JPH08138320A - Optical disc device - Google Patents

Abstract

PURPOSE: To obtain an optical disc in which the reproduction rate of a compressed digital data can be altered without altering the detection rate of the optical disc by supplying a variable clock to a demodulation circuit independently from the system clock so long as the data rate has a margin with respect to the detection rate. CONSTITUTION: Upon depression of an UP or clown button at an operating section 25, resistance of a variable resistor 28c is varied and thereby the frequency of a pitch control transmitter 28b is varied. A PLL circuit 28a compares a signal from a system controller 23 with a reference signal from the pitch control transmitter 28b and generates a pitch control clock having high frequency stability which is fed to a voice compression encoder/decoder 22 and a D/A converter 27. Consequently, the expansion rate of the voice compression encoder/decoder 22 can be altered and the performance pitch data of voice, outputted from the D/A converter 27, can be altered in the unit of 0.1% from 0.0% to ±9.9%, for example.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for reproducing a compressed signal recorded on an optical disk and compressed to a predetermined compression rate.

[0002]

2. Description of the Related Art Conventionally, an optical disk device such as a CD
Since the (compact disc) device does not compress the digital data recorded on the CD, the actual reading rate from the CD is made equal to the transfer rate up to the DA converter. Therefore, in order to control the pitch (pitch) of the audio signal at the time of reproduction, the CD device has realized the pitch control by changing the system clock of the entire device.

[0003]

However, in an optical disk device such as a conventional CD device, the system clock of the entire device must be changed in order to control the pitch of the audio signal to be reproduced. Due to the limitation of the clock extraction capability in a PLL (Phase Locked Loop) circuit or the like for obtaining it, it is not possible to drastically change the pitch.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an optical disk device capable of changing the pitch over a wide range.

[0005]

In order to solve the above-mentioned problems, according to the invention of claim 1, in an optical disk device for reproducing a compressed signal recorded on an optical disk and compressed to a predetermined compression ratio, the compressed signal is predetermined. Detecting means for detecting at a detection rate, a converting circuit for converting the detected compressed signal into compressed digital data, a memory means for temporarily storing the compressed digital data, and a compressed digital circuit connected to the memory means. A demodulation circuit that transmits and receives data and performs expansion processing; a variable demodulation clock supply circuit that is connected to the demodulation circuit and that supplies a variable clock to the demodulation circuit;
It is connected to the modulation circuit, the memory means, and the demodulation circuit, supplies compressed digital data to the memory means while monitoring an empty area of the memory means, and responds to a data request signal requested from the demodulation circuit. A memory management unit that supplies the compressed digital data stored in the memory means to the demodulation circuit.

[0006]

As described above, in the optical disk device according to the first aspect of the invention, the demodulation circuit sends and receives compressed digital data.
In this case, the data rate is only required to be the detection rate of the detection means at a rate corresponding to the compression rate of the compressed signal. For example, with a compression rate of 1/5, only 1/5 the detection rate requires the data rate.

Therefore, as long as the demodulation circuit is supplied with a variable clock in addition to the system clock, the expansion rate of the compressed digital data can be varied to change the pitch over a wide range as long as the data rate has a margin with respect to the detection rate. You can Further, the reproduction speed of the decompressed compressed digital data can be changed without changing the system clock and without changing the detection rate from the optical disk.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the main configuration of an embodiment of the present invention. The optical disc device 11 of the present invention is a device for recording compressed data on an MD (mini disc) manufactured as a rewritable music disc for consumer music and reproducing the MD. MD is stored in a plastic cartridge, and CLV is spiral track from the center.
It is an optical disc which is recorded by a (Constant Linear Velocity) system at a compression rate of 1/5 or which reproduces a signal recorded at a compression rate of 1/5.

There are three types of MDs, a premaster dedicated to reproduction, a recordable recordable and recordable hybrid, and a hybrid having both characteristics. The optical disk device 11 uses the system oscillator 26 to the memory unit 21,
The data is transmitted at a rate of 1.4 Mbit / s. An optical pickup 1 serving as detection means for the MD 13 which is rotationally driven by the spindle motor 12 in the CLV method.
A laser beam is emitted from the lens 4 through the objective lens 15.

The reproduction signal read by the reflected light at this time is read by the MD 13 at a detection rate of 1.4 Mbit / s which is the same as the CD, and is amplified by the RF amplifier 16 to be EFM (Eight to Fourteen Modulation).
And ACIRC (Advanced Cross Interleave Read Solom
on Code) encoder / decoder 17.

A system oscillator 26 is connected to the EFM and ACIRC encoder / decoder 17. EFM and ACIRC encoder / decoder 17
Is a conversion circuit for converting a reproduction signal sent from the MD 13 into compressed digital data, which performs EFM encoding and decoding, ACIRC encoding and decoding, ADIP (Address In Pregroove) decoding, and EFM / CLV control by ADIP is performed, and digital conversion similar to that of a conventional CD device or the like is performed.

The digital data obtained from the EFM / ACIRC encoder / decoder 17 is supplied to the vibration-proof memory controller 20. The anti-vibration memory controller 20 is connected to a memory unit 21 which is a memory means composed of a DRAM of several M bits. The vibration-proof memory controller 20 serves as a memory management unit, and
Digital data supplied from the M / A CIRC encoder / decoder 17 is temporarily stored in the memory unit 21, and the data stored in the memory unit 21 is output in response to a request from the audio compression encoder / decoder 22. To do.
In addition, the memory unit 21 has a TOC (Tabl
e Of Contents) and UTOC (User's TOC) are also stored.

When the anti-vibration memory controller 20 outputs the data for one sector, it notifies the system controller 23 that the data for one sector is requested. The system controller 23 reads the TOC or UTOC stored in the memory unit 21 through the anti-vibration memory controller 20, and instructs the encoder / decoder 17 of the EFM and ACIRC to read the next sector.

In response to this, the EFM / ACIRC encoder / decoder 17 passes the data of the next sector to the anti-vibration memory controller 20. However, when the end of the part of the MD 13 is reached, the head sector of the next part must be read by the optical pickup 14. Therefore, the system controller 23 always grasps the part data currently being reproduced, checks whether or not the requested sector of the vibration-proof memory controller 20 is within the range of the part, and when it comes to the end of the part. , The next part data stored in the TOC or UTOC stored in the memory unit 21 is read.

The system controller 23 is composed of a microcomputer, and includes a CPU, ROM, RAM, not shown.
Includes I / O bus. The I / O bus is connected to a display unit 24, an operation unit 25, an EFM / ACIRC encoder / decoder 17, a vibration-proof memory controller 20, and the like. By checking the read request signal for each sound group sent from the anti-vibration memory controller 20 to the anti-vibration memory controller 20 from the audio compression encoder / decoder 22 and the memory unit 21, the encoder / decoder of the EFM and ACIRC. The read request signal for each sector sent to 17 is input to the system controller 23.

The audio compression encoder / decoder 22 is a demodulation circuit including compression data expansion processing, and expands 0.3 Mbit / s compressed digital data supplied from the anti-vibration memory controller 20. This is sent to the DA converter 27. As a result, voice can be output.
The operation unit 25, the audio compression encoder / decoder 22
A variable demodulation clock supply circuit 28 is connected to the D-A converter 27.

The variable demodulation clock supply circuit 28 includes a PLL circuit 28a connected to the audio compression encoder / decoder 22 and the DA converter 27, and the PLL circuit 28a.
The pitch control oscillator 28b is connected to the circuit 28a, and the variable resistor 28c is connected to the pitch control oscillator 28b and the operating section 25.

When the UP button or DOWN button of the operation unit 25 is operated, the resistance value of the variable resistor 28c changes.
As a result, the frequency of the pitch control oscillator 28b changes. The PLL circuit 28a includes a signal from the system controller 23 and a pitch control oscillator 28b.
Compared with the reference signal from, good frequency stability,
A clock for pitch control is generated and supplied to the audio compression encoder / decoder 22 and the DA converter 27.

As a result, the expansion rate of the audio compression encoder / decoder 22 can be changed, and the audio performance pitch data output from the DA converter 27 can be, for example, 0.0% to ± 9.9. % Can be changed in units of 0.1%. When the PITCH button of the operation unit 25 is pressed and the LED (light emitting diode) is lit, the pitch control mode is set, and when the PITCH is displayed on the display of the display unit 24, the CLR button of the operation unit 25 is displayed. When is pressed, the pitch data is 0.0
It is also possible to perform control so that it is reset to%.

Therefore, the pitch can be changed over a wide range without changing the system clock as long as there is a margin in the data reading speed. The lower limit of the pitch is infinite, and the upper limit of the pitch is infinite as long as it is based on the performance of the encoder / decoder 22 for voice compression. Also,
For recording on a recordable disc, audio is converted into digital data by an A / D converter 29, compressed by an audio compression encoder / decoder 22, and modulated by the EFM / ACIRC encoder / decoder 17 with almost the same modulation method as CD. An error correction method is used, and a magnetic field modulation overwrite method is used in which a recording magnetic head 19 connected to a head drive circuit 18 is used together.

[0021]

As described above, according to the invention of claim 1,
As long as there is a margin in the data rate with respect to the detection rate, the expansion rate of the compressed digital data can be changed by supplying a variable clock to the demodulation circuit separately from the system clock, and the pitch can be changed over a wide range. It is possible to change the reproduction speed of the decompressed compressed digital data without changing the above, and without changing the detection rate from the optical disc.

[Brief description of drawings]

FIG. 1 is a main configuration diagram of an embodiment of the present invention.

[Explanation of symbols]

 11 optical disk device 13 MD 14 optical pickup 17 EFM and ACIRC encoder / decoder 20 vibration-proof memory controller 21 memory unit 22 audio compression encoder / decoder

Claims (1)

[Claims] 1. An optical disk device for reproducing a compressed signal recorded on an optical disk and compressed to a predetermined compression rate, and a detecting means for detecting the compressed signal at a predetermined detection rate, and a compression digital signal for the detected compressed signal. A conversion circuit for converting to data, a memory means for temporarily storing this compressed digital data, a demodulation circuit connected to this memory means for transmitting / receiving the compressed digital data and expanding the data, and connected to this demodulation circuit, A variable demodulation clock supply circuit for supplying a variable clock to the demodulation circuit, the modulation circuit, the memory means, and the demodulation circuit are connected, and compressed digital data is supplied to the memory means while monitoring an empty area of the memory means. And the compression digitizer stored in the memory means in response to a data request signal requested from the demodulation circuit. And a memory management section for supplying the demodulation circuit with the memory data.