Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Control of information signal processing channel
Reexamination Certificate
1999-05-04
2001-06-26
Young, W. R. (Department: 2651)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Control of information signal processing channel
C369S047270, C369S053150, C369S053350
Reexamination Certificate
active
06252837
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an error compensation device for a disk signal reproduction apparatus that reads out digital data from a digital disk on which the digital data is recorded along a spiral track, such as a CD, and reproduces a signal.
2. Description of the Related Art
Conventionally, in a digital audio disk, when there is a region from which signal pits of the disk cannot be read by an optical pickup because of a damage of the disk, contamination, or the like, a problem is produced that reproduction of an audio signal is stopped there, or, even when reproduction of the audio signal is continued, the reproduced sound is once interrupted and a time lag is produced in the reproduced music.
Japanese Patent Unexamined Publication No. Hei. 6-12773 discloses the following technique. When audio data is read out from data on a disk and an audio signal is reproduced at a high speed, a memory for CD-ROM data is used as an input buffer memory of an audio signal processing unit. While EFM demodulated data is sequentially written into the memory, the written data is sequentially read out at the single speed. When the writing of data into the audio signal processing unit almost exceeds the read address, the data writing is stopped, only the reading is conducted, and an optical pickup is jumped back by a predetermined number of tracks. At the timing when a vacant area is produced in the memory, the data after the stop of the writing is again written into the memory.
Japanese Patent Unexamined Publication No. Hei. 6-168541 discloses the following technique. “A quintuple speed mode or a double speed mode is set as a special reproduction mode. In the case where an instruction for automatic level response is given, the sound state is checked. If the current state is a silent state, the system waits for generation of sound for a constant time period. If sound is generated, data of the sound signal is written into a memory. The sound signal data is read out from the memory, namely, the timing of starting the reproduction of the sound signal is changed, so that the rising of the sound is reproduced. In the case where an instruction for forced level response is given, the timing of starting the reproduction is changed irrespective of the sound state, so that the rising of the sound is reproduced.”
In both of the conventional techniques, when there is a region from which signal pits of a disk cannot be read by an optical pickup because of a damage of the disk, contamination, or the like, there arises a problem that reproduction of an audio signal is stopped, or, even when reproduction of the audio signal is continued, the reproduced sound is once interrupted and a time lag is produced in the reproduced music.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an error compensation device for a disk signal reproduction apparatus which can solve the problem of the conventional techniques that, when there is a region from which signal pits of a disk cannot be read by an optical pickup because of a damage of the disk, contamination, or the like, reproduction of an audio signal is stopped, or, even when reproduction of the audio signal is continued, the reproduced sound is once interrupted and a time lag is produced in the reproduced music, and which can therefore prevent such a time lag from being produced in the reproduced music.
In order to achieve the above object, according to the invention, there is provided an error compensation device for a disk signal reproduction apparatus, comprising: a data read unit which reads out data from a disk on which the data is recorded along a spiral track; a signal memory unit which stores output data of the data read unit; a servo control unit which controls operations of focussing and tracking in the data read unit; a control microcomputer which controls the servo control unit and the signal memory unit; a storage unit for microcomputer control which controls the control microcomputer; a D/A conversion unit which coverts data stored in the signal memory unit into an analog signal; and a signal mute unit which is connected to a signal transmission path in a preceding or subsequent stage of the D/A conversion unit and which is controlled by the microcomputer, wherein when there is an unreproducible region in which, during a process of reading out a signal from the disk, reading of data is disabled by a tracking failure due to a damage of the disk or contamination, the storage unit for microcomputer control stores the region as an error region, signal data stored in the signal memory unit is sequentially read out at a reference speed to reproduce a signal, and, if, during reproduction, it is detected from a read control signal from the storage unit for microcomputer control that reproduced output data is data read out from the error region, the signal mute unit mutes a transmission signal.
REFERENCES:
patent: 4017677 (1977-04-01), Baker
patent: 4309726 (1982-01-01), Tanaka et al.
patent: 5428592 (1995-06-01), Endo
patent: 5598390 (1997-01-01), Saitoh et al.
patent: 6-12773 (1994-01-01), None
patent: 6-168541 (1994-06-01), None
Funai Electric Co. Ltd.
Morgan & Lewis & Bockius, LLP
Young W. R.
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