OPTICAL RECORDING/REPRODUCING DEVICE HAVING A SYSTEM FOR THE REDUCTION OF LASER NOISE WHEN READING DATA FROM THE RECORD CARRIER

摘要

The device described has a first operational state for writing information onto a record carrier (1) and a second operational state for reading information from a record carrier (1). The device comprises a phase-locked loop (3-6) for generating a clock signal (CL) from a reference signal (SCL). The device further comprises a control unit (7) for generating a pulsed transducer control signal (Str) in response to an information signal (Sinfo) and the clock signal (CL). The device also comprises a transducer (10) for generating physically detectable patterns in the record carrier (1) in response to the transducer control signal (Str). The device also comprises a transducer (10) for generating a read signal (Sls) in response to physically detectable patterns in the record carrier (1) in the second operational state. The transducer (10) for generating the read signal (Sls) comprises a radiation source (11). The device further comprises a power supply (7) which supplies the radiation source (11) with an electric power. The phase-locked loop (3-6) comprises memory means (12) for memorizing, in the first operational state, a memory value which is a measure of the supplied clock signal (CL). In the second operational state, the phase-locked loop (3-6) generates the clock signal (CL) in response to the memorized memory value and causes a high-frequency modulation in the electric power supplied by the power supply (7).