Abstract: A a recording method and apparatus for an optical disk employs a data format having a fixed pattern sync portion in which a minimum run length of zeros and the maximum run length of zeros are not adjacent to each other. As such temperature difference caused during recording the optical disk may be made smaller, thermal stress applied upon the medium may be reduced, the deterioration thereof may be restrained, and the repetitive frequency of the medium may be improved.

Abstract: A recording method and apparatus for an optical disk employs a data format having a fixed pattern sync portion in which a minimum run length of zeros and a maximum run length of zeros are not adjacent to each other. As such temperature difference caused during recording the optical disk may be made smaller thermal stress applied upon the medium may be reduced, the deterioration thereof may be restrained, and the repetitive frequency of the medium may be improved.

Abstract: A recording method and apparatus for an optical disk employs a data format having a fixed pattern sync portion in which a minimum run length of zeros and a maximum run length of zeros are not adjacent to each other. As such, temperature difference caused during recording the optical disk may be made smaller, thermal stress applied upon the medium may be reduced, the deterioration thereof may be restrained, and the repetitive frequency of the medium may be improved.

Abstract: An optical disk for recording audio and video information in unit of field or sector has a recording format that provides an area for recording all audio information to be recorded in each unit immediately after an area used to set the power of the optical beam to a desired level. Also, an audio and video information recording method using the optical disk having the recording format mentioned above is disclosed. According to this method, after-recording of audio information is made at a desired level of the power of the optical beam.

Abstract: A recording method and apparatus for an optical disk employs a data format having a fixed pattern sync portion in which a minimum run length of zeros and a maximum run length of zeros are not adjacent to each other. As such, temperature difference caused during recording the optical disk may be made smaller thermal stress applied upon the medium may be reduced, the deterioration thereof may be restrained, and the repetitive frequency of the medium may be improved.

Abstract: A clock changeover apparatus including a reference frequency divider for dividing a reference clock by a first frequency division number; a comparative frequency divider for dividing by a second frequency division number an output clock obtained by the clock changeover apparatus; a phase comparator for comparing phase of a signal of the reference frequency divider with that of the comparative frequency divider; a clock controller for changing the output clock so as to make the phase of the signal of the reference frequency divider coincident with that of the comparative frequency divider; a clock determining member which gives an initial value of the output clock to the clock controller and is capable of selecting the initial value of the output clock arbitrarily; a changeover member for effecting changeover between the first and second frequency division numbers; and a phase lock detector for monitoring whether or not the phase of the signal of the reference frequency divider coincides with that of the compa