JPH04287528A - Optical space transmitter - Google Patents

Abstract

PURPOSE:To attain free arrangement of the transmitter by devising a music source to be operated at a hand of the user and sending making wireless between the transmitter and a speaker. CONSTITUTION:A digital signal extracted from a CD 3 is inputted to a digital modulation circuit 12. A reproduction output of a tape 4 is A/D-converted and modulated into a format the same as that of a CD. The circuit 12 modulates a signal in the CD format into a form suitable for optical transmission and outputs the result to a light emission section 2. Then the light emitting diode is driven to allow an infrared ray digital signal 6 to radiate in space. A light receiving section 8 of a receiver receives the signal 6 and the result is restored to an analog signal through processing via a digital demodulation signal processing circuit 18 and a D/A converter 19 and the signal is reproduced as sound from a speaker 20. On the other hand, a signal from a key entry section is fetched by a system control section 30 to control the entire transmitter and a remote control signal 14 is outputted. Thus, free layout is attained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless signal transmission for audio playback devices, and more particularly to the configuration of a signal transmitting and receiving device.

0002

2. Description of the Related Art Methods for spatially transmitting electrical signals by converting them into optical signals have been proposed in Japanese Patent Laid-Open Nos. 63-152250 and 64-68030. In this paper, an audio playback device was proposed that consisted of a sound source device and headphones. However, the use of headphones is limited as a way to listen to music, and if the sound source device is located far away, you have to go to the sound source device every time you change a disc, etc. The benefits of wireless were diminishing.

[0003] Furthermore, in systems that employ optical analog transmission of audio signals, the signals deteriorate due to spatial transmission, resulting in problems with sound quality such as increased noise.

0004

SUMMARY OF THE INVENTION The present invention provides a configuration of an optical transmitter/receiver that can effectively utilize the advantages of wireless spatial transmission as an audio playback device while employing optical digital transmission of audio signals. The aim is to enable new ways to use and enjoy audio equipment by making it wireless, while also achieving high sound quality through digital transmission.

[0005]

[Means for Solving the Problems] In the present invention, a music source and an operation unit are integrated, a signal is optically spaced digitally transmitted from there to a speaker, and a signal processing circuit, an amplifier, and a power supply are integrated on the speaker side. This allows the user of the audio device to operate it at hand, and since the connection to the speaker is wireless, it is possible to freely layout the device.

[0006]

[Operation] The playback signal of the music source CD or tape is
After being converted to the EFM format, which is the signal recording format for CDs, it is converted into a digital signal suitable for optical transmission.
The data is modulated by a code conversion means that reduces the probability of occurrence of data that causes the light emitting diode to emit light, and is emitted into space as infrared output from the light emitting diode.

On the speaker side, an infrared signal is received by a photodiode to obtain a received electrical signal, and then EFM format demodulation and digital signal processing are performed to reproduce a digital audio signal. This signal is digital/
After passing through an analog converter and being restored to a music signal, it is amplified by the speaker's built-in amplifier and drives the speaker. The signal processing circuit and amplifier power circuit inside the speaker are also built into the speaker, so the connection between the optical transmission side where the music source is located and the speaker side is completely wireless, allowing for flexible placement of equipment. It will be like that.

[0008] Furthermore, since optical transmission is carried out,
This eliminates the problems of interference and interference that often occur with conventional radio wave systems, allowing high-quality music playback.

[0009]

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

FIG. 1 is a block diagram of an optical space transmission device according to an embodiment of the present invention. Music source CD3 or tape4
The audio signal taken out by the performance device is modulated into a digital signal and input to the light emitting section 2, which drives the light emitting diode. The output of the light emitting diode becomes an optical digital signal 6 of infrared light and is emitted from the light emitting section 2 into space. In addition, operation sections such as the key input section 5 are also integrated together with the CD 3, the tape 4, and the light emitting section 2 as the optical wireless transmitter 1.

On the other hand, in the wireless receiving speaker 7 on the receiving side, a light receiving section 8 using a photodiode receives the optical digital signal 6, and a receiving circuit converts the amount of light into an electrical signal, and performs demodulation and digital signal processing. The demodulated and signal-processed digital audio signal passes through a digital/analog converter (D/A converter) to obtain an analog audio signal. This audio signal is amplified by an amplification circuit (amplifier) provided in the wireless receiving speaker 7 to drive the speaker. Further, a power supply circuit that supplies power to these circuits is also located within the wireless receiving speaker 7, and receives power through the power plug 9.

According to this embodiment, when the user of the audio device changes the music source CD 3 or tape 4 or controls the system from the key input section 5, the integrated optical Wireless transmitter 1
You will be able to operate it at your fingertips. There is no need to run a speaker cord between the optical wireless transmitter 1 and the wireless receiving speaker 7 because the transmission is by infrared rays. In addition, since all the circuits from receiving light to making the speaker sound are integrated in the wireless receiving speaker 7, the speakers can be arranged in any location.

[0013] Since the wireless transmission method modulates infrared rays with a digitized audio signal, it solves the problem of increased noise caused by signal deterioration during spatial transmission, which occurred with the conventional optical analog signal transmission method. This eliminates the problems of interference and interference that occur with conventional radio wave systems, and provides the same sound quality as a wired connection.

Although the light emitting section 2 is integrated into the optical wireless transmission device 1 in FIG. 1, almost the same effect can be obtained even if the light emitting section 2 is separated from the optical wireless transmission device 1 and connected by a wire. can be given.

Furthermore, in FIG. 1, the wireless reception speaker 7
Although the power source of the device was taken in from the outside through the power plug 9, the degree of freedom in arrangement will be further increased if a battery is built-in.

Next, the circuit operation of one embodiment of the present invention will be explained with reference to the block diagram of the optical space transmission apparatus shown in FIG.

The digital signal taken out from the CD 3 is input to the digital modulation circuit 12. Since the signal reproduced from the tape 4 is an analog signal, it is converted from analog to digital in the digital modulation circuit 12 and then modulated into the same format as a CD. Other music sources,
For example, even when tuner 10 is connected, tape 4
The process is the same as . The digital modulation circuit 12 further modulates the CD format (EFM format) signal into a type suitable for optical transmission and outputs it to the light emitting section 2. The light emitting unit 2 drives a light emitting diode to emit light into space as an infrared optical digital signal 6.

On the other hand, the signal from the key input section 5 is input to the system control section 30, which controls the entire device and also drives the remote control transmitting diode 13 to transmit the remote control signal 1.
Roll a 4.

The above circuit is integrated with the power supply circuit 11 as the optical wireless transmitter 1.

Next, on the receiving side, the optical digital signal 6 is received by the light receiving section 8, demodulated into EFM format, and a digital audio signal is obtained by the digital signal processing circuit. This signal is returned to an analog signal by a D/A converter, amplified by an audio amplifier to a level capable of driving a speaker, and finally reproduced as sound from the speaker 20.

The remote control signal 14 is transmitted to the photodiode 1
5 to the control unit 16, and controls the volume and the like.

Further, the circuit within the speaker is supplied with power from a power source 17, and the wireless reception speaker 7 is integrated in the form of a speaker with a built-in amplifier.

In the embodiment shown in FIG. 2, the light emitting section 2 and the remote control transmitting diode 13 are different diodes.
It is also possible to send the signals from one diode in a superimposed manner. In this case, the receiving side can distinguish the two signals based on the difference in modulation frequency.

Next, a signal modulation/demodulation method in one embodiment of the present invention will be explained in detail with reference to a block diagram of a digital modulation/demodulation circuit shown in FIG.

When CD3 is used as a music source, the signal is taken out by the pickup 21 and sent from the RF amplifier 22 to the EF.
An M signal 29 is obtained. Next, the EFM signal 29 is modulated in the edge signal generation circuit 23 by a code conversion means that reduces the probability of occurrence of data emitted by the diode so as to become a digital signal suitable for optical transmission. is emitted into space as an infrared optical digital signal 6.

The light receiving section 8 receives the optical digital signal 6, and
Converts light signals into electric current. The current is turned into a voltage by IV conversion 24, only the necessary band of the signal is extracted by filter 25, waveform shaped by data slice 26, and passed through EFM signal demodulation 27 to obtain the original EFM signal. This signal is converted into a digital audio signal by digital signal processing 28 and is output to the next D/A converter.

[0027]

[Effects of the Invention] As described above, according to the present invention, the user of the audio playback device can operate it at hand, and the connection with the speaker is wireless, so that the device can be freely laid out. In addition to its advantages, high-quality music playback can also be achieved through optical digital transmission.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an optical space transmission device showing an embodiment of the present invention.

FIG. 2 is a block diagram of an optical space transmission device illustrating the circuit configuration of an embodiment of the present invention.

FIG. 3 is a block diagram of a digital modulation/demodulation circuit, which explains in detail a signal modulation/demodulation method in one embodiment of the present invention.

[Explanation of symbols]

1. Optical wireless transmitter, 2... Light emitting part, 6. Optical digital signal, 7. Wireless receiving speaker, 8... Light receiving section.

Claims (1)

[Claims] 1. In an audio playback device that modulates a music signal and transmits it spatially using light, on the optical transmission side, a performance equipment section such as a music source such as a CD or a tape, and a key input section for system control are connected to the audio playback device. A connected type that can be operated by the user of the playback device,
It is characterized by adopting an operation method in which the reproduced signal of the music source is modulated into a digital signal and transmitted wirelessly using light, and on the speaker side, which is the optical receiving side, a receiving section and a receiving circuit that receive the optical signal are used. and an optical space characterized by having a receiving section structure integrated with a speaker, having a digital signal processing circuit that demodulates the signal, and also includes an amplifier circuit and a power supply circuit that amplifies the received and demodulated audio signal. Transmission device.