| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve problems that it is difficult to completely cancel a noise, DC is necessary for a reproducing RF signal/power monitor output, and it is difficult to perform non-adjustment, in the conventional noise cancellation circuit using the reproducing RF signal of an optical disk and the monitor signal of a laser beam. <P>SOLUTION: The monitor signal of a laser beam is inputted to a transversal filter 35 via an HPF 33. A reproducing RF signal is subtracted from the pseudo laser noise of a multiplier 37 by a subtractor 32 via the HPF 31. A gain unit 36 supplies a value corresponding to the balance shift of the noise amount of positive and negative polarities of the output signal of the subtractor 32 to the multiplier 37, and multiplies it by the output signal of the transversal filter 35. A noise residual amount corresponding to the modulation signal of the output signal of the subtractor 32 is converged in the place where the positive polarity and the negative polarity are balanced, and a pseudo laser noise component with a modulation noise component eliminated is extracted from the multiplier 37. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
