JP2004046911A - Optical disk reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce unnecessary power consumption without complicating the process of a CPU for controlling a system in an optical disk reproducing device. <P>SOLUTION: The optical disk reproducing device is provided with an audio output circuit part 35 and an error correcting circuit part 34 for CD-ROM data and a recorded digital signal is reproduced from a disk to which the digital signal is recorded. The optical disk reproducing device is provided with a sub code demodulation part 32 demodulating a sub code signal from an EFM demodulated signal from the disk and a controlling circuit 33 discriminating the kinds of the EFM demodulated digital signal by the state of a control bit of a sub code Q channel in the demodulated sub code signal and controls so that if the EFM demodulated digital signal is discriminated as the audio data by the controlling circuit 33, the audio output circuit part 35 is made to operate and the error correcting circuit part 34 for CD-ROM data is suspended and if the demodulated digital signal is discriminated as CD-ROM data, the audio output circuit part 35 is suspended and the error correcting circuit 34 for the CD-ROM data is made to operate. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disc reproducing apparatus capable of discriminating discs of different formats, and more particularly to an optical disc for discriminating and reproducing discs recorded in different formats such as CD (Compact Disk) -DA (Digital Audio), CD-ROM, etc. It relates to a playback device.
[0002]
[Prior art]
For a disc in which digital audio data (CD-DA) and CD-ROM data are mixed and recorded on one disc, it is necessary to perform a reproduction process corresponding to each format. This is because when a CD-ROM disc is reproduced by a CD-DA player, digital data that is not an audio signal is demodulated by a digital signal processing circuit, and digital data of the CD-ROM is converted from a digital audio data output by a D / A converter into analog data. It is converted into an audio signal and output as a loud noise sound. In order to prevent such noise noise of digital data, the type of data is determined, and a reproduction process according to each format is performed.
[0003]
To switch the reproduction process, usually, the start time of each data is read from a TOC (Table Of Contents) recorded in the innermost peripheral portion of the disc in advance, and each format is read out from this information by the system control CPU. Control the reproduction process corresponding to.
[0004]
FIG. 1 is a block diagram showing a schematic configuration of a CD-ROM drive. The EFM signal read from the disk 11 by the pickup 12 is amplified by a read amplifier 13 and then demodulated by an EFM demodulation unit 14. The servo control unit 15 controls a motor driver 16 based on the demodulated EFM signal, and 12 and the disk motor 17 are driven. The demodulated EFM signal is supplied to the sub-code demodulation unit 22, and the sub-code demodulation unit 22 demodulates the sub-code from this data.
[0005]
The demodulated EFM signal is supplied to an interleaver / error correction unit 21, where the error correction is performed by the interleaver / error correction unit 21, and the recording data is stored in a CD-ROM error correction unit 24 and an audio output circuit unit 25. Is given. If the recording data is ROM data, the CD-ROM error correction unit 24 further corrects the error and demodulates the ROM data. On the other hand, when the recording data is CD-DA data, the audio data is demodulated by the audio output circuit unit 25 into an audio analog signal.
[0006]
Whether the data is CD-DA data or CD-ROM data is determined by the system control CPU 23 by comparing it with the TOC information. If the current information is CD-DA data, the error correction for CD-ROM is performed. The processing stop control of the section 24 may be performed, and conversely, if the current information is CD-ROM data, the audio circuit section 25 may be controlled to mute.
[0007]
[Problems to be solved by the invention]
However, in the conventional reproduction processing, the system control CPU always controls the reproduction processing by comparing the current time of the subcode Q channel information in the subcode signal recorded on the disc with the previously read TOC information. Alternatively, it is necessary to calculate the number of tracks from the previously read TOC information to the reproduction processing control switching point and compare the number of tracks with the current track position to perform the reproduction processing control.
[0008]
For this reason, not only does the processing of the system control CPU become complicated, but also it is difficult to perform detailed temporal control with the control from the system control CPU. From these facts, in the conventional reproducing apparatus, during the CD-DA reproduction, the operation of the CD-ROM error correction unit circuit itself is continued, but only the data processing is not performed. During the ROM reproduction, the operation of the audio output circuit section itself is continued, but only the mute setting is performed.
[0009]
As described above, the circuits in the CD-ROM error correction unit and the audio circuit unit consume power even during periods when they do not need to operate.
[0010]
The present invention has been made in consideration of the above-described conventional problems, and has as its object to reduce unnecessary power consumption without complicating the processing of the system control CPU.
[0011]
[Means for Solving the Problems]
An optical disk reproducing apparatus according to the present invention includes an audio output circuit and an error correction circuit for CD-ROM data, and reproduces a digital signal recorded from a disk on which a digital signal is recorded. Means for demodulating a sub-code signal from the demodulated signal; determining means for determining the type of the EFM-demodulated digital signal based on a state of a control bit of a sub-code Q channel in the demodulated sub-code signal; If the digital signal EFM demodulated by the determination means is determined to be audio data, the audio output circuit is operated and the error correction circuit for CD-ROM data is stopped, so that the demodulated digital signal is -If the audio data is determined, The force circuit to stop the unit, and controlling to perform the processing for operating the error correction circuit for the CD-ROM data.
[0012]
The subcode Q channel format determines whether the currently reproduced recording data is audio data (CD-DA data) or CD-ROM data, based on the state of the CONTROL section consisting of 4 bits following S0 and S1 in the data string. ing. Specifically, when the first two bits of the four bits are "00", the data is defined as CD-DA data, and when the first two bits are "01", the data is defined as CD-ROM data.
[0013]
According to the present invention, it is determined from the state of the CONTROL bit whether the data is CD-DA data or CD-ROM data. If the demodulated digital signal is CD-DA data, the audio output circuit is operated and the CD-ROM data is operated. The data error correction circuit is stopped. Conversely, if the demodulated digital signal is CD-ROM data, the audio output circuit is stopped and the CD-ROM data error correction circuit is operated.
[0014]
With the above configuration, it is possible to control CD-DA or CD-ROM data without using complicated control for the system control CPU, and to reduce unnecessary power consumption. be able to.
[0015]
Also, an optical disk reproducing apparatus of the present invention is an optical disk reproducing apparatus that includes an audio output circuit and an error correction circuit for CD-ROM data, and reproduces a digital signal recorded from a disk on which a digital signal is recorded. And a sector synchronization signal detecting means for detecting whether a sector synchronization signal is included in the 12-byte data at the head of the sector of the digital signal demodulated through EFM demodulation and error correction processing, and when the sector synchronization signal is detected. Activating the CD-ROM data error correction circuit and stopping the audio output circuit. If the sector synchronization signal is not detected, the CD-ROM data error correction circuit is stopped and the audio output circuit is disabled. The feature is to control to perform the process to operate the circuit That.
[0016]
The CD-ROM format includes a 12-byte synchronization code before recording data. This synchronization code consists of a sequence of 1-byte "0", 10-byte "FF", and 1-byte "0", and this data sequence does not appear in CD-DA. From this, it is possible to determine by detecting the appearance of the synchronization code. By utilizing this, it is possible to control CD-DA or CD-ROM data without using complicated control for the system control CPU, and to reduce unnecessary power consumption. can do.
[0017]
The audio output circuit has an audio output unit for performing digital processing and a D / A converter. When the audio output circuit is in the stop state, the operation clock of the audio output unit for performing digital processing is stopped to reduce the power consumption. It may be configured to shift to the power state.
[0018]
The D / A converter may be configured to have means for reducing or cutting off the analog power supply current when in the stop state.
[0019]
Further, the CD-ROM data error correction circuit may be configured such that, when in the stop state, the operation clock of the circuit is stopped and the circuit shifts to a low power consumption state.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram showing the first embodiment of the present invention. After the EFM signal read out from the disk by the pickup is amplified by the read amplifier and then demodulated by the EFM demodulation unit, the configuration is the same as that shown in FIG. 1 described above. 2 shows a circuit configuration after a sub-code demodulation unit to which a demodulated signal is given and a deinterleaver / error correction unit.
[0021]
FIG. 2 shows a subcode Q channel format, which is demodulated by the subcode demodulator 32 in FIG. In the subcode Q channel format, whether the currently reproduced recording data is CD-DA data or CD-ROM data is determined based on the state of the CONTROL section consisting of 4 bits following S0 and S1 in the data string. Specifically, when the first two bits of the four bits are "00", the data is defined as CD-DA data, and when the first two bits are "01", the data is defined as CD-ROM data.
[0022]
In the embodiment of the present invention, it is determined from the state of the CONTROL bit whether the data is CD-DA data or CD-ROM data. If the demodulated digital signal is CD-DA data, the audio output circuit is operated. The CD-ROM data error correction circuit is stopped. Conversely, if the demodulated digital signal is CD-ROM data, the audio output circuit is stopped and the CD-ROM data error correction circuit is operated.
[0023]
A first embodiment of the present invention will be described with reference to FIG. The demodulated EFM signal is provided to a subcode demodulation unit 32 and a deinterleaver / error correction unit 31. The subcode demodulation unit 32 demodulates the subcode based on the supplied EMF signal. The demodulated subcode data is supplied to the control circuit 33.
[0024]
The EMF signal supplied to the interleaver / error correction unit 31 is subjected to error correction in the interleaver / error correction unit 31, and recording data is supplied to the CD-ROM error correction unit 34 and the audio output circuit unit 35. .
[0025]
If the recording data is ROM data, the CD-ROM error correction unit 34 further corrects the error and demodulates the ROM data. The operating clock is supplied to the CD-ROM error correction unit 34 via a gate 34c, and the gate 34c is controlled by a CD-ROM error correction unit control signal from the control circuit 33.
[0026]
On the other hand, if the recording data is CD-DA data, it is demodulated by the audio output circuit unit 35 into an audio analog signal.
[0027]
The audio output circuit section 35 includes a digital audio output circuit, an error data interpolation circuit, an attenuator, a digital filter, a de-emphasis circuit, a mute circuit, a D / A converter, and the like. In FIG. The audio output circuit section 35a and the D / A converter section 35b of the digital portion are described. Then, digital processing of the error-corrected recording data is performed in the audio output circuit unit 35a, and the D / A converter unit 35b converts the digital signal into an analog signal and outputs an audio analog signal.
[0028]
The audio output circuit section 35a is supplied with an operation clock via a gate 35c, and the gate 35c is controlled by an audio circuit section control signal from the control circuit 33. Further, the D / A converter 35b controls the reduction or disconnection of the analog power supply current based on the audio circuit control signal from the control circuit 33.
[0029]
The control circuit 33 monitors the sub-code from the sub-code demodulation unit 32, and according to the state of the CONTROL unit consisting of four bits following S0 and S1 in the data string, the currently reproduced recording data is CD-DA data. Or CD-ROM data. As described above, when the first two bits of the four bits are "00", the data is defined as CD-DA data, and when the first two bits are "01", the data is defined as CD-ROM data. The CONTROL section determines whether the data is CD-DA data or CD-ROM data. If the data is CD-DA data, the control circuit 33 sets the CD-ROM error correction unit control signal to the “L” level and outputs the same, and sets the audio circuit unit control signal to the “H” level and outputs the same. Conversely, if the data is CD-ROM data, the control circuit 33 sets the CD-ROM error correction section control signal to the "H" level and outputs it, and sets the audio circuit section control signal to the "L" level and outputs it.
[0030]
The gates 34c and 35c stop supplying the operation clock when the applied control signal is at "L" level, and supply the operation clock when they are at "H" level.
[0031]
When the CD-ROM error correction unit control signal is at “H” level, the operation clock is supplied to the CD-ROM error correction unit 34. Conversely, when the CD-ROM error correction unit control signal is at "L" level, the clock supply to the CD-ROM error correction unit 34 is stopped, and power consumption is reduced.
[0032]
When the audio circuit control signal is at "H" level, the audio output circuit (digital unit) 35a is supplied with an operating clock and the power supply to the D / A converter 35b. Conversely, when the audio circuit control signal is at "L" level, the clock supply to the audio output circuit (digital) 35a is stopped and the power supply to the D / A converter 35b is cut off or consumes less power. Mode transitions are taken to reduce power consumption.
[0033]
By adding a circuit for performing the above processing control, it becomes possible to control CD-DA or CD-ROM data without using the control of the system control CPU as shown in FIG. In addition, unnecessary power consumption can be reduced.
[0034]
Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted here to avoid duplication of description.
[0035]
The second embodiment achieves the same effects as the first embodiment by using the respective features of the demodulated recording data instead of the subcode Q channel data used in the above embodiment. It is.
[0036]
FIG. 4 shows the recording format of each of the CD-DA and the CD-ROM. As shown in FIG. 4, the CD-ROM format includes a 12-byte synchronization code before recording data. This synchronization code consists of a sequence of 1-byte "0", 10-byte "FF", and 1-byte "0", and this data sequence does not appear in CD-DA. From this, it is possible to determine by detecting the appearance of the synchronization code.
[0037]
FIG. 5 shows a configuration diagram in the second embodiment. As shown in FIG. 5, the demodulated EFM signal is provided to a subcode demodulation unit 32 and a deinterleaver / error correction unit 31. The subcode demodulation unit 32 demodulates the subcode based on the supplied EMF signal. The demodulated subcode data is provided to the control circuit 33a for use in system control or the like.
[0038]
The EMF signal supplied to the interleaver / error correction unit 31 is subjected to error correction in the interleaver / error correction unit 31, and recording data is supplied to the CD-ROM error correction unit 34 and the audio output circuit unit 35. . Further, in this embodiment, the recording data from the interleaver / error correction unit 31 is provided to the control circuit 33a.
[0039]
The control circuit 33a detects the appearance of the synchronization code. When detecting a 12-byte synchronization code from the data supplied from the interleaver / error correction unit 31, the control circuit 33a determines that the recording data is CD-ROM data. If no synchronization code is detected, the recording data is determined to be CD-DA. If the discrimination result indicates that the data is CD-DA data, the control circuit 33a outputs the CD-ROM error correction section control signal at "L" level and outputs the audio circuit section control signal at "H" level. And output. Conversely, if the data is CD-ROM data, the control circuit 33 sets the CD-ROM error correction section control signal to the "H" level and outputs it, and sets the audio circuit section control signal to the "L" level and outputs it. Hereinafter, the same processing as in the above embodiment is performed. That is, when the CD-ROM error correction unit control signal is at “H” level, the operation clock is supplied to the CD-ROM error correction unit 34. Conversely, when the CD-ROM error correction unit control signal is at "L" level, the clock supply to the CD-ROM error correction unit 34 is stopped, and power consumption is reduced.
[0040]
When the audio circuit control signal is at the “H” level, an operation clock is supplied to the audio output circuit (digital unit) 35 a and power is supplied to the D / A converter 35 b. Conversely, when the audio circuit control signal is at "L" level, the clock supply to the audio output circuit (digital) 35a is stopped and the power supply to the D / A converter 35b is cut off or consumes less power. Mode transitions are taken to reduce power consumption.
[0041]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the power consumption of the blocks unnecessary for the conventional operation, and to control the CD-DA or CD-ROM data without using the control of the system control CPU. And the load on the system control CPU can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a CD-ROM drive.
FIG. 2 is a diagram illustrating a subcode Q channel format.
FIG. 3 is a block diagram showing a first embodiment of the present invention.
FIG. 4 is a diagram showing a recording format of each of a CD-DA and a CD-ROM.
FIG. 5 is a block diagram showing a second embodiment of the present invention.
[Explanation of symbols]
31 deinterleaver / error correction unit 32 subcode demodulation unit 32
33 control circuit 34 CD-ROM error correction section 34c gate 35 audio output circuit section 35a audio output circuit section 35b D / A converter section 35c gate

Claims (5)

An optical disc reproducing apparatus for reproducing a digital signal recorded from a disk on which a digital signal is recorded, comprising an audio output circuit and an error correction circuit for CD-ROM data, wherein a subcode signal is obtained from a signal EFM demodulated from the disk. Means for demodulating the EFM, and discriminating means for discriminating the type of the EFM demodulated digital signal based on the state of the control bit of the subcode Q channel in the demodulated subcode signal. When the demodulated digital signal is determined to be audio data, the audio output circuit is operated and the CD-ROM data error correction circuit is stopped, and when the demodulated digital signal is determined to be CD-ROM data, The audio output circuit is stopped and the CD Optical disk reproducing apparatus, characterized by controlling so as to perform the processing for operating the error correction circuit for ROM data. An optical disk reproducing apparatus comprising an audio output circuit and an error correction circuit for CD-ROM data and reproducing a digital signal recorded from a disk on which a digital signal is recorded, wherein the disk is demodulated through EFM demodulation and error correction processing. A sector synchronizing signal detecting means for detecting whether a sector synchronizing signal is included in the 12-byte data at the head of the sector of the digital signal, and when the sector synchronizing signal is detected, the CD-ROM data error correction circuit And the audio output circuit is stopped, and if the sector synchronization signal is not detected, the CD-ROM data error correction circuit is stopped and the audio output circuit is operated. An optical disc reproducing apparatus characterized in that: The audio output circuit includes an audio output unit that performs digital processing and a D / A converter. When the audio output circuit is in the stopped state, the operation clock of the audio output unit that performs the digital processing is stopped to reduce the power consumption. The optical disk reproducing device according to claim 1, wherein the process proceeds to (c). 4. The optical disk reproducing apparatus according to claim 3, wherein the D / A converter has means for reducing or cutting off an analog power supply current when in the stop state. 3. The optical disk reproducing device according to claim 1, wherein the CD-ROM data error correction circuit stops operating when the circuit is in the stopped state and shifts to a low power consumption state.

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