JP2014045401A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent erroneous synchronization at each repeater at the time of start in a communication system in which data is transmitted between devices via a plurality of repeaters.SOLUTION: At the time of start before all repeaters 40 get synchronized, all switch parts 63 of a communication path switching unit 60 connect upstream side communication paths 30 and transmission/reception switching units 41 of the repeaters 40, and a switch part 63 connected with an upstream side master unit 10 or a repeater which received a synchronization signal from a repeater 40 and completed synchronization connects a downstream side communication path 30 and the transmission/reception switching unit 41 of the repeater 40. Regarding the synchronization signal, synchronization signals with different patterns are used at adjacent relay sections.

Description

  The present invention relates to a communication system in which devices are connected to each other via a plurality of repeaters via a wired communication line, and more particularly to a communication system using time division relay transmission.

A conventional communication system using time-division relay transmission connects a plurality of repeaters to a single-wire communication line (twisted pair wire consisting of two core wires as an example), and connects an upstream master unit (or downstream slave unit). Data transmission to the child device (or parent device) in order from the adjacent device via the adjacent relay device.
The repeater is used as a means for signal amplification when there is a device to be transmitted at a position beyond the signal reachable range, or when the signal arrives but the speed is not obtained due to insufficient strength.
In this case, all the repeaters are not operated at the same time, but are operated by time division in order from the upstream (or downstream) repeaters.

  That is, in the range where the signals of the two repeaters constituting one relay section reach, at the same time, only two repeaters in one section operate as repeaters and transmit to the adjacent repeater. By transmitting the signal to the adjacent repeater at the next time, signals are transmitted far away while preventing mutual signal interference.

In such a conventional communication system using time division relay transmission, since a communication signal from one modem reaches all wirings of the communication line, only one modem can transmit the communication signal at the same time. Only one section can be operated in a plurality of relay sections at the same time.
For this reason, as the number of repeaters increases, there is a problem that the time during which communication is not performed on the communication line increases and the effective speed of communication decreases.

As a communication system in which signals are not transmitted simultaneously between zones that spatially interfere with each other, it is known that a signal is transmitted by time division of different time slots in one zone and a plurality of zones. (See Patent Document 1).
Also, in the case where each wireless node relays a packet to each other and transmits a signal from the start node to the end node, in order to prevent radio wave interference between the wireless nodes and keep the throughput constant regardless of the number of relay stages, The node intermittently transmits a packet at a transmission cycle corresponding to the frequency reuse interval, receives the packet at each relay node, and relays the packet to the next relay node after a transmission standby time corresponding to the frequency reuse interval. A transmission is known (see Patent Document 2).

Patent Document 1 relates to communication between a plurality of base stations and a passing train in mobile radio, and Patent Document 2 relates to a wireless multi-hop network, both of which are wireless communication systems.
As described above, in the radio, a communication system in which interference occurs at least in an adjacent section has been proposed as various methods for preventing interference.
However, in the case of wired communication, interference often occurs when a signal leaks from a communication line, or when signals are congested and transmitted and overlapped with each other, and therefore, there are few measures taken for signal interference. It is.

Therefore, the same inventor as this application, in the invention of Japanese Patent Application No. 2011-96065, makes communication efficiency (speed) without causing signal interference by physically or electrically separating the communication lines in units of relay sections. A communication system that can be improved is proposed.
FIG. 12 is a schematic configuration diagram of the communication system, and FIG. 13 is an explanation of operation along the time of the communication system.

  FIGS. 12 (a) and 12 (b) show a state that is shifted by one period in time, and the configuration is the same. In FIG. 12, the modem of the master unit 10 and the modem of the slave unit 20 are connected in series by a plurality of physically wired communication lines 30a to 30d (subscripts are omitted in general terms). Connected to the communication line 30 between the slave units 20 are modems of a plurality of relay units 40a to 40c (in the figure, three units, subscripts omitted when collectively referred to). In addition, communication path switching units 60a to 60c are provided at connection portions between the relay devices 40a to 40c and the communication lines 30a to 30d via terminal blocks 50a to 50c. Here, the direction in which the parent device 10 is arranged is upstream, and the direction in which the child device 20 is arranged is downstream.

  Each of the communication path switching units 60a to 60c (subscripts are omitted when collectively referred to) are connected to two input / output connection points 61 and 62 and a transmission / reception switching unit which is a signal input / output unit of the repeaters 40a to 40c. A switch unit 63 that performs an operation of being alternately connected to the two input / output connection points 61 and 62 is provided. The input / output connection point 61 is connected to the upstream communication path of the communication line 30 with respect to the repeater 40, and the input / output connection point 62 is connected to the downstream side of the communication line 30 with respect to the relay machine 40.

With such a configuration, the operation state of the relay device 40 between the parent device 10 and the child device 20 will be described based on FIG. 13 along the time t axis.
As shown in FIG. 13, in period 1 (FIG. 12A), the switch unit 63 of the relay unit 40a falls to the upstream communication path (base unit 10 side), and the relay unit of the adjacent downstream communication path When the switch unit 63 of 40b falls to the downstream communication path (relay machine 40c side), the master unit 10 and the repeater 40a are connected via the communication line 30a, and communication between both is possible, and the repeater 40b side It is separated from the communication line 30b. Therefore, even if the repeater 40 including the repeater 40b in the period 1 communicates, it does not interfere with the signal in the section of the master unit 10-relay 40a.

  That is, in the relay section 3 shifted by one from the relay section 1 between the master unit 10 and the relay machine 40a, the switch unit 63 of the relay machine 40b falls to the downstream communication path (relay machine 40c side) and the downstream communication path The switch unit 63 of the relay unit 40c falls to the upstream communication path (the side of the relay unit 40b), so that the relay unit 40b and the relay unit 40c are connected via the communication line 30c and communication between the two is possible. Thus, the relay section 1 and the relay section 3 can communicate simultaneously without causing signal interference.

  In cycle 2 (Fig. 12 (b)) following cycle 1, switch unit 63 of relay device 40a falls to the downstream communication path (relay device 40b side), and at the same time, switch unit 63 of relay device 40b is connected to the upstream communication channel ( By falling to the side of the repeater 40a, the repeater 40a and the repeater 40b are connected via the communication line 30b, and communication between them is possible, and the communication line 30c on the repeater 40c side is separated. Therefore, even if the further relay 40 including the relay 40c communicates in the same time zone, it does not interfere with the signal in the section between the relay 40a and the relay 40b.

That is, in the relay section 4 shifted by one from the relay section 2 of the repeater 40a and the repeater 40b, the switch unit 63 of the repeater 40c falls down to the downstream communication path (slave unit 20 side), so that the repeater 40c The handset 20 is connected via the communication line 30d, and communication between both becomes possible. In this way, the relay section 2 and the relay section 4 can communicate simultaneously without causing signal interference.
As described above, in the cycle 1, the relay section 1 between the parent device 10 and the relay machine 40a and the relay section 3 between the relay machine 40b and the relay machine 40c can communicate, and the relay between the relay machine 40a and the relay machine 40b. In section 2, the relay section 4 between the relay device 40c and the child device 20 cannot communicate.
Next, in the cycle 2, the relay section 2 between the relay device 40a and the relay device 40b and the relay section 4 between the relay device 40c and the slave device 20 are communicable, and between the parent device 10 and the relay device 40a. Relay section 1 and relay section 3 between relay machine 40b and relay machine 40c cannot communicate.

  When the communication path switching unit 60 connected to all the repeaters 40 performs the above operation in synchronization, the transmission signal reachable range of the repeater 40 is limited to upstream or downstream adjacent repeaters, causing signal interference. Since one skipped relay section can be communicated simultaneously in the same period, communication efficiency (speed) compared to conventional time-division relay transmission, which was able to communicate in only one section in the signal control range even if there were multiple relay sections. Can be improved.

In the above configuration, an operation description at the time of activation for synchronizing all the communication path switching units 60 will be described based on FIG.
First, at the start-up before synchronization of the communication system, as shown in FIG. 14A, all the switch units 63 of the communication path switching units 60 a to 60 c connected to each relay device 40 are upstream of the communication line 30. It falls to the input / output connection point 61 side connected to the side communication line.
When a synchronization signal is transmitted from the parent device 10 in this state, the synchronization signal is received by the first repeater 40a via the communication line 30a and the communication path switching unit 60a. The repeater 40a obtains timing information from the synchronization signal detected by the internal synchronization / carrier detection unit, and the repeater 40a is synchronized with the master unit 10.

Next, after the relay unit 40a completes synchronization with the base unit 10, the switch unit 63 of the communication path switching unit 60a of the relay unit 40a alternately switches to the input / output connection points 61 and 62 at a constant period according to the synchronized timing. To start.
The repeater 40a transmits a synchronization signal during a period when the switch 40a and the repeater 40b are connected via the communication line 30b when the switch of the switch unit 63 falls to the input / output connection point 62 side. Receives the synchronization signal. The repeater 40b obtains timing information from the synchronization signal detected by the internal synchronization / carrier detection unit, and the repeater 40b is synchronized with the repeater 40a. Hereinafter, similarly, the repeater 40c is sequentially synchronized with the repeater 40b.

In this way, all the repeaters 40 are synchronized with the nearest upstream repeater 40. In this state, the switch units 63 of the communication path switching units 60 of all the repeaters 40 are synchronized with each other. Switching operation is performed alternately at a constant cycle. The period of this fixed period is N times the period of the synchronization signal (N is an integer of 1 or more).
As described above, the switching operation of the switch unit 63 after all the relay units 40 are synchronized is performed by the switch unit 63 connected to the predetermined relay unit 40n as the input / output connection point 61 of the upstream communication path. Is connected to the input / output connection point 62 of the downstream communication path, the switch unit 63 connected to the adjacent repeater 40n + 1 on the downstream side of the repeater 40n. Conversely, when the switch unit 63 connected to the predetermined repeater 40n is connected to the input / output connection point 62 of the downstream communication path, it is connected to the adjacent repeater 40n + 1 on the downstream side of the repeater 40n. The switch unit 63 is connected to the input / output connection point 61 of the upstream communication path.

However, even in the above configuration, depending on the wiring configuration and the circuit configuration of the switch of the communication path switching unit 60, the synchronization signal may leak to the adjacent relay section, and erroneous synchronization may occur at startup.
Hereinafter, this problem will be described with reference to FIGS. FIGS. 14B and 14C show a state in which a synchronization signal leaks to an adjacent relay section at the time of activation and erroneous synchronization occurs.

  FIG. 14B shows a case where two core wires connecting the communication lines 30a and 30b and the input / output connection points 61 and 62 of the communication path switching unit 60a are accommodated in the same cable assembly 70 and arranged close to each other. A synchronization signal from the master unit 10 to the relay unit 40a leaks from the upstream communication path to the downstream communication path as indicated by a dotted arrow, and the leaked synchronization signal passes to the relay unit 40b via the communication line 30b in the relay section 2. This causes a problem of mis-synchronization in which the relay device 40b is connected in synchronization with the parent device 10 instead of the relay device 40a.

Further, as shown in FIG. 14C, the synchronization signal from the master unit 10 to the repeater 40a is generated in the switch unit 63 due to insufficient signal separation in the circuit elements in the switch unit 63 of the communication path switching unit 60a. As shown by the dotted line arrow due to the sneak due to the limit of the signal separation degree, it leaks to the communication line 30b side of the relay section 2, and this leaked synchronization signal flows into the repeater 40b via the communication line 30b of the relay section 2, There arises a problem of erroneous synchronization in which the repeater 40b is connected in synchronization with the master unit 10 instead of the repeater 40a.
In this way, the relay unit 40b synchronizes the leaked weak synchronization signal from the base unit 10 with the assumption that it is a synchronization signal from the relay unit 40a, and as a result, the switch unit 63 of the communication path switching unit 60b of the relay unit 40b. Becomes the same switch operation as the switch unit 63 of the channel switching unit 60a of the repeater 40a, and there arises a problem that data transmission is impossible even if synchronization is possible.

JP-A-10-117375 JP 2005-143046 A

In the above-described prior invention, as described with reference to FIGS. 12 and 13, the communication line is physically or electrically independent for each relay section, and the communication path switching unit 60 is provided at the connection point between the repeater 40 and the communication line 30. By switching between upstream and downstream communication paths, even if there are multiple relay sections, one skipped relay section can simultaneously communicate during the same period, improving communication efficiency (speed) without causing interference. Can be made.
However, as described with reference to FIG. 14, depending on the wiring configuration and the circuit configuration of the switch unit of the communication path switching unit 60, there is a problem in that the synchronization signal leaks to the adjacent relay section and erroneous synchronization occurs at startup. .

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a communication system in which erroneous synchronization is eliminated even when a synchronization signal leaks to an adjacent relay section. Is.

A communication system according to the present invention is a communication system in which a master unit and a slave unit are connected by a communication line via a plurality of relay units to transmit and receive data, and the connection point between the relay unit and the communication line In addition, two input / output connection points respectively connected to the upstream communication path and the downstream communication path of the communication line, and a switch for performing an operation of alternately connecting the two input / output connection points to the transmission / reception switching unit of the repeater A switching part of the communication path switching unit is synchronized with all the repeaters, and the switch part connected to the predetermined repeater n is an input / output connection point of the upstream communication path In the communication system in which the switch unit connected to the adjacent repeater n + 1 on the downstream side of the repeater n is connected to the input / output connection point of the downstream communication path,
At start-up before all repeaters are synchronized, all switch units of the communication path switching unit connect the upstream communication path and the transmission / reception switching unit of the repeater, and from the upstream master unit or repeater The switch unit connected to the repeater that has received the synchronization signal and has completed synchronization connects the downstream communication path and the transmission / reception switching unit of the repeater, and the synchronization signal has a different pattern in the adjacent relay section. Is to be used.

The communication system of the present invention is a communication system in which a master unit and a slave unit are connected by a communication line via a plurality of relay units to transmit / receive data, and the relay unit and the communication line are connected to each other. Two input / output connection points respectively connected to the upstream communication path and the downstream communication path of the communication line at the connection point, and an operation of alternately connecting these two input / output connection points to the transmission / reception switching unit of the repeater A communication path switching section having a switch section to perform is provided, the switching timing of the switch section of the communication path switching section is synchronized with all the repeaters, and the switch section connected to the predetermined repeater n is the input / output of the upstream communication path When connected to the connection point, in the communication system in which the switch unit connected to the adjacent repeater n + 1 on the downstream side of the repeater n is connected to the input / output connection point of the downstream communication path,
At start-up before all repeaters are synchronized, all switch units of the communication path switching unit connect the upstream communication path and the transmission / reception switching unit of the repeater, and from the upstream master unit or repeater The switch unit connected to the repeater that has received the synchronization signal and completed synchronization connects the downstream communication path and the transmission / reception switching unit of the repeater, and the repeater receives the power value of the received synchronization signal pattern. It is designed not to synchronize with the signal of the reception synchronization signal pattern that is lower than the predetermined power threshold.

The communication system of the present invention is a communication system in which a master unit and a slave unit are connected by a communication line via a plurality of relay units to transmit / receive data, and the relay unit and the communication line are connected to each other. Two input / output connection points respectively connected to the upstream communication path and the downstream communication path of the communication line at the connection point, and an operation of alternately connecting these two input / output connection points to the transmission / reception switching unit of the repeater A communication path switching section having a switch section to perform is provided, the switching timing of the switch section of the communication path switching section is synchronized with all the repeaters, and the switch section connected to the predetermined repeater n is the input / output of the upstream communication path When connected to the connection point, in the communication system in which the switch unit connected to the adjacent repeater n + 1 on the downstream side of the repeater n is connected to the input / output connection point of the downstream communication path,
At start-up before all repeaters are synchronized, all switch units of the communication path switching unit connect the upstream communication path and the transmission / reception switching unit of the repeater, and from the upstream master unit or repeater The switch unit connected to the repeater that has received the synchronization signal and completed synchronization connects the downstream communication path and the transmission / reception switching unit of the repeater, and the repeater receives for receiving a plurality of synchronization signals. A period is provided, and the synchronization operation is performed only on the synchronization signal having the maximum power among the synchronization signals received within the reception period.

In this invention, the switch part of the communication path switching unit connected to all the repeaters performs the operation of switching between the upstream communication path and the downstream communication path of the communication line synchronously, so that the transmission signal reach of the repeater is reduced. It is limited to upstream or downstream adjacent repeaters, and one skipped relay section can be simultaneously communicated in the same period without causing interference, so even if there are multiple relay sections, only one section can be communicated within the signal control range. Compared to the conventional time division relay transmission, the communication efficiency (speed) can be improved.
Further, at the time of start-up before all the repeaters are synchronized, the synchronization signal uses a different pattern of synchronization signals in the adjacent relay section, so that the occurrence of false synchronization is reduced. In addition, since the repeater has a reception period for receiving a plurality of synchronization signals, and the synchronization operation is performed only on the synchronization signal having the maximum power among the synchronization signals received within the reception period, the occurrence of erroneous synchronization may occur. Less.

It is a functional lineblock diagram in a connecting part of a communication line of a communication system in Embodiment 1 of this invention, a repeater, and a repeater. It is the figure which showed an example of the structure of the communication path switching part used in Embodiment 1 of this invention. It is the figure which showed the example of a setting of the synchronizing signal pattern in Embodiment 1 of this invention. It is the figure which showed the classification of the synchronizing signal pattern in Embodiment 1 of this invention. It is a function block diagram in the connection part of a communication system of Embodiment 2 of this invention, the connection part of a relay machine, and a relay machine. It is a function block diagram in the connection part of the communication line of the communication system in Embodiment 3 of this invention, and the connection part of a relay machine, and a relay machine. It is operation | movement explanatory drawing of the communication system in Embodiment 3 of this invention. It is a schematic block diagram of the communication system in Embodiment 4 of this invention, and a block diagram of the low-pass filter used for it. It is a figure which shows the frequency characteristic of the filter used in Embodiment 4 of this invention. It is a block diagram of the ferrite core used in Embodiment 5 of this invention. It is a schematic block diagram of the communication system in Embodiment 6 of this invention. It is a schematic block diagram of the communication system of prior invention. It is operation | movement explanatory drawing along the time of the communication system of prior invention. It is the figure which showed the state which the synchronization signal at the time of starting leaks in prior invention.

Embodiment 1 FIG.
A communication system according to Embodiment 1 of the present invention will be described below with reference to FIGS.
The schematic configuration diagram of the communication system has the same configuration as that described in FIG. 12, and FIG. 1 shows a functional configuration diagram of the connection portion of the communication line 30 and the repeater 40 and the repeater. 2 is a configuration diagram showing an example of the communication path switching unit 60, FIG. 3 is a diagram showing an example of setting a synchronization signal pattern, and FIG. 4 is a diagram showing types of the synchronization signal pattern.

  In FIG. 1, a terminal block 50, communication path coupling units 70 a and 70 b, and a communication path switching unit 60 are connected between the communication line 30 and the repeater 40. The communication path coupling unit 70a connects the communication line connected to the terminal block 50 and the upstream communication path connected to the input / output connection point 61 of the communication path switching unit 60. It is composed of circuits such as transformers and capacitors for the purpose. Similarly, the communication path coupling unit 70b connects the communication line connected to the terminal block 50 and the downstream communication path connected to the input / output connection point 62 of the communication path switching unit 60. It is composed of circuits such as transformers and capacitors for the purpose of insulation.

The communication path switching unit 60 performs an operation of alternately connecting the two input / output connection points 61 and 62 and the two input / output connection points 61 and 62 to the transmission / reception switching unit 41 of the repeater 40 as described with reference to FIG. The switch unit 63 is configured.
Although the communication path switching unit 60 is represented by a logical function as a three-terminal switch in FIG. 12, it is actually configured by an electronic circuit having a switching function, which is configured on a substrate with elements such as transistors or FETs and resistors. Has been. Therefore, the communication path switching unit 60, for example, as shown in FIG. 2, the input / output connection point 61 connected to the upstream communication path of the communication line 30 and the input / output connected to the downstream communication path of the communication line 30. The connection point 62 and the two input / output connection points 61 and 62 may be configured by switch units 63a and 63b that perform an operation of alternately connecting to the transmission / reception switching unit 41 of the repeater 40.
The communication path coupling units 70a and 70b and the communication path switching unit 60 are described as being configured outside the repeater 40 in FIG. 1, but the communication path coupling units 70a and 70b and the communication path switching unit 60 are Alternatively, it may be configured so as to be taken into the repeater 40.

The repeater 40 includes a transmission / reception switching unit 41, a receiving unit 42, a transmitting unit 43, a synchronization / carrier detection and timing generation unit 44, and a data holding / control unit connected to the switch unit 63 of the communication path switching unit 60. 45, a transmission synchronization signal pattern selection unit 46T and a reception synchronization signal pattern selection unit 46R, a transmission synchronization signal pattern holding unit 47T, and a reception synchronization signal pattern holding unit 47R.
The transmission synchronization signal pattern holding unit 47T and the reception synchronization signal pattern holding unit 47R hold a plurality of different synchronization patterns in advance or are inputted and held from the outside. The reception synchronization signal pattern selection unit 46R selects one to be used from the plurality of synchronization patterns.
In the same one repeater 40, different patterns are selected for the transmission synchronization signal pattern and the reception synchronization signal pattern as will be described later.

The transmission / reception switching unit 41 has a function of switching between a reception signal received by the reception unit 42 and a transmission signal transmitted from the transmission unit 43.
The reception unit 42 includes a reception filter unit 421 that passes only a predetermined frequency band from the reception signal received by the transmission / reception switching unit 41, a reception signal gain adjustment unit 422 that adjusts the gain of the reception signal, and an AD that converts an analog signal into a digital signal. Converter 423 corrects the synchronization of the entire received signal (the received signal includes a frequency deviation between the transmitting modem and the receiving modem, but corrects the deviation), to perform time / frequency conversion of the received signal Fast Fourier transform (FFT) unit 425, a map for converting the map data on the coordinate axes after being converted by the fast Fourier transform (FFT) unit 425 to a binary signal of “0” and “1” → data conversion unit 426, The frame decomposition unit 427 is configured to decompose a binary signal having a defined frame structure and extract desired information.

  The transmission unit 43 includes a frame assembly unit 431, data for converting frame data into map data → map conversion unit 432, an inverse Fourier transform (IFFT) unit 433 for frequency / time conversion of signals, and a transmission synchronization signal pattern selection unit 46T. A synchronization correction unit / synchronization generation unit 434 that includes a synchronization signal generation unit that generates a synchronization signal to be transmitted based on the signal of the transmission synchronization signal pattern selected in step 1 and a synchronization signal correction unit that adjusts the timing of the synchronization signal. A DA conversion unit 435 that converts a signal into an analog signal and a transmission signal gain adjustment unit 436 that adjusts the gain of the transmission signal are included.

  The synchronization / carrier detection and timing generation unit 44 detects a frequency deviation between the transmission modem and the reception modem from the information output from the fast Fourier transform (FFT) unit 425, and detects a carrier signal, FFT timing information, and the like. A synchronization signal pattern detection unit 442 that detects a pattern of a synchronization signal received from information output from the detection unit 441, a fast Fourier transform (FFT) unit 425, and a reception synchronization signal pattern detected by the synchronization signal pattern detection unit 442; Timing for generating various timing signals based on information from the synchronization signal pattern comparison unit 443, the carrier detection unit 441, and the synchronization signal pattern comparison unit 443 that compare the reception synchronization signal patterns selected by the reception synchronization signal pattern selection unit 46R. Generated by the generation unit 444 and the timing generation unit 444 And a communication path switching timing generator 445 for generating a switching timing signal of the switch unit 63 of the communication path switching unit 60 from the signal.

For the pattern discrimination in the synchronization signal pattern comparison unit 443, any means such as an analog waveform or a demodulated bit string may be used, or a plurality of means may be combined.
When the synchronization signal pattern matches in the synchronization signal pattern comparison unit 443, synchronization is performed with the signal, and the reception synchronization correction unit 424 and the synchronization correction unit / synchronization generation unit 434 correct the entire signal based on the signal. If the synchronization signal pattern comparison unit 443 determines that the reception synchronization signal patterns do not match, the reception synchronization correction unit 424 discards the reception synchronization signal.
Note that the Fourier operation of the fast Fourier transform (FFT) unit 425 and the inverse Fourier transform (IFFT) unit 433 is performed by the timing signal generated by the timing generation unit 444.

The data holding / control unit 45 temporarily holds data transmitted from a device such as an adjacent repeater 40, and sends it to the transmission unit 43 side to relay the held data, or is connected by a LAN or the like. Whether to send data to an external device (not shown) such as a personal computer or to send data from the external device to the transmission unit 43 is performed.
Note that an external device such as a personal computer is not necessarily connected to the relay device 40, and there are some devices that perform only a relay operation without being connected to the relay device 40.

  In the above configuration, the operation at the time of activation for synchronizing all the communication path switching units 60 is as described in FIG. In this case, the synchronization signal is sequentially sent from the master unit 10 to the repeater 40a and from the repeater 40a to the repeater 40b to synchronize all the modems. As described above, depending on the configuration and the circuit configuration of the switch of the communication path switching unit 60, the synchronization signal may leak to the adjacent relay section, and erroneous synchronization may occur.

Therefore, in the present invention, as shown in FIG. 3, the synchronization signal uses different patterns of synchronization signals in adjacent relay sections.
That is, in FIG. 3, the pattern of the synchronization signal transmitted from the base unit 10 to the repeater 40a is A pattern, the pattern of the synchronization signal transmitted from the repeater 40a to the repeater 40b is B pattern, and relayed from the repeater 40b. The pattern of the synchronization signal transmitted to the machine 40c is changed to the A pattern again.

  In this case, the transmission synchronization signal pattern selected by the transmission synchronization signal pattern selection unit 46T of the repeater 40a is a B pattern, and the reception synchronization signal pattern selected by the reception synchronization signal pattern selection unit 46R is an A pattern. The transmission synchronization signal pattern selected by the transmission synchronization signal pattern selection unit 46T of the repeater 40b is an A pattern, and the reception synchronization signal pattern selected by the reception synchronization signal pattern selection unit 46R is a B pattern. The transmission synchronization signal pattern selected by the transmission synchronization signal pattern selection unit 46T of the repeater 40c is a B pattern, and the reception synchronization signal pattern selected by the reception synchronization signal pattern selection unit 46R is an A pattern.

By doing so, for example, the repeater 40b waits in anticipation of the synchronization signal pattern B, so that the synchronization signal pattern A transmitted from the master unit 1 to the repeater 40a becomes the communication path switching unit 60a of the repeater 40a. Even if it is leaked and transmitted to the repeater 40b side, it is not synchronized with the leaked synchronization signal pattern A. Therefore, the repeater 40b is not erroneously synchronized.
That is, if the received synchronization signal pattern selected by the received synchronization signal pattern selection unit 46R of the repeater 40b is the B pattern, and the received synchronization signal pattern is the A pattern, the synchronization signal pattern comparison unit 443 determines that there is a mismatch. The reception synchronization correction unit 424 discards the synchronization signal and does not synchronize.

If the amount of leakage of the synchronization signal is large, not only the two patterns A and B but three or more patterns may be prepared to change the synchronization signal pattern in the section other than the adjacent one.
As an example of the synchronization signal pattern, as shown in FIG. 4, when the synchronization signal is a bit string, the pattern A is “10101010”, the pattern B is “01010101”, the pattern C is “11001100”, and so on. And

Thus, all the repeaters 40 are synchronized with the nearest upstream repeater 40 without being erroneously synchronized, and in this state, the switch unit 63 of the communication path switching unit 60 of all the repeaters 40 is obtained. The switching operation or the on / off operation is alternately performed at a constant cycle at the synchronized timing. The period of this fixed period is N times the period of the synchronization signal (N is an integer of 1 or more).
As described above, the switching operation of the switch unit 63 of the communication channel switching unit 60 is performed when the switch unit 63 connected to the predetermined relay unit 40n is connected to the input / output connection point 61 of the upstream communication channel. The switch unit 63 connected to the adjacent repeater 40n + 1 on the downstream side of the machine 40n is connected to the input / output connection point 62 of the downstream communication path. Conversely, when the switch unit 63 connected to the predetermined repeater 40n is connected to the input / output connection point 62 of the downstream communication path, it is connected to the adjacent repeater 40n + 1 on the downstream side of the repeater 40n. The switch unit 63 is connected to the input / output connection point 61 of the upstream communication path.

In such a communication system, the operation state according to the time t axis of the repeater 40 between the master unit 10 and the slave unit 20 when the data information after synchronization is time-division relayed is the same as in FIG. Therefore, detailed description is omitted.
That is, in period 1, the master unit 10 and the relay unit 40a are connected via the communication line 30a, and communication between both is enabled, and the communication line 30b on the relay unit 40b side is separated. At the same time, in the relay section 3 that is shifted by one from the relay section 1 between the master unit 10 and the relay machine 40a, the relay machine 40b and the relay machine 40c are connected via the communication line 30c, and communication between both becomes possible. Thus, the relay section 1 and the relay section 3 can communicate simultaneously without causing signal interference.

  In cycle 2 subsequent to cycle 1, the relay device 40a and the relay device 40b are connected via the communication line 30b to enable communication therebetween, and are separated from the communication line 30c on the relay device 40c side. At the same time, in the relay section 4 that is shifted by one from the relay section 2, the relay device 40c and the slave device 20 are connected via the communication line 30d, and communication between both becomes possible. In this way, the relay section 2 and the relay section 4 can communicate simultaneously without causing signal interference.

As described above, in the cycle 1, the relay section 1 between the parent device 10 and the relay machine 40a and the relay section 3 between the relay machine 40b and the relay machine 40c can communicate, and the relay between the relay machine 40a and the relay machine 40b. In section 2, the relay section 4 between the relay device 40c and the child device 20 cannot communicate.
Next, in the cycle 2, the relay section 2 between the relay device 40a and the relay device 40b and the relay section 4 between the relay device 40c and the slave device 20 are communicable, and between the parent device 10 and the relay device 40a. Relay section 1 and relay section 3 between relay machine 40b and relay machine 40c cannot communicate.

  Since all the repeaters 40 perform the above operation in synchronism, the transmission signal reachable range of the repeater 40 is limited to upstream or downstream adjacent repeaters, and one skipped relay section is the same without causing signal interference. Since simultaneous communication can be performed during a period, communication efficiency (speed) can be improved compared to conventional time-division relay transmission in which communication is possible only in one section in the signal control range even if there are a plurality of relay sections.

Note that, in the above, the transmission synchronization signal pattern holding unit 47T and the reception synchronization signal pattern holding unit 47R are provided in the repeater 40, and the transmission synchronization signal pattern and the reception synchronization signal are transmitted from the plurality of synchronization signal patterns by the synchronization signal pattern selection units 46T and 46R. Although the pattern has been selected, if the transmission synchronization signal pattern and the reception synchronization signal pattern held are different, the synchronization signal pattern selection units 46T and 46R can be omitted.
In addition, the parent device 10 and the child device 20 do not need such synchronization signal pattern selection units 46T and 46R. However, if it is desired to change the transmission synchronization signal pattern in the parent device 10, the transmission synchronization signal pattern holding unit 47T and Only the transmission synchronization signal pattern selection unit 46T may be provided. Similarly, only the reception synchronization signal pattern holding unit 47R and the reception synchronization signal pattern selection unit 46R may be provided in the slave unit 20 when it is desired to change the reception synchronization signal pattern.

Embodiment 2. FIG.
Next, the communication system in Embodiment 2 of this invention is demonstrated based on FIG.
The schematic configuration diagram of the communication system is the same as that described in FIG. 12, and FIG. 5 is a functional configuration diagram of the connection portion of the communication line 30 and the repeater 40 and the repeater of the communication system in the second embodiment. Yes.
The invention of the second embodiment is configured so as not to synchronize with the signal of the received synchronization signal pattern in which the power value of the received synchronization signal pattern falls below a predetermined power threshold.

  In the repeater 40 shown in FIG. 5, the synchronization signal reception power threshold holding unit 48 that sets and holds the power threshold so as not to synchronize with the signal of the reception synchronization signal pattern that is lower than the predetermined power threshold, and the reception power threshold holding unit 48 A synchronization signal reception power comparison unit 446 that compares the held power threshold value with the power value of the reception synchronization signal that is the output of the synchronization signal pattern detection unit 442 is provided. Here, the reception synchronization signal pattern selection unit 46R and the reception synchronization signal pattern holding unit 47R are not provided. Other configurations are the same as those in FIG. 1 of the first embodiment, and the same or corresponding parts are denoted by the same reference numerals and description thereof is omitted.

The synchronization signal reception power comparison unit 446 compares the power threshold set and held in the synchronization signal reception power threshold holding unit 48 with the power value of the reception synchronization signal detected by the synchronization signal pattern detection unit 442 and receives the received synchronization. When the power value of the signal is lower than the power threshold, the reception synchronization correction unit 424 discards the reception synchronization signal to prevent erroneous synchronization. On the other hand, when the power value of the received synchronization signal is greater than or equal to the power threshold value, synchronization is performed with the signal, and the entire signal is corrected by the reception synchronization correction unit 424 and the synchronization correction unit / synchronization generation unit 434 based on the signal.
By adopting a configuration in which the operation for synchronization is performed with a synchronization signal whose power value of the received synchronization signal pattern is equal to or greater than a predetermined power threshold, even if the synchronization signal leaks to the adjacent relay section, the leakage signal Since the power value of is low, it is possible to prevent erroneous synchronization due to the leaked synchronization signal.
Note that the invention of the second embodiment may be used together with the invention in which the synchronization signal pattern described in the first embodiment is made different between adjacent relay sections.

Embodiment 3 FIG.
Next, the communication system in Embodiment 3 of this invention is demonstrated based on FIG. 6, FIG.
The schematic configuration diagram of the communication system is the same as that described with reference to FIG. 12, and FIG. 6 is a functional configuration diagram of the connection portion of the communication line 30 and the repeater 40 and the repeater of the communication system according to the third embodiment. These show operation explanatory diagrams of the communication system in the third embodiment.
In the third embodiment, a predetermined reception period for selecting a synchronization signal is provided, and a synchronization operation is performed only on the synchronization signal having the maximum power among a plurality of synchronization signals received within the period. .

  In the synchronization / carrier detection and timing generation unit 44 of the repeater 40 shown in FIG. 6, the synchronization signal detection unit 442 receives a plurality of synchronization signals during a certain period. The synchronization signal received power calculation unit 447 calculates the power value of each of the plurality of synchronization signals detected by the synchronization signal detection unit 442. The synchronization signal reception power holding unit 448 holds the power values of the plurality of synchronization signals calculated by the synchronization signal reception power calculation unit 447. The synchronization signal power comparison / extraction unit 449 compares the power values of the plurality of synchronization signals held in the synchronization signal reception power holding unit 448, extracts the one with the maximum power value from among them, and the subsequent synchronization signals are Only the synchronization signal with the maximum power value is received. Other configurations are the same as those in FIG. 1 of the first embodiment, and the same or corresponding parts are denoted by the same reference numerals and description thereof is omitted.

  With such a configuration, the synchronization signal detection unit 442 receives a plurality of synchronization signals A1 to A5 having the same synchronization pattern during a predetermined period from time t1 to time t2, as shown in FIG. The synchronization signal reception power calculation unit 447 calculates the power values of the plurality of synchronization signals A1 to A5 detected by the synchronization signal detection unit 442, and the synchronization signal reception power holding unit 448 holds the power values of the plurality of synchronization signals. ing. The synchronization signal power comparison / extraction unit 449 compares the plurality of synchronization signals A1 to A5 held in the synchronization signal reception power holding unit 448, and extracts the synchronization signal A3 having the maximum reception power value from the comparison.

  The synchronization signal received power comparison / extraction unit 449 controls the reception synchronization correction unit 424 so that synchronization signals received thereafter by the reception unit 42 are synchronized only with the extracted synchronization signal A3. On the other hand, the synchronization signal received power comparing / extracting unit 449 discards the received synchronization signal by the reception synchronization correcting unit 424 for the synchronization signal other than the extracted synchronization signal A3 having the maximum received power, thereby preventing erroneous synchronization. Like that.

Thus, by selecting a synchronization signal having the maximum power value from a plurality of synchronization signals received within a predetermined time, and performing the operation for synchronization with the synchronization signal of the synchronization signal thereafter, for example, adjacent Even if the synchronization signal leaks in the relay section, the power value of the leakage signal is small, so that erroneous synchronization due to the leaked synchronization signal can be prevented.
Note that the invention of the third embodiment may be used in combination with the invention in which the synchronization signal pattern described in the first embodiment is made different between adjacent relay sections.

Embodiment 4 FIG.
Next, a communication system according to Embodiment 4 of the present invention will be described with reference to FIGS. FIG. 8 is a schematic configuration diagram of a communication system and a configuration diagram of a low-pass filter used therefor, and FIG. 9 is a diagram illustrating frequency characteristics of the filter.
In FIG. 8A, the difference from the first embodiment is a low-pass filter that can cut off the communication frequency band of data communication so as to short-circuit the terminal block 50 connected between the communication line 30 and the repeater 40. 80, the communication lines 30a to 30d are electrically independent for each relay section. FIG. 8B is an enlarged view of the low-pass filter 80 connected to the terminal block 50. Other configurations are the same as those of the first embodiment, and the same reference numerals are given and description thereof is omitted.

As shown in FIG. 9, the filter characteristic of the low-pass filter 80 is such that a signal having a frequency equal to or higher than the cutoff frequency fc is cut off and a frequency equal to or lower than the cutoff frequency fc is passed. Is in the range of f1 to f2 that is equal to or higher than the cut-off frequency fc, so that these data cannot be transmitted without going through the repeater 40.
On the other hand, since the low-pass filter 80 can pass a signal by a telephone such as a voice having a frequency equal to or lower than the cut-off frequency fc, for example, a voice is transmitted.
In this way, even if the data cannot be transmitted due to a failure of the repeater 40 or the like, the master unit 10 and the slave unit 20 can talk over the telephone or the like so that the transmission of the telephone and the data can coexist. Become.

Embodiment 5 FIG.
Next, the communication system in Embodiment 5 of this invention is demonstrated based on FIG. The invention of the fifth embodiment uses a ferrite core instead of the low-pass filter 80 of the fourth embodiment to electrically isolate the communication lines 30a to 30d in units of relay sections.
FIG. 10A shows a configuration diagram of the ferrite core 90 wound around the communication line 30 so as to short-circuit the terminal block 50, and is used instead of the low-pass filter 80 used in the fourth embodiment.
As shown in FIG. 10 (b), the ferrite core 90 is divided into upper and lower halves and wound around the communication line 30 in close contact with each other, and the communication frequency band of data communication is cut off by the magnetic force of the core. It is what you do.
If the ferrite core 90 is used in this way, the relay method of the first embodiment can be used even when the communication line 30 is not physically divided in units of relay sections.

Embodiment 6 FIG.
Next, the communication system in Embodiment 6 of this invention is demonstrated based on FIG.
FIG. 11 shows a schematic configuration diagram of the communication system. Communication lines 30a (configured by 30a1 and 30a2) and 30b (configured by 30b1 and 30b2) between the base unit 10 and the relay unit 40a or between the relay unit 40a and the relay unit 40b. A plurality of slave units 200a to 200n and 200n + 1 to 200m different from the slave unit 20 on the most downstream side are connected to the configuration).
In addition, although the connection to the communication line 30 of the some subunit | mobile_unit 200a-200n and 200n + 1-200m is connected via the terminal block 50 in illustration, a connection location and a connection method are not specified in particular. . Other configurations are the same as those of the first embodiment, and the same reference numerals are given and the description thereof is omitted.

The slave units 200a to 200n and 200n + 1 to 200m are configured such that the upstream master unit 10 or the relay unit 40 manages the communication of each of the slave units 200a to 200n and 200n + 1 to 200m. That is, the slave units 200a to 200n are managed by the master unit 10, and the slave units 200n + 1 to 200m are managed by the relay unit 40a.
And the subunit | mobile_unit 200a-200n transmits / receives data transmission between the main | base station 10 or the relay machine 40a with the period which the main | base station 10 and the relay machine 40a can communicate. The slave units 200n + 1 to 200m perform data transmission / reception with the relay unit 40a or the relay unit 40b in a cycle in which the relay unit 40a and the relay unit 40b can communicate with each other.

In this way, by connecting the plurality of slave units 200a to 200n and 200n + 1 to 200m to the communication line 30 between the base unit 10 and the relay unit 40 or between the plurality of relay units 40, simultaneous transmission between the conventional relay units 40 is possible. Not only parallel transmission, but also simultaneous transmission of data can be made to each slave connected between them, and the application can be expanded.
Note that the number of slave units connected to the communication line 30 between the master unit 10 and the relay unit 40 or between the plurality of relay units 40 is not limited to a plurality and may be one.
It should be noted that within the scope of the present invention, the embodiments can be freely combined, or the embodiments can be appropriately modified or omitted.

10: Master machine, 20: Slave machine,
30, 30a-30d: communication line, 40, 40a-40c: repeater,
41: Transmission / reception switching unit, 42: Reception unit,
43: Transmission unit 44: Synchronization / carrier detection and timing generation unit,
45: Data holding / control unit, 46T, 46R: Sync signal pattern selection unit,
47T, 47R: synchronization signal pattern holding unit, 48: synchronization signal received power threshold holding unit,
441: carrier detection unit, 442: synchronization signal pattern detection unit,
443: synchronization signal pattern comparison unit, 444: timing generation unit,
445: communication channel switching timing generation unit, 446: synchronization signal received power comparison unit,
447: synchronization signal received power calculation unit, 448: synchronization signal received power holding unit,
449: synchronization signal power comparison / extraction unit,
50: Terminal block (transmission path coupling part), 60: Communication path switching part,
61, 62: input / output connection section, 63, 63a, 63b: switch section,
70a, 70b: communication path coupling unit,
80: Low-pass filter, 90: Ferrite core,
200a-200n, 200n + 1-200m: cordless handset.

Claims (11)

A communication system in which a master unit and a slave unit are connected by a communication line via a plurality of relay units to transmit and receive data, wherein the communication line is connected to a connection point between the relay unit and the communication line. Have two input / output connection points respectively connected to the upstream communication path and the downstream communication path, and a switch unit for performing an operation of alternately connecting the two input / output connection points to the transmission / reception switching unit of the repeater. The switching timing of the switch section of the communication path switching section is synchronized with all the repeaters, and the switch section connected to a predetermined repeater n is an input / output connection point of the upstream communication path. When connected, in the communication system in which the switch unit connected to the adjacent relay n + 1 on the downstream side of the relay n is connected to the input / output connection point of the downstream communication path,
At the time of start-up before all the repeaters are synchronized, all the switch units of the communication path switching unit connect the upstream communication path and the transmission / reception switching unit of the repeater, and the upstream master unit or relay The switch unit connected to the relay unit that has received the synchronization signal from the machine and has completed synchronization connects the downstream communication path and the transmission / reception switching unit of the relay machine, and the synchronization signal is in the adjacent relay section. A communication system that uses synchronization signals of different patterns.   The communication system according to claim 1, wherein the switch unit of the communication path switching unit performs a switching operation alternately at a constant cycle.   The communication system according to claim 1 or 2, wherein the repeater includes a synchronization signal pattern selection unit that can select a transmission synchronization signal pattern and a reception synchronization signal pattern from a plurality of synchronization signal patterns.   4. The communication system according to claim 3, wherein the repeater includes a sync signal pattern comparison unit that compares the selected received sync signal pattern with a sync signal pattern received from an upstream master unit or repeater.   2. The relay apparatus according to claim 1, wherein a reception period for receiving a plurality of synchronization signal patterns is provided, and a synchronization operation is performed only on a synchronization signal pattern having a maximum power among the synchronization signal patterns received within the reception period. The communication system according to claim 1. A communication system in which a master unit and a slave unit are connected by a communication line via a plurality of relay units to transmit and receive data, wherein the communication line is connected to a connection point between the relay unit and the communication line. Have two input / output connection points respectively connected to the upstream communication path and the downstream communication path, and a switch unit for performing an operation of alternately connecting the two input / output connection points to the transmission / reception switching unit of the repeater. The switching timing of the switch section of the communication path switching section is synchronized with all the repeaters, and the switch section connected to a predetermined repeater n is an input / output connection point of the upstream communication path. When connected, in the communication system in which the switch unit connected to the adjacent relay n + 1 on the downstream side of the relay n is connected to the input / output connection point of the downstream communication path,
At the time of start-up before all the repeaters are synchronized, all the switch units of the communication path switching unit connect the upstream communication path and the transmission / reception switching unit of the repeater, and the upstream master unit or relay The switch unit connected to the relay unit that has received the synchronization signal from the machine and has completed synchronization connects the downstream communication path and the transmission / reception switching unit of the relay machine, and the relay unit receives the synchronization signal A communication system in which the power value of a pattern is not synchronized with a signal of a reception synchronization signal pattern that is lower than a predetermined power threshold. A communication system in which a master unit and a slave unit are connected by a communication line via a plurality of relay units to transmit and receive data, wherein the communication line is connected to a connection point between the relay unit and the communication line. Have two input / output connection points respectively connected to the upstream communication path and the downstream communication path, and a switch unit for performing an operation of alternately connecting the two input / output connection points to the transmission / reception switching unit of the repeater. The switching timing of the switch section of the communication path switching section is synchronized with all the repeaters, and the switch section connected to a predetermined repeater n is an input / output connection point of the upstream communication path. When connected, in the communication system in which the switch unit connected to the adjacent relay n + 1 on the downstream side of the relay n is connected to the input / output connection point of the downstream communication path,
At the time of start-up before all the repeaters are synchronized, all the switch units of the communication path switching unit connect the upstream communication path and the transmission / reception switching unit of the repeater, and the upstream master unit or relay The switch unit connected to the relay unit that has received the synchronization signal from the machine and has completed synchronization connects the downstream communication path and the transmission / reception switching unit of the relay machine, and the relay machine transmits a plurality of synchronization signals. A communication system in which a reception period for receiving is provided, and a synchronization operation is performed only on a synchronization signal having the maximum power among the synchronization signals received within the reception period.   The filter according to any one of claims 1 to 7, wherein a filter capable of blocking a signal in a frequency band for performing data communication is connected between an upstream communication path and a downstream communication path of a communication line to which the repeater is connected. The communication system according to claim 1.   The communication system according to claim 8, wherein the filter is a low-pass filter that allows a signal in a frequency band lower than a frequency band in which data communication is performed to pass.   The communication system according to any one of claims 1 to 7, wherein a ferrite core capable of blocking a signal in a frequency band for performing data communication is disposed around a communication line to which the repeater is connected.   The communication system according to any one of claims 1 to 10, wherein a slave unit is connected to a communication line between the master unit and the relay unit or between a plurality of relay units.

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