JPS61101132A - Multiplexing method - Google Patents

Abstract

PURPOSE:To reproduce even a multiplex signal or sound information by a conventional reproducer when both are transmitted by assigning the sound signal and a non-sound signal multiplexed on a digital signal to separate bits so as to separate the non-sound information and the sound information on a spectrum. CONSTITUTION:A signal C0 repeating alternately phi and 1 and a 1-bit non-sound information b0 are inputted to an exclusive OR operating device 1, the least significant bit a0 of sound information (a3, a2, a1, a0) subject to 4-bit quantization is replaced by the output signal and a data D=(a3, a2, a1, b0+c0) is transmitted to a transmission line. The spectrum of sound information included in the data is shown in figures 12 and 14. Further, the distribution of the spectrum of the non-sound information included in the D is shown in 13. The signal having a band of the spectrum 12 only of the sound information is reproduced from the signal D via a D/A converter 15 and a low pass filter 16 having a cut-off frequency fc. On the other hand, the non-sound information b0 is obtained from the (b0+c0) being the least significant bit of the signal D by an exclusive OR operation device 18.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for multiplexing non-acoustic information into acoustic information using a PCM audio recording or transmission medium.

Conventional configurations and their problems Digital audio has been progressing at a rapid pace in recent years, and efforts are underway to develop tape recorders exclusively for digital audio or to unify standards.

In addition, compact discs (hereinafter referred to as CDs) are rapidly being put into practical use. In this digitization of audio, not only acoustic information but also non-acoustic information such as image data or text data can be simultaneously recorded on digital audio recording media to improve the functionality of digital audio equipment from an audio/visual perspective. The direction is blessed with good luck.

A conventional multiplexing method will be described below with reference to the drawings. One conventional example of recording non-acoustic information together with acoustic information is a CD subcode system. Figure 1 is C
1 is a block diagram showing the configuration of a sub-cordon stem of D, in which reference numeral 1 denotes an analog-to-digital converter (hereinafter abbreviated as A/D converter) to which acoustic information is input via a terminal T1;
2 is an encoder, 3 is an encoder into which non-acoustic information is input via terminal T2, 4 is a multiplexer, 5 is a distributor, 6 is a decoder, and 7 is a code that outputs non-acoustic information to terminal T4. 8 is a D/A converter that outputs acoustic information to terminal T3, and 9 is a compact disc device (hereinafter abbreviated as CD).

The operation of the CDs subcode system configured as described above will be explained below. The acoustic information converted into digital data through the A/D converter 1 is sent to the encoder 2.
A code for error detection and correction is added thereto, and the signal is input to the multiplexer 4. On the other hand, the valve acoustic information is added with a code for error detection and correction by an encoder 3 and inputted to a multiplexer 4. Within the multiplexer 4, the acoustic information and non-acoustic information from the encoder 2 and the encoder 3 are transmitted on a single signal line in a time-division manner and recorded on the CD 9. On the other hand, during reproduction, the signal containing acoustic information and non-acoustic information reproduced from the CD 9 is divided into acoustic information and non-acoustic information in the distributor 5, and a signal encoder 6.
The signals are input to the decoder 7 for non-acoustic information and undergo error detection and correction operations separately. The acoustic information output from the decoder 6 passes through the D/8 converter 8 and is output as an analog signal, and the non-acoustic information output from the decoder 7 is output outside as a digital signal.

However, such a configuration requires a decoder for non-acoustic information in addition to a post-coder for acoustic information.
This has the problem that the device becomes a major loss.

In addition, methods have been devised to multiplex and record other information on recording media for image recording, such as recording FM audio signals on a VTR or recording PCM audio signals on an optical video disc, but these are analog The entire recording medium is used as the basics, and it searches for an empty part of the frequency band of the image signal to be recorded and records by adding other information to that band, or records by using the azimuth difference of the head. Therefore, these methods have problems such as the need for special filters, demodulation equipment, etc. that are not found in normal playback equipment to separate the multiplexed signals in order to play back the multiplexed information. It had

OBJECTS OF THE INVENTION It is an object of the present invention to provide a
It is an object of the present invention to provide a means for recording or transmitting non-acoustic information such as image data and character data without changing the recording or transmitting method of commercial audio.

Structure of the Invention The multiplexing method of the present invention is based on N-bit digital data A = (aN-1°aN-) obtained by quantizing acoustic information.
2,..., ao) f M-bit digital data B= ("M-1, 'M-2, -.
・,bo) and every bit of the valley data is an anti-pit digital signal C=(CM-1,
CM-2゜..., Co) bit data BOC-(bM-1■C) obtained by exclusive OR operation of
N-bit data D-(aN-1, aN-2, """, aM
, bM-1■cM-1. bM-2■CM-2.・・・・・・
..., bo■co), and thereby the transition frequency band between the aliasing frequency that always exists in a PCM audio system and the audio cutoff frequency set to 20. use,
Moreover, by assigning the acoustic signal and non-acoustic signal that are multiplexed on the digital signal to separate focuses, non-acoustic information can be reproduced while minimizing the deterioration of the audio signal within the audible band without making any changes to the playback device. can be multiplexed.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram for realizing multiplexing when acoustic information is quantized with 4 bits and non-acoustic information is 1 bit in one embodiment of the present invention, and 10 is a block diagram for realizing multiplexing when acoustic information is quantized with 4 bits. A/D converter, 11 is terminal T6
This is an exclusive OR operation unit that performs an operation between the non-acoustic information bo inputted from the terminal T7 and a signal C6 which alternately repeats "φ°" and "1°" inputted from the terminal T7.

FIG. 3 shows 4-bit digital signals (C3, C2, al, b) multiplexed by the circuit shown in FIG.

■It is a diagram showing the spectrum of C0), 12.14 is the spectrum of acoustic information (C3, C2, al, φ), 1
3 is a spectrum of non-acoustic information (φ, φ, φ, bo■co).

FIG. 4 is a block diagram of a reproducing device for a 4-bit digital signal multiplexed according to FIG.
A 4-bit audio information reproducing device includes a bit D/A converter 15 and a low-pass filter 16. Reference numeral 18 is an exclusive OR operator, which serves as a non-acoustic information reproducing device.

The operation of the multiplexing method of this embodiment configured as described above will be described below. 1 Exclusive OR operator 11
1-bit non-acoustic information B=-(b.) and a signal C-4Co) which alternately repeats φ and 1 are input to the lower pitch a). is replaced, data D = (a 3. C2゜al, bo
(2) Co) is transmitted to a transmission path or recorded on a recording medium. At this time, the acoustic signal A has a frequency f lower than 1/2 of the sampling frequency 18. The spectrum of the acoustic information (C3+"2+a1.φ) included in the data D is 12 and 14 in FIG. 3 because the band is limited to .

Since C0 is a digital signal that alternately repeats φ and 1 on the spectrum of φ, φ, bo■co), f8/2
A digital signal around the line spectrum of.

The distribution 13 has a spectrum spread of .

A signal with such a spectrum is transmitted to the D/A converter 1 of the 4-bit audio information reproducing device 17 shown in FIG.
5 and is converted to an analog signal, but the D/A
The output signal of the i-switcher 14 has an uninterrupted wave number f. Since it is input to the low-pass filter 16 of
4 has been removed and is purely a spectrum of acoustic information 12
A signal with a band of only - The least significant bit of the input signal, b0Co, is the exclusive OR of a signal that alternately repeats O's and 1's, similar to the digital signal used for multiplexing.

is performed by the exclusive OR operator 18, and the result is non-acoustic information. can be obtained.

In the above implementation, the acoustic information is 4 bits.

Although the non-acoustic information was set to 1 bit, the acoustic information iN pit,
The operation of the present invention is exactly the same even for non-acoustic information iM pits. If M is greater than 2, the signal C-(CM-1
, CM-2, . . . C0), it is clear that any bit pattern may be used as long as each bit is made to alternately repeat 1 and φ for each signal.

Effects of the Invention As is clear from the above explanation, the present invention is a method of converting the lower M bits of digital data obtained by quantizing audio information iN bits into an M-bit digital method in which each bit alternately repeats ○ and 1 for each data. Since the configuration is configured to replace the non-acoustic information with M-bit data that is multiplexed with the signal by a logical OR operation, the non-acoustic information and the acoustic information are separated on the spectrum. Therefore, even if multiplexed signals are transmitted, even if N-bit acoustic information is transmitted, it can be reproduced by a normal reproduction device, and an excellent effect with high compatibility can be obtained. Furthermore, since the multiplexed non-acoustic information is assigned to different bits from the audio information, there is also the advantage that the non-acoustic information can be separated very easily. In addition, since encoding and decoding are performed as M-bit non-acoustic information and N-M-bit acoustic information (iN-bit acoustic information), there is no need for complex encoders and decoders dedicated to non-acoustic information. It will be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a subcode system of a conventional compact disc device, and FIG. 2 is a block diagram showing the configuration of a subcode system of a conventional compact disc device. A block diagram showing the configuration when information is multiplexed into 1 bit. Figure 3 is a diagram showing the spectrum of a 4-bit multiplexed signal multiplexed according to Figure 2. Figure 4 is a diagram showing the spectrum of a 4-bit multiplexed signal multiplexed according to Figure 2. FIG. 2 is a block diagram of a reproducing apparatus for a 4-bit digital signal. 1o...A/D converter, 15...D/A
Converter, 11.18...exclusive OR operator,
12, i4... Spectrum of acoustic information, 1
3... Spectrum of non-acoustic information, 16...
...Low pass filter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] N-bit digital data A obtained by quantizing acoustic information = (a_N_-_1, a_N_-_2, ...
..., a_0) on a transmission medium for transmitting or recording medium for recording M (M is an integer of N>M>0) bits of digital data B=(b_M_-_1, b
_M_-_2, ......, b_0) and an M-bit digital signal C = (C_M_-_1, C_M_-_2, ...) where every bit alternately repeats 1 and φ for each data.
..., C_0) M-bit data B■C=(b_M_-_1■C_M_
-_1,b_M_-_2■C_M_-_2,・・・・・・
N-bit data D = (a_N_-_
1, a_N_-_2, ......, a_M, b_M_
−_1■C_M_-_1, b_M_-_2■C_M_-
A multiplexing method for transmitting or recording _2, ..., b_0■C_0).