Sony MD Walkman MZ-G755 - Manual (Page 73)

73
Explanations
How the MiniDisc got so small
The 2.5-inch MiniDisc, encased in a plastic cartridge that looks like a 3.5-
inch diskette (see illustration above), uses a new digital audio
compression technology called ATRAC (Adaptive TRansform Acoustic
Coding). To store more sound in less space, ATRAC extracts and encodes
only those frequency components actually audible to the human ear.
The meaning of “no sound”
“No sound” describes a recorder condition in which the input level is
about 4.8 mV during analog input or less than –89 dB during optical
(digital) input (with 0 dB as full bit (the maximum recordable level for a
MiniDisc)).