JPS623467A - Recording and reproducing method - Google Patents

Abstract

PURPOSE:To execute recording and reproducing for a long time by time-dividing plural digital information signals to align them serial, recording them on a disk, and selecting and reproducing one of serial compound signals of plural digital information signals detected by one reproducing system. CONSTITUTION:In a recording system 8, the sound signals of, for example, four different pieces A, B, C and D of music are restricted out of the band by filters 1a, 1b...1d, and A/D-converted 2a, 2b...2d. The obtained digital signal is for example, compressed 3a, 3b...3d to 8 bits, and by a multiplexer 4, signals A1, B1, C1, D1, A2, B2, C2, D2 and A3... are outputted. The output is added 5 with an error correcting signal, digital-converted 6, added with a synchronizing signal and recorded to a disk D by a recording head 7. ON the other hand, in a reproducing system 9, the data of the disk D are detected by a pick-up 10, digital-demodulated 11 and synchronized-detected 12. One digital information signal of serial compound signals of the detected plural digital information signals is selected by a selector 14.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method that enables long-term recording and reproduction using a disk as a recording medium for information signals.

[Background Art] A digital audio disc called a compact disc has stereo signals (L, R) as 16-bit digital signals, respectively, L+, B+, B2, R2, B3, .
It is recorded in a spiral shape on the neck of ..., approximately 1
Time signal reproduction is possible. When playing such a disc and using it as so-called bank background music, it is conceivable to use the disc's auto-change mechanism to play it for a long time.
Since the autochanger mechanism is complex and requires a certain amount of time to change discs, there are times when the playback sound is interrupted.

C. Problems to be Solved by the Invention The present invention makes it possible to record and reproduce signals for a long time, although the sound characteristics are slightly degraded, such as by narrowing the dynamic range of the signal and/or converting a stereo signal into a monaural signal. It is something.

2. Means for solving the problem by time-sharing multiple (for example, four A, B, C, and D) digital information signals (including those obtained by sampling and digitizing analog information No. 18). Arrange in series. That is, A+, B+, C+, I) 1, A2, B2, C2, B
Arrange them as 2, A3,...

This signal is recorded on the disk in a spiral shape.

On the playback side, only one playback system is prepared, and one digital information signal is selectively played out of the serial composite signal of multiple digital information signals detected from the disc using one playback system. do.

E. Effect: Long playback is possible by reproducing information A in the first scan (scanning from the beginning of the disc playback to the end) and reproducing information B in the second scan. becomes.

EXAMPLE This example shows a case where four different pieces of information (four pieces of music) are recorded and reproduced. Figure 1 shows the recording circuit (8)
It shows four different songs (A.

B, C, D) audio signals are filtered (ig) (lb)
(1c) The band is limited by (1d), and the A/D converter (2
a) (2b) (2c) (2d). This A/
A D converter samples the audio signal at, for example, 44.1KH2 and converts it into a 10-bit digital signal.

This 10-bit digital signal is processed by compression circuits (3a) (3).
b) Convert to 8-bit digital signal in (3C) and (3d). As this compression circuit, a conventionally known circuit using RAM can be used. The 8-bit signal output from the compression circuit is alternately rearranged by the multiplexer (4) in units of 8 bits for each song. ,
C2, B2. Signals A3, B3, . . . (subscripts indicate sampling timing) (each signal is 8 bits) are output. The signal output from the multiplexer (4) is input to an error correction code addition circuit (5), where an error correction code is added, and further subjected to digital modulation suitable for recording at a digital modulation vAu path (6). Thereafter, a synchronization signal (SYNC) for data synchronization is added, and the data is recorded on the disk (D) by the recording head (7). Optical recording is possible as a recording method, by modulating the light beam intensity based on the digital signal and forming bits (concavities) on the disk based on this modulated light beam. The signal may be recorded on disk.

Therefore, the signal format recorded on the disc is as shown in FIG. Note that the error correction code (redundant bits) is not shown in this figure, and the information signal (
Only the format of the audio signal) is shown. Furthermore, in reality, data can be rearranged (called interleaving) to convert burst errors into random errors, which is used when recording digital signals. However, in a broad sense, this interleaved data is also arranged in chronological order as shown in Figure 2, and the present invention applies to such interleaved data as well. Of course, it can be applied.

The reproduction system circuit (9) is as shown in the third @. The signal recorded on the disk (D) is detected by a pickup (10) and sent to a digital demodulation circuit (11) and a synchronization detection circuit (
12) The impression is false. The synchronization signal detected by the synchronization detection circuit (12) is used as a data synchronization signal in each circuit. Also, although not shown, a pickup (1
A clock (timing signal) synchronized with the reproduced signal detected at 0) is created, and each subsequent circuit is operated based on this clock.

Now, the data signal digitally demodulated in the digital demodulation circuit M (11) is applied to the error correction circuit (13),
If an error is detected, it is corrected.

Furthermore, if interleaving was performed during recording, dinterleaving is performed to rearrange the data in the original order. Thus, 8-bit audio signals (A, B, C, D) are output in parallel from the error correction circuit (13). One of these four types of signals (A, B, C, D>) is selected by the selector (14).
) is applied with a selection signal instructing which signal to select.0 The selected signal (8 bits) is expanded to the original 10-bit signal in the expansion circuit (15), and the D/A
It is converted into an analog signal by a conversion circuit (16), and then sent to a speaker (1) via a filter circuit (17) and an amplifier circuit (18).
9) and one audio signal is reproduced.

After detecting the end of playback of one signal, the pick-up (1
By repeating the operation of returning 0) to the disc playback start edge and playing the next signal, the signal channels A and B
, C, and D can be played continuously.

The feature of the above-described embodiment is that it is possible to record and play over a long period of time without making any major changes to the currently available compact disc system. That is, the above-mentioned compact disc system converts two channel stereo signals into one
Recording is possible with a 16-bit signal per channel and playback is possible for one hour, but by recording a monaural signal as an 8-bit signal, playback for four hours is possible. FIG. 4 shows the relationship between the compact disc system and the signal format of the present invention. In the present invention, the signal A+ (8 bits) is assigned to the upper 8 bits of the L channel signal in the compact disc system. Signal B1 (8 bits) is assigned to the lower 8 bits of the L channel signal, signal C+ (8 bits) is assigned to the upper 8 bits of the R channel signal, and signal D1 (8 bits) is assigned to the lower 8 bits of the R channel signal. By allocating signals in this way, subsequent processing can be performed in exactly the same way as in the compact disc system.In the compact disc system, each 16-bit signal of the R channel is divided into two, and 8 Subsequent processes such as creation of an error correction code and digital modulation are performed using bits as one unit (one symbol), and the present invention allows the processing circuits of these recording systems to be used as they are. Similarly, in the system, the synchronization detection circuit, digital demodulation circuit, error correction circuit, etc. can be used as they are.

In order to distinguish between discs recorded in the format of the original compact disc system (2 channel stereo signal, 16 bits) and discs recorded in the format of the system of the present invention (monaural signal, 8 bits), an identification signal is used. In a compact disc system where recording is desirable, a control/display signal called a subcode signal is prepared in addition to the data signal, so it is possible to use this subcode signal for identification. It is possible.

FIG. 5 shows a reproducing circuit having both a reproducing system of a compact disc system and a reproducing system of the system of the present invention. The reproduction system up to the error correction circuit (13) is similar to the circuit shown in FIG. For the circuit shown in Figure 3, 16
Bit D/A converter (20L><2OR>, filter circuit (21L) (21R), amplifier (22L) (22R)
), speakers (23L) (23R), and switching circuits (24) (2SL) (2SR) are added. When the identification signal indicates that the disc is related to Funbakuto disc, the switching circuit (25L) (25
R) is closed, indicating that it is a disk according to the system of the invention, the switching circuit (24) is closed.

When a disc recorded in the format according to the present invention shown in FIG. The Rf-channel signal becomes the sum signal of the high-level signal C and the low-level signal. Therefore, for example, if an English audio signal is recorded on signal (channel) A and a corresponding Japanese audio signal is recorded on signal (channel) B, the reproduction according to the system of the present invention shown in the upper part of FIG. By playing back through the circuit, you can selectively listen to either English or Japanese audio, and by playing back through the playback circuit related to the compact disc system shown in the lower part of Figure 5, you can listen to both high-level English audio and low-level English audio. You can listen to Japanese audio at the same time.

In place of the format shown in Figure 2, L channel 16
An 8-bit A channel signal may be assigned to even bits, an 8-bit B channel signal may be assigned to odd bits, and in the same way, C and D channels may be assigned to 16 bits of an R channel. in this case,
It is of course possible to selectively listen to any one of the signals A, B, C, and D using the reproducing circuit according to the system of the present invention shown in the upper part of FIG. 5
When playing with the playback circuit related to the compact disc system shown in the lower part of the figure, signals A and B, which are approximately the same level, are L.
+ Signal C, which is reproduced from Cancel and is also at approximately the same level.
D will be played from the R channel.

G. Effects of the Invention According to the present invention, by scanning one disk multiple times, it becomes possible to record and reproduce over a long period of time.

[Brief explanation of drawings]

1I50 is a diagram showing the recording system circuit, FIG. 2 is a diagram showing the signal format, FIG. 3 is a diagram showing the reproduction system circuit, and FIG. 4 is a diagram showing the relationship between the signal format of the compact disc system and the system of the present invention. The figure shown in FIG. 5 is a diagram showing another embodiment of the reproduction system circuit. (mutual) is a recording circuit, and (9) is a reproduction circuit.

Claims (1)

[Claims] (1) A plurality of digital information signals are time-divided and arranged in series, recorded in a spiral shape on a disk, only one reproduction system is prepared on the reproduction side, and the plurality of digital information signals detected from the disk are Among the serial composite signals of information signals,
A recording and reproducing method characterized by selectively reproducing one digital information signal.