JPH0736264B2 - Disk playback device - Google Patents

Description

The present invention relates to a disc reproducing device such as an optical compact disc (CD) player, and more particularly to a CD-ROM (read only memory). It relates to those suitable for use in reproduction.

(Prior art) As is well known, in the field of audio equipment, information signals such as audio signals are digitalized by PCM (Pulse Code Modulation) technology in order to achieve high-density and high-fidelity recording and reproduction. 2. Description of the Related Art A digital recording / reproducing system is widely used, which is converted into digitized data, recorded on a recording medium such as a disk or a magnetic tape, and reproduced. Of these, the one that uses a disc as the recording medium,
Compact discs, in which a pit string corresponding to digitized data is formed on a disc with a diameter of 12 cm and are read optically, are now the mainstream.

On the other hand, a compact disc player for reproducing a compact disc as described above moves an optical pickup including a semiconductor laser and a photoelectric conversion element in a linear tracking manner from the inner peripheral side to the outer peripheral side of the disc, Compact discs with constant linear velocity (CL
By rotating the V) system, the data recorded on the compact disc is read.

In addition, in the above compact disc, a huge amount of information capable of performing stereo reproduction for about one hour on one side is recorded in the program area (radius 25 to 58 mm), and the index data and the like are recorded in the lead-in area (radius 23
It is possible to achieve high-density recording not seen in conventional analog recording / playback systems, and to realize advanced control functions and performance.

Here, on the compact disc as described above, subcode data is recorded together with digitized data of audio signal components in order to improve operability and realize more advanced functions. This subcode data is P,
It consists of 8 types called Q, R, S, T, U, V, W.
One frame of the digitized data contains one bit each, for a total of eight bits, and one subcode frame is composed of 98 frames.

Of these, the sub-code data P indicates the transition of a plurality of data recorded on the disc (hereinafter described as music). The subcode data Q is called address data. In the program area, the song number (TNO), section number (index), elapsed time (relative address) and program of each song recorded are recorded. The total elapsed time (absolute address) from the beginning of the area is shown.

The other sub-code data R to W are currently used to display a graphics image on the screen of the television receiver in synchronization with the reproduced audio data.
It is used as graphics image display data and data for operating the graphics display screen.

On the other hand, in the lead-in area of the disc, the start position of each song in the program area is indicated by the absolute address.
TOC (Table of Contents) data is recorded as main information. Further, in the subcode data Q in the lead-in area, the elapsed time (address) in the lead-in area is recorded. However, the address by the subcode data Q in this lead-in area,
The absolute address based on the subcode data Q in the program area is not related.

That is, in the sub-code data Q, in the program area, the relative address indicating the elapsed time for each music as shown in FIG. 3A and the program area start end portion as shown in FIG. An absolute address indicating the total elapsed time is recorded. Also, the subcode data Q includes
In the program area, as shown in FIG. 3A, an address indicating the elapsed time is recorded.

Here, the compact disc player is provided with a data search function for selecting a desired music piece at high speed using the address information based on the subcode data Q. That is, when the power switch is turned on, the compact disc player automatically enters the lead-in area TOC data of the disc, stores it in the memory, and then enters the standby state.

Therefore, if the user externally sets the song number (TNO) of the desired song, the lead-in area stored in the memory will be
Based on the TOC data, the absolute address of the start position of the song with the set song number can be obtained. Then, based on the absolute address, the number of tracks No. interposed between the start end of the program area and the target position is calculated.

On the other hand, the compact disc player reads the program area data with the optical pickup while the disc is in the playback state, obtains the absolute address of the current position of the optical pickup, and based on this absolute address, it starts from the start end of the program area to the current position. The number of tracks Np interposed between the positions is calculated.

After that, the compact disc player performs a calculation of (Np-No), determines the direction in which the optical pickup is moved and the number of tracks to be crossed by the optical pickup, and moves the optical pickup based on the decision items. Let Then, thereafter, the same operation is repeated until the absolute address of the target position and the absolute address of the current position of the optical pickup match, and the data search is performed there.

Here, the CD system as described above was developed for the purpose of recording and reproducing audio data, but recently, focusing on the enormous recording capacity of a compact disc, a compact disc is used, for example, in a computer or the like. The so-called CD-ROM system has been developed, which is used as a read-only data recording medium for the arithmetic processing control system.

In this CD-ROM system, a new format is added without changing the recording / reproducing format of the CD system so that recording / reproducing of digital information can be performed. That is, the CD method is a method in which a 2-channel analog audio signal is sampled at 44.1 kHz, PCM-converted into 16-bit digitized data, and recorded.
In the D-ROM system, as shown in FIG. 4, the 16 bits are divided into 8 bits (1 byte) and 2352 bytes are recorded as one block to record data.

Here, in FIG. 4, the synchronization pattern is for recognizing the start of each block and is composed of 12 bytes. The header is address information of a block corresponding to the subcode data Q in the CD system, and is composed of 4 bytes. Further, the user data is an area used by the user and is composed of 2048 bytes. The error correction data is provided for two purposes, that is, to detect and correct data errors (mode 1) and to be used by the user (mode 2). It consists of 288 bytes.

Of these, mode 1 is used when the error cannot be corrected by the C1 and C2 sequence parity correction in the audio CD format, and the error rate is finally 10 ^−12.
It has been improved to 1) and can be sufficiently used as a recording medium of a computer. Also, by using mode 2, the amount of data available to the user can be increased to 2048 + 288 = 2336 bytes, but the data error rate is 10 ^-9.
Becomes

One block in the CD-ROM system is the above-mentioned CD.
It corresponds to one subcode frame in the system,
One block is played every 1/75 second. For example, in mode 1, 2 kbytes of data is recorded per block, so the data transfer rate is 2 k × 75 = 150 bytes / sec. Therefore, it is possible to record 150 x 60 x 60 = 540 megabytes of information on a CD-ROM disc with one hour of data recorded on one side.

This recording capacity is 500 to 100 for a normal floppy disk.
It corresponds to 0 sheets, or about 270,000 sheets of a document in which 2000 characters are written per page. That is, the CD-ROM system has a low error rate and a large recording capacity.

Further, in the CD-ROM system, a part of the disc can be used for recording audio data instead of being a data recording medium for all computers. That is, in the data area and the audio area, the subcode Q
By rewriting the control bit of, it becomes possible to mix data for computer and audio data.

In the CD-ROM system, in order to obtain data from a disc, a keyboard of a computer is operated to transfer a predetermined command to a CD-ROM reproducing device. Then the CD
-The ROM playback device searches for the desired absolute address specified by the command, transfers the data recorded at the position of the absolute address to the computer, and the computer processes the data. Data can be transferred from the computer to the computer.

By the way, as described above, since the CD-ROM system is used as a data recording medium for an arithmetic processing control system such as a computer, it is required that the data reading speed, that is, the data searching operation is executed at high speed. . As described above, the data search operation generally uses the method of moving the optical pickup while counting the number of tracks by referring to the absolute address of the subcode data Q. For this reason, if external vibration is applied or there is a large scratch on the disc during movement of the optical pickup due to data retrieval, the movement amount of the optical pickup becomes inaccurate and the optical pickup leads It may enter the area.

In such a case, in the lead-in area of the disc,
Although the address showing the passage of time is recorded, it is not related to the absolute address in the program area, so it is not possible to escape the optical pickup from the lead-in area by normal data search operation. It will be impossible.

Therefore, in the conventional CD-ROM reproducing apparatus, it is detected that the optical pickup enters the lead-in area by utilizing that all the song numbers of the sub-code data Q are "0" in the lead-in area. Kicking is performed for each predetermined number N of tracks, and the pickups are sequentially returned to the program area optically.

However, in order to prevent hunting when the optical pickup converges after the kick operation is completed, it is not possible to increase the number of tracks that can be jumped in one kick operation, so the optical pickup is deep in the lead-in area. If it gets inside, it takes time to get out of the lead-in area and it becomes impossible to perform high-speed data search.

(Problems to be Solved by the Invention) As described above, in the conventional disc reproducing apparatus, when the pickup enters the lead-in area of the disc, it takes time to return to the program area again.
There is a problem that a high speed data search operation cannot be performed.

Therefore, the present invention has been made in consideration of the above circumstances, and even if the pickup enters the lead-in area of the disc during data retrieval, it can be quickly returned to the program area, and high-speed data can be obtained. It is an object of the present invention to provide an extremely good disk reproducing device capable of performing a search operation.

[Configuration of the Invention] (Means for Solving the Problems) That is, in the disc reproducing apparatus according to the present invention, a main recording area in which a first information signal is recorded together with first address information, and a second recording area For reading the first and second information signals from a disc having a sub-recording area in which the information signal of No. 1 is associated with the second address information which is not related to the first address information. Is in the main recording area of the disc, the pickup is performed from the first address information of the current position of the pickup and the first address information of the externally set target position based on a data search request given from the outside. It also has a data search means to move the pickup to the target position by calculating the number of tracks between the current position and the target position. It is directed to.

Further, it is provided with a storage means capable of recording the second address information at an arbitrary position of the sub recording area of the disc, and whether or not the current position of the pickup is in the main recording area of the disc based on the data search request. Determine if it is in the area,
With the pickup determined to be in the sub recording area,
The second address information of the current position of the pickup is compared with the second address information stored in the storage means.

If a comparison result that the current position of the pickup is closer to the main recording area than the position indicated by the second address information stored in the storage means is obtained, the second address information stored in the storage means is obtained. The second of the current position of the pickup
Address information is updated and the pickup is forcibly moved to the main recording area side until the first address information is obtained.

Further, when the comparison result that the current position of the pickup is farther from the main storage area than the position indicated by the second address information stored in the storage means is obtained, the second address information of the current position of the pickup is stored. Second stored in the means
The number of tracks interposed between the current position of the pickup and the position indicated by the second address information stored in the storage means is calculated based on the address information of The pickup is moved to the main recording area side by the number of tracks in which the number of tracks interposed between the part and the target position is added.

(Operation) According to the above configuration, the current position of the pickup is in the sub-recording area and is stored in the storage means.
, The main recording is performed in the number of tracks interposed between the current position of the pickup and the position indicated by the second address information stored in the storage means when it is farther from the main storage area than the position indicated by the address information. The pickup is moved to the main recording area side by the number of tracks added to the number of tracks interposed between the start edge of the area and the target position. If it gets inside the in-area, the pickup can be quickly returned to the main recording area (program area) without repeating the kick operation as in the past, and a high-speed data search operation can be performed. it can.

Also, the current position of the pickup is in the sub recording area,
Further, when the position indicated by the second address information stored in the storage means is closer to the main recording area, the second address information stored in the storage means is used as the second address information of the current position of the pickup. Since the second address information stored in the storage means comes closer to the main recording area every time it is updated, it effectively assists the above-described return operation to the main recording area. Is what you can do.

(Embodiment) Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a CD-ROM to which the present invention is applied.
First, an outline will be described. That is, the control circuit 11 drives and controls the disc motor 13 and the pickup feed motor 14 via the disc reproduction system control circuit 12. When the optical pickup 15 reproduces the recorded data on the disc 16, the reproduction signal is guided to the RF detection circuit 17.

The RF detection circuit 17 amplifies the input reproduction signal and generates a signal component supplied to the servo circuit 18 and a signal component supplied to the EFM demodulation circuit 19. Of these, the servo circuit 18
Has a function of generating various signals for performing focus servo and tracking servo for the optical pickup 15, CLV servo for the disk motor 13, and linear tracking servo for the pickup feed motor 14. It is something to do.

Various servos for the optical pickup 15, the disc motor 13, and the pickup feed motor 14 include various signals output from the servo circuit 18 and various control signals generated by the control circuit 11 via the disc reproduction system control circuit 12. And based on.

On the other hand, the EFM demodulation circuit 19 waveform-shapes the reproduced signal output from the RF detection circuit 17 and performs EFM demodulation (14-bit to 8-bit conversion), and separates the synchronization signal to be the subcode data from the demodulated signal. The sync signal is supplied to the sub-code Q detection circuit 20, and the demodulated signal from which the sync signal is separated is supplied to the D / A (digital / analog) conversion circuit 21, the unscrambler 22 and the sync detection circuit 22.

When the detected subcode data Q is TOC data in the lead-in area, the subcode Q detection circuit 20 sends the TOC data to the program RAM (random access memory) 24 via the control circuit 11. To memorize
I am trying to use it for data retrieval.

Further, the D / A conversion circuit 21 converts the demodulated signal that is input into an analog signal, performs necessary error correction and error correction processing, and outputs the result to the speaker drive circuit 25.
The speaker is driven to play.

The above configuration is the same as that of the CD type disc reproducing apparatus, and by adding the configuration described below, the CD-RO
To realize an M type disc player. That is, in the demodulated signal output from the EFM demodulation circuit 19, after the sync detection circuit 23 detects the block sync pattern of the CD-ROM shown in FIG. 4 and the unscrambler 22 unscrambles the data. , One block of data shown in FIG. 4 is written in the decode RAM 26.

Further, the respective outputs of the unscrambler 22 and the synchronization detection circuit 23 are supplied to the header detection circuit 27, the header data in one block is detected, and the header data is taken into the control circuit 11. Here, when performing a data search, the control circuit 11 outputs the subcode data Q output from the subcode Q detection circuit 20,
The header data output from the header detection circuit 27 is used. This is because, according to the standard, the address by the subcode data Q and the address by the header data are allowed to differ by up to 1 second.
The final data search is always performed using the header data.

Furthermore, the data written in the decoding RAM 26 is
When a predetermined error detection process is performed and an error has occurred, the control circuit 11 drives the RAM controller 28 and the error correction circuit 29 to execute the error correction.

Then, the data of the decoding RAM 26 that has been subjected to the error correction processing is written in the buffer RAM 30. In this case, not all the data stored in the decode RAM 26 is written in the buffer RAM 30, but the control circuit 11 uses the RAM.
By controlling the controller 31, only the user data shown in FIG. 4 is written in the buffer RAM 30.

When all the data is written in the buffer RAM 30 in this way, the control circuit 11 generates a data read request signal to the computer 33 via the interface 32.
Then, the computer 33 generates a predetermined signal to the control circuit 11 via the interface 32 after the preparation for reading the data is completed. When the control circuit 11 receives the predetermined signal, the control circuit 11 controls the address of the user data written in the buffer RAM 30 via the RAM controller 31 and operates to transfer the data to the computer 33.

Incidentally, the CD-ROM type disc reproducing apparatus shown in FIG.
Normally, by operating the keyboard 33a of the computer 33, a predetermined command is sent to the control circuit 11 via the interface 32 to operate the disc reproducing system in a predetermined state. A key switch group 34 is provided so that a simple operation can be performed even when 33 is not connected.

Similarly, in this disc reproducing apparatus, the necessary display is normally performed on the CRT screen 33b of the computer 33, but in consideration of the case where the computer 33 is not connected, a simple display is a display output control circuit. The display unit 36 can be operated via the unit 35.

In the figure, 37 is a program ROM, which is the program RAM 24
At the same time, a program for operating the control circuit 11 is stored.

In the CD-ROM type disc reproducing apparatus having the above-mentioned configuration, the data searching operation will be described below.
This will be described with reference to the flowchart shown in the figure. First, when started (step S1), as described above, the lead-in area is automatically reproduced, and the TOC data is written in the program RAM 24. Then, the control circuit 11
Address of the lead-in area at the time when the writing of TOC data to the program RAM 24 is completed in step S2
The TL is written and stored in the program RAM 24.

Then, in step S3, the control circuit 11 causes the computer 33 to
It is determined whether or not the data search is requested by operating the keyboard 33a of the device, and when the data search is requested (YES), step S4
Then, the absolute address of the data of the target position input and set by the keyboard 33a is read from the program RAM 24, and the number No of tracks interposed between the start end of the program area and the target position is calculated.

Thereafter, the control circuit 11 determines in step S5 whether or not the subcode data Q is stably read, and if it is stably read (YES), in step S6, based on the read subcode data Q. , The absolute address Tp of the current position of the optical pickup 15 is obtained, and the number of tracks Np interposed between the start position of the program area and the current position is Np.
To calculate.

Then, in step S7, the control circuit 11 determines whether or not the current position of the optical pickup 15 is within the lead-in area. This determination is performed by utilizing the fact that the TNOs of the subcode data Q are all "0" in the lead-in area, as described above. If it is not within the lead-in area (NO), the control circuit 11 determines in step S8 that
(Np-No) is calculated, and in step S9 it is determined which direction the optical pickup 15 should be moved from the current position.

Thereafter, the control circuit 11 actually moves the optical pickup 15 in step S10, and determines in step S11 whether or not the data search is completed. This determination is performed by reading the absolute address of the subcode data Q when the movement of the optical pickup 15 is completed and determining whether the absolute address matches the absolute address of the target position.

Then, if the data search is completed (YES), the process is ended as it is (step S12), and if the data search is not completed (NO), the process returns to step S5 and the above-described operation is repeated. .

On the other hand, if it is determined in step S7 that the optical pickup 15 is in the lead-in area (YES),
In step S13, the control circuit 11 compares the address TL written in the program RAM 24 with the address Tp of the current position in the lead-in area.

If TL <Tp, that is, if the current position of the optical pickup 15 is closer to the program area than the position displayed by the address TL (YES), the control circuit 11 proceeds to step S
At 14, program address Tp instead of address TL above
The stored contents are updated so as to be stored in the RAM 24.

Then, in step S15, the control circuit 11 sets a certain kick amount in order to return the optical pickup 15 to the program area by the click operation, and
In S16, set the kicking direction. Then, in step S10, the control circuit 11 repeats the kick operation for the optical pickup 15, and returns the pickup 15 to the program area by a fixed amount.

If TL <Tp is not satisfied in step S13, that is, if the current position of the optical pickup 15 is farther from the program area than the position indicated by the address TL (NO), the control circuit 11 proceeds to step S1.
At 7, the address TL previously stored in the program RAM 24
Address TL from the beginning of the lead-in area
The number NL of tracks interposed up to the position indicated by is calculated.

The control circuit 11 then proceeds to step S18, where steps S4 and S
Based on the number of tracks No, Np, NL obtained in 6, S17, the calculation No + (NL-Np) is performed, and the calculated result is the optical pickup.
The number of tracks to be crossed to 15. That is, the above calculation is performed from the current position of the optical pickup 15 to the address TL.
In the number of tracks intervened up to the position indicated by,
The number of tracks obtained by adding the number of tracks interposed between the start end of the program area and the target position is obtained.

After that, in step S16, the moving direction of the optical pickup 15 is set, and in step S10, the optical pickup 1
5 is moved in the set moving direction so as to cross the tracks by the number of tracks calculated in step S18.

Therefore, according to the configuration of the above embodiment, when the optical pickup 15 is in the lead-in area and is located farther from the program area than the position indicated by the address TL stored in the program RAM 24, The number of tracks intervening from the current position of the optical pickup 15 to the position indicated by the address TL plus the number of tracks interposing from the start end of the program area to the target position Since the optical pickup 15 is moved to the program area side, it is possible to quickly move the optical pickup 15 to the vicinity of the target position without repeating the kick operation unlike the conventional case, and perform high-speed data search. Is something that can be done.

If the optical pickup 15 is in the lead-in area and is closer to the program area than the position indicated by the address TL stored in the program RAM 24, the address of the current position of the optical pickup 15 is set.
Tp is the address T previously stored in the program RAM 24
Since it is stored instead of L, the position indicated by the address will approach the program area every time the stored contents of the address are updated.
It is possible to effectively assist the return operation to the program area performed in S7 and S18.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

[Effect of the Invention] Therefore, as described in detail above, according to the present invention, even if the pickup enters the lead-in area of the disc during data retrieval, the pickup can be quickly returned to the program area. It is possible to provide an extremely good disc reproducing apparatus capable of performing high-speed data search.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a disc reproducing apparatus according to the present invention, FIG. 2 is a flow chart for explaining the operation of the main parts of the embodiment, and FIG. 3 is a lead-in area of the disc. FIG. 4 is a diagram showing a relationship between addresses recorded in the program area and FIG. 4 is a diagram showing a data format in the CD-ROM system. 11 ... Control circuit, 12 ... Disc playback system control circuit, 13 ...
… Disc motor, 14 …… Pickup feed motor, 15
...... Optical pickup, 16 ... Disc, 17 ... RF detection circuit, 18 ... Servo circuit, 19 ... EFM demodulation circuit, 20 ...
… Subcode Q detection circuit, 21 …… D / A conversion circuit, 22 ……
Unscrambler, 23 ... Sync detection circuit, 24 ... Program RAM, 25 ... Speaker drive circuit, 26 ... Decode RA
M, 27 ... Header detection circuit, 28 ... RAM controller, 29
...... Error correction circuit, 30 …… Buffer RAM, 31 …… RAM controller, 32 …… Interface, 33 …… Computer, 34 …… Key switch group, 35 …… Display output control circuit, 36 …… Display section, 37 ...... Program ROM.

Claims (1)

[Claims] 1. A main recording area in which a first information signal is recorded together with first address information, and a second information signal comprises second address information which is not related to the first address information. A method for reading the first and second information signals from a disc having a recorded sub-recording area through a pickup, and a data search request given from the outside while the pickup is in the main recording area of the disc. Based on the first position of the current position of the pickup.
Data for moving the pickup to the target position by calculating the number of tracks interposed between the current position of the pickup and the target position from the address information of the pickup and the first address information of the externally set target position. In a disc reproducing apparatus equipped with a retrieval unit, a storage unit for recording second address information at an arbitrary position in a sub recording area of the disc, and a current position of the pickup based on the data retrieval request is the main position of the disc. Discriminating means for discriminating whether the pickup is in the storage area or the sub-recording area, and the second address information of the current position of the pickup in the state where the discriminating means judges that the pickup is in the sub-recording area of the disc. Comparing means and the second address information stored in the storing means, and the comparing means When the comparison result that the current position of the backup is closer to the main recording area than the position indicated by the second address information stored in the storage means is obtained, the second address information stored in the storage means is stored. By the first control means for updating the second address information of the current position of the pickup and forcibly moving the pickup until the first address information on the main recording area side is obtained, and the comparing means. When a comparison result that the current position of the pickup is farther from the main recording area than the position indicated by the second address information stored in the storage means is obtained, the second address information of the current position of the pickup is obtained. From the second address information stored in the storage means, the second address information stored in the storage means from the current position of the pickup The number of tracks intervened up to the position shown is calculated, and the number of tracks interleaved from the starting end of the main recording area to the target position is added to the calculated value, A disc reproducing apparatus comprising: a second control means for moving to the main recording area side.