JPH08287591A - Disk player - Google Patents

Abstract

PURPOSE: To control a spindle motor so that the transfer rate of a digital recorded signal can be settled within the processable speed range of a signal processing system at the time of access after the transfer rate can be set at the peak speed in the ability range of the processing speed of a signal processing circuit. CONSTITUTION: At the time of ordinary reproduction and at the time of access, the driving system of a spindle motor 2 is switched by a speed control selecting means 25 for selectively operating a linear velocity constant control means 4 and an angular velocity constant control means 5 corresponding to the operation of an access control means 24. Thus, at the time of ordinary reproduction, the spindle motor 2 is controlled by a linear velocity fixing system and at the time of access, the spindle motor 2 is controlled by an angular velocity fixing system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital recording signal using a bit clock synchronized with the bits of the digital recording signal in a signal processing step of reproducing a digital recording signal of a disc recorded by a constant linear velocity method. Regarding a disc player configured to decrypt information and obtain information data,
In particular, the present invention relates to a disc player in which a disc is driven at a higher speed than the rated speed, and the access operation is accelerated in a model in which the transfer rate is increased.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-5-189885.
As disclosed in Japanese Patent Laid-Open Publication No. JP-A-2003-187, in order to decode information data from a digital recording signal read from a disc, a decoding process of the digital recording signal is performed by using a bit clock synchronized with the bits of the digital recording signal. There is a disc player.

In this disc player, since the bit clock is inevitably synchronized even if the disc driving speed fluctuates and the information data transfer speed fluctuates, the disc driving is not strictly controlled. However, the information data can be decrypted. Therefore, when interlaced reproduction of a disc is performed by access to a disc of a constant linear velocity method such as a CD format disc,
Even if the drive speed of the disc deviates from the drive speed corresponding to the diameter at the disc reading position due to the track jump of the pickup that reads the digital recording signal of the disc, when the track jump of the pickup is completed, the drive speed of the disc changes. Decoding of the information data can be started before the servo circuit controls the constant linear velocity so that the access time can be shortened.

[0004]

By the way, the signal processing circuit for reproducing the digital recording signal of the disk has a limitation in the processing speed.

On the other hand, in a constant linear velocity type disc, the number of revolutions of the disc greatly differs between the innermost circumference and the outermost circumference, and in the case of the CD format disc, there is a difference of 2.4 times in the rated speed. Therefore, in the disc player that performs the decoding process of the digital recording signal using the bit clock described above, the information data can be promptly decoded even if the drive speed of the disc does not match immediately after the end of the track jump at the disc reading position by the optical pickup. In order to start the above, the signal processing circuit needs to have a signal processing speed capability that is higher than the multiplication factor of the rotational speed difference between the innermost circumference and the outermost circumference of the disk.

By the way, in the disc player,
A disc drive has been developed in which the drive speed of the disc is set to twice or four times as high as the rated speed, and the digital recording signal of the disc is read at a speed higher than the rated speed to increase the data transfer rate.

In such a disc player,
For CD format discs, 4.8 at 2x speed
There is a rotation speed difference of 9.6 times at double speed and 4 times speed, and if the speed is increased in this way, the processing speed capability range of the current signal processing circuit is exceeded. Therefore, even in a disc player that uses a bit clock to decode a digital recording signal, the disc drive speed changes immediately after the end of the track jump at the disc reading position, which may cause the signal processing circuit to exceed the processing speed capability range. In some cases, the decoding of information data cannot be started, so the digital recording signal read while controlling the disc rotation speed to match the pickup disc reading position can be processed by the signal processing circuit. It is necessary to wait until the speed falls within the speed range, and in this case, there is a problem that the access time becomes long.

Further, if the processing speed of the signal processing circuit exceeds the capability range, the model does not include a control system for controlling the drive speed of the disk by a signal system other than the signal processing circuit, such as by using a rotary encoder. Since the control of the disc drive speed becomes impossible, if you try to keep it within the processable speed range of the signal processing circuit, allow a margin for the processing speed of the signal processing circuit and drive speed of the disc during normal playback. Therefore, there is a problem in that the drive speed of the disk cannot be maximized within the processable speed range of the signal processing circuit.

[0009]

According to the present invention, there is provided a constant linear velocity control means for controlling a spindle motor for driving a disk in a constant linear velocity system, and a constant angular velocity control means for controlling the spindle motor in a constant angular velocity system. Access control means for controlling the access operation by causing the reading position of the disk to jump to the track, and speed control selection means for selectively operating the constant linear velocity control means and the constant angular velocity control means according to the operation of the access control means. With and
The spindle motor is controlled by the constant linear velocity method during normal reproduction, and the spindle motor is controlled by the constant angular velocity method during access.

[0010]

According to the present invention, in a disk player for decoding a digital recording signal by using a bit clock, the transfer rate is controlled by controlling the disk drive at a constant linear velocity according to the disk system during normal reproduction. When the maximum speed can be set within the range of the processing speed of the signal processing circuit for reproducing, and the disk of constant linear velocity type is controlled for high speed reproduction by controlling the disk drive with constant angular velocity during access. Also, in the case of (1), the processing speed of the signal processing circuit is kept within the capability range regardless of the reproduction position of the disc.

[0011]

1 is a circuit block diagram of a CD player showing an embodiment of the present invention. In FIG. 1, 1 is a CD format disc, 2 is a spindle motor for rotating the disc 1, and 3 is a motor servo circuit for controlling the drive of the spindle motor 2.

The motor servo circuit 3 controls the spindle motor 2 by a constant linear velocity control means 4 for controlling the spindle motor 2 by a constant linear velocity method corresponding to a digital recording signal recorded on the disk 1.
And a constant angular velocity control means 5 for controlling the spindle motor 2 in a constant angular velocity system. The constant linear velocity control means 4 has a processable speed range of a signal processing system (described later) for reproducing the digital recording signal. In the above, the spindle motor 2 is controlled at a constant linear velocity higher than the rated linear velocity, and the constant angular velocity control means 5 makes the transfer rate of the digital recording signal at the outermost periphery of the disk within the processable speed range of the signal processing system. The upper limit is set to a predetermined angular velocity that is higher than the rated transfer rate, and the spindle motor 2 is controlled within the upper limit angular velocity.

Reference numeral 6 denotes an optical pickup which emits a reading beam of laser light for tracing the disc 1 to read out a digital recording signal of the disc 1, and 7 denotes an RF signal (high frequency signal) of the digital recording signal read out from the optical pickup 6. An RF amplifier that amplifies and shapes the waveform, 8 is the R
The output of the optical pickup 6 is fed back through the F amplifier 7 to perform focusing control for focusing the read beam on the signal surface of the disc 1 and tracking control for causing the read beam to follow the signal track of the disc 1, and the optical pickup 6 This is a pickup control circuit that performs sled feed control for sending itself in the radial direction of the disc 1.

Reference numeral 9 detects a frame synchronization signal indicating the beginning of a frame from the digital recording signal whose waveform has been shaped by the RF amplifier 7, and outputs the digital recording signal by EFM.
A synchronization detection / EFM demodulation circuit for demodulation 10 separates a subcode signal from the digital recording signal EFM-demodulated by the synchronization detection / EFM demodulation circuit 9 and demodulates a Q code included in the subcode signal. Code separation / Q
A code demodulation circuit, 11 is an error detection / correction circuit for information data (audio data) in the digital recording signal extracted by the synchronization detection / EFM demodulation circuit 9, and 12 is a rearrangement of digital recording signals and an error in information data. The first RAM, 13 used as a correction buffer is the first RAM
A first address generation circuit that generates a write address that controls the write timing to the RAM 12 and a read address that controls the read timing from the first RAM 12, and 14 is information data that cannot be error-corrected by the error detection / correction circuit 11. Is an interpolation circuit for interpolating with reference to information data obtained before and after, and 15 is composed of a PLL circuit, and reproduces a bit clock synchronized with a bit included in the digital recording signal from the digital recording signal via the RF amplifier 7. It is a clock recovery circuit.

Here, a synchronization detection / EFM demodulation circuit 9, a subcode separation / Q code demodulation circuit 10, an error detection / correction circuit 11, a first address generation circuit 13 and an interpolation circuit 14 which are surrounded by a dashed line in the figure. Constitutes a signal processing circuit 16 for digitally processing a digital recording signal to reproduce information data, and is incorporated in a single signal processing LSI.

Each circuit constituting the signal processing circuit 16 performs each signal processing by the bit clock reproduced by the clock reproducing circuit 15, and the first R
In the AM 12, writing and reading of data are controlled by a write address and a read address generated in synchronization with the bit clock from the first address generation circuit 13. Therefore, even if the drive speed of the disk 1 changes, the first RAM 12 does not overflow, and the digital recording signal can be normally processed as a digital signal.

Reference numeral 17 denotes a serial / parallel conversion circuit for converting information data of a serial signal obtained through the interpolation circuit 14 into a parallel signal, and 18 temporarily stores the information data output from the serial / parallel conversion circuit 17. The second RAM, 19 serving as an earthquake-resistant buffer memory is the second RAM.
A second address generation circuit 20 for generating a write address for controlling the write timing to the RAM 18 and a read address for controlling the read timing from the second RAM 18, and 20 uses a crystal oscillator 21 to generate a reference clock of crystal oscillation accuracy. It is a reference oscillator.

Here, the second address generation circuit 19 generates the write address in synchronization with the bit clock from the clock recovery circuit 15, and the read address according to the sampling frequency of the information data. It occurs in synchronization with.

Reference numeral 22 is a parallel / serial conversion circuit for converting the information data of the parallel signal read from the second RAM 18 into a serial signal, and 23 is D / for converting the information data output from the parallel / serial conversion circuit 22 into an analog signal. It is an A converter.

Reference numeral 24 is an access control circuit for controlling an access operation for causing the optical pickup 6 to perform a track jump of the disc reading position, and 25 is the access control circuit 2.
4 is a speed control selection circuit for selectively operating the constant linear velocity control means 4 and the constant angular velocity control means 5 of the motor servo circuit 3 in accordance with the operation of 4.

Next, the operation will be described. The digital recording signal recorded on the disk 1 is read by the optical pickup 6, amplified by the RF amplifier 7, waveform-shaped, and supplied to the signal processing circuit 16.

The signal processing circuit 16 demodulates the digital recording signal whose waveform has been shaped by the RF amplifier 7 by each internal circuit, decodes various data contained in the digital recording signal, and Error detection and error correction processing of information data (audio data) is performed, and missing information data is interpolated.

The information data decoded by the signal processing circuit 16 is converted into a parallel signal by the serial / parallel conversion circuit 17, and then the second address generation circuit 19 is used.
Is written in the second RAM 18 in accordance with the write address from. Then, the information data written in the second RAM 18 is read according to the read address from the second address generation circuit 19, converted into a serial signal by the parallel / serial conversion circuit 22, and then transferred to the D / A converter 23. Supplied.

The information data supplied to the D / A converter 23 is converted into an analog signal and separated into stereo left and right channel components, and then supplied to an audio circuit (not shown) in the subsequent stage. It

In the process of reproducing the information data described above, each circuit constituting the signal processing circuit 16 is operated by the bit clock generated by the clock reproducing circuit 15, so that each circuit of the signal processing circuit 16 is a disk. Operates without being affected by the drive speed deviation.

The information data written in the second RAM 18 is synchronized with the bit clock and includes a jitter component caused by the disc drive speed deviation. The information data read from the second RAM 18 is read from the reference oscillator 20. It is synchronized with the reference clock of. Therefore, the jitter component of the information data is absorbed by the second RAM 18, and the information data having no time axis fluctuation is supplied to the D / A converter 23. That is, if the second RAM 18 does not overflow or become empty, normal reproduction can be performed even if there is a disc drive speed deviation.

In the disc player shown in FIG. 1, during normal reproduction, the spindle motor 2 is driven by the motor servo circuit 3 so that the disc 1 is rotated at a constant linear velocity higher than the rated linear velocity of the disc 1. Controlled.

In the motor servo circuit 3, by operating the constant linear velocity control means 4 during normal reproduction, there is no pulse width less than the shortest pulse width (3T) in the digital recording signal, and the shortest pulse width is predetermined. The speed of the spindle motor 2 is controlled so that the period becomes, and thereafter, the reproduction clock and the reference clock are frequency-divided and the phases are compared, and the spindle motor 2 is subjected to phase servo to make the disk 1 move at a predetermined high linear velocity. Drive at a constant rate. In this case, the transfer rate of the digital recording signal is set to approximately the highest speed within the processable speed range of the signal processing circuit 16.

As described above, in the disc player of FIG. 1, since the disc 1 is driven at a high constant linear velocity, the disc 1 is driven by the optical pickup 6 accordingly.
The digital recording signal of is read at high speed, and various data demodulated by the signal processing circuit 16 is processed by each circuit at a high transfer rate and transmitted.

On the other hand, the reading speed of the information data from the second RAM 18 is matched with the sampling frequency, and the information data is reproduced according to the sampling frequency. That is, the transmission rate of the second RAM 18 at the time of writing is higher than that at the time of reading. Therefore, if the information data is not correctly decoded due to external shock or swing using this difference in transmission rate, gain time to reread the digital recording signal containing the information data. You can

In this case, the access control circuit 24 operates so as to retrieve the address data (Q code of the subcode signal) of the frame of the digital recording signal including the information data that could not be correctly decoded, and the disc by the optical pickup 6 is operated. The read position is track-jumped to perform the access operation, and the digital recording signal including the information data that could not be correctly decoded is read again.

When the information data is properly decoded, the second RAM is reproduced as the disc 1 is reproduced.
The data capacity stored in 18 increases and the second RAM 1
8 eventually causes an overflow.

In this case, the access operation is performed by operating the access control circuit 24 so as to search the address data of the frame of the digital recording signal including the information data which could not be written in the second RAM 18 due to the occurrence of overflow. The digital recording signal including the information data is read again. Information data stored in the second RAM 18 is consumed by the time for rereading the digital recording signal, and a data capacity for storing newly decoded information data is secured in the second RAM 18.

By the way, when the access control circuit 24 is activated, the speed control selection circuit 25 causes the motor servo circuit 3 to operate the constant angular velocity control means 5. Therefore, during the access operation, the spindle motor 2 is controlled by the constant angular velocity method, and the constant angular velocity control means 5 controls the spindle motor 2 so as to maintain the angular velocity at the start of the access, that is, the number of revolutions thereof. In this case, since the access operation is performed from the outer peripheral side to the inner peripheral side of the disc 1 due to the relationship of returning the disc reading position by the optical pickup 6, the drive speed of the disc 1 is maintained so that the disc reading position is As a result, the linear velocity of the disc 1 is lowered, and the reading speed of the digital recording signal by the optical pickup 6 is reduced. Therefore, the transfer rate of the digital recording signal supplied to the signal processing circuit 16 is within the processable speed range of the signal processing circuit 16.

Therefore, when the track jump due to the access operation is completed and the reading of the digital recording signal from the disk 1 is started, the information data can be immediately decoded and the access time can be shortened.

Next, the operation when the access operation for performing the interlaced reproduction of the disc is selected, or when the access operation is performed by an external impact or swing will be described.

Now, assuming that the access operation is selected by the input operation, the access control circuit 24 operates and the desired reproduction portion inputted by the input operation, for example, the address data corresponding to the desired music number is set as the access target. Then, the access operation by the optical pickup 6 is performed to retrieve the address data of the access target. By the access operation, the access target address data is retrieved, and the optical pickup 6 starts reading the digital recording signal of the frame having the address data, and the interlaced reproduction of the disc 1 is achieved.

When the reading of the digital recording signal of the disc 1 by the optical pickup 6 is interrupted by an external impact or swing, the continuity of the Q-codes of the frames of the digital recording signal processed by the signal processing circuit 16 is maintained. There is a break, and an abnormal reading of the digital recording signal is detected. When this abnormality is detected, the access control circuit 24 operates, the last stored Q code is set as an access target, and the access operation by the optical pickup 6 is performed to search the Q code of the access target. By the access operation, the access target Q code is eventually searched, and the optical pickup 6 starts the reading of the digital recording signal of the frame having the Q code, and the reading of the digital recording signal immediately before the interruption of the reading of the digital recording signal is performed. It is restarted by the optical pickup 6.

In these cases as well, the access control circuit 24 is activated and the speed control selection circuit 25 causes the motor servo circuit 3 to operate the constant angular velocity control means 5. Therefore, during the access operation, the spindle motor 2 is controlled by the constant angular velocity method, and the constant angular velocity control means 5 controls the spindle motor 2 to maintain the angular velocity at the start of the access. Here, when the outer peripheral side of the disc 1 is accessed to the inner peripheral side, the constant angular velocity control means 5 controls the spindle motor 2 so as to maintain the angular velocity at the start of access, but from the inner peripheral side of the disc 1. When the outer peripheral side is accessed, the linear velocity of the disc 1 is increased with respect to the disc reading position because the drive velocity of the disc 1 is maintained, and the reading speed of the digital recording signal by the optical pickup 6 is increased. It will be faster. Therefore, there is a possibility that the angular velocity at the time of starting access exceeds the upper limit of the controllable angular velocity set in the constant angular velocity control means 5, but in this case, the constant angular velocity control means 5 has Since the spindle motor 2 is controlled, the transfer rate of the digital recording signal supplied to the signal processing circuit 16 falls within the processable speed range of the signal processing circuit 16.

Therefore, in the access operation in this case, the transfer rate of the digital recording signal exceeds the capability range of the processing speed of the signal processing circuit 16, especially when the disk 1 is accessed from the inner circumference side to the outer circumference side. Therefore, the information data can be immediately decoded regardless of the drive speed of the disk after the track jump is completed, and the access time can be shortened.

In the above-mentioned embodiment, the description has been made with respect to the CD-DA compatible disc player which handles audio data as information data, but the present invention is not limited to this, and according to the present invention, a computer is used as information data. It can be applied to a CD-ROM that handles data and a disc player compatible with a disc of a constant linear velocity system.

[0042]

As described above, the present invention does not depend on the reproducing position of the disc even when the disc of the constant linear velocity system is controlled to drive at high speed by controlling the disc drive at a constant angular velocity during access. Since it is set within the processing speed capability of the signal processing circuit, the disk drive speed during normal playback can be set without considering the disk drive speed change during access. In the disc player that performs the decoding process of the above, the transfer rate is set to the maximum within the processing speed capability of the signal processing circuit that reproduces the digital recording signal by controlling the disc drive at a constant linear velocity according to the disc system during normal reproduction. It can be set at high speed.

Further, according to the present invention, by switching from the constant linear velocity control to the constant angular velocity control at the time of access, the transfer rate of the digital recording signal is signal processed even when the disc is accessed from the inner circumference side to the outer circumference side. Since the spindle motor is controlled so as to be within the processable speed range of the system, the information data can be immediately decoded after the track jump is completed regardless of the drive speed of the disk, and the access time can be shortened.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of a CD player showing an embodiment of the present invention.

[Explanation of symbols]

 2 spindle motor 3 motor servo circuit 4 linear velocity constant control means 5 angular velocity constant control means 6 optical pickup 15 clock regeneration circuit 16 signal processing circuit 18 second RAM 24 access control circuit 25 speed control selection circuit

Claims (3)

[Claims] 1. A data processing step for reproducing a digital recording signal of a disc recorded by a constant linear velocity method, wherein the digital recording signal is decoded by using a bit clock synchronized with a bit included in the digital recording signal to obtain information data. And a constant linear velocity control means for controlling the spindle motor in a constant linear velocity system, and a constant angular velocity control means for controlling the spindle motor in a constant angular velocity system. And an access control means for controlling the access operation by making a track jump of the reading position of the disk, and a speed control for selectively operating the constant linear velocity control means and the constant angular velocity control means in accordance with the operation of the access control means. Equipped with selection means, spindle motor is controlled by constant linear velocity during normal playback In addition, the disc player is configured to control the spindle motor with a constant angular velocity method during access. 2. The constant angular velocity control means is set with an upper limit of a predetermined angular velocity such that the transfer rate of the digital recording signal at the outermost periphery of the disc falls within the processable speed range of the signal processing system for reproducing the digital recording signal. Controlling the spindle motor within its upper limit angular velocity.
The described disc player. 3. The constant linear velocity control means is capable of processing a signal processing system for reproducing the digital recording signal at a transfer rate of the read digital recording signal at a constant linear velocity higher than the rated linear velocity. The spindle motor is controlled so as to be within the speed range, and the constant angular velocity control means is configured so that the transfer rate of the digital recording signal at the outermost periphery of the disk falls within the processable speed range of the signal processing system and is higher than the rated transfer rate. 2. The disc player according to claim 1, wherein a predetermined angular velocity that is the transfer rate is set as an upper limit, and the spindle motor is controlled within the upper limit angular velocity.