JPH04347941A - Audio signal multiplexing analog transmission system - Google Patents

Abstract

PURPOSE:To solve the problem of leakage or the like between multiple signals generated at the time of modulating audio signals to SSB to perform multiplex transmission and to perform transmission without a digital transmission system. CONSTITUTION:This system consists of an audio multiplexing transmission equipment 1 and an audio multiplexing reception equipment 3 which are connected through an analog transmission system 2. The audio multiplexing transmission equipment 1 subjects audio input signals inputted from plural input terminals to A/D conversion and stores than as parallel inputs in a digital memory and converts them to serial sinals and calls them and transmits then after D/A conversion. The audio multiplexing reception equipment 3 stores multiplexed analog signals in a digital memory after A/D conversion and converts them to parallel signals and calls them and outputs them after D/A conversion.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for multiplexing and transmitting a plurality of audio signals as analog signals.

0002

[Background Art] Conventional audio signal multiplex transmission methods include a frequency division method in which multiple audio signals are converted into SSB signals and multiplexed, or a frequency division method in which multiple audio signals are converted into digital signals and time-division multiplexed. A digital time division transmission method that multiplexes and transmits data has been proposed.

0003

[Problem to be solved by the invention] The above-mentioned conventional SSB
In signal frequency division multiplexing, phase distortion,
There is a problem that amplitude distortion or deterioration of frequency-amplitude characteristics occurs, and there is also a problem that leakage occurs between each SSB signal due to non-linear distortion of the transmission line that transmits the multiplexed signal. Furthermore, a buffer frequency band must be provided between these adjacent SSB signals to prevent mutual interference, and therefore the multiplexing bandwidth must be wider than the sum of the audio input frequency bandwidths.

On the other hand, in the digital time division transmission system,
Although it is possible to solve these problems caused by frequency division multiplexing of SSB signals, this method has the problem that a special transmission system must be prepared to transmit digital signals. SUMMARY OF THE INVENTION An object of the present invention is to provide an audio signal multiplexing analog transmission system which can solve the problems caused by the frequency division multiplexing transmission system using SSB and which can also be transmitted using a conventional analog transmission system.

[0005]

[Means for Solving the Problems] The audio signal multiplexing analog transmission system of the present invention is composed of an audio multiplexing transmitting device and an audio multiplexing receiving device that are connected via an analog transmission system. It is configured to multiplex and transmit the same. The audio multiplexing and transmitting device includes a plurality of A/D converters that convert audio input signals inputted from a plurality of input terminals into digital signals, and stores each output from these A/D converters as parallel inputs. It also includes a digital memory that can be serially converted and recalled, and a D/A converter that converts the output of this digital memory into an analog signal. Further, the audio multiplexing receiving device includes an A/D converter that converts the transmitted multiplexed analog signal into a digital signal, and an output of the A/D converter that can be stored, converted in parallel, and recalled. digital memory and multiple D/D converters that convert the output of this digital memory into analog signals.
A conversion is included.

[0006]

According to the present invention, problems caused by SSB modulation and demodulation of audio signals can be solved, and at the same time, a digital transmission system is not required.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a system diagram of one embodiment of the present invention. In FIG. 1, 1 has n audio signal input terminals 11 to 1n, and n
2 is a transmission system for transmitting the output signal of the audio multiplexing and transmitting apparatus 1; 3 processes the output signal of the audio multiplex transmitter transmitted via the transmission system 2;
This is an audio multiplexing receiving device having n audio output terminals 31 to 3n for returning the original audio signal.

FIG. 2 is a system diagram of the audio multiplex transmitter 1. As shown in FIG. In the figure, 11 to 1n are n audio input terminals, 41 to 4n are A/D converters that convert the audio signals input to each of the audio input terminals 11 to 1n into digital signals,
A digital memory 5 is connected to the digital signal outputs of these A/D converters 41 to 4n and stores them. In this digital memory 5, the stored signals are sequentially read out and output. 6 is a D/A converter that converts the output signal from the digital memory 5 into an analog signal and outputs it to the output terminal 21. The output of the audio multiplexing transmitter 1 has a frequency band that is the sum of the audio band signals from the input terminals 11 to 1n.

FIG. 3 is a system diagram of an embodiment of the audio multiplexing receiving device 3. As shown in FIG. In the figure, 22 is a multiplexed signal input terminal, and 7 is an A/D converter that converts an analog signal input from the multiplexed signal input terminal 22 into a digital signal. Numeral 8 is a digital memory connected to the output of the A/D converter 7, which converts the time-division multiplexed signals into parallel signals, and sequentially reads and outputs the signals to n outputs. 91-9n are D/A converters connected to the output of the digital memory 8, and are connected to the audio output terminals 31-3n, respectively. The audio output terminals 91 to 9n output audio signals corresponding to the input signals of the input terminals 11 to 1n of the audio multiplexing and transmitting device 1.

0010

As explained above, the present invention multiplexes and transmits multiple audio signals as analog signals in a time-division manner, so the frequency bandwidth required for multiplexing is the sum of each audio input signal. You can get away with it. Furthermore, since the signals are multiplexed in a time-division manner, it is possible to eliminate leakage between signals due to non-linear distortion in the transmission system. Furthermore, there is an advantage that modulation distortion caused by the conventional method of converting to an SSB signal and demodulation distortion caused by demodulating the SSB signal to the original audio signal, that is, deterioration of amplitude, phase distortion, and frequency-amplitude characteristics, etc. do not occur. Furthermore, since the analog signal is transmitted as it is, it can be transmitted using the same analog signal transmission system as in the past.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing the overall configuration of an embodiment of the method of the present invention.

FIG. 2 is a system diagram of an audio multiplexing and transmitting device.

FIG. 3 is a system diagram of an audio multiplex receiving device.

[Explanation of symbols]

1 Audio multiplex transmitter 2 Transmission system 3 Audio multiplexing receiving device 41~4n A/D converter 5 Digital memory 6 D/A converter 7 A/D converter 8 Digital memory 91~9n D/A converter

Claims (1)

[Claims] [Claim 1] Consisting of an audio multiplex transmitter and an audio multiplex receiver connected via an analog transmission system,
The audio multiplexing and transmitting device includes a plurality of A/D converters that convert audio input signals inputted from a plurality of input terminals into digital signals, and stores each output from these A/D converters as parallel inputs. The audio multiplexing receiving device includes a digital memory that can be serially converted and recalled, and a D/A converter that converts the output of this digital memory into an analog signal, and the audio multiplexing receiving device receives the transmitted multiplexed analog signal. An A/D converter that converts the signal into a digital signal, and this A/D
An audio signal multiplexing analog device characterized in that it includes a digital memory that can store the output of a converter, convert it in parallel, and recall it, and a plurality of D/A converters that convert the output of this digital memory into an analog signal. Transmission method.