JPH09161395A - Optical information reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate excess capacity for absorbing jitters for a working memory of a first error correction processing circuit and to unnecessitate a rotary motor with strong torque in an optical information reproducing device for variably reproducing an optical disk in which modulation signals of data are recorded on a spiral track at a constant linear velocity. SOLUTION: In this device, the operation of a signal processing circuit excepting data read-out operation of a buffer memory circuit 17 is entirely controlled by a synchronizing clock signal 59 synchronized with the modulation signal 51 of the data read out from the optical disk 11. Further, the data read-out operation of the buffer memory circuit 17 is controlled by the signal selecting either one of data read-out request signal 57 from a reference clock signal 60 or an interface circuit 18. When the data are the audio data, a D/A converter 21 is connected to the buffer memory circuit 17, and the data read-out operation of the buffer memory circuit 17 is controlled by the reference clock signal 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant linear velocity (hereinafter referred to as "constant linear velocity") method in which a data modulation signal (hereinafter referred to as a modulation signal) is applied to a spiral track.
ty, hereinafter referred to as CLV), which relates to a device for reproducing data from an optical disc recorded in ty (hereinafter, referred to as CLV), for example, a compact disc or a CD-ROM disc, and in particular, an optical system for improving a clock signal operated by a signal processing circuit for data reproduction The present invention relates to an information reproducing device.

[0002]

2. Description of the Related Art Conventionally, an optical information reproducing apparatus that reproduces audio data, visual data, information data, and the like from an optical disk on which CLV is recorded, employs a CLV reproducing method and operates as follows. The rotation motor on which the optical disk is mounted is operated so that the optical pickup can read the modulation signal from the optical disk at a predetermined bit rate, so that the frequency of the reference clock signal of the crystal oscillator and the synchronous clock signal generated from the modulation signal or the frequency of each divided clock signal are obtained. Alternatively, it is controlled to rotate at a predetermined speed based on the comparison result of the speeds.

The read modulated signal is demodulated into demodulated data in accordance with the synchronous clock signal generated from the modulated signal, and then written in the working memory of the first error correction processing circuit. Then, the demodulated data written in the working memory of the first error correction processing circuit is subjected to the first error correction by the first error correction processing circuit according to the reference clock signal.

[0004] After the first error correction process, data subjected to the first error correction is subjected to different signal processing depending on the type of data. That is, when the data is audio data, the data is converted from digital to analog by a DA converter to generate an audio signal, and then output to an audio output terminal. On the other hand, when the data is data other than audio data, the data is subjected to a second error correction by a second error correction processing circuit, and further temporarily stored in a buffer memory circuit provided for performing a smooth protocol with an external device. After being stored, it is output to a data output terminal via an interface circuit that performs a protocol with an external device.

In an optical information reproducing apparatus, a high-speed access operation, that is, an optical pickup for reading a modulated signal is moved from a current reading position on an optical disk to a target reading position, and target data is searched for and reproduction is started. A quick series of operations is required.

In this case, in order to achieve the above-mentioned high-speed access operation in the conventional CLV reproducing type optical information reproducing apparatus, since the modulation signal of the optical disk is recorded in the CLV, light is emitted according to the track radius on the optical disk. Since the required rotation speed of the disc changes, the rotation of the rotation motor is driven by a powerful CLV rotation motor servo so that the bit rate of the modulation signal at the target position read by the optical pickup quickly becomes the predetermined bit rate. It is necessary to control the speed, establish synchronization with the modulation signal, and start various signal processing for data reproduction.

However, in order to drive a rotary motor servo of a strong CLV, a rotary motor having a strong torque must be used, and there is a problem that it is expensive.
Further, in order to drive a powerful CLV rotary motor servo, a large current is frequently applied to the electromagnetic coil of the rotary motor, especially when a random search is frequently performed like a CD-ROM disk. However, there are problems that the rotary motor and the rotary motor drive circuit generate heat and power consumption increases.

In order to solve the above-mentioned problems of the conventional optical information reproducing apparatus of the CLV reproducing method, an optical information reproducing apparatus of a variable speed reproducing method for reproducing data from an optical disk at a variable speed has been proposed ( Nikkei Electronics, 1
Published February 13, 995, no. 628, pp. 111
To 119). According to this optical information reproducing apparatus, the broadband synchronous clock signal generation circuit is provided so that the synchronous clock signal of the modulated signal can be generated before the bit rate of the modulated signal read from the optical disk reaches a predetermined bit rate. At the same time, various signal processing for data reproduction is performed according to the synchronous clock signal.
Synchronization is easily established before the bit rate of the modulated signal reaches a predetermined bit rate, various signal processing can be started, and high-speed access is possible.

Further, even when a high-speed access is made, a strong C
It is not necessary to run the rotary motor servo of the LV, and there is no need to use a rotary motor having a strong torque, so it is inexpensive. Heat generation of the drive circuit can be suppressed, and power consumption can be reduced.

Hereinafter, a conventional variable speed reproduction type optical information reproducing apparatus will be described with reference to FIG. The conventional optical information reproducing apparatus of the variable speed generation system uses an optical disc 11
An optical pickup 113 that reads a data modulation signal 151 from the data signal No. 1 and a demodulated data 15 obtained by demodulating the modulation signal 151.
2, a first error correction processing circuit 115 that receives demodulated data 152 to obtain first error-corrected data 153, and a data 153.
It has a selector 132 for selecting an output destination of the data 153 according to the switching signal 161.

When the data 153 is an audio signal, the DA converter 1 inputs the data 153 and outputs the audio signal 154 to the audio output terminal 124.
21, when the data 153 is a signal other than audio, a second error correction processing circuit 116 that inputs the data 153 to obtain data 155 subjected to the second error correction processing;
Buffer memory circuit 117 for temporarily storing data 155
And the data 155 temporarily stored in the buffer memory circuit 117, perform a protocol with an external device (not shown), and output the data 155 to the data output terminal 125 as the output data 156.
have.

Further, a reference clock signal generating circuit 120 for generating a reference clock signal 160 for giving a reference operation speed of the optical information reproducing apparatus, and a synchronous clock signal 159 synchronized with the modulated signal 151 by inputting and referring to the modulated signal 151.
Wideband synchronous clock signal generation circuit 119 for generating
And the reference clock signal 160 and the synchronous clock signal 159
Selector 1 that selects either the reference clock signal 160 or the synchronous clock signal 159 by the switching signal 161 and outputs the clock signal 164
31.

A rotation control signal 163 for controlling the rotation speed of the rotation motor 112 by inputting each clock signal of the reference clock signal generation circuit 120 and the synchronous clock signal generation circuit 119 or a divided clock signal of each clock signal.
And a demodulation circuit 1
The sequencer 122 performs decoding with reference to the identification information 162 attached to the demodulated data 152 demodulated by 14 and outputs a switching signal 161 based on the decoding result, and performs sequence control of the entire optical information reproducing apparatus.
And is constituted by.

Next, the operation of such a conventional variable speed generation type optical information reproducing apparatus will be described. The rotation motor 112 loaded with the optical disk 111 is a conventional CLV
As in the case of the optical information reproducing apparatus of the reproducing system, the modulated signal 151 is
At a predetermined bit rate, the rotation control signal 163 which is an output of the rotation control signal generation circuit 123 based on the comparison result of the frequency or speed of the reference clock signal 160 and the synchronous clock signal 159 or the respective divided clock signals. , Are almost controlled by CLV.

The read modulated signal 151 is the modulated signal 1
51 is input and a broadband synchronous clock signal generation circuit 1
After being demodulated into demodulated data 152 by the demodulation circuit 114 in accordance with the synchronous clock signal 159 generated in step 19, the first
Working memory (not shown) of the error correction processing circuit 115
Is written to. At the same time, the sequencer 122
The identification information 162 attached to the demodulated data 152 demodulated by the demodulation circuit 114 is input.
2 to determine whether the data is audio data, and generate a switching signal 161.

The operation of the signal processing circuit after the first error correction processing differs depending on whether the data type is audio data or not. If the data is data other than audio data, the signal processing operation after the first error correction processing, that is, data to the first error correction processing circuit 115, the second error correction processing circuit 116, and the buffer memory circuit 117 All the write operations are performed according to the synchronous clock signal 159.

The interface circuit 118 receives the information data request signal 157 from the external device input to the information data request signal input terminal 126, outputs an information data read signal 158 to the buffer memory circuit 117, and outputs the information data read signal 158 to the buffer memory circuit 117. The second data 155 is output to the information data output terminal 125 as information data 156.

On the other hand, when the data is audio data, the first error correction processing operation in the first error correction processing circuit 115 is performed in accordance with the reference clock signal 160, and the first error corrected data 153 is output. DA conversion into an audio signal by the DA converter 121,
It operates to output to the audio signal output terminal 124.

Therefore, when the data is data other than audio data, the operation of all the signal processing circuits except the operation of reading data from the buffer memory circuit 117 is as follows.
Since all the operations are performed in accordance with the synchronous clock signal 159 and the synchronous clock signal generating circuit 119 of a wide band is provided, various signal processes can be started before the modulation signal 151 reaches a predetermined bit rate reproduction speed. it can.

The selector 131 and the selector 132
Are simultaneously controlled by the switching signal 161. The connection / disconnection state of the selector 131 and the selector 132 in FIG. 2 indicates a state where the data is other than audio data.

[0021]

However, in the above-mentioned conventional optical information reproducing apparatus of the variable speed reproducing method, when the data is audio data, the signal processing after the first error correction is operated according to the reference clock signal. Therefore, as in the case of the conventional optical information reproducing apparatus of the CLV reproducing method, the jitter absorbing process caused by the rotation unevenness of the rotary motor is performed by the data write operation and the data read operation to the working memory of the first error correction processing circuit. It will be performed between operations. For this reason, the capacity of the working memory of the first error correction processing circuit requires an extra capacity for jitter absorption processing in addition to the memory capacity originally required for the first error correction processing. .

In the case where high-speed access is performed when the data is audio data, the first error correction processing is performed in order to quickly control the rotation speed of the rotation motor at the target reading position of the modulation signal to a predetermined rotation speed. There is a problem that a rotating motor having a strong torque must be provided so as not to exceed an extra capacity for a jitter absorbing process of a working memory of the circuit.

The present invention has been made in view of the above problems, and does not require an extra capacity for jitter absorption processing in the working memory of the first error correction processing circuit, and has a powerful rotary motor. An object of the present invention is to provide an optical information reproducing apparatus that does not require torque.

[0024]

In order to achieve the above object, an optical information reproducing apparatus according to the present invention converts a data modulation signal from an optical disk having a spiral track recorded at a constant linear velocity to a reference clock signal. Demodulating the data in accordance with
When the data is audio data, DA conversion is performed by a DA converter to output an audio signal, and when a read request for the data is issued from an external device, the data is temporarily stored in a buffer memory circuit, and then the external device. In the optical information reproducing device for outputting via the interface circuit for performing the protocol, the operation of all the signal processing circuits except the data reading operation from the buffer memory circuit follows the synchronous clock signal synchronized with the modulated signal, The data read operation from the buffer memory circuit is configured to follow a signal that selects either the reference clock signal or the data read request signal from the interface circuit.

Further, preferably, when the data is audio data, the output of the buffer memory circuit is connected to the DA converter, and the data reading operation from the buffer memory circuit follows the reference clock signal.

According to the optical information reproducing apparatus of the present invention having the above-described configuration, the operation of all signal processing circuits except for the operation of reading data from the buffer memory circuit is completely performed by only the synchronous clock signal regardless of the type of data. Therefore, the working memory of the first error correction processing circuit only needs to have the memory necessary for the original first error correction processing, and furthermore, a strong torque can be obtained. This eliminates the need for a rotating motor.

If the data is audio data, the output of the buffer memory is output to the DA converter,
In addition, since data reading from the buffer memory circuit is operated in accordance with the reference clock signal, jitter absorption processing for the capacity of the buffer memory circuit can be performed.
Plays audio signals with high crystal-quality purity.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical information reproducing apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the optical information reproducing apparatus according to the present invention. This optical information reproducing apparatus includes a reference clock signal generation circuit 20 for generating a reference clock signal 60 for giving a reference operation speed, an optical pickup 13 for reading a modulation signal 51 from an optical disk 11, and a modulation signal It has a broadband synchronous clock signal generation circuit 19 that generates a clock signal 59 synchronized with the signal 51.

Further, the reference clock signal 60 and the synchronous clock signal 59 or the frequency-divided clock signals of the respective clock signals are inputted, and the speeds of the respective clock signals or the frequency-divided clock signals are compared. It has a rotation control signal generation circuit 23 for generating a signal 63 for controlling the rotation motor 12 for rotating the optical disk to a bit rate.

A demodulation circuit 14 for demodulating the modulated signal 51 to obtain demodulated data 52; a first error correction processing circuit 15 for inputting the demodulated data 52 to obtain first error-corrected data 53; A second error correction processing circuit 1 which receives the data 53 and obtains the second error corrected data 55
6.

A selector 31 for selecting and outputting data 53 when the data is audio data, and selecting and outputting the second error-corrected data 55 when the data is other than audio data. Buffer memory circuit 17 for inputting and temporarily storing output data of
A selector 32 for selecting the output destination of the output data of the buffer memory circuit 17 according to the type of data; and when the data is audio data, the output data of the buffer memory circuit 17 output via the selector 32 It has a DA converter 21 which inputs and outputs an audio signal 54 to an audio output terminal 24.

When there is a data read request from an external device (not shown), a data read signal 57 is input from the external device via the data request signal input terminal 26 to read the data. Generate signal 58;
The interface circuit 18 performs a series of protocol controls for outputting output data of the buffer memory circuit 17 output via the selector 32 to the information data output terminal 25 in accordance with the data read signal 58.

A selector 33 for selecting a data read signal from the buffer memory circuit 17 to be either a reference clock signal 60 or a data read signal 58 from the interface circuit 18 based on a data request signal 57.
And decodes and refers to the identification information 62 attached to the demodulated data 52, and switches the switching signal 61 based on the decoding reference result.
And a sequencer 22 for performing sequence control of the entire optical information reproducing apparatus including a process of outputting the same.

Next, the operation will be described. The rotating motor 12 loaded with the optical disk 11 is provided with a reference clock signal 60 and a synchronous clock so that the optical pickup 13 can read the modulation signal 51 from the optical disk 11 at a predetermined bit rate, similarly to a conventional CLV reproducing optical information reproducing apparatus. Rotation control signal generation circuit 2 based on comparison result of frequency or speed of signal 59 or respective divided clock signal
The CLV control is substantially performed by the rotation control signal 63 which is the output of the control signal 3.

The read modulated signal 51 is the modulated signal 51
Is input to the demodulation circuit 14 in accordance with the synchronization clock signal 59 generated by the wideband synchronization clock signal generation circuit 19.
After being demodulated into demodulated data 52, the data is written to a working memory (not shown) of the first error correction circuit 15.

At the same time, the sequencer 22 receives the identification information 62 attached to the demodulated data 52 demodulated by the demodulation circuit 14, decodes the identification signal 62 and identifies whether the data is audio data, The switching signal 61 is generated.

The above operation is the same as the operation of the conventional optical information reproducing apparatus of the variable speed reproducing system, except for the configuration and operation of the signal processing circuit after the first error correction processing. That is, from the first error correction processing, the buffer memory circuit 17
A series of signal processing operations up to the writing of data into the memory are performed in accordance with the synchronous clock signal 59 regardless of the type of data.

More specifically, when the data is audio data, the first error correction processing circuit 15 performs a first error correction process on the demodulated data 52 in accordance with the synchronous clock signal 59, and outputs the first error-corrected data. 53 is obtained and written directly into the buffer memory circuit 17 via the selector 31.

Further, the first error-corrected data 53 written in the buffer memory circuit 17 is read out according to the reference clock signal 60 and
The audio signal 54 is DA-converted by 1 and output to the audio output terminal 24. At this time, the jitter absorbing operation includes the data writing operation according to the synchronous clock signal 59 to the buffer memory circuit 17 and the reference clock signal 6.
This is performed between the data read operation according to “0”.

On the other hand, if the data is data other than audio data, the first error-corrected data 53 is input to the second error-correction processing circuit 16, where the second error-corrected data is input. 55 is obtained and written into the buffer memory circuit 17 via the selector 31. The interface circuit 18 receives the information data request signal 57 from the external device input to the information data request signal input terminal 26 and outputs the data 33 to the selector 33. The data is read out by outputting an information data read signal 58 to the buffer memory circuit 17 through the interface circuit 18.
Is output to the information data output terminal 25 as information data 56. At this time, the jitter absorbing operation is performed between a data write operation according to the synchronous clock signal 59 to the buffer memory circuit 17 and a data read operation according to the information data read signal 58 output from the interface circuit 18.

As described above, a series of signal processing operations other than the operation of reading data from the buffer memory circuit 17 are performed in accordance with the synchronous clock signal 59 regardless of the type of data. The jitter absorbing operation includes a data writing operation according to the synchronous clock signal 59 to the buffer memory circuit 17 and a reading operation according to a signal selected from the reference clock signal 60 and the data read request signal 57. Done between.

The selector 31, the selector 32 and the selector 33 are simultaneously controlled by the switching signal 61. The connection state of the selector 31, the selector 32 and the selector 33 in FIG. Shows

[0043]

As described above, according to the present invention,
Regardless of the type of data, the operation of all signal processing circuits except for the operation of reading data from the buffer memory circuit,
Since it is possible to operate only in accordance with the synchronous clock signal, various signal processings are started within the synchronizable range of the wideband synchronous clock signal generation circuit before the reproduction speed of the modulated signal read by the optical disk reaches a predetermined speed. And high-speed access is possible.

In addition, a strong C
It is not necessary to run the rotary motor servo of the LV, and it is not necessary to use a rotary motor having a strong torque, so it is inexpensive. And power consumption can be reduced.

Further, the jitter absorbing operation of the modulated signal caused by the uneven rotation of the optical disk is performed between the data write operation and the data read operation of the buffer memory circuit, so that the operation of the first error correction circuit can be performed. The memory capacity does not need to have an extra capacity for absorbing jitter of the modulation signal, and the circuit scale can be reduced.

[Brief description of the drawings]

FIG. 1 shows a block diagram of an embodiment of an optical information reproducing apparatus of the present invention.

FIG. 2 is a block diagram of a conventional variable-speed reproducing optical information reproducing apparatus.

[Explanation of symbols]

 Reference Signs List 11 optical disk 12 rotation motor 13 optical pickup 14 demodulation circuit 15 first error correction circuit 16 second error correction circuit 17 buffer memory 18 interface 19 synchronous clock signal generation circuit 20 reference clock signal generation circuit 21 DA converter 22 sequencer 23 rotation control Signal generation circuit

Claims (2)

[Claims] 1. A data-modulated signal is recorded on a spiral track at a constant linear velocity, the data is demodulated in accordance with a reference clock signal, and when the data is audio data, a DA converter is used for DA conversion. An optical system that converts and outputs an audio signal, and when an external device requests to read the data, temporarily stores the data in a buffer memory circuit and then outputs the data via an interface circuit that performs a protocol with the external device. In the information reproducing apparatus, the operations of all the signal processing circuits except the data reading operation from the buffer memory circuit follow a synchronous clock signal synchronized with the modulation signal, and the data reading operation from the buffer memory circuit is
An optical information reproducing apparatus according to a signal that selects either the reference clock signal or a data read request signal from the interface circuit. 2. The output of the buffer memory circuit is connected to the DA converter when the data is audio data, and the data read operation from the buffer memory circuit follows the reference clock signal. Optical information reproducing device.