JPH11284644A - Transmission distance extending device and tunnel disaster prevention system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a transmission distance extending device to reduce the cost and size of a system by substantially extending a transmission distance. SOLUTION: A transmission distance extending device is equipped with a shaping direction decision part 6 and a shaping circuit switching part 7 which are provided in a signal transmission system to perform base-band transmission on a polling/selecting basis and which detect the contents of bidirectionally transmitted signals and control the direction of waveform shaping, and with waveform shaping circuits 8 and 9 which shape the waveforms of the transmission signals whose waveforms shaping directions are set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission distance extending apparatus provided in a signal transmission system for performing polling / selecting type baseband transmission and capable of substantially extending a transmission distance, and a transmission distance extending apparatus. This is related to the tunnel disaster prevention system used.

[0002]

2. Description of the Related Art In a general tunnel disaster prevention system, a so-called baseband transmission method is used in which a data signal is transmitted in a form close to a prototype without moving a frequency spectrum of a data signal at a terminal. Since there is a distance limit, the inside of the tunnel is divided into districts, and baseband transmission is performed by dispersing with a relay device installed in each district.

FIG. 5 is a configuration diagram schematically showing an example of a conventional tunnel disaster prevention system. In the figure, 100A is a disaster prevention receiver as a control station, 1000A.
Reference numerals _{1 to} 1000n denote a plurality of relay devices installed for each district in the tunnel. These relay devices 1000 ₁ to 1
A plurality of terminal devices T1 to T6 such as a fire detector, a fire extinguisher, and a repeater are connected to 000n in a distributed manner. A group of terminal devices T1 to T3 and a group of terminal devices T4 to T6 are divided and connected to transmission paths of a predetermined length, for example, 1 to 2 km, respectively, in order to support baseband transmission.

[0004]

However, the conventional tunnel disaster prevention system having the above-described configuration has the following problems. That is, in baseband transmission by each relay device, a large-scale relay device is required compared to direct transmission from the disaster prevention receiver, and it is necessary to provide some communication path between the relay device and the disaster prevention receiver. However, this has been a factor in increasing the cost of the system.
In addition, since the relay device has built-in control functions and increases the size of the device, there is a problem in the installation space when installing in a tunnel.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and the transmission distance can be substantially extended to reduce the cost and size of the system. It is an object to provide an extension device and a tunnel disaster prevention system using the transmission distance extension device.

[0006]

According to a first aspect of the present invention, there is provided a transmission distance extending device provided in a signal transmission system for performing baseband transmission of a polling / selecting method, wherein the transmission distance is extended in two directions. Direction detecting means for detecting the content of the transmission signal to be transmitted and controlling the direction of waveform shaping, and waveform shaping means for shaping the waveform of the transmission signal whose waveform shaping direction has been set by the shaping direction control means. It is.

According to a second aspect of the present invention, in the transmission distance extending apparatus according to the first aspect, the shaping direction control means detects an operation solicited from the control station and a response operation from the dependent station. A time slot in the transmission direction is allocated, and the shaping direction is set.

According to a third aspect of the present invention, in the transmission distance extending apparatus according to the first or second aspect, the waveform shaping means shapes the waveform distortion and its peak value within a predetermined time.

According to a fourth aspect of the present invention, there is provided a tunnel disaster prevention system for performing a polling / selecting type baseband transmission, wherein the transmission distance is extended in a transmission line. It is the one where the device is installed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a block diagram showing Embodiment 1 of the present invention. In the figure, reference numerals 1 and 2 denote a pair of transmission lines extending from a control station (disaster prevention receiver) side, 1 denotes a positive transmission line, and 2 denotes a negative transmission line. 1T and 2T are input terminals of a transmission distance extending device connected to the signal transmission lines 1 and 2, respectively, and 3 and 4 are a pair of transmission lines connected to a slave station (terminal equipment) side, and 3T and 4T are transmission lines. Output terminals of the transmission distance extending devices connected to the lines 3 and 4, respectively.

A transmission receiving circuit 5 is connected between the input terminals 1T and 2T and receives transmission signals from the control station side and the subordinate station side. A transmission connection circuit 6 is connected to the transmission receiving circuit 5 and receives the received contents. A shaping direction judging unit 7 for judging the signal content by a CPU or the like (not shown) is controlled based on the judgment result of the shaping direction judging unit 6, and connects the transmission line 1 to a waveform shaping circuit 8 described later or This is a shaping circuit switching unit that switches whether to connect to the circuit.

The waveform shaping circuit 8 has a receiving circuit 81 for receiving a transmission signal from the control station, and a transmission circuit 82 for shaping the waveform of the received signal and transmitting it to the subordinate station. The receiving circuit 81 has, for example, a light emitting diode 8 whose cathode is connected to the input terminal 2T and whose anode is connected to the fixed terminal a of the shaping circuit switching unit 7 via the resistor 81b.
1a.

The transmission circuit 82 includes a light emitting diode 8
A phototransistor 82a for receiving light from 1a;
An output transistor 82b having a base connected to the collector of the phototransistor 82a; a resistor 82c provided between the collector of the output transistor 82b and the power supply terminal + B; And a resistor 82d provided therebetween. The connection point between the collector of the output transistor 82b and the resistor 82c is connected to the output terminal 3T, and the emitters of the phototransistor 82a and the output transistor 82b are both connected to the output terminal 4T. The light emitting diode 81a as a light emitting element and the phototransistor 82a as a light receiving element constitute a so-called photocoupler.

The waveform shaping circuit 9 has a receiving circuit 91 for receiving a response transmission signal from the dependent station, and a transmitting circuit 92 for shaping the waveform of the received signal and transmitting the signal to the control station. The receiving circuit 91 has a cathode connected to the output terminal 4T, and an anode connected to the output terminal 3T via a resistor 91b.
, For example, a light emitting diode 91a.

The transmitting circuit 92 includes a light emitting diode 9
A phototransistor 92a for receiving light from 1a;
An output transistor 92b whose base is connected to the collector of the phototransistor 92a; a resistor 92c provided between the collector of the output transistor 92b and the power supply terminal + B; And a resistor 92d provided therebetween. The connection point between the collector of the output transistor 92b and the resistor 92c is connected to the fixed terminal b of the shaping circuit switching unit 7, and the photo transistor 92a and the output transistor 9
The emitters 2b are both connected to the input terminal 2T.

A light emitting diode 91 as a light emitting element
a and a phototransistor 92a as a light receiving element constitute a so-called photocoupler. 10 is a waveform shaping circuit 8
And a power supply circuit for supplying power to the transmission circuit 82 of the waveform shaping circuit 9 and the power supply terminal + B. The shaping direction determining unit 6 and the shaping circuit switching unit 7 constitute a shaping direction control unit, and the waveform shaping circuits 8 and 9 constitute a waveform shaping unit.

Next, the operation will be described with reference to FIG. Normally (when power is turned on), the shaping circuit switching unit 7 is connected to the waveform shaping circuit 8 via the contact a, and the transmission signal direction of the transmission lines 1 and 2 is from the control station to the slave station. It is in the one-way notification control state. Therefore, the operation signal solicited from the control station can be immediately notified to the dependent station. In the case of the polling / selecting method, after the solicitation operation from the control station, a response operation from the subordinate station is performed. However, the solicitation operation from the control station is performed by the transmission reception circuit 5 and the shaping direction determination unit 6. Is received, the connection of the transmission line 1 is switched to the waveform shaping circuit 9 via the contact b by the shaping circuit switching unit 7, so that the response operation from the slave station can be notified to the control station. .

Further, the transmission / reception circuit 5 and the shaping direction judging unit 6 receive the end of the response operation from the dependent station, and after the reception is completed, the shaping circuit switching unit 7 switches the connection to the waveform shaping circuit 8 via the contact a. If so, it becomes possible to receive the invitation operation from the control station again. In this way, the transmission control is determined, and the time slot in the transmission direction is allocated according to the content, thereby performing the waveform shaping processing of the bidirectional transmission signal.

Here, the principle of controlling the shaping direction will be further described with reference to FIG.
This will be described in detail with reference to FIG. FIG. 2A shows a standard transmission model in the polling / selecting system. One frame transmission process is started by an invitation transmission from the control station, and is completed when the corresponding subordinate station transmits a response. In the transmission receiving circuit 5, as shown in FIG.
2 are received.

As shown in FIG. 2C, the shaping direction judging section 6 discriminates whether the transmission content received by the transmission receiving circuit 5 is a control station solicitation or a dependent station response, and performs a corresponding switching control on the shaping circuit switching. 2 and the shaping circuit switching unit 7
As shown in (d), the waveform shaping circuit 8 or 9 is connected according to the notification. That is, in the case of solicitation transmission from the control station, the shaping circuit switching unit 7 first connects to the waveform shaping circuit 8 and then switches to the waveform shaping circuit 9 side to perform response transmission from the subordinate station. By the switching connection of these waveform shaping circuits, it is possible to notify the subordinate station of the invitation transmission from the control station by using the waveform shaping circuit 8 (see FIG. 2 (e)). Thus, the response transmission from the dependent station can be notified to the control station (see FIG. 2 (f)).

Next, the waveform distortion in the waveform shaping circuits 8 and 9 and the reduction of the peak value will be described with reference to FIG. Various means are conceivable for shaping the waveform distortion generated when the distance of the transmission line is extended and the decrease in the peak value thereof. In the present embodiment, FIG.
In the waveform shaping circuit 8 and the waveform shaping circuit 9 described above, a circuit model (waveform shaping using a photocoupler and a circuit that newly receives power supply from the power supply circuit 10 and improves the peak value) is used.

For example, in the waveform shaping circuit 8 of FIG. 1, a predetermined peak value (for example, a voltage level applied to the power supply terminal + B) as shown in FIG. When a rectangular wave output signal is generated, the output signal is distorted due to capacitance or the like of a transmission line on the way, and its level is also reduced due to line resistance or the like. As a result, the waveform shaping circuit 8 shown in FIG. A signal having a waveform as shown in b) is input. This signal is received as a light signal from the light emitting diode 81a of the receiving circuit 81 in the waveform shaping circuit 8 by the phototransistor 82a of the transmitting circuit 82.

In the transmission circuit 82, a threshold value TH substantially determined by the ON levels of the phototransistor 82a and the output transistor 82b is set. Accordingly, the signal from the receiving circuit 81 is waveform-shaped by the receiving circuit 82, and the output side thereof, that is, between the collector and the emitter of the output transistor 82b has no distortion as shown in FIG. A rectangular wave output signal whose level has been corrected to a peak value corresponding to the voltage level applied to the power supply terminal + B is obtained.

As described above, in the present embodiment, in the baseband transmission of the polling / selecting method,
Conventionally, by shaping the waveform distortion and the decrease of the peak value that occur when the transmission distance is extended, the waveform is shaped within a predetermined time, and the operation solicited from the control station and the response operation from the subordinate station are detected. A general waveform shaping circuit can shape the waveform in bidirectional transmission, and the transmission distance can be easily extended with a simple circuit configuration. Further, only one set of the transmission / reception circuit, the shaping direction determination unit, and the shaping circuit switching unit is required.

Embodiment 2 FIG. 4 is a block diagram showing a case where a plurality of the transmission distance extending devices of FIG. 1 are used as an example in a transmission line of a tunnel disaster prevention system. In the figure, 100 is disaster prevention receiving panel is a control station, 200 ₁ transmission distance extension device connected to the disaster prevention receiving plate 100 via a pair of transmission lines 11 and 12, 300 ₁ ~300n the pair of transmission lines 11 and connected terminal unit between 12 (fire sensor, the dependent station of fire extinguishing equipment or repeater), also 200 ₂ transmission distance extension connected to the transmission distance extension device 200 ₁ via a pair of transmission lines 21 and 22 Device.

The terminals 400 _{1 to} 400 n are connected to a terminal (fire sensor,
Dependent station of fire extinguishing equipment or repeater) 200 ₃ transmission distance extension device 2 via a pair of transmission lines 31 and 32
00 ₂ connected to the transmission distance extension device, 500 ₁ to 500
n is a terminal connected to the pair of transmission lines 31 and 32 (a dependent station such as a fire sensor, a fire extinguisher or a relay), and 600 _{1 to} 600 n are terminals connected between the pair of transmission lines 41 and 42. (A subordinate station such as a fire sensor, a fire extinguisher or a repeater). Of course, the number of cascaded transmission distance extension devices can be set arbitrarily according to the length of the tunnel.

Next, the operation will be described. Disaster prevention receiver 100
The transmission between the terminal devices 300 ₁ ~300n is performed directly, the transmission distance extension device of the transmission line 11 and 21 200
The waveform deterioration of the transmission signal becomes large in the portion close to _1, the transmission distance extension device 200 ₁ is subjected to waveform shaping processing of the transmission signal is connected between the next stage of the transmission line 21 and 22 a terminal 400 ₁ Transmission is performed with 400n. Further, the transmission distance extension device 200 for the transmission lines 21 and 22
Since than the portion close to the _second waveform degradation of the transmission signal is generated again, connected between the next stage of the transmission line 31 and 32 is subjected to waveform shaping processing of the transmission signal at a transmission distance extension device 200 _second terminal 500 Transmission is performed with _{1 to} 500n. Here the final stage, established a transmission distance extension device 200 _3, compensates for the transmission of the connected terminal unit 600 ₁ ~600n between the next stage of the transmission line 41 and 42.

As described above, in the present embodiment, by installing the transmission distance extending device that can easily extend the transmission distance, direct transmission from the disaster prevention receiver is possible even when the tunnel length becomes long. The conventional large-scale relay device and the communication between the disaster prevention receiver and the relay device become unnecessary,
Problems such as cost are improved. In addition, by installing a plurality of transmission distance extension devices, direct transmission from the disaster prevention receiver is possible even in a long tunnel. In addition, since the present system can be configured with a simple circuit, the system can be reduced in size as compared with a large-scale relay device, and the problem of installation space in a tunnel can be solved.

In the second embodiment, the transmission distance extending device according to the first embodiment is applied to a tunnel disaster prevention system as an example. However, the present invention is not limited to this. The present invention can be similarly applied to other signal transmission systems that require

[0030]

As described above, according to the present invention, in the baseband transmission of the polling / selecting method, the waveform distortion caused when the transmission distance is extended and the decrease in the peak value are reduced within a predetermined time. By shaping and detecting an operation solicited from the control station side and a response operation from the subordinate station side, a conventional general waveform shaping circuit enables waveform shaping in bidirectional transmission, and thus a simple circuit. The configuration has an effect that a transmission distance extending device that can easily extend the transmission distance can be obtained.

Further, according to the present invention, by installing a transmission distance extending device capable of easily extending the transmission distance in the transmission line, even if the tunnel length becomes long, the direct transmission from the disaster prevention receiver can be performed. This eliminates the need for a conventional large-scale relay device and communication between the disaster prevention receiver and the relay device, thereby improving the cost and other problems.In addition, by installing a plurality of transmission distance extension devices, even in long tunnels, In addition, the direct transmission from the disaster prevention receiver is possible, and the configuration can be made with a simple circuit. Therefore, it is possible to reduce the size compared to a large-scale repeater, and to solve the problem of the installation space in the tunnel. There is an effect that it can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram for describing a control principle of a shaping direction according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining a waveform distortion and a shaping operation of a decrease in a peak value thereof according to the first embodiment of the present invention;

FIG. 4 is a configuration diagram showing a second embodiment of the present invention.

FIG. 5 is a configuration diagram schematically showing an example of a conventional tunnel disaster prevention system.

[Explanation of symbols]

1, 2, 3, 4, 11, 12, 21, 22, 31, 32, 41,
42 transmission line, 5 transmission receiving circuit, 6 shaping direction determination unit, 7 shaping circuit switching unit, 8, 9 waveform shaping circuit, 1
0 power supply circuit, 100 disaster receiving plate, 200 ₁
200 ₃ transmission distance extension device, 300 ₁ ~300n,
400 _{1 to} 400n, 500 _{1 to} 00n, 600 _{1 to} 60
0n terminal.

Claims (4)

[Claims] A transmission distance extending apparatus provided in a signal transmission system for performing polling / selecting baseband transmission, wherein the shaping for detecting the content of a transmission signal transmitted in two directions and controlling the direction of waveform shaping. A transmission distance extending apparatus, comprising: a direction control unit; and a waveform shaping unit that shapes a waveform of a transmission signal whose waveform shaping direction is controlled by the shaping direction control unit. 2. The shaping direction control means detects an operation solicited from the control station and a response operation from the dependent station, allocates a time slot in the transmission direction, and sets the shaping direction. The transmission distance extending device according to claim 1. 3. The apparatus according to claim 1, wherein said waveform shaping means shapes the waveform distortion and its peak value within a predetermined time.
Or the transmission distance extending device according to 2. 4. A tunnel disaster prevention system for performing polling / selecting type baseband transmission, wherein the transmission distance extending device according to claim 1 is installed in a transmission line. Disaster prevention system.