摘要:
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.
摘要:
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.
摘要:
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. Then a search is conducted through a jump over tracks equal to or less in number than the number of tracks of a predetermined smallest amount of information from that jump position, and the last piece (e.g., song) is detected by a sub code acquired at a jump position immediately previous to the re-occurrence of reading failure. A CD player capable of ensuring reproduction of all the pieces of recorded information during playback of a PRD updates the last track number to the newly detected track number when detecting a next track number in an area following an area of a memorized last track number during playback of a PRD.
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:
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:
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.
摘要:
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.
摘要:
A focus control apparatus for a multilayer optical recording medium which performs an appropriate focus jump on a multilayer optical recording medium. This focus control apparatus implements such focus jump control as to temporarily release a focus servo on one layer of a loaded multilayer optical recording medium, shift the focus position of read light on another target layer and then restart the focus servo on the another target layer, detects an ambient temperature, sets a drive signal condition according to the temperature detection output, and moves the focus position of the read light under the set drive signal condition. Specifically, this apparatus generates an acceleration signal to start moving the focus position of read light and a deceleration signal to decelerate movement of the focus position of the read light, as drive signals for a focus actuator in order to execute a focus jump operation, detects an ambient temperature of the focus actuator, and sets signal conditions for the acceleration signal and the deceleration signal according to the detected temperature.