending on the contents of a CD.

When using the AUTO MARK function, track numbers may not be registered properly depending on the contents of the CD.

Digital inputs may not be acceptable.

When digital recording is attempted from recorded material with copyrights, digital dubbing cannot be performed to a recordable MD from another MD recorded in digital, because of the built-in record restriction function which complies with the SCMS* standard.

*SCMS (Serial Copy Management System) is the standard to restrict single digital dubbing between the digital audio system thus protecting copyrights.

(prerecorded”s%und source) Digital dubbing

:7’’”9FE9

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