摘要:
Two sum output signals from two sets of the photodetector elements located symmetrically each other with respect to a light-receiving center of the photodetector of the optical pickup are amplified individually by two amplifiers. A focus error signal is generated in accordance with a difference between respective output levels of the two amplified signals. The gains of the two amplifiers are adjusted in accordance with the focus error signal. A predetermined bias voltage is applied to the focus error signal line in the focus servo control means in accordance with the focus error signal.
摘要:
Method and Apparatus for playing a CD are designed to allow playback of a partially recorded disk of CD-Rs (CD-Recordable) having the DRAW (direct read after write) capability. It is determined if a target disk is a partially recorded CD-R recording medium. When a reverse command to return to a predetermined address of the recording medium to execute playback is input, the absolute time for information being reproduced is detected and it is then determined if the absolute time is within a predetermined actual pause period. When the absolute time is determined to be within the actual pause period, the reverse command is canceled. It is therefore possible to properly operate a servo system within that recording area of the recording medium where information has already been recorded, thereby allowing a return to a predetermined address associated with the reverse command. This prevents the loss of control of the servo system. When the pickup position is in a lead-in area of the partially recorded CD-R recording medium, thus ensuring the proper reading control.
摘要:
Disclosed is a CD player that ensures a setup operation and reproduction of information even when a partially recorded CD-R is set therein. The CD player sequentially performs the setup operation, starting from the first setup position located at the innermost periphery of the CD, predetermined for the setup operation, until the setup operation is complete at any of n-th (n=2, 3, . . . ) setup positions lying outwardly of the first setup position. If the setup operation is not completed even at an n-th setup position located at the outermost periphery of the CD, the CD player performs the setup operation again at at least one setup position lying inwardly of the n-th setup position. Also disclosed is a CD player that can discriminate a partially recorded, additionally recordable CD-R, and can execute the reproduction control for the PRD. This CD player discriminates a set disk as an additionally recordable one when a mirror-finished portion is detected in the control to detect the lead-in area or when the lead-in area cannot be detected and the TOC information cannot be read.
摘要:
A table music system includes an enclosure having a top surface and a front surface free of manually mechanically actuable controls for controlling functions of the table music system. A radio receiver and powered speakers system are located within the enclosure. A display is located on the front surface of the enclosure for displaying at least time. An alarm in the enclosure is configured to be set by a user to produce an alarm signal at a user-selectable time. A touch-sensitive area on the enclosure allows the user to control a function of the take music system. A wireless remote control permits the user to control functions of the table music system.
摘要:
A focus control apparatus for a multilayer optical recording medium performs an adequate focus jump on a multilayer optical recording medium. Threshold values are set according to the amount of a level change in a focus error signal of a loaded multilayer optical recording medium, and focus jump control is conducted based on the result of comparison between the level of the focus error signal and the set threshold values. Positive and negative threshold values to be compared with the level of the focus error signal to detect a zero-crossing point of the focus error signal are set in accordance with the amount of a level change in the focus error signal, after which an acceleration operation of the focus actuator is started in response to a focus jump instruction to shift the focus position of read light for a focus jump, the acceleration operation is stopped in accordance with zero-crossing detection, a deceleration operation of the focus actuator is started thereafter and is stopped in accordance with zero-crossing detection, so that the operation returns to the focus servo operation.
摘要:
Apparatus and method for focus control are devised to cope with a fluctuation of an optimum gain of a focus servo loop due to a difference between light reflectance of recording surfaces or the like and to allow an optimum focal position of read light to preferably trace a target recording surface. The focus control apparatus of the invention includes: reading device for generating a read signal of a recording medium 1; a focus servo loop for allowing an optimum converging position of the read light to trace the target recording surface in accordance with a focus error signal FE by using a focusing actuator to displace the optimum converging position of the read light in the optical axial direction; a level detecting unit of the read signal; a level detecting unit of an error signal FE; amplifiers and of a read signal RF and the error signal FE; and a control unit for driving the actuator so as to allow the optimum converging position of the read light to approach the recording surface in the set-up mode and for controlling gains of the amplifiers so that a detection level by the detecting unit in the set-up mode reaches a predetermined level and a detection level by a detecting unit reaches a predetermined level.
摘要:
An unbalanced waveform of a tracking error signal is automatically corrected within a short period of time. A peak value and a bottom value of a tracking error signal are obtained by a peak-hold circuit and a bottom-hold circuit, respectively. Based on the peak value and the bottom value, an amount of offset measured from a reference level and an amplitude of the tracking error signal are computed. An adjustment value is computed for correcting the unbalance between the peak value and the bottom value based on the amount of offset and the amplitude of the tracking error signal. The adjustment value is fed back to a tracking balance circuit so that the waveform of the unbalanced waveform of the tracking error signal is corrected.
摘要:
Disclosed is a CD player that ensures a setup operation and reproduction of information even when a partially recorded CD-R is set therein. The CD player sequentially performs the setup operation, starting from the first setup position located at the innermost periphery of the CD, predetermined for the setup operation, until the setup operation is complete at any of n-th (n=2, 3, . . . ) setup positions lying outwardly of the first setup position. If the setup operation is not completed even at an n-th setup position located at the outermost periphery of the CD, the CD player performs the setup operation again at at least one setup position lying inwardly of the n-th setup position. Also disclosed is a CD player that can discriminate a partially recorded, additionally recordable CD-R, and can execute the reproduction control for the PRD. This CD player discriminates a set disk as an additionally recordable one when a mirror-finished portion is detected in the control to detect the lead-in area or when the lead-in area cannot be detected and the TOC information cannot be read.
摘要:
A playing apparatus for a compact disc on which TOC information comprising at least first to third point data has repetitively been recorded in a lead-in area. A reading point by a pickup is moved in the lead-in area from the disc outer rim side in accordance with a TOC information reading command. When it is detected that the reading point was positioned to a recording track of third point data locating on the disc inner rim side in each of the TOC information, the reading point is jumped to the disc inner rim side by at least only two tracks. After that, the reading point is moved toward the disc outer rim side along the track, thereby reading the TOC information including the first, second, and third point data.
摘要:
A focus jump control apparatus of a player for playing a multilayer recording disc surely achieves a focus jump. This apparatus includes: a focusing servo loop for allowing a focal point to trace a recording surface in accordance with a focusing error signal by using a focusing actuator to displace the focal point of read light to a disc in the optical axial direction; and a tracking servo loop for allowing the focal point to trace disc tracks. A loop opening/closing control unit opens/closes focusing/tracking servo loops in response to an instruction and closes the focusing servo loop when the movement of the focal point from one of the recording surfaces to the other. During the movement of the read light focal point, the closing state of the tracking servo loop is maintained. Jump driving means generates a drive signal of the actuator to move the focal point from one of the recording surfaces to the other based on the error signal under the opening/closing control of the focusing/tracking servo loops.