JPS58133690A - Disc reproducer - Google Patents

Abstract

PURPOSE:To prevent failed display such as missing of a part of characters, to be displayed clearing the screen of a display or holding a preceded normal display data, when a pickup means is moved at higher speed than that at normal reproduction. CONSTITUTION:The player 1 searches to reproduce the display data intermittently and to display a failure such as missing of a part of one character and simultaneously by display different contents. As an example of this invention, a normal preceding data before searching stored in a video RAM13 is held with a detection signal notching the state of search from a system control circuit 8. In this case, the screen of a CRT display is cleared or a prepared content is displayed during the search.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital audio disc playback device in which audio PCM signals are recorded on the disc as geometric patterns.

In a digital audio disc (hereinafter referred to as a compact disc), data consisting of an audio PCM signal and an error correction code is processed by 7-bit synchronization and sub-coding signals (also referred to as user's bits) as shown in Figure 1A. C1~('14) are added to the data structure.Similar to conventional analog discs, such compact discs are used to create master tapes by supplying playback data from the master tape to an optical cutting device. A large number of discs are copied using a stamping process.When recording original data on a disc, channel coding is performed to convert 1 bit to /1 bit.

Therefore, the above-mentioned subcoding signal CI/-014
The data is 1 bits of d1 to d, and these are called subcoding signals of P channel, Q channel, . . . W channel. These subcoding signals have control information and display information. Each of the subcoding signals has separate information;
Each l bit is inserted every /7 frames of data. When the bits recorded in a dispersed manner are taken out, as shown in FIG. 1B, they are serialized in units of 9t frames from Q to DEF of the data. The subcoding signal P-w of frames 0 and / forms 80.8J sync bits, which are a predetermined bit pattern. Furthermore, a CRC code for error detection is inserted into the terminal 76 frames of the tlr frames.

The P channel is a flag indicating pause and music, and has a low level for music and a high level for pause, and has a pulse of 2 Hz period in the lead-out section. Therefore, by detecting and counting the P channels, it becomes possible to select and reproduce designated music. The Q channel can perform the same type of control in a more complicated manner, for example, by importing Q channel information into a microcomputer installed in the disc playback device,
It is possible to perform random music selection, such as immediately switching to playing other music even in the middle of music playback. Other R
Channel to W channel are used to display the lyricist, composer, explanation, poem, etc. of the song recorded on the disc.

The present invention relates to a display channel in the above-mentioned subcoding signal, and is designed to prevent abnormal display during a search in which a pickup device moves in the radial direction of a disc at a higher speed than during normal playback. This is what I did.

Hereinafter, one embodiment of the present invention will be explained. FIG. 2 shows one of the R-W channels in this embodiment.
It shows the data structure of a block of a channel, for example, the R channel. This is sync bit 8@, 2 of 81
After the bit, there is a 6-bit command that is an instruction (microcode) to the microcomputer, a 10-bit location (display position data) to indicate the display position on the screen, and t display data of 1 bit each. D
The array is such that OND7 and 11-bit CRC code are located sequentially. This CRC code is the command, p
This is a cyclic code used to detect errors in display data.

In this embodiment, the same data is recorded for the same location two or more times, for example, twice. The same data written in a single manner is recorded continuously or in a distributed manner at appropriate intervals.

Further, FIG. 3 shows the configuration of an embodiment of the present invention. In the same figure, 1 surrounded by a broken line is compact disc 2.
A part of the player is shown, and 3, which is also surrounded by a broken line, represents a decoder and display section for sub-coding signals. The disk 2 is rotated by a servo device 4 at a constant linear velocity. On the signal side of disk 2, data 1#, %Ol
A bit is formed in correspondence with the cursor, and is optically read by the pickup device 5. The output of the pickup device 5 is supplied to the reproduction decoder 1 via the RF amplifier 6, where demodulation and error correction are performed.

This error correction is performed on the audio PCM signal and the redundant code for error correction, and this error-corrected PCM data is converted into an analog signal by a VA converter (not shown).

Further, a timing and control signal is supplied from a reproduction decoder 7 to a system control circuit of the player part 2 shown at 8, and a control signal for the pickup device 5 is generated from the system control circuit 8. In a normal reproduction operation, the pickup device 5 moves radially from the inner circumferential side to the outer circumferential side of the disk 2, and a spiffle-shaped signal track formed on the disk 2 is read and scanned by a laser beam. Further, during a search operation for finding the beginning of a song or for randomly selecting a song, the pickup device 5 moves in the radial direction of the disc 2 at a higher speed than during a normal playback operation. Such operation of the pickup device 5 is performed under the control of the system control circuit 8.

Further, the sub-coding signal, frame clock, and sync bit 130S91 of the sub-coding signal separated by the reproduction decoder 7 are added to the decoder and display unit 3. - As an example, if the frame clock frequency is 7.
JjkHz, the frequency of the sync bit is (73!;0
'-91=73Hz).

The sync bits and frame clock are supplied to a timing control and sync detection circuit 9, and the reproduced l-bit sync bits are arranged in a predetermined bit pattern 90.
, 31, and a tie sync signal synchronized with the reproduced data are obtained. The sub-coding signal is supplied to an error check circuit 10, and serial-to-parallel conversion and error checking are performed using the frame click, 1 timing control, and the sync signal from the sync detection circuit 9. This error check is performed under the control of the microcomputer 11. Error check circuit 10 and microcomputer 11
The system control circuit 8 of the disc player part 1 transmits timing signals from the system control circuit 8 of the disc player part 1 to the address and data bus 12 between the power-on and search operations, as well as the timing signals from the tie control reel and sync detection circuit 8. Detection signals indicating each of these are added.

Further, 13 indicates a video RAM, and data corresponding to pixels on the screen of the CRT display 14 is stored in the video RAM.
13. The data read from this video RAM 13 is displayed on the CRT display 14. The configuration of the displayed characters in this embodiment is /II (horizontal) x 76 (vertical) = 2 columns (dots) as shown in FIG. speed) is said to be 20jm8. However, the display data is divided into 7 (horizontal) ×! characters as shown by A1 to A4, taking into consideration the display of one-sided kana. (vertical>=16C dots), and the display on the CR'I' display 14 is also performed in this unit. In addition, the configuration of the seven screens of the CRT display 14 is 110 (horizontal) X J$ (vertical) = 9tO (characters) in units of the above-mentioned divisions, so all characters on the /M side are transferred. The speed is C! ;J, Jrna X 9bu0=! ;/, 2
a).

po N of the aforementioned sub-coding signal (see Figure 2)
D? Each display data corresponds to one line in each region of Al to person 4. There are 960 display positions on one screen of the CRT display 14, and these are designated by four cages. And C.R.
The display operation starts from the upper left side of the screen of the T-display 14, and the composer, lyricist, etc. of the music played from the disc 2 are displayed. The location of this display start position is a specific IO bit code, for example, a code in which all 10 bits are %0#.

Further, in this embodiment, a 6-bit F command is used, and 61 I- instructions can be used. An example using 70 of them is shown below. 0 oooooo: No operation.

00000/: Clear stage 8.

000///: Clear page l.

001000: Write 7 onts to the address indicated by the location of page l.

0O100/: The contents of page l are displayed on the CRT display 14 instead of those of pageco.

00////: Clear page 2.

010000: Write 7 onts to the address indicated by the location of page 2.

01000/: The contents of page λ are displayed on the CRT display instead of those of page l.

o/1ooo: Clear the / line indicated by the 0 case.

The above-mentioned page l and page 2 are as shown in FIG.
A memory area of the video RAM 13, which is switched to 0 by a command from the microcomputer 11 based on the above-mentioned command.Furthermore, the error check circuit 10 checks whether the sub-coding signal is in error. The Mitaro computer 11 controls this error checking operation, and the flow at that time is shown in the fs diagram.

The error checking operation will be explained below with reference to FIG.

First, a number N is set as a criterion for determining how many of the multiplexed (singlely written in this embodiment) subcoding signals must match to determine that the data is correct. Next, the interface section with the disc player part 1 is reset, the video RAM 13 is cleared, and the CRT display 14 is reset.

Next, a check is made to see if the player part 1 is searching. When a detection signal indicating that a search is in progress is supplied from the system control circuit 8,
No error checking is done. Error checking is performed during normal playback operation.

Then, a check is made to see if the sync bit of the sub-coding signal could be extracted, and a check for CRC7 lag, which is the result of the CRC check, is performed. As a sync bit, h.

and Sl are used as a checking target, and it is checked whether or not a sync signal corresponding to a sync bit is supplied from the tie sync control and sync detection circuit 9 during the wind pulse period. Error checking using the sync bit and CRC flag is performed as described below.

(1) The sync bit is normal and the C! of the data in that block is normal. When RC7 lag indicates no error,
Determine the data as correct 0 (2) Even if the sync bit is normal, if the CRC7 lag of the data in the block indicates an error, the data is determined to be an error.

(3) If the sync bit cannot be extracted, but the CRC7 lag of the data in that block indicates no error, the data is determined to be correct.

(4) If the sync bit cannot be extracted and the CRC7 lag of the data in that block indicates the presence of an error, that data is determined to be an error.

Data that is determined to be correct as a result of the error check using the SYNCPIF and CRC flag is then transferred to an error check using multiple writing. In this case, to find out how many of the da items are the same, −
A counter for counting the number of times is provided in the error check circuit 1o.

This counter is reset and its count value CN is set to O. Next, a verification operation is performed based on the data determined to be error-free by the CRC7 lag, and each time there is a match, the counter is incremented, and the CRC7
Data with correct lags is stored in the buffer memory. Then, it is checked whether the counted value CN of this counter is equal to or greater than a preset number N. this(
If CN≧N holds true, the reproduced sub-coding signal is finally determined to be correct, and the commands therein are decoded and executed. Then, the same error check as described above is performed again on the sub-coding signal of the next block.

Also, when the player part 1 is performing a search operation, the display data is played back in fragments, so for example /
Abnormal display occurs, such as parts of characters being missing or different contents being displayed at the same time. Therefore, in one embodiment of the present invention, the video RAM 13 is
The normal data stored in the search operation is held before proceeding to the search operation. In this case, the screen of the CRT display 14 may be cleared during the search operation, or a previously prepared screen may be displayed.

Furthermore, when the pickup device 5 of the player part 1 is turned on or stopped during a search operation, the playback start position is not at the beginning of a program, but playback starts from the middle, so the display on the CRT display 14 is A part of it will be missing.

In this way, in order to prevent the display from being displayed from the display start position, a detection signal indicating the power-on time and search time is supplied from the system control circuit 8 to the microcomputer 11, and the data at the display start position is transferred to the disk. Processing is performed in which the reproduced data is not treated as data to be displayed until it is reproduced from 2. Whether or not the data is at the display start position can be known from the locator 1.

In this case, a command indicating that it is the first of seven screens may be used, and this may be interpreted by the microcomputer 11.

Note that, unlike the above embodiment, a display or other display device in which display segments made of light emitting diodes or liquid crystals are arranged horizontally may be used.

As can be understood from the description of the above embodiment, according to the present invention, sub-coding signals for display can be recorded on a compact disc, and a related predetermined display can be performed while playing music. In addition, in this case, it is possible to prevent abnormal displays such as parts of displayed characters being missing when performing a search operation for review during random song selection. .

[Brief explanation of drawings]

Figures 1 and 2 are route maps used to explain the data structure in an embodiment of the present invention, Figure 3 is a block diagram showing the configuration of an embodiment of the invention, and Figure 1 is an embodiment of the invention. FIG. 5 is a route map used to explain a display pattern in the example, FIG. 5 is a route map used to explain a part of an embodiment of this invention, and FIG. 4 is a flowchart used to explain an error check operation of an embodiment of this invention. It is. 1...Part of the player, 2...Mountain compact disc, 3...Decoder and display section, 5...
... Pickup device, 8 ... System control circuit, 10 ... Error check circuit,
11... Kawa Mike 4 computers, 14...
CRT display. Agent Masaaki Sugiura Figure 1 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A code signal including an audio PCM signal and display data related to the contents of the audio PCM signal is reproduced from the disk, and the display data in the reproduced signal is supplied to a display device, and A disc playback device that clears the screen of the display device or holds previously normal display data when a pickup means moves at a higher speed than during normal playback.