JPH0352154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a playback device for a disc such as a digital audio disc.

BACKGROUND ART AND PROBLEMS In a digital audio disk, digitized audio signals are recorded as program information in a spiral track on a rotating disk.

The format of the digital signal to be recorded is, for example, as shown in Figure 1, where the repetition frequency is
The frequency is 7.35 kHz, which means that the repetition period is 136.1 microseconds and is continuous in units of small frames. For convenience, each small frame is arranged vertically in the figure. Each small frame consists of a part 11 of synchronization information A of a small frame period, a subcode part 12, and a data part 13 containing program information. Address information and the like are inserted into the subcode section 12 in units of large frames consisting of 98 small frames, ie, a repetition frequency of 75 Hz and a repetition period of 13.3 msec. That is, the subcode section 12 is divided into eight channels from channel P to channel W, and the subcode section 12 of the first and second small frames of each large frame has a large frame period from channel P to channel W. Synchronization information B
and C are inserted, and address information is inserted into the channel Q of the subcode section 12 of the remaining 96 small frames in large frame units along with the program information of the data section 13.

FIG. 2 shows an example of the format of this channel Q. In addition to the synchronization information B and C, the channel Q includes portions 14 and 1 of data TNO representing the track number which is the number for each program information. A data section 15 representing an index, which is a number for each section in one program information, and a data section representing the minutes and seconds of time from the beginning of each section in one program information. 16 and 17, as well as a part 18 of the data FRA representing the number for the 75 large frames in a second, and these contain one bit for each small frame of one large frame, as shown in FIG. They are distributed and inserted one by one.

In this way, address information is inserted in units of large frames, and therefore, even when playing a disc, address information is extracted for each large frame, that is, every 1/75 seconds = 13.3 milliseconds. Become.

By the way, when playing such a disc, for example, when the program information is accompaniment for singing, when dubbing the program information, and furthermore when the program information is for educational purposes. There are cases where it is desired to selectively reproduce only desired program information.

In such a case, conventionally, when the desired program information, for example, a desired song, is finished, by pressing an operation button, the reading position on the disk by the information reading means is changed as shown in FIG. Program information, e.g. the point immediately after the end of the song
_{X I}
The object then flies in a direction across the track, and then, as shown in loop 1, it goes around the track once as the disk rotates, and at point X _O it flies back to X _I , creating a pause state.

However, it is troublesome to manually enter the pause state after the reproduction of one piece of program information, for example, one song. Furthermore, if this manual operation is delayed, the reading position on the disk by the information reading means may advance to the point where the next program information, for example the next song, is recorded, as shown by arrow 2 in Figure 3. Shut up,
There is an inconvenience that undesired next program information, such as the beginning of the next song, is played.

Purpose of the Invention In view of the above-mentioned points, the present invention is designed to automatically enter a pause state at a point immediately after the end of one piece of program information when the reproduction of one piece of program information ends, thereby reducing the troublesome operation. This eliminates the need to play back the beginning of the next program information that is not desired.

SUMMARY OF THE INVENTION In the present invention, the spiral track of the disk includes program information as well as data TNO representing the track number which is the number for each program information of the channel Q explained in FIG. Focusing on the fact that information whose contents change between program information is recorded, the information whose contents change between program information is separated and extracted from the information read from the disk by the information reading means, and the information whose contents change between the program information is extracted. In addition, the end of one program information or the beginning of the next program information can be detected by detecting a change in the content of information that changes between program information, and the detection output can be used to enter the above-mentioned pause state. do.

Embodiment FIG. 4 shows an embodiment of the disc playback device of the present invention, in which the digital audio disc 31 includes:
A digitized audio signal is recorded in the aforementioned format in a spiral track in an optically readable manner by an array of pits. The disk 31 is rotated at a predetermined constant linear speed by a spindle motor 32, and an optical block 33 is attached to a guide 34 extending in the radial direction of the disk 31, and is rotated by a feed motor 35 via a suitable deceleration transmission mechanism. disc 3 along guide 34.
1 radial direction. The optical block 33 includes an optical head 36 as an information reading means, and
A two-axis driving device for focus control and racking control of the optical head 36 is housed, and the optical head 36 reads information from the spiral track of the disk 31. This read information is supplied to a waveform conversion circuit 42 via an amplifier 41, converted into a digital signal with an appropriate waveform, and then supplied to a decoder 43, from which program information is obtained as serial data. The program information is supplied to a program information processing circuit 44 from which a reproduced audio output signal is obtained.

Separately, the data of channel Q of the subcode section 12 described above is taken out as serial data from the decoder 43. The data of this channel Q is then supplied to the shift register 51 and written therein. As mentioned above, the channel Q includes, for each large frame, synchronization information B and C, data TNO representing a track number which is a number for each program information, and a number for each section in one program information. Data representing the index IND, data representing the minutes and seconds of time from the beginning of each segment in one program information, and the number for the 75 large frames within the second. data FRA, etc.
Since the data consists of a total of 98 bits, the shift register 51 is composed of 98 bits, and the data of this channel Q is written every large frame. Further, the data of channel Q once written to this shift register 51 is serially read out from the shift register 51 and written to a shift register 52 having the same configuration as the shift register 51 in the next large frame. That is, the shift register 51
The data of the channel Q of the large frame at that time is written into the shift register 52, while the data of the channel Q of the previous large frame is written into the shift register 52.

Then, from the shift register 52, 8-bit data TNO representing the track number, which is the number for each program information mentioned above, of the channel Q data of the previous large frame is read out in parallel. It is supplied to one input end of switch 53. The switch 53 is connected to the operating section 5 in advance.
4, when the selection switch is switched to one side, it is switched to the state shown in the figure by a switching signal from the operating section 54, and therefore the shift register 5 is switched to the state shown in the figure.
The 8-bit data TNO representing the track number of the previous large frame read from 2 is supplied to one input terminal of the data comparison circuit 55 through this switch 53. In addition, the shift register 51
Separately, 8-bit data TNO representing the track number, which is the number for each program information, of the data of channel Q of the large frame at that time is read out in parallel, and this is read out in parallel by the other side of the data comparison circuit 55. is supplied to the input end of Then, in the data comparison circuit 55, data TNO representing the track number of the previous large frame is compared with that of the large frame at that time.

As shown in FIG. 5, signals are recorded on the spiral track of the disk 31 such that there is an interval of several seconds between the end of one program information EN and the beginning ST of the next program information. If so, 8 represents the track number of channel Q.
The contents of the bit data TNO change from n to n+1 in a large frame immediately after the end EN of one program information but not yet reaching the start ST of the next program information. Furthermore, as shown in Figure 6, even when signals are recorded so that there is no interval between the end of one program information EN and the beginning ST of the next program information, the data
TNO is a large frame immediately after EN, the end of one program information, whose contents change from n to n+.
Changes to 1.

Then, when one program information, for example, one song, has been played back and the contents of the data TNO representing the track number change from n to n+1, the data comparison circuit 55 compares the contents of the two input data. Since this is different, the end EN of this one program information is detected, and the detection signal is supplied to the control circuit 56 to automatically enter the above-mentioned pause state. That is, when the detection signal is supplied to the control circuit 56, the tracking servo circuit 57 controls the reading position on the disk 31 by the optical head 36 by the control signal supplied from the control circuit 56 to the tracking servo circuit 57. A tracking error signal indicating a deviation with respect to the track is supplied to, for example, a DC linear motor for tracking control of a two-axis drive device for focus control and tracking control of the optical head 36, which is housed in the optical block 33. When the tracking servo is released,
A tracking jump signal is supplied to this DC linear motor for tracking control, and as described above, the reading position on the disk 31 by the optical head 36 is determined to be the end of one piece of program information.
It is blown across the track from point X _O immediately after EN to point X _I , which is returned by one lap around the track.
Thereafter, as the disk 31 rotates, it goes around once along the track and returns to point _XI from point _XO .

Note that from such a pause state, the operation unit 54
When the playback button is pressed, a pause state release signal is given to the control circuit 56 from the operation unit 54, and the read position on the disk 31 by the optical head 36 changes from the point on the loop 1 described above to the disk 31.
The data comparison circuit 5 moves along with the rotation of the program information, and immediately after the end of the previous program information EN, the data comparison circuit 5
Even if the above-mentioned detection signal is obtained from 5, the _point
Without jumping to X _I , the program moves along the track as indicated by arrow 2 above, and the next program information is played from the beginning.

Note that when the selection switch is switched to the other side in advance in the operation unit 54, the switch 53 is switched to the opposite state to that shown in the figure, and the track number of the large frame at that time read out from the shift register 51 is The data TNO representing TNO is supplied to one input terminal of the data comparison circuit 55 through the switch 53 on the one hand, and is supplied as it is to the other input terminal of the circuit 55 on the other hand, even after the reproduction of one program information is completed. , data comparison circuit 55
It is not detected at , and therefore, the above-mentioned pause state is not put in place, and the next program information continues to be played.

In the embodiment shown in FIG. 4, the end of one piece of program information EN is detected from the change in the content of data TNO representing the track number, which is the number for each piece of program information on channel Q. The beginning ST of the next program information may be detected from the change in the content of one bit of data for each small frame of the channel P explained in the figure, and the pause state may be established. In the spiral track of the disk 31, as shown in FIG. 5, the end of one program information EN and the start of the next program information ST
If the signal is recorded with an interval of several seconds between
It is 1 where it does not exist. Furthermore, as shown in Fig. 6, if the signals are recorded so that there is no interval between the end of one program information EN and the beginning ST of the next program information, the last of one program information It is 1 at 2 seconds, and 0 elsewhere. Therefore, the point where the data content of this channel P changes from 1 to 0 always becomes the beginning ST of the next program information.

Effects of the Invention According to the present invention, information whose contents change between program information is separated and retrieved from information read from a disk by an information reading means, and the retrieved information whose contents change between program information is extracted. The end of one program information or the beginning of the next program information is detected by detecting a change in the content of the program information, and the detection output automatically enters a pause state when the playback of one program information ends. This eliminates the troublesome operation and eliminates the inconvenience of playing the beginning of the next program information that is not desired.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams for explaining an example of the format of a digital signal recorded on a digital audio disk, and Figure 3 is a diagram for explaining the movement of the reading position on the disc in a pause state. , FIG. 4 is a diagram showing an embodiment of the disc playback device of the present invention, and FIGS. 5 and 6 are diagrams for explaining its operation. In the figure, 31 is a digital audio disk, 36 is an optical head as an information reading means,
43 is a decoder, 51 and 52 are shift registers, 55 is a data comparison circuit, 56 is a control circuit, 5
7 is a tracking servo circuit.

Claims (1)

[Claims] 1 Information reading means for reading information from a disk in which information whose contents change between the program information is recorded in a spiral track along with program information, and information whose contents change between the program information from the read information. means for separating and extracting the program information, and means for detecting a change in the content of the information whose content changes between the extracted program information;
When a change in the content is detected, the reading position on the disk by the information reading means jumps in a direction across the track to a point where it is returned by one or several turns of the track, and then,
A disc playback device comprising means for creating a pose state in which the disc moves one or several times along the track as the disc rotates.