JPH0617408Y2 - Home bus system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a home bus system used in the field of home electronics.

(Prior Art) Recently, development of a home bus system that uses a power line in a home as a transmission line is underway.

In this home bus system, data is exchanged between a plurality of data terminal devices connected via a power line by a spread spectrum (SS) modulation / demodulation method. Each data terminal device receives various control commands from a keyboard, an infrared remote controller, a telephone line, or the like, and controls various electronic devices such as a television receiver, a video tape recorder, an audio device, and an air conditioner.

As one of the typical operation modes in this home bus system, a control command issued from an infrared remote controller to a certain terminal device is converted into an electric signal and transferred to another terminal device, and this transfer destination terminal device. Is converted into infrared rays again and emitted toward the electronic device to be controlled. For example, there is a case where a control command is issued from an infrared remote controller to a terminal device installed on the first floor to start recording on a video tape recorder installed on the second floor.

(Problems to be solved by the invention) In the home bus system currently under development, it is planned to convert the control command from the infrared remote controller into an electric signal, spread the frequency, and send it out on the power line.
However, this method has a problem that a high-speed processor is required and the system becomes expensive.

That is, a control command issued from the infrared remote controller generates a baseband signal of a predetermined format by pulse-position modulating a pulse train of several KHz according to a data code.
The subcarrier in the frequency range of KHz to 40 KHz is amplitude-modulated, and the infrared light, which is the main carrier, is amplitude-modulated by the amplitude-modulated subcarrier. Therefore, an electric signal obtained by photoelectrically converting the control command received by the infrared from the remote controller includes a high-frequency component of 40 KHz or more, and therefore a high-speed processor is required to process this and generate a packet.

(Means for Solving the Problem) In the home bus system of the present invention, the data terminal device which receives a control command issued from the infrared remote controller to another data terminal device as a transfer destination converts the control command into an electric signal. , A means for demodulating to a baseband signal and detecting a subcarrier frequency, modulating frequency information of a demodulated baseband signal and a detected subcarrier by frequency spreading, and providing a means for sending out on the power line as transfer data, Another terminal device that receives the transfer data from this power line amplitude-modulates the subcarrier of the same frequency generated based on the frequency information included in the transfer data demodulated by the inverse frequency spread with the demodulated baseband signal. It is provided with means for amplitude-modulating and outputting infrared rays.

That is, according to the home bus system of the present invention, instead of the control command including the high-frequency subcarrier, the control command returned to the baseband signal is frequency-spread and transmitted to the power line and detected by the transmitting side. By notifying the receiving side of the frequency of the specified subcarrier and reproducing and using the subcarrier of the same frequency as this, the processor does not need to process the electric signal including the high frequency subcarrier component, and the system cost is reduced. Is configured to.

Hereinafter, the operation of the present invention will be described in detail with reference to embodiments.

(Embodiment) FIG. 1 is a block diagram showing the configuration of a home bus system according to an embodiment of the present invention, in which 10 and 20 are terminal devices,
30 is a power line, 40 is an infrared remote controller, 5
Reference numeral 0 is an electronic device to be controlled.

The terminal device 10 includes an optical / electrical conversion unit 11, a demodulation unit 12, a subcarrier frequency detection unit 13, a processor 14, and an SS modem 15. The terminal device 20 includes an electric / optical conversion unit 2
1, a modulator 22, a subcarrier generator 23, a processor 24, and an SS modem 25.

A user of this system can control the operation of the remote electronic device 50 via the power line 30 and the terminal device 20 by sending a control command from the infrared remote controller 40 to the terminal device 10. The control command sent from the infrared remote controller 40 is converted into an electric signal by the optical / electrical conversion unit 11 of the terminal device 10, and demodulated by the demodulation unit 12 into a baseband signal. In parallel with the demodulation into the baseband signal, the subcarrier frequency detection unit 13 detects the frequency of the subcarrier from the photoelectrically converted electrical signal.

The processor 14 adds the frequency information of the subcarrier detected by the subcarrier frequency detection unit 13 to the end of the baseband signal received from the demodulation unit 12 and performs spread spectrum modulation to obtain data to be transferred to the terminal device 20. Deliver on power line 30.

In the terminal device 20, the transfer data appearing on the power line 30 is demodulated by the inverse modem in the SS modem,
It is transferred to the processor 24. Processor 24 is SS
The baseband signal transferred from the modem 25 is transferred to the modulation unit 22, the frequency information of the subcarrier added to the end is extracted, and the subcarrier generation unit 23 is instructed to generate the subcarrier of the same frequency. To do. The subcarrier generation unit 23 is composed of a variable frequency oscillator, generates subcarriers in the frequency range of 33 KHz to 40 KHz according to the frequency information of the subcarriers received from the processor 24, and supplies them to the modulation circuit 22.

The modulation circuit 22 modulates the subcarrier supplied from the subcarrier generation circuit 23 with the baseband signal received from the processor 24, and passes the subcarrier to the electro-optical conversion unit 21. The electric / optical conversion unit 22 amplitude-modulates the infrared light having a predetermined wavelength with the electric signal supplied from the modulation unit 22, and emits the infrared light toward the electronic device 50. In response to the infrared control signal, the electronic device 50
The one selected as the control target operates.

FIG. 2 is a block diagram showing an example of the configuration of the subcarrier frequency detection unit 13 in the terminal device 10 of FIG.
R is a shift register, CLK is a clock generation circuit, CT
Is a counter, and A1 and A2 are AND gates.

FIG. 3 is a waveform diagram for explaining the operation of the subcarrier frequency detection circuit of FIG.

Optical / electrically converted electrical signal S supplied to the input terminal IN
2.8ms ~ for the leader part arranged at the beginning of
33KHz which keeps constant amplitude for a predetermined period of 4ms
Subcarriers in the frequency range of -40 KHz appear. For the details of this signal format, refer to the materials of Infrared Remote Control Study Group of Home Appliances Association. The electric signal S including the reader portion is supplied to the shift register SR and shift-input in synchronization with the clock signal CK supplied from the clock generation circuit CLK.

One clock cycle after the electric signal S rises to high, the first output bit D0 of the shift register SR rises to high and the second output bit D1 is kept low.
Along with this, the output of the AND gate A1 rises to high, and the counter CT is reset. When two clock cycles have elapsed from the rise of the electric signal S, the shift register S
The second output bit D1 of R also rises to high, and the subsequent clock signal CK passes through the AND gate A2 and the counter CT.
Begins to be supplied to.

The counting of the clock signal by the counter CT is continued until the electric signal S falls to low. Clock signal C
The frequency of K is set to a value of about several tens of the frequency of the subcarrier to be detected. Clock frequency is 4MHz
In this case, if the subcarrier frequency is 33 KHz, the count value of the counter CT is 60, and if the subcarrier frequency is 40 KHz, the count value of the counter CT is 50. The processor 14 identifies the subcarrier frequency from the count value of the counter CT.

(Effect of the Invention) As described in detail above, the home bus system of the present invention spreads the control command, which is a control command including the high-frequency subcarrier, back to the baseband signal and spreads the frequency on the power line. In addition to sending the signal to the receiving side, the frequency of the subcarrier detected on the transmitting side is notified to the receiving side, and the subcarrier having the same frequency as this is reproduced and used.
There is no need for the processor to process an electric signal containing a high-frequency subcarrier component, and there is an effect that the cost of the system can be reduced.

[Brief description of drawings]

1 is a block diagram showing the configuration of a home bus system according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the subcarrier frequency detection circuit of FIG. 1, and FIG. 3 is of FIG. It is a waveform diagram for explaining the operation of the circuit. 10, 20 ... Terminal device, 11 ... Optical / electrical conversion unit, 12
...... Demodulator, 13 ...... Subcarrier frequency detector, 14
... processor, 15 ... SS modem, 21 ... electric / optical conversion unit, 22 ... modulation unit, 23 ... subcarrier generation unit, 24 ... processor, 25 ... SS modem, 30 ...
… Power line, 40… Infrared remote controller, 50
...... Controlled electronic device.

Claims (1)

[Scope of utility model registration request] 1. A home bus system in which a plurality of data terminal devices are connected via an indoor power line, wherein the data terminal device receives a control command issued from an infrared remote controller to another data terminal device as a transfer destination. , Converts this control command to an electrical signal, demodulates it to a baseband signal and detects the subcarrier frequency, modulates the demodulated baseband signal and the detected subcarrier frequency information by frequency spreading, and transfers the data. As a result, the other terminal device that receives the transfer data from this power line demodulates the subcarrier of the same frequency generated based on the frequency information included in the transfer data demodulated by the inverse frequency spread. Equipped with a means to amplitude-modulate the already-generated baseband signal and then amplitude-modulate the infrared rays Home bus system, wherein the door.