Abstract: An apparatus for carrying out a fine servo control and a rough servo control with respect to the rotation of a motor for rotating a recording medium in accordance with information recorded on the recording medium. A fine servo signal is generated on the basis of a reproduction clock, filtered by a first filtering device, and used for the fine servo control. A rough servo signal is generated on the basis of a frame synchronizing signal, filtered by a second filtering device, and used for the rough servo control. The first filtering device has a first frequency band, and the second filtering device has a second frequency band. The upper limit of the second frequency band is lower than that of the first frequency band.

Abstract: A gain controlling apparatus is provided with: an adjusting device (6, 7, 8) for adjusting a gain of a generation signal, which is generated on the basis of a light reception signal obtained by receiving a reflection light of a light beam from an information recording medium (1); and a detecting device (21, 14, 16) for detecting whether or not the generation signal is generated and outputting a detection signal when the generation signal is generated. The gain controlling apparatus is also provided with a controlling device (18) for controlling the adjusting device to increase the gain by a predetermined value set in advance when the detection signal is not outputted by the detecting device.

Abstract: 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.

Abstract: An automatic gain control device includes: reading unit for reading information signal from a recording medium; servo loop including servo control unit for controlling position of the reading unit with respect to the recording medium; mixing unit for mixing a disturbance signal into the servo loop; gain control unit detecting gain of the servo loop in accordance with level of the disturbance signal and varying the gain of the servo loop; and level detecting unit for discriminating whether level of the information signal read by the reading unit is higher than a predetermined level or not, wherein the mixing unit mixes the disturbance signal into the servo loop when the level of the information signal is higher than the predetermined level.

Abstract: An automatic gain control device includes: reading unit for reading information signal from a recording medium; servo loop including servo control unit for controlling position of the reading unit with respect to the recording medium; mixing unit for mixing a disturbance signal into the servo loop; gain control unit detecting gain of the servo loop in accordance with level of the disturbance signal and varying the gain of the servo loop; and level detecting unit for discriminating whether level of the information signal read by the reading unit is higher than a predetermined level or not, wherein the mixing unit mixes the disturbance signal into the servo loop when the level of the information signal is higher than the predetermined level.

Abstract: An automatic gain control apparatus for an optical disc player is equipped in a servo loop to perform a servo control by use of an error signal in the optical disc player.

Abstract: An automatic gain control device includes: servo loop for performing servo control based on an error signal; gain control unit for controlling gain of the servo loop in accordance with gain control value; and storage unit for storing gain control values. The gain control unit starts gain control using the gain control value stored in the storage unit as default value with which the gain control is started, and stores the gain control value newly obtained by the gain control to the storage unit after the gain control is completed.

Abstract: 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.

Abstract: 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.

Abstract: A CD player capable of detecting the recording end of a partially recorded CD-R (PRD) during playback. When an unrecorded area (URA) is detected, an address immediately before that of the URA is held and a setup is performed at the position of that detection. If the setup is unsuccessful, a setup is performed at a reference setup position, and when this setup operation is complete, playback starts from the held address position. When the playback from the position and detection of the URA are repeated a predetermined number of times, the held address position is discriminated as the recording end. According to a method of searching for the last piece of recorded information in the program area on a PRD, when reading failure occurs in a search, the pickup is moved back to a previous jump position to the occurrence of the reading failure.

Abstract: 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.

Abstract: 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.

Abstract: A detachable operating unit for connection with a main unit comprises at least two power supply units for applying operating voltages to the detachable operating unit, the power supply units generating two different voltages, respectively; at least two power supply terminals for engaging the detachable operating unit and the main unit to receive two different voltages applied to the power supply units, respectively; a ground terminal for engaging the detachable operating unit and the main unit; a protective circuit for applying a reverse voltage in repsonse to a differential voltage between voltages of the power supply units, the protective circuit being disposed between one of power supply units which generates the operating voltage lower than that of the other power supply unit, and the ground terminal.

Abstract: Address search method for use in a disk player repeatedly performing a track jump operation for jumping over a plurality of recording tracks at one time. The present method changes to a jump state from a locking state in which a tracking servo system of the disk player is locked so that an information reading light spot of a pickup of the disk player follows a recording track. Subsequently, a present address obtained from read output of the pickup is compared with a target address and the tracking servo system is placed in the locking state. The preceding steps for comparing the addresses are repeated until the target address is exceeded by the present address.

Abstract: The invention provides an improved playing method for a CD (compact disk) player whereby the same selection is inhibited from being played twice in a row. Also, disks and selections more in accordance with the user's preference are played more frequently. Volume and other playing characteristics are automatically adjusted for each disk in accordance with stored values corresponding to manual adjustments made the first time the disk was played.

Abstract: The invention provides an improved playing method for a CD (compact disk) player whereby the same selection is inhibited from being played twice in a row. Also, disks and selections more in accordance with the user's preference are played more frequently. Volume and other playing characteristics are automatically adjusted for each disk in accordance with stored values corresponding to manual adjustments made the first time the disk was played.