JPS6315777B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplex signal transmission system in which information related to musical tone signals is transmitted using binary codes on sub-channels of multiplex broadcasting.

Traditionally, as an example of multiplex broadcasting in Japan,
There are VHF band FM stereo broadcasts, television audio multiplex broadcasts, etc. In these broadcast media,
Since it occupies a relatively wide frequency band, there is still some room left to provide other information transmission channels within the occupied frequency band.

However, this additional information transmission channel has transmission characteristics (frequency characteristics, dynamic range, S/N) comparable to the main audio channel.
), and the frequency band is considerably limited and the S/N ratio is not sufficient.

The present invention aims to transmit equivalently high-quality music through such a transmission path with insufficient quality, and a musical tone signal generator is prepared on the receiver side to generate this musical tone signal. In this system, the control signal that controls the section is converted into a binary code and sent to the receiver side via the above-mentioned transmission line with insufficient quality, and the receiver decodes it to generate a high-quality musical tone signal. be.

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

Figure 1A shows one code format transmitted according to the present invention, and to simplify the explanation, a 4-bit binary code is used for the fundamental frequency of one musical tone signal. (denoted as tone control in Figure 1), also a 4-bit binary code for its harmonic content (denoted as harmonic control in Figure 1), and a again 4-bit binary code for its envelope or amplitude level. (referred to as envelope control in FIG. 1), and a 4-bit frame synchronization signal is added so that the combination of the above-mentioned binary codes can be easily identified at the receiving terminal.

FIG. 1B shows a case where the level of only the frame synchronization signal is increased so that the frame synchronization signal can be more easily identified, and when FSK modulation is adopted, it is shown that ternary FSK is used.

Figure 1C shows the case where the pulse width of only the frame synchronization signal is made wider so that the frame synchronization signal can be more easily identified, and Figure 1D shows the case where the pulse width is made wider.
In order to achieve narrower band transmission, the signal shown in Figure 1A is converted to the NRZ format.

On the transmitting side, various methods can be considered to generate the code string shown in Figure 1, such as AD conversion of the movement of the keyboard of a synthesizer-type instrument, so we will not discuss them in further detail. is omitted.

Each code string shown in FIG. 1 performs FSK modulation on a subcarrier provided outside the audible band of the main audio channel. For example, the frequency of the subcarrier is as follows:
For VHF/FM broadcasting, 67KHz, 76KHz, etc. are desirable.

The binary code string sent out by FSK modulation of the subcarrier is received and demodulated by an ordinary receiver, and a waveform as shown in FIG. 1 is reproduced.

The process up to reception and demodulation is processed by normal receiver technology, so a detailed description will be omitted.

FIG. 2 is a block diagram showing a binary code decoder section and a tone generating section provided on the receiver side to which the present invention can be applied. The signal received and demodulated by the receiver is applied to a waveform shaping circuit 2 through an input terminal 1, and a series of binary information signals as shown in FIG. 1A are obtained at its output terminal. This output signal is applied to the subsequent bit synchronization and frame synchronization detection circuit 3, tone control signal detection gate 4, harmonic control signal detection gate 5 and envelope control signal detection gate 6.

A gate control signal obtained from the bit synchronization/frame synchronization detection circuit 3 described above is applied to the three types of gates 4, 5, and 6 at the same time, and the tone control signal and harmonic control signal shown in FIG. , the corresponding gates are controlled to be opened only during a period corresponding to the envelope control signal.

The above bit synchronization and frame synchronization detection circuit 3
is, for example, a narrowband bandpass waver and amplitude limiter with a center frequency equal to the bitrate,
It can be constructed using a PLL circuit, a counter, a gate circuit, etc., but since this specific construction can be achieved by various methods well known in the field of ordinary pulse communication technology, further detailed explanation will be omitted.

A 4-bit tone control signal, a 4-bit harmonic control signal obtained from the tone control signal detection gate 4, harmonic control signal detection gate 5, and envelope control signal detection gate 6, and
The 4-bit envelope control signal is applied to the transcoder-cum-retainer 7, 8, 9, respectively, where:
A signal in a convenient format for controlling the voltage-controlled sawtooth variable frequency oscillator 10, the voltage-controlled passband variable wave generator 11, and the voltage-controlled variable level controller 12; The oscillation frequency of the frequency oscillator 10, the passband of the variable wave generator 11, and the variable level controller 12
Determine the level control amount.

Since the code converters/retainers 7, 8, and 9 described above can be easily constructed by, for example, a plurality of gate circuits, flip-flops, etc., further detailed description thereof will be omitted.

The output of the variable frequency oscillator 10 is applied to the variable wave generator 11, where its harmonic content is controlled, and then applied to the variable level controller 12, whose envelope is controlled, and the output The signal becomes a synthesized musical tone signal and is sent to output terminal 1.
Obtained from 3.

The variable frequency oscillator 10, the variable wave generator 11,
The variable level controller 12 can be easily used, for example, in a synthesizer type musical instrument.

The musical tone signal obtained at the output terminal 13 is then
Via a suitable amplifier, the loudspeaker can be driven.

FIG. 3 shows one code format compatible with a stereo signal as an example of applying the present invention to a multi-channel musical tone signal. , which shows the left.

In this case, it goes without saying that the number of decoder sections and tone generation sections shown in FIG. 2 must be increased by one channel.

FIG. 4 shows one code format in which an auxiliary I code and an auxiliary code are added in addition to the tone control, harmonic control, and envelope control codes described above as control signals for musical tone signal generation. Corresponding to the auxiliary code, a code for giving a slight frequency modulation to the variable frequency oscillator 10 for adding a vibrato effect to musical tones, and a code for generating relatively simple rhythm sounds such as mambo, waltz, and samba separately from the musical tone signal. Codes for generation and control can be considered.

The decoder section and musical tone generating section of the receiver corresponding to the symbols in FIG. 4 can be easily constructed by expanding the blocks shown in FIG. 2, and therefore detailed description thereof will be omitted.

In addition, in order to enable the receiver operator to color the music, or to support narrow-band transmission paths, some of the combinations of binary codes that control the various musical tone generators mentioned above are transmitted. It is not a good idea to delete some of these musical tone generators on the side or delete them on the receiver, and then allow the person operating the receiver to freely control some of these musical tone generators using a control section installed in the receiver. It goes without saying that this is included in the idea of invention.

In this embodiment, a case is shown in which one set of control signals is composed of 4 bits, but it goes without saying that in practical use, it is desirable to increase or decrease the number of bits as appropriate depending on each object to be controlled.

As is clear from the above explanation, according to the present invention, since the control signal of the musical tone generator is transmitted using binary codes, equivalent high-quality It can transmit music signals, and its practical effects are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one code format for controlling a musical tone generator transmitted according to the present invention, and FIG. 2 is a block diagram showing a decoder section and a musical tone generating section of a receiver applicable to the present invention. FIGS. 3 and 4 are diagrams showing other code formats for controlling the musical tone generator that are transmitted according to the present invention. 2... Waveform shaping circuit, 3... Bit period/frame synchronization detection circuit, 4... Tone control signal detection gate, 5... High frequency control signal detection gate, 6...
Envelope control signal detection gate, 7, 8, 9...
... code converter/retainer, 10... voltage controlled sawtooth variable frequency oscillator, 11... voltage controlled pass band variable wave generator, 12... voltage controlled variable level controller.

Claims (1)

[Claims] 1. A musical tone signal is defined by at least a combination of binary codes corresponding to its fundamental frequency, a combination of binary codes corresponding to its harmonic content, and a binary code corresponding to its envelope or amplitude level. The subcarrier provided outside the audible band of the audio signal is modulated by frequency shift keying using a series of binary codes created from the combination of the above three types of binary codes, and the audio frequency signal and the above
Transmitting the audio signal and musical tone signal by frequency modulating or phase modulating the broadcasting carrier wave with a signal obtained by adding the FSK modulated subcarrier wave, and extracting the subcarrier wave from the transmitted broadcast wave at the receiver, After demodulating, it is decomposed into a combination of the three types of binary codes mentioned above, and a signal having a constant period containing a large amount of harmonics is generated by the combination of the binary codes corresponding to the demodulated and decomposed fundamental frequency. A binary bandpass characteristic of a wave generator for controlling the signal period of the signal generator and increasing or decreasing the high frequency of the signal generated by the signal generator corresponding to the demodulated and decomposed harmonic content. Adjust the level control amount of the level controller that controls the envelope or the level of the signal waved by the waver by a combination of signals and a combination of binary codes corresponding to the demodulated and decomposed envelope or amplitude level. A multiple signal transmission method characterized by generating a musical tone signal at a receiver by doing so. 2. In the multiplex signal transmission system according to claim 1, information that gives a slight frequency modulation to the fundamental frequency of the musical tone signal is newly added to the combination of the three types of binary codes as a combination of binary codes, After the receiver demodulates and decomposes the above-mentioned combination of added binary codes, the combination of binary codes indicates information that gives slight frequency modulation to the fundamental frequency of the demodulated and decomposed musical tone signal. A multiple signal transmission method characterized by controlling a frequency modulator or phase modulator newly added to a signal generator. 3. In the multiplex signal transmission system according to claim 1, information indicating various rhythm signals is newly added and transmitted as a combination of binary codes to the combination of the three types of binary codes, and the information is transmitted to the receiver. hand,
A multiplex signal transmission system characterized in that after demodulating and decomposing the combination of the added binary codes, a rhythm generator is newly controlled separately from the signal generator using the combination of the binary codes. 4. In the multiple signal transmission system according to claim 1, 2, 3, or 4, some of the combinations of binary codes that control various musical tone generators are omitted on the transmitting side. , or omitted or removed from the receiver, and a part of these musical tone generating sections is newly installed in the receiver with a control section that allows the person operating the receiver to freely control it. A multiplex signal transmission method that uses