Circuit for measuring parameter of time-base error of pulse train, and optical disk recording apparatus

摘要

A PLL circuit ( 24 ) reproduces a clock signal from a reproduction EFM signal of an optical disk ( 10 ). A phase error signal (pco) of the PLL circuit ( 24 ) is converted into an absolute value by an absolute value circuit ( 38 ), and is averaged for each subcode frame period by an accumulator ( 40 ). The recording beam power of a laser beam is determined on the basis of an output of the accumulator ( 40 ). A pulse-length discrimination circuit ( 26 ) discriminates the pulse length of the reproduction EFM signal. A specific-pulse-length phase-error-signal extracting circuit ( 42 ) extracts the phase error signal (pco) of a specific pulse length. The extracted phase error signals (pco) are averaged for the respective subcode frame periods by a accumulator ( 44 ). The time base of the corresponding pulse length of the recording EFM signal is corrected on the basis of the output of the accumulator ( 44 ).