Generational Changes in the Minidisc System

Generational Changes in the Minidisc System
August 2002

A few diagrams from Sony documentation indicate the changes that have been made to the Minidisc system over the years.

Intro: Nov 92, MZ-1
ATRAC IC: CXD-2527R. Two chips were used, one each for the left and right channels.
``ATRAC 1 compression and noisy ADC and DAC introduced quite a few digital artifacts and noise into recordings.''

Intro: Dec 93, MZ-R2.
ATRAC IC: CXD-2531AR. Both channels were integrated onto a single chip.
``ATRAC 2 was greatly improved and was possibly one of the biggest leaps in improvement, with noise and digital artifacts greatly reduced.''

Intro: May 95, MZ-R3
ATRAC IC: CXD-2536R. In the third generation, Shock Proof memory controller functions were integrated onto the chip.
ATRAC 3: word and coefficient lengths were improved to 24/16-bits (previous to ATRAC 3 they were entirely 16-bit).
ATRAC 3.5: input width was improved to 20-bits. (Intro: Feb 96, MDS-JA3ES)

Intro: 1996, MZ-R30, MDS-JE500.
ATRAC IC: CXD-2652R. In the fourth generation, EFM ACIRC Encoder/Decoder, ADIP demodulator, and Servo Signal processor functions were integrated onto the chip.
``ATRAC 4 works entirely in 24-bits and has a neat feature that Sony calls Wide Bit Stream'' (Sony defines Wide Bit Stream thus: "The input circuit, the output circuit and their peripheral circuits operate on the 20-bit audio data so that the maximum performance of the ATRAC IC which operates on 20-bit and higher can be fully utilized.")
``ATRAC 4.5 has an improved "Wide Bit Stream" audio resolution of 20 and 24-bits.'' (Intro: Dec 96, MDS-JA50ES)
``ATRAC Type-R has two times more signal processing power than the 4.5 version.'' (Intro: May 98, MDS-JA22ES)