JPS61238131A - Repeater for power line carrier communication system - Google Patents

Abstract

PURPOSE:To transmit a signal for a long range without violating the regulations by providing a high band stop filter between lines, connecting two pairs of signal frequency amplifier circuits between two lines in two-way and using a signal subject to waveform shaping based on an output signal of a signal demodulation circuit so as to control the amplification factor of other signal amplifier circuit. CONSTITUTION:When a signal being the superimposition between a commercial frequency AC component and a high frequency signal comes to a commercial power line A which is sectioned by a carrier block filter 1 blocking a high frequency signal only, a carrier high frequency signal B passing the high frequency signal component only by a carrier high frequency signal pass filter 2 is obtained. The signal B is detected by a signal demodulation circuit 3 in response to the envelope of signal and further a gate signal D subject to waveform shaping is obtained. The carrier high frequency signal B becomes a delayed carrier high frequency signal C delayed by a time (t) at a signal delay circuit 4, amplified by a signal amplifier 5 to obtain a high frequency signal with a sufficient amplitude. Then the signal E is outputted to another commercial power line F sectioned by a high frequency transfer 6 and the filter 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a repeater for a bidirectional carrier wave superimposition communication system using an indoor commercial power line as a transmission path.

Conventional technology Conventionally, communication systems using commercial power lines as transmission paths have used a frequency sufficiently higher than the commercial high frequency as a carrier to facilitate the separation of commercial frequency components and signal components. It is modulated and transmitted.

Problems that the invention aims to solve When superimposing high-frequency signals on commercial power lines, there are legal regulations such as the Radio Act and electrical equipment technical standards, and there are restrictions on the frequency and signal strength of high-frequency signals that can be superimposed. . The impedance of a commercial power line as a transmission path changes depending on the connected home appliances, and the signal level also changes. Therefore, for low-impedance devices with limited transmission path lengths, it was necessary to insert an impedance upper between the devices and lines to increase the impedance and prevent the signal quality from deteriorating due to low-impedance devices. .

The present invention aims to solve the above-mentioned problems and enable long-distance signal transmission without violating legal regulations.

Means for Solving the Problems In order to solve the above problems, the repeater of the present invention provides a high frequency blocking filter between the electric lines of the power line carrier communication system, and bidirectional communication between the two electric lines with two pairs of signal frequency amplification circuits. The amplification degree of the other signal amplification circuits is controlled by a signal whose waveform is shaped based on the output signal of the signal demodulation circuit.

Operation With the above configuration, the signal attenuated by the repeater is amplified and output, thereby avoiding failure of transmission due to signal attenuation.

EXAMPLE Hereinafter, an example of the present invention will be explained using FIGS. 1 and 2. FIG. 1 is a block diagram of a repeater according to the present invention, and FIG. 2 is a signal waveform of the first coupling section.

If there is a signal in which a commercial frequency AC component and a high frequency signal are superimposed on one commercial power line A that is separated by a carrier wave rejection filter 1 that blocks only high frequency signals, the carrier high frequency signal pass filter 2 filters out only the high frequency signal component. A passed carrier high frequency signal B is obtained. The signal B is detected by the signal demodulation circuit 3 according to the envelope of the signal, and a gate signal whose waveform has been further shaped is obtained. The carrier high-frequency signal B becomes a delayed carrier high-frequency signal C which is delayed by the distance between the electric lines by the signal delay circuit 4, and is amplified by the signal amplification circuit 5.
A high frequency signal E with sufficient amplitude is obtained. Then, the signal E is outputted by the high frequency transformer 6 to the other commercial power line F separated by the filter 1.

Carrier wave high frequency signal passing filter 7, signal demodulation circuit 8, signal delay circuit 9. Signal amplification circuit 10. High frequency transformer 11
operates in the same way as each section 2 to 6 described above in the direction from commercial power line F to A.

By operating the signal frequency amplification circuit 13, the high frequency signal on the commercial power line A side is sufficiently amplified and output to the F side. On the other hand, if the signal frequency amplifying circuit 14 is operating at the same time, the circuit system will oscillate unless the output of the circuit 13 is amplified and then returned to the input of the circuit 13. Therefore, the signal obtained by the signal demodulation circuit 3 is used to stop the operation of the signal amplification circuit 1o of the circuit 14, thereby preventing oscillation due to the positive feedback loop.

A-F in Figure 2 corresponds to A and F in Figure 1, and B
, C, D, t is the signal delay caused by the signal delay circuit 4, t
2 is a signal delay caused by the signal demodulation circuit 3. Circuit 14 also operates in a similar manner. FIG. 3 shows signal waveforms at each part of the circuit 14. The basic operation is the same as circuit 13. Here, t3 is the signal delay caused by the signal delay circuit 9, and t4 is the signal delay caused by the signal demodulation circuit 8. 0 In other words, the signal amplification circuit 1o on the circuit 14 side operates only in the section where the high frequency signal is superimposed on the commercial power line on the A side. By stopping the operation of the signal amplifying circuit 6 on the circuit 13 side only in the section where the high frequency signal is superimposed on the commercial power line on the F side, it is possible to relay bidirectional communication between AFs. Signal attenuation due to extending the transmission distance by inserting the repeater according to the present invention into the transmission communication path.

The effect of signal attenuation due to low impedance loads can be extremely minimized.If a repeater is installed on a transmission line of a constant length, communication will be impossible due to an increase in the length of the transmission line, and communication will not be possible due to the connection of low impedance equipment. can be avoided, and the effect is great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a power line carrier communication system according to an embodiment of the present invention, and FIGS. 2 and 3 are signal waveform diagrams of each part of FIG. 1. 2,7...
・Carrier high frequency signal passing filter, 3, 8... Signal demodulation circuit, 4.9... Signal delay circuit, 6, 1
o... Signal amplification circuit, 6, 11... High frequency transformer, 13.14... Signal frequency amplification circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3

Claims (1)

[Claims] This is a carrier communication system that performs two-way communication by superimposing high-frequency signals on a commercial power line.The commercial power line is interrupted, a high-frequency blocking filter is inserted between the interrupted lines to trap only the high-frequency signal components, and a high-frequency blocking filter is inserted between the two lines. Carrier high frequency signal passing filter that passes only the carrier high frequency signal Two pairs of signal frequency amplification circuits consisting of a signal demodulation circuit, a signal delay circuit, a signal amplification circuit, and a high frequency transformer are bidirectionally connected, and the output signal of the signal demodulation circuit is A repeater for a power line carrier communication system, which controls the amplification degree of other signal amplification circuits using a signal whose waveform is shaped based on .