JPS5845220B2 - track repeater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surge protection circuit having the function of preventing surges from entering a line repeater due to a line accident on a relay transmission line or a lightning strike.

In a multi-reply transmission line, a line repeater is usually loaded onto the line to form a relay transmission line, and since this line repeater is usually installed inside a manhole or on a pole, the interval between the repeaters must always be adjusted. It is generally difficult to make it constant.

For the reasons mentioned above, the actual repeater spacing usually does not match the design center value of the repeater. This is called a BON).

In this case, several types of BONs are usually prepared, and the most suitable BON for the relay interval to be installed is selected and used. One way to select and use this BON is to relay several types of BONs in advance. The switch is built into the repeater itself, and it is electrically switched or shifted from outside the repeater to select and use the appropriate ON state.

One object of the present invention is to provide an improved electrical switch circuit for conducting or disconducting a plurality of line loss compensation networks provided within the repeater.

In addition, in so-called relay transmission lines including conventional repeaters, there is a tendency for either positive or negative surges to enter, especially depending on the switching and insertion mode of the line loss compensation circuit network, which is a special problem. There is a defect in that even if two surge blocking TL circuits are inserted in parallel, it is still not complete.

The main object of the present invention is to, in such a system of relay transmission lines, accompany the switching operation of the line loss compensation network,
Even if a positive or negative surge enters,
It is an object of the present invention to provide an in-line surge protection circuit that can effectively prevent this.

Figures 1 and 2 show BON in a conventional relay transmission line.
This is an example of a switching circuit, and in these figures, the only difference is the position of the application end of the switching voltage, so
The code is the same.

In FIGS. 1 and 2, 1 is an input terminal, and 2 is an output terminal of this circuit, after which an amplification circuit using transistors is usually connected to form a so-called repeater.

BONs 3 and 4 each have a different time constant, and one of the BONs is selected as necessary and inserted into the signal path.

In the case of FIG. 1, by connecting the positive power supply to the external terminal 5, the diodes 6 and 7 become conductive, so that the BON 3 is inserted into the signal path.

Furthermore, by connecting a positive power source to the terminal 8, the diodes 9 and 10 can be made conductive and the BON 4 can be inserted into the signal path.

In the case of Fig. 2, by connecting the negative power source to terminal 5 and the positive power source to terminal 6, the diode 7.8 becomes conductive and BON3 is inserted into the signal path, and conversely, the positive power source is connected to terminal 5. , when a negative power supply is connected to terminal 6, diodes 9 and 10 become conductive, and BON 4 is selected and inserted into the signal path.

Note that in the figure, capacitors 11, 12, 13, and 14 are for blocking the branching of the current that controls conduction and non-conduction of each diode.

Looking at the above two examples, in either case, BON
The diodes to be controlled are in the same direction with respect to the signal path on the output side of the BON, and are configured so that positive or negative surges can enter regardless of which BON is switched to. , and therefore vulnerable to incoming surges.

On the other hand, in the surge protection circuit according to the present invention, the directions of such diodes are opposite to each other, so that regardless of the switching state, the surge protection circuit can protect against the ingress of either positive or negative surges. It has a function to prevent this.

Next, one embodiment of this invention will be described.

FIG. 3 shows an embodiment of the surge protection circuit according to the present invention, in which 1' is an input terminal of this circuit, 2' is also an output terminal, and 3' is one BON 4' is another one.
N and 5' are external input terminals, 6' and 7' are diodes connected in opposite directions to BON 3', 9' and 10' are diodes connected in opposite directions to BON 4', and 11 '.

12' is a capacitor for blocking the control current of each diode.

In such a configuration, for example, if a positive voltage is supplied to terminal 5', diodes 6' and 7' become conductive, and BON3' is naturally inserted into the signal path, and conversely, a negative voltage is supplied to terminal 5'. When the voltage is not supplied, the diodes 9' and 10' become conductive, and the BON 4' is inserted into the circuit and utilized.

Therefore, if a positive voltage surge enters this circuit from the input terminal 1', the diode 10'.

In the path of BON4', diode 9' or output terminal 2', the surge is blocked by diode 10', and in the path of diode 7', BON3' diode 6' or output terminal 2', diode 7' conducts. However, the surge is blocked by the diode 6', and the surge is surely prevented from entering the circuit in either direction]! r, it will be done.

On the other hand, in the conventional circuit described above, when a surge of positive voltage enters, the diodes 7 and 10 in the case of FIG.
In the same way as in the case of Figure 2, a positive surge will pass through diode 8, BON 3 or diode 7, and a surge voltage will appear at terminal 2, which may damage the subsequent circuit, and the negative If the surge becomes too strong, there is a risk that the surge will enter through the path of the diode 10, BON 4, or diode 9 and damage the circuit.

As described in detail above, according to the present invention, it is possible to selectively use the internal line loss compensation circuit network by simply converting the positive or negative voltage to be applied to a single switching voltage terminal, and the internal line loss compensation network can be selectively used. Reliably blocks surge voltage
It has the advantage of being able to obtain L.

[Brief explanation of drawings]

1 and 2 are circuit diagrams illustrating conventional switching circuits, and FIG. 3 is a circuit diagram illustrating an embodiment of the present invention. 1'...Circuit input terminal, 2'...Output terminal, 3'. 4'...Line loss compensation network (BON), 5'...
External terminal, 6/, 7/...diode, 9', 10'
···diode.

Claims (1)

[Claims] 1. In a line repeater including a first line loss compensation circuit network provided in series with alternating current on a relay transmission line and a second line loss compensation network provided in parallel with said first circuit network in terms of alternating current. ,
a first pair of diodes connected to the input end and output side of the first circuit network via the first circuit network so that anodes or cathodes thereof face each other; and an input end and the output side of the second circuit network. Supplying a direct current of a desired polarity to a second pair of diodes whose cathodes or anodes are connected to face each other via the second circuit network on the output side, and to the first and second pairs of diodes. circuit network selection means that operates to conduct one of the first and second pairs of diodes and selectively insert one of the first and second circuit networks into the transmission path; A track repeater characterized by: