Abstract: For each sync frame, an AND circuit detects whether a pre-pit synchronization signal can be obtained within a window set by a timing generator. Detection result of the AND circuit is held by a shift register, where it is shifted in response to each sync frame. On the basis of a parallel output from the shift register, a decoder determines whether the detection of the pre-pit synchronization signal is accurate or erroneous. Count value of a counter is incremented by one each time the decoder determines that the detection of the pre-pit synchronization signal is accurate, but is decremented by one each time the decoder determines that the detection of the pre-pit synchronization signal is erroneous. Identification section identifies stability/instability of the pre-pit synchronization signal detection.

Abstract: There is generated a rhythm corresponding to a designated tempo and meter of a music piece to be recorded. Performance of a musical instrument is started at specific timing according to the generated rhythm, and the musical information resulting from the performance is recorded onto an MD (Mini Disk). The address on the MD read out when the performance of the music piece is started is retrieved as a start address of the music piece. After the recording, the retrieved start address is recorded onto the UTOC (User's-table-of-contents) area of the disk along with the designated tempo and meter. By reading out the start address, tempo and meter to calculate a measure number and start address of a desired measure on the basis of the read out information, display of a measure number being currently reproduced and quick access to the starting point of any desired measure can be achieved.

Abstract: There is generated a rhythm corresponding to a designated tempo and meter of a music piece to be recorded. Performance of a musical instrument is started at specific timing according to the generated rhythm, and the musical information resulting from the performance is recorded onto an MD (Mini Disk). The address on the MD read out when the performance of the music piece is started is retrieved as a start address of the music piece. After the recording, the retrieved start address is recorded onto the UTOC (User's-table-of-contents) area of the disk along with the designated tempo and meter. By reading out the start address, tempo and meter to calculate a measure number and start address of a desired measure on the basis of the read out information, display of a measure number being currently reproduced and quick access to the starting point of any desired measure can be achieved.

Abstract: Program information of plural channels is recorded on an optical magnetic disk in such a manner that the program information can be simultaneously reproduced together from the disk. Once other program information is overwritten on part of any of the recording channels of the disk that has become unnecessary, a UTOC generation/UTOC recording/UTOC memory controlling section generates UTOC information that designates the overwritten section as a position to be reproduced and a section other than the overwritten section as a position to be silenced or muted, and records the generated UTOC information onto the UTOC area of the optical magnetic disk. As reproduction from the optical magnetic disk is performed, the UTOC information is read out so that reproduction signal is output at the position to be reproduced, and silence signal is output at the position to be silenced.

Abstract: Test EFM signal reproduced from an optical disk is converted through a slicer into binary value, and a synchronizing signal having an 11T--11T signal pattern is detected by a frame synchronization circuit. Upon detection of the synchronizing signal, a detection timing counter predicts timing when a next synchronizing signal will be detected. The respective level values at the intermediate points of the former and latter 11T sections of the synchronizing signal are sampled and held by sample and hold circuits. Once a next synchronizing signal is detected at the predicted timing, a synchronization determination circuit transfers the outputs of the sample and hold circuits to another sample and hold circuits. The outputs of the other sample and hold circuit are averaged by filters and asymmetry is calculated by an asymmetry calculation circuit. On the basis of the calculated asymmetry, a determination circuit determines an optimum recording power value.