JP2703443B2 - Disc player - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reading out a digital signal recorded on a disk at a higher speed than the rated speed while repeating the same part while storing reproduced data in a memory once and then reading the same portion. The present invention relates to a disc player capable of re-reading and reproducing erroneous reproduction data.

[0002]

2. Description of the Related Art First, the applicant of the present invention rotates a disk at a speed higher than a rated speed, traces the disk at a high speed by a pickup, reads a digital signal recorded on the disk, and demodulates the digital signal. After writing main data such as music information to the memory at high speed in accordance with the high-speed rotation of the disc, the main data is read from the memory in accordance with the rated speed, and the amount of data in the memory is read. While managing
In order to repeatedly read the same portion of the disc, a disc player has been proposed in which the trace position of the pickup is sequentially advanced to perform reproduction (see Japanese Patent Application No. 2-319998). In this disc player, since the disc is traced at a high speed, a time for repeatedly tracing the same part while reading the main data from the memory at a rated speed is created, and errors in the reproduced main data cannot be corrected. When the reproduction of the information data is interrupted due to a shock or a swing from the outside, the digital signal including the main data which could not be read correctly can be read again. Therefore, by providing such a function, it is possible to provide a disc player excellent in anti-vibration measures, and it is suitable for a portable CD player such as a headphone stereo type or a portable type which can be carried around.

[0003] By the way, as is well known, a CD player is
After playing back the innermost lead-in area of the disc on which table of contents data called TOC, which is used as a table of contents information for use in signal search such as music selection and display on a display, is used, main data such as music information is reproduced. Is reproduced from the program area of the disk on which the data is recorded, and is reproduced from the inner peripheral side to the outer peripheral side of the disk. In the CD player, since a digital signal is recorded on the disk at a constant linear velocity, it is necessary to start the rotation of the disk at the highest speed immediately after the start of reproduction.

[0004]

By the way, at the time of reproducing a disc, it is not rare to select and reproduce only a desired song from a plurality of songs stored on the disc. In this case, after reading the table of contents data, the rotation of the disk is once started up to the maximum speed immediately after the start of reproduction, and then the rotation speed of the disk is reduced according to the diameter of the target track at the beginning of the desired music. An unreasonable action is taken. As described above, in a disk player that reads a disk at a high speed, the range of the number of rotations of the disk is expanded, so that at the time of music selection and reproduction, the time required from reading the table of contents data to reproducing the desired music. However, there is a drawback that it is prolonged.

[0005] In addition, since the table of contents data cannot be read unless the total number of music pieces and the total playing time of the disk are detected, the selection and reproduction of music cannot be performed. The number of rotations of the disc is higher than that of a disc player that reads the disc at the rated speed, and the time required to start up the disc rotation is prolonged, and the time required for performing music selection operation is extended, and operability is improved. There is a drawback that this leads to deterioration of the quality.

[0006]

SUMMARY OF THE INVENTION The present invention provides a table of contents detecting means for detecting that table of contents data has been read, and a motor control for controlling a spindle motor for rotating a disk and controlling the rotation of the disk at a rated speed and a high speed. A circuit and a speed switching means for switching a set speed of the motor control circuit so as to switch the rotation of the disk from a rated speed to a high speed. After the reading of the main data is completed, the rotation of the disk is accelerated to read the main data.

[0007]

According to the present invention, in a disk player for reading a disk at a high speed, the disk rotation is performed at a rated speed to read the index data, thereby shortening the start-up time of the disk rotation when reading the index data. In addition to making it possible to quickly perform song selection operations, the pickup rotates the disk from the rated speed to a high speed while searching for the target track at the beginning of the song to be selected by the pickup. The irrational operation of rotation is eliminated, and music selection and reproduction can be performed quickly.

[0008]

1 shows an embodiment of the present invention and is a portable CD.
FIG. 2 is a circuit block diagram of a player. In the illustrated CD player, the spindle motor 2 rotates at a rated speed and at a high speed in order to rotate the CD-type disc 1 at a speed higher than the rated linear speed (for example, 2 times) in addition to the rated linear speed. The motor servo circuit 3 for controlling the spindle motor 2 can selectively set servo constants corresponding to the two types of speeds.

In FIG. 1, reference numeral 4 denotes a pickup for optically tracing the disk 1 by an emitted light beam;
Is an RF amplifier for amplifying and shaping an RF signal (high-frequency signal) of a digital signal recorded on the disk 1 obtained by being traced by the pickup 4, and 6 is a pickup using an RF signal obtained via the RF amplifier 5. 4 for controlling the focusing of a light beam tracing the disk 1 on the signal surface of the disk 1 and the tracking control for tracking the light beam on a signal track of the disk 1.
Is a pickup servo circuit for performing control to feed the disk in the radial direction of the disk 1.

Reference numeral 7 denotes a synchronization detection / E for detecting a frame synchronization signal indicating the beginning of a frame from the EFM-modulated recording signal of the disk 1 which is shaped as a digital signal and output as a digital signal, and performs EFM demodulation.
The FM demodulation circuit 8 separates sub-code data indicating the beginning of the music, the music number, the elapsed playing time, etc. (P and Q codes) from various demodulated data EFM demodulated by the synchronization detection / EFM demodulation circuit 7. And a subcode separation / Q code demodulation circuit 9 for demodulating the Q code included in the subcode data. A table of contents 9 reproduced by the synchronization detection / EFM demodulation circuit 7 when the lead-in area of the disk 1 is traced. TOC memory for storing data (TOC), 1
0 is an error detection / correction circuit that performs error detection / correction of the main data using a parity that performs error detection and error correction of main data serving as music information extracted from a digital signal after EFM demodulation; And a first RAM 12 for temporarily storing demodulated data as an error correction buffer for main data.
A first address generation circuit 13 for generating a write address and a read address for controlling the timing of writing the demodulated data to the RAM 11 and the timing of reading the demodulated data, respectively, is used to generate main data that cannot be corrected by the error detection / correction circuit 9. This is an interpolation circuit that performs interpolation according to main data obtained before and after the interpolation.

In the figure, a synchronization detection / EFM demodulation circuit 7, a subcode separation / Q code demodulation circuit 8, a TOC memory 9, an error detection / correction circuit 10, a first address generation circuit 12, and an interpolation circuit surrounded by a chain line. The circuit 13 constitutes a signal processing circuit 14 for digital signal processing of a digital signal read from the disk 1 to obtain main data.

Reference numeral 15 denotes a clock reproducing circuit which is constituted by a PLL circuit and reproduces a clock synchronized with the bits of the digital signal output from the RF amplifier 5.

Here, each circuit constituting the signal processing circuit 14 performs each signal processing by the reproduced clock reproduced by the clock reproducing circuit 15. Since the write address and the read address generated from the first address generating circuit 12 are generated according to the timing of the reproduction clock, jitter cannot be absorbed when the rotation speed of the disk 1 changes. But the first R
AM 11 is prevented from overflowing. Further, since the reproduced clock obtained from the clock reproducing circuit 15 is generated in accordance with the rotation speed of the disk 1, each of the circuits constituting the signal processing circuit 14 is configured to output the signal from the disk 1 when the disk 1 is rotated at a high speed. , Each signal processing is performed at a higher speed than a general CD player.

Reference numeral 16 stores basic programs, such as a method of reproducing a disk, various search methods, and a method of introducing focusing of the pickup 4, and performs various basic operation controls and a display (not shown). This is a system control circuit composed of a microcomputer that performs control for displaying an image and input control for operation keys (not shown).
The system control circuit 16 includes a Q for monitoring the Q code demodulated by the subcode separation / Q code demodulation circuit 8.
A code monitoring means 17 is provided, and a track jump control means 18 for supplying a track jump signal for displacing the trace position of the pickup 4 in the radial direction of the disk to the pickup servo circuit 6 is provided.

When the lead-in area of the disk 1 is traced, the system control circuit 16
When TOC data is written to the C memory 9, T
A TOC reading detecting means 19 for detecting that the reading of the OC has been completed is provided. When the TOC reading detecting means 19 detects that the reading of the TOC has been completed, the rotational speed of the disk is changed from the rated value to the rated value. The switching signal for switching to twice the speed of the motor servo circuit 3
Is provided with a speed switching means 20 for supplying the speed.

Reference numeral 21 denotes a serial / parallel conversion circuit for converting the main data of the serial digital signal demodulated by the signal processing circuit 14 into a parallel digital signal. Reference numeral 22 temporarily stores the main data output from the serial / parallel conversion circuit 21. The second RAM 23, which is
A second address generating circuit 24 generates a write address for controlling writing of main data to the AM 22 and generates a read address of main data from the second RAM 22. This is a reference oscillator that generates a clock.

Here, the write address generated from the second address generation circuit 23 is generated in synchronization with the reproduction clock from the clock reproduction circuit 15, while the write address is generated.
The read address generated from the address generation circuit 23 is generated in synchronization with a reference clock from the reference oscillator 25 and is generated in accordance with a sampling frequency when recording main data on the disk 1. Therefore, the timing of writing the main data to the second RAM 22 is faster than the timing of reading the main data from the second RAM 22, and the second RA
The jitter component at the output timing of the main data is absorbed by M22.

26 monitors a write address and a read address of the second address generating circuit 23, and a second RAM
22 and detects the occurrence of a non-correctable signal indicating that the information data is uncorrectable from the error detection and correction circuit 10, and detects the occurrence of the non-correctable signal.
Is determined to exceed the interpolation capacity of the second RAM.
A RAM control circuit that detects the timing of stopping and restarting the writing of the main data to the second 22, and controls the second address generating circuit 23 in accordance with the detected output to control the writing of the main data to the second RAM 22. Also,
The RAM control circuit 26 generates an overflow signal indicating that the overflow of the second RAM 22 has been detected, and generates an interpolation impossible signal indicating that the overflow of the interpolation circuit 13 has occurred, when the overflow of the interpolation circuit 13 has been detected. The control means 18 generates a track jump signal for returning the reading position (trace position) of the disk by the pickup 4 by one track.

Reference numeral 27 denotes a WOK signal generation means provided in the system control circuit 16 for generating a writable signal (WOK signal) indicating that main data can be written to the second RAM 22. The WOK signal generation means 27 responds to the occurrence of the overflow signal and the interpolation impossible signal from the RAM control circuit 26 and the status of the Q code monitoring by the Q code monitoring means 17 and the operation status of the track jump control means 18. When a signal is generated, specifically, when an overflow signal or an interpolation impossible signal is generated, the WOK signal is not generated,
Further, the WOK signal is not generated at the same time as the generation of the track jump signal from the track jump control means 18, and the track jump is completed, and the disk is within the target range (within three frames before and after the target frame). When a Q code indicating the above is detected, a WOK signal is generated.

Reference numeral 28 denotes a shift register (not shown) in which the main data output from the serial / parallel conversion circuit 21 is written in synchronization with the timing of writing the main data to the second RAM 22, and an overflow of the second RAM 22 is detected. A latch circuit (not shown) for latching the main data written in the shift register, wherein the main data written in the shift register matches the main data latched in the latch circuit. To determine whether the second RAM
22 is a data coincidence determination circuit for setting the timing for restarting the writing of the main data to 22.

Reference numeral 29 denotes a parallel-to-serial conversion circuit for converting the main data of the parallel digital signal read from the second RAM 22 into a serial digital signal, and reference numeral 30 converts the main data output from the parallel-to-serial conversion circuit 29 to an analog signal. It is a D / A converter.

Next, the operation will be described.

The motor servo circuit 3 is supplied with a digital signal obtained through the RF amplifier 5, a reproduced clock obtained from the clock reproducing circuit 15, and a reference clock obtained from the reference oscillator 24.
Detects the pulse width of the shortest pulse in the digital signal,
The speed of the spindle motor 2 is controlled so that the pulse width becomes a predetermined length, and then the phases of signals obtained by dividing the reproduction clock and the reference clock are compared, and phase servo is applied to the spindle motor 2. In this way, the disk 1 is rotated at a predetermined linear speed.
At the start of playback, the player first sets the speed switching means 20 to rotate the disc 1 at the rated linear speed.
Generates a switching signal, and the servo constant of the motor servo circuit 3 is set for the rated speed. When the TOC reading detecting means 19 detects that the TOC of the disk 1 has been read, a switching signal is generated from the speed switching means 20 according to the detection output, and the servo constant of the motor servo circuit 3 is changed to the high speed speed. Is set to

When the reproduction is started, the disk 1 is traced from the lead-in area, and when the TOC recorded in the lead-in area is read, the program area is traced thereafter. Therefore, when the reproduction is started, first, the lead-in area is traced at the rated linear velocity, and after the TOC is read, the program area is traced at a predetermined high linear velocity.

On the other hand, when the pickup 4 traces the lead-in area and the program area of the disk 1, the signal recorded on the disk is converted into an RF signal (high-frequency signal) by the RF amplifier 5 via the pickup 4.
Supplied to The RF signal is amplified by the RF amplifier 5, waveform-shaped, and supplied to the signal processing circuit 14 as a digital signal. And the signal processing circuit 1
4 demodulates the digital signal and extracts various data contained in the digital signal.

When the lead-in area is traced, TOC demodulation is performed by the synchronization detection / EFM demodulation circuit 7 and the demodulated TOC data is stored in the TOC memory 9.
Is stored. When the TOC data is stored in the TOC memory 9, the fact is detected by the TOC reading detecting means 19, and as described above, the drive signal of the speed switching means 20 causes the motor servo circuit 3 to drive the spindle motor 2. The speed is switched so that the disk 1 is driven at a predetermined high linear speed, and the program area is traced by the speed.

When the program area of the disk 1 is traced at a high speed in this manner, the signal processing circuit 1
4, the main data (audio data) is demodulated, error detection and error correction of the main data are performed, and interpolation of the missing main data is performed. The main data output from the signal processing circuit 14 is converted from a serial digital signal into a parallel digital signal by a serial / parallel conversion circuit 21, and then converted in accordance with a write address from a second address generation circuit 23. The data is written to the second RAM 22. The main data written in the second RAM 22 is read in accordance with a read address from the second address generation circuit 23, and the main data is converted from a parallel digital signal into a serial data by a parallel / serial conversion circuit 29. It is converted to a digital signal. And
The main data output from the parallel / serial conversion circuit 29 is converted into an analog signal by a D / A converter 30 and separated into stereo left and right channel components, each of which is a subsequent audio circuit (not shown). Supplied to

The timing of writing the main data to the second RAM 22 is set at a high speed in accordance with the timing of the output of the main data from the signal processing circuit 14. The second RAM 2 is adapted to the sampling frequency when storing the main data.
2 is slower than the timing of writing to the data. Therefore, as the reproduction proceeds, the second RAM 22 will eventually overflow.

Here, the overflow of the second RAM 22 is detected by the RAM control circuit 26 by monitoring the write address and the read address of the second address generation circuit 23, and an overflow signal indicating the overflow is sent from the RAM control circuit 26. Is supplied to the system control circuit 16. Therefore, a track jump signal is generated from the track jump control means 18 to return the reading position of the disk by the pickup 4 by one track, and the same position on the disk is repeated by returning the tracing position of the disk by the pickup 4 by one track. Be traced. In this case, the second R
Since the main data written so far is sequentially read from the AM 22, the main data is not interrupted,
Plays continuously.

When the overflow of the second RAM 22 is detected, a stop signal for stopping the writing to the second RAM 22 is output by the RAM control circuit 26 from that point, and the writing of the main data to the second RAM 22 is stopped. Therefore, only the reading of the main data is performed, and the amount of the main data written in the second RAM 22 decreases.

On the other hand, when the digital signal read by the pickup 4 is processed by the signal processing circuit 14, the Q code contained in the digital signal is monitored by the Q code monitoring means 17 as needed, and the Q code is monitored. The code is stored in a RAM (not shown) in the system control circuit 16. Therefore, since the Q code at the time when the second RAM 22 overflows is stored in the RAM in the system control circuit 16, when the overflow of the second RAM 22 occurs, the track jump control means 1
8 is activated, the access operation starts, and the pickup 4
Is returned by one track of the disk, and a search is performed with the Q code stored in the RAM in the system control circuit 16 as a target. And
The trace position by the pickup 4 approaches the digital signal portion including the Q code at the time of overflow,
The Q code within the target range will be demodulated,
When the Q code is detected by the Q code monitoring means 17, the main data output from the serial / parallel conversion circuit 21 is taken into the data match determination circuit 28.

Here, the data coincidence judgment circuit 28 stores main data of a predetermined number of samples before the overflow of the second RAM 22 occurs, and when the main data from the serial / parallel conversion circuit 21 is taken in. The main data is compared with the main data stored in the data match determination circuit 28.
When a match between the main data is detected,
A coincidence signal indicating this is supplied to the RAM control circuit 26, and writing of the main data to the second RAM 22 is restarted.

When the writing of the main data to the second RAM 22 is restarted, the restarted main data is stored in the second RAM 22 next to the address where the last main data at the time when the writing was stopped due to the overflow. The data is sequentially written from the address, and is written following the last main data. And the second
The main data whose writing to the RAM 22 has been resumed is
Since the last main data is continuous on the disk, correct reproduction is continuously performed.

On the other hand, if a match signal cannot be obtained from the data match determination circuit 28 for some reason, the RAM control circuit 26 determines whether the write address and the read address from the second address generation circuit 23 match and the timing in the second RAM 22. Detecting that the main data becomes empty, the writing to the second RAM 22 is restarted. In this case, the read main data is not connected correctly, but the main data is stored in the second RAM so that the reproduction is not interrupted.
The main data in the block 22 is written following the last main data, and the newly written main data is read continuously to the last main data.

By the way, if the signal of the disk is not correctly read by the pickup 4 due to an external shock or swing, or a scratch or dirt on the disk, the error detection / correction circuit 10 cannot correct the error of the main data. , A non-correctable signal is generated from the error detection / correction circuit 10. Then, when the RAM control circuit 26 detects that the non-correctable signal has been continuously generated by the interpolation capability of the interpolation circuit 13 or more, the RAM control circuit 26 generates an interpolation impossible signal, and the WOK signal generation means 27 WO
The generation of the K signal is stopped. Therefore, the second address generation circuit 23 is controlled via the RAM control circuit 26,
The writing of the main data to the second RAM 22 is stopped, and the track jump control means 18 generates a track jump signal for causing the pickup 4 to jump the track so as to return the trace position of the disk. The trace position of the disk by the pickup 4 is returned to search for the Q code of the digital signal block read immediately before the read digital signal block is read.

If erroneous main data is generated due to an external shock or swing, the erroneous main data can be read again by tracing the same portion of the disk again by the pickup 4, and the correct main data can be read. Can be obtained, the data match determination circuit 2
8, the same main data as the main data immediately before the error is input, and the data match determination circuit 28 generates a match signal. The comparison of the main data by the data match determination circuit 28 is not performed immediately after the track jump of the trace position is completed, but is performed from the vicinity of the frame including the final main data written in the second RAM 22. At this time, the detection of the Q code is performed targeting the frame including the Q code corresponding to the final main data. In this case, even if the Q code is not detected in consideration of the failure of the Q code capture, A target frame is detected by adding one frame to the time information of the Q code stored at each timing when the frame is reproduced. Then, when the trace position reaches the vicinity of the target frame, the main data for comparison is taken into the data match determination circuit 28,
The data match determination circuit 28 compares the captured main data.

When a coincidence signal is generated by the data coincidence determination circuit 28, a start signal is generated from the RAM control circuit 26, and the correct main data read continuously from the main data immediately before the incorrect main data is read. Will be written.

Accordingly, in this case, the main data can be reproduced continuously without interruption.

On the other hand, if erroneous main data is generated due to scratches or dirt on the disk, the erroneous main data cannot be read again even if the same portion of the disk is traced again by the pickup 4, and the correct main data cannot be read. I can't get it. Therefore, the data match determination circuit 28
Does not obtain a coincidence signal, and only the main data in the second RAM 22 is consumed.
6, it is detected that the main data in the second RAM 22 will be emptied soon. When the detection is performed, tracing of the same portion of the disk is stopped again, the track jump control means 18 is operated to trace the next portion, and a start signal is generated from the RAM control circuit 26. Writing of the main data to the 2RAM 22 is restarted. In this case, the reread main data is not correctly connected to the main data written in the second RAM 22, but the main data is written continuously to the last main data in the second RAM 22 so that the reproduction is not interrupted. The newly written main data is read continuously from the last main data.

By the way, since the lead-in area of the disk 1 is traced at the rated linear velocity, the start-up of the disk rotation is of course shorter in comparison with the linear velocity higher than the rated. Compared with the linear velocity of about twice the rated linear velocity, it is advantageous to reduce the time required to read the TOC even if the trace time of the lead-in area is extended. Therefore, the state is promptly shifted to a state in which music reproduction can be performed while ensuring the reliability of reading the TOC.

When the music selection operation is performed, the absolute time information data corresponding to the target track which is the head of the music to be reproduced next is read out from the TOC memory 9, and the system control circuit 16 controls the current time by the pickup 4. The distance (the number of tracks) from the trace position to the target track is calculated, and a track jump signal is generated from the track jump control means 18 accordingly. The target track is searched by moving the trace position by the pickup 4. However, when music selection and reproduction are performed from the beginning after the TOC is read, the rated line at the time of tracing the lead-in area without raising the maximum rotational speed portion corresponding to the innermost track of the disk to a predetermined high-speed linear velocity is used. Directly from the speed, it will match the high-speed linear velocity at the diameter where the target track is located, During the search of the rack with can be matched to the rotational speed of the target track in response to the fast linear velocity, wasteful rising operation of the disk rotation speed is eliminated,
The time required to complete the music selection operation is reduced.

[0042]

As described above, the disc player according to the present invention reproduces a disc in which main data and table of contents data located on the inner peripheral side thereof are recorded at a constant linear velocity. When reading, the set speed of the motor control circuit is switched to the rated linear speed, and after the table of contents data is read, the set speed of the motor control circuit is switched to the high linear speed,
In addition, in the case where music selection reproduction is performed from the beginning, after the reading of the table of contents data is completed, control is performed to directly adjust from the rated linear velocity to a high-speed linear velocity corresponding to the diameter of the target track at the head of the music to be selected from the rated linear velocity. Therefore, when the song selection and playback are performed from the beginning, after the table of contents data is read, the song to be selected is not started at a high-speed linear speed corresponding to the diameter where the innermost track of the main data is located. Direct start-up at a high linear velocity according to the diameter of the target track at the head position, eliminating unnecessary start-up operation of the disk rotation that increases the number of rotations of the disk more than necessary. The time required to complete the music selection operation can be reduced by shortening the time. Then, since the reading of the table of contents data is performed at the rated linear velocity, an effect of improving the reliability of reading the table of contents data can be obtained as a secondary effect.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing one embodiment of the present invention.

[Explanation of symbols]

 2 Spindle motor 3 Motor servo circuit 4 Pickup 9 TOC memory 14 Signal processing circuit 15 Clock regeneration circuit 16 System control circuit 18 Track jump control means 19 TOC reading detection means 20 Speed switching means

Claims (1)

(57) [Claims] [Claim 1] and the main data such as music information, Meinde
Plays back a disc in which the index data, which is the index information of the main data, is recorded at a constant linear velocity on the inner side of the data .
Selection of main data using the table of contents data
In a disc player capable of performing song reproduction and reading a disc at a high speed by rotating the disc at a high speed higher than a rated rotation, a table of contents detecting means for detecting that the table of contents data has been read; and A motor control circuit for controlling the spindle motor to be rotated to control the rotation of the disk to a rated linear velocity and a high-speed linear velocity , and a set speed of the motor control circuit for switching the disk rotation from the rated linear velocity to a high-speed linear velocity Speed switching means, which reads the table of contents data.
Set the speed of the motor control circuit when performing
Switching to the rated line speed and reading the table of contents data
After completion, set the speed of the motor control circuit to the high linear speed.
At the same time, and the motor control circuit starts music selection and playback from the beginning.
When reading of the table of contents data is completed,
Target track that is the beginning of the track selected from the rated linear velocity
A system that directly adjusts to the high-speed linear velocity according to the diameter where the
A disc player characterized by performing control .