43
En
Eng
lish
AD
DITIONAL
INFO
RMA
T
ION
■
MP3 (MPEG Audio Layer-3)
One of the audio compression methods used by MPEG. It
employs the irreversible compression method, which
achieves a high compression rate by thinning out the data
of hardly audible part to the human ears. It is said to be
capable of compressing the data quantity by about 1/11
(128 kbps) while maintaining a similar audio quality to
music CD.
■
PCM (Pulse Code Modulation)
A signal that is changed to digital format without
compression. A CD is recorded with 16-bit sound at
44.1 kHz. This signal also has a type called Packed PCM
(PPCM) that can be compressed without any loss of data.
■
Sampling frequency
The number of sampling (process for digitalizing analog
signals) per second. In principle, the higher the sampling
rate, the wider the frequency range that can be played
back, and the higher the quantized bit rate, the finer the
sound that can be reproduced.
■
Track
A CD can be divided into a number of segments (tracks).
Each division is called a track number.
■
WMA (Windows Media Audio)
An audio compression method developed by Microsoft
Corporation. It employs the irreversible compression
method, which achieves a high compression rate by
thinning out the data of hardly audible part to the human
ears. It is said to be capable of compressing the data
quantity by about 1/22 (64 kbps) while maintaining a
similar audio quality to music CD.
MPEG Layer-3 audio decoding technology licensed from
Fraunhofer IIS and Thomson Multimedia.
Glossary
Audio information
Copyright and logo marks
“iPod” is a trademark of Apple Computer, Inc., registered in the
U.S. and other countries.
iPod
®
