JP2001045455A - Connection method for monitor signal for feeder and its connection circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a connection circuit that can transmit a monitor signal and a feed current through one cable by separately applying the feed current, which is inserted midway a coaxial transmission line, sent from a feeder and supplied to a repeater, and a monitor signal communicated between a center device and the feeder and superimposing the monitor signal on the feed current in a coaxial transmission line. SOLUTION: An outgoing monitor signal 26 being a request signal sent from a center device 1 is given to a terminal 11 of a transmission line connector circuit 5 through a repeater 2. The received signal passes through a capacitor 14, is given to a directional coupler 15 from which the signal is outputted to a capacitor 17 as a signal having a level attenuated in a connection direction of the directional connector 15, passes through a capacitor 17 and is outputted from a terminal 13. A superimposing signal among monitor signals 26, 27 and a feed current 28 is given to each capacitor, in which the monitor signals 26, 27 being high frequency signals are separated from the superimposed signal, the superimposed signal is given to each inductor, in which the feed current 28 with a low frequency is separated from the superimposed signal respectively. The monitor signals 26, 27 are given from a status monitor 8 to the center device 1 and the feed current 28 is given from an AC power supply 9 to a repeater 3 selectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of coupling a monitoring signal for a power supply device in a CATV system and a coupling circuit thereof, and more particularly, to a method of connecting a power supply to a repeater and communicating a monitoring signal with a center device using a single coaxial cable. The present invention relates to a method of coupling a monitoring signal for a power supply device and a coupling circuit thereof.

[0002]

2. Description of the Related Art In a CATV (cable television) system, in general, when an operation state of a power supply device attached to a plurality of repeaters is monitored by a status monitor (SMT) provided in the power supply device, A coupling circuit is provided in the middle of the coaxial transmission line, and a coaxial cable dedicated to monitoring signals is laid and connected from the power supply device to the coupling circuit in the middle of the coaxial transmission line, separately from the coaxial cable for power supply to the repeater. Was.

FIG. 6 is a block diagram showing an example of a conventional power supply monitoring signal coupling circuit. The conventional coupling circuit is inserted in the middle of a coaxial transmission line connecting the repeater 2 and the repeater 3, and connects the monitoring signal exchanged between the center device 1 and the power supply device 4 located in the upper direction. Coupler 101
And a power inserter 10 for supplying the feed current sent from the feed device 4 to the repeater 3 located in the lower direction.
2 and the respective terminals of the monitoring signal terminal 111 and the power supply terminal 112 on the power supply device side are connected by two coaxial cables 103 and 104.

[0004]

The above-mentioned conventional circuit for coupling a monitoring signal for a power supply device requires a construction work in which two long coaxial cables are laid according to the distance from the coupling point to the coaxial transmission line to the power supply device. It is necessary, and furthermore, the configuration is such that the monitoring signal and the supply current sent by each dedicated coaxial cable are coupled to the coaxial transmission line by the respective coupling circuits, so that the configuration of the equipment becomes complicated and disadvantages in operability and economy. have.

SUMMARY OF THE INVENTION An object of the present invention is to combine a monitoring signal for a power supply device with a monitoring signal for the power supply device superimposed on a coaxial cable for power supply, and the transmission of the monitoring signal and the power supply can be transmitted through a single coaxial cable. Is to provide.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method of coupling a supervisory signal for a power supply device, comprising: supplying power to a plurality of repeaters arranged in the middle of a coaxial transmission line connected to a center device; In a coupling method for connecting a power supply device for performing communication of a monitoring signal between the power supply device and the coaxial transmission line using a coaxial cable, the power supply device is inserted in the middle of the coaxial transmission line to the repeater sent from the power supply device. The power supply current to be supplied and the monitor signal communicating between the center device superimposed on the power supply current are separated and coupled to the coaxial transmission line, and the monitor signal is provided on the power supply device side and the monitor signal is provided. The present invention is characterized in that a single coaxial cable is connected from the power supply device to the coupling point to the coaxial transmission line, superimposed on the power supply current.

In addition, the power supply monitoring signal coupling circuit of the present invention supplies power to a plurality of repeaters arranged in the middle of a coaxial transmission line connected to the center device, and communicates with the center device through the repeaters. In a coupling circuit that connects a power supply device for communicating a monitoring signal and the coaxial transmission line using a coaxial cable, a power supply current that is inserted in the middle of the coaxial transmission line and supplied from the power supply device to be supplied to the repeater. And a transmission line coupling circuit that separates the monitoring signal that communicates with the center device superimposed on the power supply current and couples the monitoring signal to the coaxial transmission line. A power supply coupling circuit superimposed on the power supply current, and the power supply coupling circuit and the transmission line coupling circuit are connected by a single coaxial cable.

The transmission line coupling circuit includes means for coupling the center device side and the power supply device side bidirectionally with a predetermined degree of coupling, and positioning the power supply current from the power supply device in an upper direction. And a means for supplying to a repeater located in a lower direction.

Further, the transmission line coupling circuit includes means for coupling the center device side and the power supply device side bidirectionally with a predetermined degree of coupling, and positioning the power supply current from the power supply device in an upper direction. Switching means for feeding the repeater, the lower repeater or both repeaters,
Means for removing unnecessary waves outside the signal band provided on the power supply device side.

The power supply coupling circuit has a means for passing the power supply current and a means for passing the monitoring signal, and is provided in the vicinity of the inside or outside of the power supply device. One end of the means for passing the monitoring signal is commonly connected and connected to the coaxial cable.

Further, the transmission line coupling circuit and the power supply coupling circuit are characterized in that all connection portions of the coaxial transmission line and the coaxial cable have a characteristic impedance of 75 ohms.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of a power supply monitoring signal coupling circuit according to the present invention.

The present embodiment shown in FIG. 1 is a monitoring signal which is inserted in the middle of a coaxial transmission line connecting a repeater 2 and a repeater 3 and is communicated through the repeater 2 with a center device 1 located in an upper direction. A directional coupler 15 for passing the current in both directions, and inductances 18, 19 and capacitances 16, 17, 20 for supplying the feed current sent from the feed device 4 only to the repeater 3 located in the lower direction. A transmission line coupling circuit 5,
An inductance 25 and a capacitance for superimposing a monitoring signal communicated between the power supply device 4 and the center device 1 positioned in the upper direction and a power supply current supplied to the repeater 3 positioned in the lower direction in the power supply device 4. 24, and one coaxial cable 6 for connecting the transmission line coupling circuit 5 and the power supply coupling circuit 7 to each other.

Next, the detailed configurations of the transmission line coupling circuit 5 and the power supply coupling circuit 7 will be described. Transmission line coupling circuit 5
Has terminals 11, 12 and 13 and receives from the terminal 11 a downstream monitoring signal sent from the center device 1 and outputs a main signal and a branch signal having a coupling degree of, for example, 10 to 20 dB with respect to the main signal. Directional coupler 15, and a series connection inductance 18, 19 for inputting a superimposed signal of the upstream monitor signal and the feed current output from the feed device 4 from the terminal 13 and supplying the feed current only to the repeater 3. And capacitors 17 and 16 for blocking the supply current through a high-frequency upward monitoring signal
And 14.

The feed coupling circuit 7 has terminals 21, 22 and 2
3, a capacitor 24 for inputting the downstream monitoring signal output from the transmission line coupling circuit 5 from the terminal 21 and passing a high frequency downstream monitoring signal, and an inductance 25 for blocking the downstream monitoring signal.
And an up monitor signal, which is a response signal input from the terminal 22 to the down monitor signal, and a feed current input from the terminal 23 are connected to the capacitance 24 and the inductance 25.
, And superimposed and output at a terminal 21.

Next, the example of the directional coupler shown in FIG.
The road configuration is shown in FIG. In FIG. 2, the terminal 51 is
The terminal 52 is connected to the repeater 2 side, and the terminal 52 is connected to the repeater 3 side.
The terminal 53 is connected to the power supply device 4 side. Arrows in the figure
Solid lines 56 and 57 indicate transmission directions, and solid lines 58 and 59 indicated by arrows.
Is the connection direction, and the dotted lines 60 and 61 are non-transmission directions.
Indicates the direction. Here, the number of primary and secondary turns of the transformer 55
Assuming that the ratio is n, insertion of the solid lines 56 and 57 which are the transmission directions
The loss is 20 Log (1 + 1 / 2n ^Two )
The degree of coupling between the solid lines 58 and 59 is 20 Logn. one
On the other hand, the degree of coupling between the dotted lines 60 and 61 in the non-transmission direction is large.
Generally, about 30 dB is obtained, so that there is no practical problem.
No. The turns ratio of the transformer 55 is determined by the coaxial transmission of the monitoring signal.
To minimize the influence of the transmission line on the main signal,
The coupling degree of the coupler 15 is generally in the range of 10 to 20 dB.
Is set.

The above-described transmission line coupling circuit 5 and power supply coupling circuit 7
In this case, the monitoring signal and the power supply current can be connected to the coaxial transmission line using a single coaxial cable.

Since the coaxial transmission line and the coaxial cable generally have a characteristic impedance of 75 ohms, the terminals 11, 12 and 13 of the transmission line coupling circuit 5 and the power supply coupling circuit 7
Is connected to the coaxial transmission line or coaxial cable 6 after being matched to 75 ohms in the signal band of the monitoring signal.

FIG. 3 is a block diagram showing the flow of the monitoring signal in FIG.

Next, the operation of the present embodiment will be described in more detail with reference to FIGS. The downlink monitoring signal 26, which is a request signal transmitted from the center device 1,
To the terminal 11 of the transmission line coupling circuit 5 The input signal is output as a level attenuated in the coupling direction of the directional coupler 15 through the capacitor 14 and output from the terminal 13 through the capacitor 17. The signal output from the terminal 13 is input to the terminal 21 of the power supply coupling circuit 7 on the power supply device 4 side through the coaxial cable 6, passes through the capacitor 24, and is connected to the status monitor 8 via the terminal 22.

The up monitor signal 27, which is a response signal output from the status monitor 8, is input from the terminal 22, passes through the capacitor 24, is input to the terminal 23, passes through the inductance 25, and is superimposed on the 60 VAC power supply current 28 at the terminal 21. The signal is output to the coaxial cable 6.

The superimposed signal of the upstream monitor signal 27 and the supply current 28 input to the terminal 13 of the transmission line coupling circuit 5 is separated by the capacitance 17 and the inductance 18 and the upstream monitor signal 2
7 is output from the terminal 11 through the capacitor 17, the directional coupler 15 and the capacitor 14, and transmitted to the center device 1 through the repeater 2. On the other hand, the power supply current 28 is blocked by the capacitor 17, is output to the terminal 12 through the inductances 18 and 19, and is supplied to the repeater 3. Inductance 18,
A capacitor 20 is connected to the ground at the connection point 19 to remove high frequency components.

In the above description, the superimposed signal of the monitor signals 26 and 27 and the feed current 28 is obtained by superposing the monitor signals 26 and 27, which are high-frequency signals, by the respective capacitances and the low-frequency feed current 28.
Are separated by the respective inductances, and the monitoring signals 26 and 27 are transmitted from the status monitor 8 to the center device 1.
The case where the power supply current 28 is selectively connected from the 60 VAC power supply 9 to the repeater 3 has been described. It is also possible to selectively supply to.

FIG. 4 is a circuit diagram showing another embodiment of the transmission line coupling circuit. Referring to FIG. 4, the switches 32, 33 of the transmission line coupling circuit 5a are connected in series with the inductances 18, 34 for passing the power supply current 28, and the power supply direction is arbitrarily set to the lower direction, the upper direction, or both directions. . By controlling the switches 32 and 33, when a failure occurs in another power supply device that supplies power to a relay located in an upper direction where power is not supplied, the power supply direction is changed to a relay located in an upper direction. Since the communication of the monitoring signal with the center device can be maintained by switching, the reliability can be improved. Here, the switches 32 and 33 only need to have a current capacity for switching the power supply current 28, and the control circuit and the control method are not particularly limited.

The filter 31 is a low-pass filter or a band-pass filter having a band necessary for passing both the downstream monitor signal 26 and the upstream monitor signal 27, and can remove unnecessary waves outside the band. .

FIG. 5 is a circuit diagram showing another embodiment of the feed coupling circuit of the present invention. Referring to FIG. 5, the power supply coupling circuit 7 a is installed close to the outside of the power supply device 4 having the monitoring signal terminal 46 and the power supply output terminal 47 independently, and includes a combination of a high-pass filter 44 and a low-pass filter 45. It consists of a wave device. The high-frequency upward monitoring signal 27 is output from the terminal 42 to the terminal 41 through the high-pass filter 44, and the power supply current 28 is output from the terminal 43 to the terminal 41 through the low-pass filter 45. The upstream monitor signal 27 and the supply current 28 at the common terminal 41
Are superimposed and output to the coaxial cable 6. Further, the high frequency downstream monitoring signal 26 input from the common terminal 41 is
High-pass filter 4 blocked by low-pass filter 45
4 and is output from a terminal 42 and connected to a status monitor 8 provided in the power supply device 4. In addition, as an example of installation of the power supply coupling circuit 7a, a case where the power supply coupling circuit 7a is close to the outside of the power supply device 4 is shown, but the inside and outside of the power supply device 4 are not limited.

[0027]

As described above, the present power supply device monitoring signal coupling circuit has the following effects by combining the transmission line coupling circuit and the power supply coupling circuit.

The first effect is that the power supply and the monitoring signal for the power supply device can be transmitted by one coaxial cable, so that a transmission path system with a simplified transmission path configuration and excellent economic efficiency can be realized.

The second effect is that the direction of supply of the feed current can be selected at the connection point of the coaxial transmission line. Therefore, if a fault occurs in another feeder that feeds the repeater located in the upper direction, the feed will be lost. By switching the direction from the repeater located in the lower direction to the repeater located in the upper direction, or by feeding power to both repeaters, communication of the monitoring signal with the center device is maintained as long as the uplink transmission path is not hindered. Reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a monitoring signal coupling circuit for a power supply device according to the present invention.

FIG. 2 is a circuit diagram showing a configuration of an example of the directional coupler shown in FIG.

FIG. 3 is a block diagram showing a flow of a monitor signal of a monitor signal combining circuit shown in FIG. 1;

FIG. 4 is a circuit diagram showing another embodiment of the transmission line coupling circuit shown in FIG. 1;

FIG. 5 is a circuit diagram showing another embodiment of the feed coupling circuit shown in FIG. 1;

FIG. 6 is a block diagram showing an example of a conventional power supply monitoring signal coupling circuit.

[Explanation of symbols]

 Reference Signs List 1 center device 2, 3 repeater 4 power supply device 5, 5a transmission line coupling circuit 6, 103, 104 coaxial cable 7, 7a power supply coupling circuit 8 status monitor 9 AC power supply 14, 16, 17, 20, 24, 36 capacity 15 Directional coupler 18, 19, 25, 34, 35 Inductance 26 Downlink monitoring signal 27 Uplink monitoring signal 28 Supply current 31 Filter 32, 33 Switch 44 High-pass filter 45 Low-pass filter 55 Transformer 101 Directional coupler 102 Power inserter

Claims (6)

[Claims] 1. A power supply device for supplying power to a plurality of repeaters arranged in the middle of a coaxial transmission line connected to a center device and communicating a monitor signal with the center device through the repeater, and the coaxial transmission line And a connection method using a coaxial cable to connect the center device superimposed on the power supply current inserted into the coaxial transmission line and supplied from the power supply device to the repeater and superimposed on the power supply current. The monitoring signal exchanged between the power supply device and the monitoring signal is separated and coupled to the coaxial transmission line, the monitoring signal is provided on the power supply device side, the monitoring signal is superimposed on the power supply current, and the coupling from the power supply device to the coaxial transmission line is performed. A method for combining monitoring signals for a power supply device, wherein a single coaxial cable is used to connect to a location. 2. A power supply device for supplying power to a plurality of repeaters arranged in the middle of a coaxial transmission line connected to a center device and communicating a monitoring signal with the center device through the repeater, and the coaxial transmission line And a center circuit superimposed on the power supply current, which is inserted in the middle of the coaxial transmission line and supplied to the repeater, and which is superimposed on the power supply current. A transmission line coupling circuit that separates the monitoring signal communicated between the two and couples to the coaxial transmission line; a power supply coupling circuit provided on the power supply device side for superimposing the monitoring signal on the power supply current; A power supply monitoring signal coupling circuit, wherein the coupling circuit and the transmission line coupling circuit are connected by a single coaxial cable. 3. The transmission line coupling circuit includes means for coupling the center device side and the power supply device side bidirectionally with a predetermined degree of coupling, and positioning the power supply current from the power supply device in an upper direction. And a means for supplying to a repeater located in a lower direction.
A circuit for coupling a monitoring signal for a power supply device according to any one of the preceding claims. 4. The transmission line coupling circuit includes means for coupling the center device side and the power supply device side bidirectionally with a predetermined degree of coupling, and positioning the power supply current from the power supply device in an upper direction. Switching means for supplying the signal to the repeater, the repeater located in the lower direction, or both of the repeaters, and means provided on the power supply device side for removing unnecessary waves outside the signal band. A circuit for coupling a monitoring signal for a power supply device according to claim 2. 5. The power supply coupling circuit includes a means for passing the power supply current and a means for passing the monitoring signal, and is provided near or inside the power supply device, and each of the power supply currents or 5. The power supply monitoring signal coupling circuit according to claim 2, wherein one end of the means for passing the monitoring signal is commonly connected and connected to the coaxial cable. 6. The transmission line coupling circuit and the power supply coupling circuit, wherein all connection portions of the coaxial transmission line and the coaxial cable have a characteristic impedance of 75 ohms. Or a coupling circuit of the monitor signal for the power supply device according to 5.