JPH02292920A - Optical transmission type four-channel stereo system - Google Patents

Abstract

PURPOSE:To reduce the crosstalk and to improve the reliability by connecting optical transmission lines between a sound source and four speakers and multiplexing four channel audio signals in time division with respect to optical signals propagated on respective optical transmission lines. CONSTITUTION:Four A/D converting parts 12a to 12d independent of one another convert audio signals which are inputted from signal input terminals 11a to 11d to digital signals. A time division multiplexing part 13 multiplexes signals outputted from converting parts 12a to 12d in time division by four-fold sampling frequencies of respective channels, and these signals are converted to optical signals by electrooptical converting parts 14a to 14d and are radiated to the air. These optical signals are converted to multiplexed audio signals by optical/electric signal converting parts 15a to 15d and are separated to signals of four channels by demultiplexing parts 16a to 16d. These signals are converted to analog signals by D/A converting parts 17a to 17d and are supplied to speakers 19a to 19d through amplifying parts 18a to 18d and are louded and outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a four-channel
It relates to a stereo system, especially an optical transmission type 4-channel optical transmission system that connects the sound source and speakers with an optical transmission line.
It concerns stereo systems.

(Prior Art) One of the ways to create a sound field in a 4-channel stereo system is a surround type. In this surround type, four speakers that output audio signals of each channel are placed at the front, rear, left and right sides of the listener.

Conventionally, in order to transmit the audio signals of each channel from the sound source side to the speakers placed on the left, right, front, and rear of the listener, each of the four channels of analog audio signals was amplified, and four electrical signal lines were used to reach each speaker. It is transmitting.

(Problems to be Solved by the Invention) The conventional four-channel stereo system described above uses four electrical signal lines to transmit the audio signal of each channel to the corresponding speaker.

For this reason, there are drawbacks in that it takes time and effort to connect the devices and the reliability of the connection is impaired.

(Means for Solving the Problems) The optical transmission type 4-channel stereo system of the present invention has four
4 systems of A/D converters that convert each of the electrical signals of the channels from analog to digital; a time division multiplexer that time division multiplexes the digital signals output from these A/D converters; Four electrical/optical converters that convert the multiplexed electrical signals output from the multiplexer into multiplexed optical signals and output them, and receive the multiplexed optical signals output from each of these electrical/optical converters. 4 systems of optical/electrical converters that convert into multiplexed electrical signals and output them, and these optical/electrical converters.
Four time-division multiplexing/demultiplexing units that separate and output the digital signals of each channel from the multiplexed electrical signals output from each of the electrical conversion units, and each channel output from the time-division multiplexing/demultiplexing units of each of these systems. 4 systems of D/A converters that convert digital signals into analog signals, and these D/A converters.
It is equipped with four systems of amplifiers that amplify the analog output of the /A converter and four systems of speakers that amplify the output of these amplifiers, and an electric signal line that connects the sound source side and the four speakers. It is configured so that it is not necessary.

Hereinafter, the operation of the present invention will be explained in detail together with examples.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an optical transmission 4-channel stereo system according to an embodiment of the present invention, where lla to lid are signal input terminals for each audio channel, and 12a to 12d are An A/D conversion unit for each audio channel, 13 is a time division multiplexing unit, and 142 to 14d are electrical/optical conversion units for each audio channel. Furthermore, 15a
-15d are optical/electrical converters, 16a-16d are demultiplexers, 17a-17d are D/A converters, 18a-18d are amplifiers, and 19a-19d are subakers.

The four independent A/D converters 128 to 12d convert the audio electrical signals of each channel input from the corresponding signal input terminals 11a to lid into digital audio signals of each channel. The time division multiplexer 13 time division multiplexes the digital audio signals output from the four independent A/D converters 12a to 12d at a sampling frequency that is four times the sampling frequency of each channel.

The time-division multiplexed four-channel audio signals output from the time-division multiplexer 13 are converted into optical signals by electrical/optical converters 14a to 14d installed corresponding to each channel, and then It is radiated to The optical signals radiated into the air are converted into multiplexed audio electrical signals by optical/electrical signal converters 158 to 15d installed corresponding to each channel. The audio signals of each channel included in these multiplexed audio electrical signals are separated into different channels by demultiplexing units 162 to 16d.
By extracting only the channel, it is separated into four channels of electrical signals. The digital audio signals separated into each channel are converted into analog audio signals in D/A converters 17a to 17d, and then converted to analog audio signals in amplifiers 18a to 18d.
After being amplified, the signal is supplied to speakers 19a to 19d and output as amplified sound.

The optical propagation paths formed between the electrical/optical converters 14a to 14d and the corresponding optical/electrical converters 15a to 15d are as shown in FIG.

(Effects of the Invention) As explained in detail above, the optical transmission type 4-channel stereo system of the present invention has a configuration in which the sound source side and the four speakers are connected by optical transmission lines, so that the electrical signal Unlike conventional systems that connect using wires, this system eliminates the need to connect electrical signal lines and improves the reliability of the connection.

In addition, since the optical signal propagating through each optical transmission path is in the form of time division multiplexed audio signals for four channels, the audio signals for each channel are converted into optical signals for each channel and propagated independently. This has the advantage that crosstalk between channels caused by reflections along the propagation path can be reduced compared to the conventional case.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an optical transmission two-four channel stereo system according to an embodiment of the present invention, and FIG. 2 shows the electrical/optical converters 14a to 14d and the optical/electrical converter 15a of FIG. 1. 15d is a plan view showing an example of an optical transmission line formed between 11a to lid...input terminals for audio signals of each channel, 12a to 12b...A/
D conversion section, 13... time division multiplexing section, 14a to 14d
...Electrical/optical converter, isa-15d... Optical/electrical converter, 16a-16b... Demultiplexer, 17a ~
17d...-D/A conversion section, 18a-18d... amplification section, 19a-19d... speaker.

Claims (1)

[Claims] Four systems of A/D converters that convert each of the four channels of electrical signals from analog to digital, and a time division multiplexer that time division multiplexes the digital signals output from these A/D converters. four systems of electrical/optical converters that convert the multiplexed electrical signals output from the time division multiplexer into multiplexed optical signals and output the multiplexed optical signals; Four systems of optical/electrical converters receive multiplexed optical signals, convert them into multiplexed electrical signals, and output them, and digital signals for each channel are generated from the multiplexed electrical signals output from each of these optical/electrical converters. four systems of time division multiplex demultiplexers that separate and output the signals; and four systems of D/A converters that convert the digital signals of each channel output from the time division multiplex demultiplexers of these respective systems into analog signals; An optical transmission type 4-channel stereo system characterized by having four systems of amplifiers that amplify the analog outputs of these D/A converters, and four systems of speakers that amplify the outputs of these amplifiers.