A novel design of physical format coding system (PFCS) is presented based on Multi-level read-only memory disc (ML
ROM) in order to solve the problem of low efficiency and long period of disc testing during system development. The
PFCS is composed of four units, which are 'Encode', 'Add Noise', 'Decode', 'Error Rate', and 'Information'. It is
developed with MFC under the environment of VC++ 6.0, and capable to visually simulate the procedure of data
processing for ML ROM. This system can also be used for developing other optical disc storage system or similar
channel coding system.
A new high efficient DC-free 3-ary run-length limited (RLL) code for 3-level optical recording system is presented. Signal processing techniques, partial-response maximum-likelihood (PRML), which is used for recovery data from readout signal, is discussed.
In order to meet the requirement of focusing in the multi-wavelength mastering system, a pneumatic sensing system is designed. It detects the objective lens position signals and sends to the focus control system as the focus error signals instead of the feedback signals of light intensity used traditionally. So it can solve the auto-focus problem caused by introducing multi-wavelength lasers. The static and frequency response characteristics of the system are tested. It is proved by the experiment that the focus error is under ±0.1μm and can meet the needs of the three-wavelength system.