SJ-MD100
– 8 –
Y
The figure below shows the composition of an MD system. An MD system uses six LSIs that were specifically
developed for MD. The following is a description of the functions of those six LSIs.
Y
This LSI controls the laser and performs the detection processing of the servo signals and of the audio signals from
the disc needed to correct the position of the laser spot.
Y
This LSI receives the laser spot position correction signals from the RF amplifier and controls the focus servo that
ensures that the laser spot is correctly focused on the disc surface and the tracking servo that controls the disc
rotation direction to ensure that the pits on the disc surface are traced correctly.
Y
This LSI demodulates the address signals that are recorded in the pre-group on a playback/record magnetooptic
disc MD. In addition to reading the absolute addresses, the address decoder also functions to control the rotation
speed so that the servo signal is obtained at a constant linear speed at the location being read.
Y
This is the main signal processing LSI. EFM is a circuit which converts 8-bit digital signals into the 14-bit format
recorded on the disc. It also performs signal processing for error correction, changing the interleaving format in
order to use the ideal algorithm for MD. In addition, this LSI also performs other tasks such as encoding during
recording and decoding during playback.
Y
This memory controller provides a "shock-proof" memory.
Y
This LSI performs the signal processing for the ATRAC compression technology that was specifically developed
for MD.
Y
New genaration LSIs developed for higher performance of MD system.
There are reduced to three LSIs.
1. RF amplifire
2. 4 ch driver (servo control)
3. Signal processor
U
Development of 6 LSIs
A
RF amplifier
B
Servo control circuit
C
Address decoder
D
EFM and ACIRC encoder/
decoder
E
A n t i - v i b r a t i o n m e m o r y
controller
F
Audio signal compression
encoder/decoder
U
New generation LSIs
D
Composition of an MD system
Block Diagram for playback/record MD circuit
