| 摘要 |
PURPOSE:To make possible high speed driving of a laser source through a simple structure by selecting a plurality of multipulse serieses depending on the length of a record mark, subjecting the multipulse series thus selected to P/S conversion, and driving a laser source based on a multipulse pattern obtained by modulating the sum of the plurality of multipulse serieses. CONSTITUTION:An ON/OFF decision circuit 7 decides 1/0 of a PWM signal based on an output from a run length decision circuit 6. When the circuit 7 makes a decision of '1' for next output, pattern memories 9a, 9b load a multipluse(MP) serieses determined by an output from the circuit 6 to shift registers 10a, 10b. Gate circuits 11a, 11b are switched by means of a clock counter 8 and output MP patterns A, B. Level setting circuits 12a, 12b set predetermined recording levels of the outputs A, B and an adder 13 produces a modulated sum of MPs which is then fed to a laser drive circuit 14. Consequently, a laser light source 15 is driven based on an MP pattern. |
