OPTICAL INFORMATION RECORDING AND REPRODUCING DEVICE

摘要

PURPOSE:To prevent a reproduction signal from having a DC component before it is binary-coded in a reproduction mode with an optical recording disk having a sector structure, by modulating and recording a signal obtained after an exclu- sive OR is secured between the data given from a sector buffer memory and a code string of an artificial random series. CONSTITUTION:The parallel data of four bits is delivered from a sector buffer memory 18 in the timing of a CLK1. Then an exclusive OR is obtained forever bit between said parallel data and the output of a scramble ROM34 which uses the output of a counter 33 using the CLK1 as a clock input as an address input. Then the parallel data is turned into an address input of an ROM35 for modulation and then converted into the modulation data. This modulation data is loaded to a shift register 36 in the timing of the CLK1 and then turned into the serial data by a CLK2 to be supplied to a semiconductor laser driving circuit. An exclusive OR is secured between the modulation data and a random code series by the scramble ROM. Thus it is possible to convert a fixed repetition data into a random form and to modulate it. Then the input data is converted into a random form before modulation, and the ratio between ''1'' and ''0'' of the modulation data is bronght close to 1:1.