JPH0666790B2 - Transmission equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transmission device using a remote repeater for multi-drop connection.

[Conventional technology]

FIG. 4 is a block diagram showing a configuration of a conventional transmission device disclosed in, for example, Japanese Patent Laid-Open No. 61-187440.
In the figure, reference numerals 11 and 21 denote first and second signal lines (transmission buses) for signal transmission, and generally twist cables or coaxial cables are often used.

12, 13, 22, 23 are the first and second signal lines 11,
Terminal resistors for impedance matching of transmission lines connected to both ends of 21, 21, 15, 24, 25 are stations capable of transmission and reception connected to the first and second signal lines 11, 21; 1, 1st and 2nd remote repeaters connected to the 2nd signal lines 11 and 21, 31 shows the cable for remote repeaters which connects the 1st and 2nd remote repeaters 11 and 21, and twist cable or A coaxial cable is used.

The remote repeater line is composed of first and second remote repeaters 11 and 21 and a cable 31.

FIG. 5 shows the first remote repeater 16 shown in FIG.
FIG. 4 is a block diagram showing the configuration of FIG.
Reference numeral 1 is the first and second receivers for receiving signals from the first signal line 11 and the cable 31, 42 and 52 are first and first for adjusting the waveforms of the signals received by the first and second receivers 41 and 51. Second waveform shaping circuit, 43 and 53 are first and second carrier detection circuits for detecting carriers from the signals output from the first and second receivers 41 and 51, and 44 is first and second carrier detection Judgment circuits for judging the detection order of the carriers output by the circuits 43, 53, and 45, 55 for inputting the outputs of the first and second waveform shaping circuits 42, 52 and the judgment circuit 44, respectively. AND circuit, 46 and 56 are first and second
The first and second drivers that output the outputs of the AND circuits 45 and 55 to the first signal line 11 and the cable 31 are shown.

The first remote repeater 16 includes the first and second receivers 41 and 51 and the first and second drivers 46 and 56.
It has a bidirectional structure.

The second remote repeater 26 has the same configuration as the first remote repeater 16.

Next, the operation when transmitting a signal from the station 14 will be described.

First, when a signal is transmitted from the station 14 to the first signal line 11, the first receiver 41 of the first remote repeater 16 receives the carrier from the first signal line 11, and the first carrier detection circuit 43 It turns on and the judgment circuit 44
Confirms that the carrier has been received from the first signal line 11, and outputs the output for opening the first AND circuit 45. Therefore, the signal received by the first receiver 41 is shaped by the first waveform shaping circuit 42, and then is output from the first driver 46 to the cable 31 through the first AND circuit 45.

Next, the second remote repeater 26, which has received the signal from the cable 31, waveform-shapes the signal received from the cable 31 in the same manner as the first remote repeater 16, and then performs the second shaping.
Output to the signal line 21 of the station 24, 25
Can receive signals from station 14.

When operating as described above, the problem is that the signal output from the first driver 46 of the first remote repeater 16 is directly received by the second receiver 51 and the second carrier detection circuit 53 is turned on. Is to be.

However, since the determination circuit 44 detects which of the first and second carrier detection circuits 43 and 53 is activated first and determines the output, the second driver 56 is activated to operate the first signal line 11 It does not disturb the signal waveform of. That is, as shown in the time chart of FIG. 6, the first AND circuit 45 is opened and the second AND circuit 55 is closed.

Next, when the station 14 stops transmitting the signal, the first carrier detection circuit 43 turns off and the determination circuit 44
Closes the first AND circuit 45 and waits for the next carrier detection.

Further, the operation of the first remote repeater 16 when transmitting a signal from the station 24 will be described.

First, the second receiver 5 of the first remote repeater 16
1 receives the carrier from the cable 31, the second carrier detection circuit 53 is turned on, and the determination circuit 44 confirms that the carrier is received from the cable 31 and sends an output for opening the second AND circuit 55. . Therefore, the signal received by the second receiver 51 is shaped by the second waveform shaping circuit 52, and then output from the second driver 56 to the first signal line 11 through the second AND circuit 55. .

Therefore, stations 14 and 15 are
The signal from 4 can be received.

[Problems to be solved by the invention]

Since the conventional transmission device is configured as described above, that is, since the remote repeater line that connects the first and second signal lines 11 and 21 is one line, a cable that is wired over a long distance outdoors. If 31 is disconnected due to construction or the like, there is a problem that transmission becomes impossible.

The present invention has been made in order to solve the above problems, and provides a transmission device with improved reliability by using a plurality of remote repeater lines for connecting the first and second signal lines. The purpose is to get.

[Means for solving problems]

A transmission device according to the present invention is a first control signal for generating, to a first and a second remote repeater, a signal for opening a second AND circuit from a significant signal for opening a second AND circuit from an input terminal. The remote repeater circuit is provided with a generation circuit and a second control signal generation circuit that generates an insignificant signal that closes the second AND circuit from the signal output from the second receiver and the significant signal and outputs the signal from the output terminal. And connecting a plurality of the remote repeater lines in parallel between the first and second signal lines, and having an input terminal and an output terminal between the first remote repeater and the second remote repeater. It is connected in an end shape.

[Action]

Since the transmission device according to the present invention has a priority order from the first and second remote repeaters to which the significant signal is input, the remote repeater line having the highest priority order is effective when all the cables are healthy. Become.

When the cable of the remote repeater line having the highest priority is disconnected, the lower remote repeater line becomes valid.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same or corresponding parts as those in FIGS. 4 and 5 are designated by the same reference numerals, 16A, 16B and 16C are first remote repeaters, and 31A, 31B and 31C are first remote repeaters. A cable for a remote repeater that connects 16A, 16B, 16C and a second remote repeater (not shown) is shown, and a twisted cable or a coaxial cable is used.

Reference numeral 61 is an input terminal, 62 and 63 are inverters as a first control signal generating circuit for generating a signal for opening the second AND circuit 55 from a significant signal of the input terminal 61, and 64 is a second carrier detecting circuit 52. A NOR circuit that receives the output of the inverter 62 as an input, and 65 indicates an output terminal.

The second AND circuit 55 is a 3-input AND circuit, and + 5V as a significant signal is applied to the input terminal 61 of the first remote repeater 16A.

Then, the second control signal generation circuit for generating the insignificant signal for closing the second AND circuit 55 from the signal output from the second receiver 51 and the significant signal is composed of the inverter 62 and the NOR circuit 64.

FIG. 2 shows the first remote repeater 16 shown in FIG.
It is a block diagram which shows the transmission device comprised by A, 16B, and 16C, and 26A, 26B, and 26C are the 2nd.
Of remote repeaters of the same construction as the first remote repeaters 16A, 16B and 16C.

Next, the operation will be described.

When signals are transmitted from the stations 14, 15 or 24, 25, the first or second signal lines 11, 21
First remote repeaters 16A, 16 for receiving the signal of
Since the operation of B, 16C or 26A, 26B, 26C is the same as the above-mentioned operation, its explanation is omitted and the cable 31
A signal from A, 31B, 31C is transmitted to the first remote repeater 1
6A, 16B, 16C or second remote repeater 2
6A, 26B, and 26C receive the first and second signal lines 1
The case of outputting a signal to 1, 21 will be described with reference to the first remote repeaters 16A, 16B, 16C.

When the signals from the cables 31A, 31B, 31C are received by the first remote repeaters 16A, 16B, 16C,
Since each second carrier detection circuit 53 is turned on by detecting the carrier received by each second receiver 51, each determination circuit 44 confirms that the carrier has been received, and sets each second AND circuit 55. Send the output to open the circuit.

The signal received by each second receiver 51 is
After being shaped by the waveform shaping circuit 52, the signal is output to each second AND circuit 55.

At this time, the input terminal 6 of the first remote repeater 16A
Since the significant signal (high level “H”) is applied to 1, the second AND circuit 55 is opened by the signal through the inverters 62 and 63, and the signal from the second waveform shaping circuit 52 is the second signal. Is output from the driver 56 to the first signal line 11.

However, the output terminal 65 of the first remote repeater 16A
To the insignificant signal x (low level “L”) from the NOR circuit 64.
Is output, the second AND circuit 55 of the first remote repeater 16B remains closed, and the signal from the second waveform shaping circuit 52 is output from the second driver 56 to the first signal line 11. As a result, the signal is not output to the first signal line 11 from the first remote repeater 16C as well. FIG. 3 shows a time chart for such an operation.

As described above, if the cables 31A, 31B, 31C are sound, the signal is output from the first remote repeater 16A to the first signal line 11.

However, when the cable 31A is disconnected, a significant signal (high level “H”) is output from the output terminal 65 of the first remote repeater 16A, so that the signal is output from the first remote repeater 16B to the first signal line 11. Is output.

Therefore, each first remote repeater 16A, 16
B and 16C will be provided with a priority order, and even if the cable 31A of the remote repeater line having the highest priority order cannot be used due to a disconnection or the like, another remote repeater line can be used, so that reliability is improved. .

In the above embodiment, the first and second signal lines 11 and 21 are connected by the three remoter repeater lines, but the remote repeater line may be two or more lines,
The greater the number, the more reliable the transmission.

Further, although the twisted cable or the coaxial cable is used as the cables 31A, 31B, 31C, the optical fiber cable may be used.

Further, although one input of the NOR circuit 64 is the output of the second carrier detection circuit 53, the same operation is performed even if it is the output of the second receiver 51.

Further, although the case where the significant signal applied to the input terminal 61 is high level is shown, when the low level signal is significant signal, the inverter 62 becomes unnecessary and the NOR circuit 64 becomes an OR circuit.

〔The invention's effect〕

As described above, according to the present invention, the first and second remote repeaters generate the signal for opening the second AND circuit from the second AND circuit from the input terminal or the significant signal for opening the first AND circuit. And a control signal generation circuit for generating a nonsense signal for closing the second AND circuit from the signal output from the second receiver and the significant signal, and outputting the signal from the output terminal.
And a control signal generation circuit for configuring a remote repeater circuit, and connecting a plurality of the remote repeater lines in parallel between the first and second signal lines, as well as between the first remote repeaters and the second remote repeater. Since the input terminal and the output terminal between the repeaters are connected endlessly, when the cable of the remote repeater line with the highest priority is disconnected, the lower remote repeater line is enabled, so one line of the remote repeater line is activated. Since other remote repeater lines can be used even if they cannot be used due to disconnection or the like, there is an effect that reliability is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first remote repeater constituting a transmission device according to an embodiment of the present invention, and a second diagram.
FIG. 1 is a block diagram showing a transmission device composed of the first remote repeater shown in FIG. 1, FIG. 3 is a time chart of the first remote repeater shown in FIG. 1, and FIG. 4 is a conventional transmission. FIG. 5 is a block diagram showing an apparatus, FIG. 5 is a block diagram showing a configuration of the first remote repeater shown in FIG. 4,
FIG. 6 is a time chart of the first remote repeater shown in FIG. In the figure, reference numerals 11 and 21 denote first and second signal lines, 14,
15 and 24, 25 are stations, 16A, 16
B and 16C are first remote repeaters, 26A and 26C.
B and 26C are second remote repeaters, 31A and 31
B and 31C are cables, 41 and 51 are first and second receivers, 43 and 53 are first and second carrier detection circuits, 4
4 is a determination circuit, 45 and 55 first and second AND circuits,
46 and 56 are first and second drivers, 61 is an input terminal,
62 and 63 are inverters, 64 is a NOR circuit, and 65 is an output terminal. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first or second AND circuit is opened based on an output of a determination circuit that determines which one of the first and second receivers operates first, and the first and second receivers are opened. Transmitting and receiving signals between stations by connecting the first and second remote repeaters, which output from the first and second drivers, in series with a cable, and connecting the remote repeater line between the first and second signal lines. In the transmission device, the first and second remote repeaters are connected to the second signal from the significant signal for opening the second AND circuit from the input terminal.
A first control signal generating circuit for generating a signal for opening the AND circuit, and a signal output from the second receiver and the significant signal for generating and outputting an insignificant signal for closing the second AND circuit. A second control signal generation circuit for outputting from a terminal is provided to configure the remote repeater line, and a plurality of the remote repeater lines are connected in parallel between the first and second signal lines and the first repeater line is connected. 2. The transmission device, wherein the input terminal and the output terminal are connected in an endless manner between the remote repeaters and between the second remote repeaters.