JP3053441B2 - CATV system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CATV system provided with an amplifier for amplifying a signal transmitted through a communication line and an emergency power supply for supplying power to the amplifier when a power failure occurs.

[0002]

2. Description of the Related Art FIG. 3 shows an overall configuration of an amplifier and an emergency power supply of a conventional CATV system. Reference numeral 20 denotes a bidirectional amplifier, 21 denotes a power supply, 22 denotes an emergency power supply, and 23 denotes a power inserter.

The bidirectional amplifier 20 is connected to a communication line via high-pass / low-pass filters 25, 25, has a down-amplifying circuit 26 and an up-amplifying circuit 27, and has a status monitor for confirming a power supply state and the like. 28 and a power supply circuit 29 for converting the supplied AC power into DC power. The power supply unit 21 is connected to an AC power supply (AC 100 V).
Coaxial cable 30 that converts to 30V and constitutes a communication line
To the bidirectional amplifier 20 via the The emergency power supply unit 22 includes a battery 31, a DC / AC converter 32 that converts a DC power supply of the battery 31 into an AC power supply (AC 30 V), and a charging circuit 33 that charges the battery 31 using power supply from the power supply unit 21. The AC power is supplied to the bidirectional amplifier 20 when the power supply unit 21 cannot be used due to a power failure.

A relay 34 is turned off when the input of AC 100 V is cut off due to a power failure.
Reference numeral 36 denotes a relay that is turned on when the switch 4 is turned off and switches to the emergency power supply unit 22, and a relay 36 is turned on when the relay 34 is turned off. The relay 36 is provided in the emergency power supply unit 22, and is connected to the status monitor 28 of the bidirectional amplifier 20 via a signal line 37.

[0005] In a normal state, power is supplied from the power supply unit 21. At this time, the relay 34 is on, and both the relay 35 and the relay 36 are off. The status monitor 28 recognizes that power is being supplied from the power supply unit 21 because the relay 36 is off. On the other hand, when an input from the power supply unit 21 is cut off due to a power failure, the relay 34 is turned off, and the relays 35 and 36 are turned on accordingly. By turning on the relay 35,
The emergency power supply unit 22 is switched. The bidirectional amplifier 20
The status monitor 28 recognizes that the switching to the emergency power supply unit 22 has been made due to the relay 36 being turned on.

[0006]

However, the conventional CAT
In the V system, the bidirectional amplifier 20 is turned on and off by the relay 36 provided in the emergency power supply section 22 as described above.
Since the power supply source is recognized by the status monitor 28, a signal line 37 connecting the relay 36 and the status monitor 28 is required in addition to the coaxial cable 30. Usually, the bidirectional amplifier 20 and the emergency power supply unit 22 Since there is a considerable distance, there is a problem that the work of erection of the signal line requires time and effort.

The present invention solves the above-mentioned conventional problems and eliminates the need for a signal line connecting a status monitor and an emergency power supply unit.
C that eliminates the labor and time required for erection work
It is an object to provide an amplifier for an ATV system.

[0008]

SUMMARY OF THE INVENTION The present invention, which achieves the above objects and solves the conventional problems, comprises an amplifier for amplifying a signal transmitted through a communication line and an emergency power supply for supplying power to the amplifier in the event of a power failure. In a CATV system including a power supply for use, the amplifier includes a status monitor having a counter for counting the frequency of the supplied AC power,
The emergency power supply unit includes a battery, a voltage detection circuit for detecting a voltage of the battery, and an AC power supply having a frequency corresponding to a voltage value from the voltage detection circuit different from a normal AC frequency. DC / A to convert and output
A status converter for detecting the frequency of the supplied AC power supply, identifying the power supply state, and transmitting the power supply state to a center device connected to the communication line.

[0009]

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a CATV according to an embodiment of the present invention.
FIG. 3 is a circuit diagram showing a configuration of a system amplifier, and FIG.
Portions denoted by the same reference numerals as those in the drawings show a common configuration, and description of those portions will be omitted.

In this embodiment, the status monitor 28 of the bidirectional amplifier 20 is provided with a terminal for measuring the voltage of the AC power supply, and is connected to the power supply circuit 29. Further, the status monitor 28 is provided with a counter (not shown) for counting the AC frequency at the same time as the AC voltage is measured. Battery 31 of emergency power supply unit 22 and DC / AC
A voltage detection circuit 11 for detecting an output voltage of the battery 31 is provided between the converters 32. Further, the relay 36 and the signal line 37 are not provided as in the related art. Here, the status monitor 28 will be specifically described. For example, a 70 MHz band channel is used from the center device side, and an address is designated to each status monitor by a polling signal and called. The status monitor 28 that has received the call returns information on the monitoring items set in advance of the bidirectional amplifier 20 to the center device side, and the center device monitors the state of the bidirectional amplifier 20 based on the information.

FIG. 2 is a circuit diagram showing a detailed configuration of the emergency power supply section 22. The voltage detection circuit 11 includes a plurality of comparators 12, 12,.... The comparators 12, 12,...
The voltage values are set as V, 25V, 26V,
A predetermined comparator 1 according to the voltage value of the battery 31
Are output to the DC / AC converter 32 via 2, 12,.... The DC / AC converter 32 includes a frequency dividing circuit 15 and an oscillation circuit 16. The DC / AC converter 32 changes the frequency of the output AC power supply according to which comparator 12, 12,..., That is, the voltage value of the battery 31. For example, when the voltage value of the battery 31 is 25 V
Is changed to 90 Hz, to 24 V, to 80 Hz, and to 23 V, to 70 Hz. In addition, DC / AC
The frequency of the AC output from the converter 32 is 50 or 60 H, which is the frequency of a general AC power supply (AC 100 V).
A frequency that can be distinguished from z is set, and is not limited to the above frequency value as long as the frequency can be distinguished. In that case, by setting the frequency higher, it is possible to improve the electrical efficiency.

Next, the operation of the embodiment constructed as described above will be described. Normally, the normal power supply from the power supply unit 21 is used.
Measures the voltage and counts the AC frequency. In this case, since the frequency is 50 or 60 Hz,
The status monitor 28 can recognize that the power supply unit 21 is operating. Here, the relay 3
4 is turned off and the relay 35 is turned on to switch to the emergency power supply unit 22 as described above.
Alternatively, an alternating current having a frequency different from 60 Hz is output. The status monitor 28 counts the frequency at the time of voltage measurement, thereby recognizing that the emergency power supply unit 22 has been switched. In the above embodiment, the battery 31
Is configured to output a different frequency according to the voltage of the battery, the voltage of the battery 31 can be known from the value of the frequency, whereby the duration of the emergency power supply unit 22 can be estimated. Specifically, a bidirectional amplifier having a normal status monitor sends back various state information when the bidirectional amplifier is called by a polling signal from the center device side, and one of the state information is a power supply state. Is returned to the center device side, the voltage value of the emergency power supply unit 22 can be confirmed on the center device side. The center device estimates the duration from the transition of the voltage value based on the time measured by the emergency power supply unit 22.

In the above embodiment, the emergency power supply 22
Is provided with a voltage detection circuit 11 to change the AC frequency in accordance with the voltage of the battery 31. However, if only the switching to the emergency power supply unit 22 is recognized, the voltage detection circuit 11 No need to provide. In this case, D
The C / AC converter 32 outputs an alternating current having a certain frequency other than 50 or 60 Hz.

[0015]

As described above, according to the amplifier for a CATV system of the present invention, whether the power supply is a normal power supply or an emergency power supply is identified by counting the AC frequency with the status monitor. Therefore, it is not necessary to separately provide a signal line for connecting the status monitor and the emergency power supply unit, and the labor involved in providing the signal line can be omitted. In addition, since the power supply voltage having a different frequency is transmitted according to the voltage value of the battery of the emergency power supply, the voltage of the battery can be known from the value of the frequency, and the duration of the emergency power supply can be predicted.

[0016]

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an amplifier and an emergency power supply of a CATV system according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of an emergency power supply unit shown in FIG.

FIG. 3 is a circuit diagram of an amplifier and an emergency power supply unit of a conventional CATV system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Voltage detection circuit 12 Comparator 15 Divider circuit 16 Oscillation circuit 20 Bidirectional amplifier 21 Power supply unit 22 Emergency power supply unit 28 Status monitor 31 Battery 32 DC / AC converter

Claims (1)

(57) [Claims] 1. A CATV system comprising : an amplifier for amplifying a signal transmitted via a communication line; and an emergency power supply for supplying power to the amplifier in the event of a power failure . A status monitor having a counter for counting a frequency, wherein the emergency power supply unit includes a battery and a power supply for detecting a voltage of the battery;
A pressure detection circuit, and a DC / AC converter for converting the DC power supply of the battery into an AC power supply having a frequency corresponding to a voltage value from the voltage detection circuit different from a normal AC frequency and outputting the AC power supply. the status monitor identifies the state of the power supply by detecting the frequency of the AC power supplied, the communication line
A CATV system for transmitting a power supply status to a center device connected to a CATV system.