JPH0746491B2 - Digital audio-disk playback device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus for reproducing recorded information from a digital audio disc.

BACKGROUND ART In a small digital audio disc having a diameter of about 12 cm, which is called a CD (compact disc), a control signal useful for a function such as the beginning of a song is recorded together with music data. The signals for this control are P,
It is composed of eight types of channel bits Q, R, S, T, U, V, and W. Each channel bit constitutes one sub-coding block with 98 bits and is recorded on the disc at a rate of 1 bit / frame to form a sub-coding frame as shown in FIG. Also,
As shown in FIG. 7, the first 2 bits of the Q-channel sub-coding block are bits that represent a synchronization pattern. 4 bits subsequent to the 2 bits are a control signal and indicate a recording mode such as the type of data in the block (digital data, audio data), presence / absence of pre-emphasis, and the like. Following this control signal, time data as address information, that is, position data indicating the recording position of the record information is recorded. The time data includes label data called a track number or music number and data indicating the elapsed time from the start edge of the disc.

The conventional reproducing apparatus for reproducing the recorded information of such a digital audio disc has a function of alternately performing reading of address information and jump operation of jumping over a recording track to search for a target address. However, since it was configured to set the mode by the control signal in the read subcode after the end of the search for the target address, the demodulation of audio data was not performed until the subcode was read, and the beginning of the song was searched. However, there is a drawback that operations such as the above cannot be performed quickly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital audio disc capable of promptly performing an operation such as the beginning of a song and a program play from a digital audio disc on which a plurality of pieces of recording information each having a different recording mode are recorded. -To provide a disc reproducing device.

A digital audio disc reproducing apparatus according to the present invention reproduces record information from a digital audio disc on which record information and mode data indicating a record mode of the record information are recorded and responds to an address search command. A reproducing device having a function of transferring an information detection point of a pickup to a target address, which reads the mode data from the digital audio disc in response to the mounting of the digital audio disc and stores the mode data in a memory. Means for storing the information, a transfer means for transferring the information detection point to the target address in response to an address search command, and a read signal read at the information detection point by performing a reproduction process according to a mode control signal. A reproducing means for reproducing the recorded information from the Has a configuration having said reproducing means and supplies the mode setting means which mode data corresponding to the target address is read from the memory as the mode control signal in response to the search command.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4.

In FIG. 1, a laser beam emitted from, for example, a laser diode 2 in a pickup 1 passes through a prism 3, a tracking mirror 4, an objective lens 5 and the like to become spot light (information detection point) and a recording track of a disc 6. (Pit row) 7 is irradiated. The reflected light of the spot light passes through the objective lens 5, the tracking mirror 4, and the prism 3 and is incident on a so-called four-divided detector 8 including a photodiode or the like built in the pickup 1. The total output of the 4-division detector 8 is the read RF signal.
It is supplied to the demodulator 10 via the RF amplifier 9,
Data demodulation circuit 11 and data processing circuit 20 after demodulation by
Is supplied to. The data extraction circuit 11 extracts address information from the demodulated output, and the address information is stored in the controller.
Supplied to 12.

The data processing circuit 20, after performing processing such as deinterleaving, error detection, correction, and correction of the output data of the demodulator 10, temporarily stores the output data in the data memory 21, and outputs it from a clock generation circuit (not shown). It is configured to be read by a clock signal of a constant cycle and supplied to one of the D / A (digital / analog) converter 22 and the digital data output terminal OUT1 by a mode control signal from the controller 12. The data supplied from the data processing circuit 20 to the D / A converter 22 is converted into an analog signal. This analog signal is supplied to the de-emphasis circuit 24 via an LPF (low-pass filter) 23 and at the same time serves as one input of a changeover switch 25. The output of the de-emphasis circuit 24 is the other input of the changeover switch 25. A mode control signal is supplied from the controller 12 to the changeover switch 25. The changeover switch 25 is configured to selectively output one of the two inputs according to the mode control signal. This changeover switch 25 to LPF23
And the output of the de-emphasis circuit 24 are selectively output and supplied to the audio signal output terminal OUT2.

Each output of the 4-division detector 8 is also supplied to the tracking error signal generation circuit 13. As a method of generating the tracking error signal, there is a so-called 1-beam method, a 3-beam method, or the like, and the 1-beam method includes a so-called push-pull method, a heterodyne method, or the like. The tracking error signal generated by the tracking error signal generation circuit 13 is
As shown in FIG. 2, it has a so-called S-curve characteristic of zero crossing at the center of the recording track 7, and a drive coil for the tracking mirror 4 via a mirror drive circuit 14.
By being supplied to 15, the mirror 4 is driven to rotate.

Reference numeral 16 denotes a slider motor that mounts the pickup 1 and drives a slider (not shown) that is movable in the disk radial direction. The motor 16 is driven and controlled by a motor drive circuit 17. The motor drive circuit 17 detects the tilt angle of the tracking mirror 4 based on the output of the mirror drive circuit 14, and the slider motor 16 causes the slider motor 16 to move in the disk radial direction so that the tilt angle is zero. Position control.
The mirror drive circuit 14 and the motor control circuit 17 are also drive-controlled by a drive signal issued from the controller 12. The track pulse generation circuit 18 generates one pulse each time the spot light crosses the recording track 7 based on the tracking error signal shown in FIG. 2 when the pickup 1 moves in the disk radial direction, and sends it to the controller 12. . The controller 12 is supplied with an address search command generated by an operation by a user and data indicating a target address from an operation unit (not shown). Further, a TOC memory 26 is provided, which is address-controlled by the controller 12 and records the output data of the controller 12. The TOC memory 26 is configured such that the mode discrimination circuit 27 also controls the address. The mode discrimination circuit 27 receives the data indicating the target address from the controller 12, reads the mode data recorded in the corresponding position from the TOC stored in advance in the TOC memory 26, and sends it to the controller 12. It is configured. The controller 12 is formed by a micro computer including a processor, a ROM, a RAM, a timer and the like. In this controller 12, the processor is pre-stored in the ROM and operates according to the program based on the flowcharts of FIGS. 3 and 4.

Next, the operation of the processor in the controller 12 will be described with reference to the sequence diagram of FIG. 5 and the flowcharts of FIGS. 3 and 4.

In a recording disc, for example, a so-called compact disc, address data as position data indicating the absolute time from the innermost circumference of the disc to the beginning of each song and an area called a lead-in area located on the inner periphery of the disc and each song Of the TOC (Table Of Cont
ents) are recorded. At this time, the recording mode is a digital mode when the recording information is digital data, and an emphasis audio mode when the recording information is audio data subjected to emphasis processing, and an emphasis processing. If the audio data is not processed, the emphasis-free audio mode is set. Here, the mode data means whether the recording information recorded on the disc is the digital data, the audio data subjected to the emphasis processing, or the audio data not subjected to the emphasis processing. Can be identified. When the recording disk is loaded after the power is turned on, the processor determines whether or not the play command is issued until the play command is issued (step Sa). When the play command is issued, the processor detects that various servos such as the spindle servo are in the locked state (step Sb), then reads the TOC and writes the position data and the mode data in the TOC memory 26 (step Sc, Sd). By executing the steps Sa to Sd as described above, when the recording disk is mounted on the reproducing apparatus, the position data and the mode data are automatically read from the recording disk and stored in the TOC memory 26. After such an operation, the processor starts the play operation with the start end of the program area as the designated address position. When the address search command is issued, the processor operates according to the routine shown in the flowchart of FIG. A play operation is performed using the position indicated by the data as the designated address position (step Se).

That is, if the address search command is issued when the spot light of the pickup 1 as the information detection point is located at point (a), the processor supplies data indicating the target address to the mode discrimination circuit 27 (step S1). ).
Next, the processor extracts the data from the data extraction circuit 11 (see FIG. 1).
A read operation of the current address is performed from the address information extracted in step S2, the current address and the target address are compared with each other (step S3), and the distance between the two addresses is larger than a certain value. When it is determined that the distance is 1 minute or more, how many tracks are present between the current address and the target address is calculated (step S4). The number of tracks is calculated based on the absolute time of each address, the disk rotation speed, the track pitch, and the like. Next, the processor sets the number N of tracks obtained by this calculation as the number N'of tracks to be counted, and thereafter moves the pickup 1 in the target address direction, in the FWD direction in the example of FIG. 4 (step S
Five).

The processor counts the number of track pulses generated from the track pulse generation circuit 18 (see FIG. 1) at the same time as the pickup 1 is moved, and determines whether or not the count number has reached the track number N '( Step S
6). In step S6, the count number is the track number N '.
If not, the processor determines whether or not the mode is set by the output data of the mode determination circuit 27 (step S7). Only when the mode is not set in step S7, the processor sets the mode by the output data of the mode determination circuit 27, that is, supplies the mode control signal to the data processing circuit 20 and the changeover switch 25 (step S8), and in step S6. Repeat. If the mode has been set in step S7, the processor immediately executes step S6. Also, step S6
When it is determined that the count number has reached the track number N'at, the processor stops the movement of the pickup 1 (step S9). As a result, the spot light reaches the point (b).

The processor reads the current address again at point (b), compares the current address with the target address (steps S2, S3), and when the distance between both addresses is less than a certain value, moves to step S10 The address is compared with the target address. In step S10, if it is determined that the current address is smaller than the target address, the processor proceeds to step S11 and supplies the drive signal to the motor control circuit 17 for a predetermined time to move the spot light in the FWD direction. Forwarding is performed, but in the example of FIG. 4, the current address is larger than the target address, so the process moves to step S12 and the drive signal is supplied to the motor control circuit 17 for a predetermined time to move the spot light in the REV direction. Do a slow reverse.

After that, the processor reads the current address and compares it with the target address, and determines whether the current address is equal to or greater than the target address and the distance between the two addresses is 15 seconds or less (step S13). If it is determined that the distance between both addresses is greater than 15 seconds, the processor determines whether or not the mode setting is made by the output data of the mode determining circuit 27 (step S14), and the mode setting is not made. Only when this occurs, the mode is set by the output data of the mode discrimination circuit 27 (step S15), and step S10 is executed again. When the mode is set in step S14, the processor immediately executes step S10. As a result, the spot light reaches the point (c) where the distance from the target address is 15 seconds or less. Then, in step S13, it is determined that the distance between the current address and the target address is 15 seconds or less, and the processor proceeds to step S16 and jumps the spot light by a distance of 16 tracks to move the 16-track jump in the REV direction. To do.

After that, the processor determines whether or not the current address has become equal to or less than the target address (step S17). If it is determined in step S17 that the current address is larger than the target address, the processor determines whether or not the mode is set by the output data of the mode determination circuit 27 (step S18), and the mode is not set. Only when this occurs, the mode is set by the output data of the mode determination circuit 27 (step S19), and step S16 is executed again. When the mode is set in step S18, the processor immediately executes step S16. As a result, the spot light reaches the point (d) located inside the target address. Then, step S17
At, it is determined that the current address is less than or equal to the target address, and the processor proceeds to step S20 and performs a one-track jump in which the spot light is moved by a distance of one track in the FWD direction.

After that, the processor determines whether or not the current address has become equal to or higher than the target address (step S21). When it is determined in step S21 that the current address is smaller than the target address, the processor determines whether or not the mode is set by the output data of the mode determination circuit 27 (step S22), and the mode is not set. Only when this occurs, the mode is set by the output data of the mode discrimination circuit 27 (step S23), and step S20 is executed again. When the mode is set in step S22, the processor immediately executes step S20. As a result, the spot light reaches a point corresponding to the target address or a point deviated from the target address by a distance of one track or less in the outer peripheral direction. Then, step S2
In 1 the current address is determined to be greater than or equal to the target address and the processor moves to step S24 and performs one track jump in the REV direction 4 to 5 times and then performs a play operation (step S25). As a result, the spot light reaches the target address, and the mode setting is completed before the spot light reaches the target address.

As described above in detail, the digital audio disc reproducing apparatus according to the present invention, according to the mounting of the recording disc,
First, the mode data indicating the recording mode of each recording information is read from the recording disc and stored in the memory, and when the address search command is issued thereafter, the information of the pickup is responded to in response to the address search command. While transferring the detection point to the target address position, the mode data corresponding to the target address is read from the memory and the mode of the reproducing means is set so that the information reproducing process corresponding to the mode data is performed. There is. Therefore, according to the present invention, it is possible to end the mode setting operation of the reproducing means almost at the same time as the address search command is issued without reading the sub-code, so that the beginning of the music by the address search operation, the program play, etc. It can be done quickly.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between recording tracks and tracking error signals, and FIGS. 3 and 4 are operations of the apparatus of FIG. 5 is a sequence diagram showing an example of the search operation of the apparatus shown in FIG. 1, FIG. 6 is a diagram showing the format of a sub-coding frame, and FIG. 7 is a diagram showing a sub-coding block of the Q channel. It is a figure which shows a format. Explanation of main part symbols 12 …… Controller 26 …… TOC memory 27 …… Mode discrimination circuit

Claims (1)

[Claims] 1. A reproduction target of recording information from a digital audio disc on which mode data indicating a recording mode of the recording information is recorded together with the recording information, and the information detecting point of the pickup is targeted in response to an address search command. A reproducing device having a function of transferring to an address, a unit for reading the mode data from the digital audio disc when the digital audio disc is mounted and storing the mode data in a memory, A transfer means for transferring the information detection point to the target address in response to a search command, and a reproduction process according to a mode control signal to reproduce the recorded information from a read signal read at the information detection point. Reproducing means for performing, and corresponding to the target address according to the address search command. A mode setting device for reading mode data from the memory and supplying the mode data as the mode control signal to the reproducing device.