JP2013048357A - Antenna control system and bs modem - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna control system and a BS modem, capable of recognizing a short circuit without delay and quickly notifying an operator of it at the time when an internal conductor is shorted with an external conductor of a power feeding line connected to the BS modem.SOLUTION: The antenna control system includes an AISG device 17, a control device 16 which transmits a control signal and a power source signal to the AISG device 17, a BS modem 2 which is provided in the middle of a power feeding line 12, and superposes the power supply signal and a modulation signal having been modulated from the control signal received from the control device 16 on a power feeding signal and outputs it, and an antenna modem 14 which separates the modulation signal and the power source signal from the power feeding signal inputted from the BS modem 2, and outputs the power source signal and the control signal demodulated from the modulation signal to the AISG device 17. The BS modem 2 includes, in the middle of a power source line 4 through which the power source signal is transmitted, a short monitoring circuit 3 which detects shorting of the power feeding line 12 when a current flowing the power source line 4 comes to be a predetermined threshold value or higher and issues an alarm.

Description

  The present invention relates to an antenna control system and a BS modem that perform antenna control in accordance with the AISG (Antenna Interface Standards Group) standard.

  In mobile radio base stations, antenna tilt control can generally be performed by remote control. Initially, each manufacturer used a unique method as an antenna control method. However, in recent LTE (Long Term Evolution) radio base stations and the like, antenna control is often performed according to the AISG standard. The AISG standard is a standard standardized to ensure basic interoperability of antennas (see, for example, Patent Document 1).

  Usually, an AISG device (AISG terminal equipment) such as an antenna of a radio base station and a RET (Remote Electrical Tilt) unit that controls the antenna is arranged at a high position such as an upper part of a steel tower or a rooftop of a building. On the other hand, a radio that feeds power to an antenna and a control device (AISG control device) that controls an AISG device are generally arranged at a low position such as a lower part of a steel tower. Here, the control device transmits a control signal (RS485 standard signal) to the AISG device, controls the AISG device to control the antenna, and supplies power to the AISG device.

  The antenna and the radio are connected by a feed line (RF feed line) made of a coaxial cable, and the AISG device and the control device are connected by a control cable (AISG control cable) conforming to the AISG standard. For example, the antenna and the AISG are connected. When the device is arranged at the upper part of the steel tower and the radio device and the control device are arranged at the lower part of the steel tower, two cables of the feeder line and the control cable are laid from the upper part to the lower part of the steel tower.

  However, for example, in a steel tower as high as several tens of meters, it is very troublesome to lay cables from the upper part to the lower part of the steel tower, and the cost for the construction also increases. In order to solve this problem, the AISG standard defines a method called a coaxial interface or a modem option (hereinafter referred to as a coaxial interface method).

  As shown in FIG. 14, in the antenna control system 141 using the coaxial interface system, two modems called a BS modem 13 and an antenna modem 14 are provided in the middle of the feeder line 12 that connects the antenna 10 and the wireless device 11. The BS modem 13 and the antenna modem 14 are used to transmit a control signal and a power signal for the AISG device 17 via the feeder line 12.

  The BS modem 13 is provided in the vicinity of the wireless device 11 (for example, the lower part of the steel tower), and a control device (AISG control device) 16 is connected via a control cable 15. The antenna modem 14 is provided in the vicinity of the antenna 10 (for example, at the top of the steel tower), and an AISG device 17 is connected via the control cable 15.

  As shown in FIG. 15, in the BS modem 13, the control signal (RS485A, RS485B) input from the control device 16 via the input AISG connector 21 is modulated by the modem circuit 22 to generate a modulated signal. The modulation signal and the power supply signal input from the control device 16 are combined by the combining circuit 23, and the combined signal (referred to as an AISG signal) is output to a bias T circuit (Bias Tee) 24. The bias T circuit 24 is configured by combining a DC blocking capacitor (capacitance element) and an AC blocking inductor (inductive element). The bias T circuit 24 receives the AISG signal input from the synthesis circuit 23 from the wireless device 11 as an input side RF. The signal is superimposed on the power supply signal (RF signal) input via the connector 25 and output from the output side RF connector 26 to the power supply line 12 on the antenna 10 side.

  As shown in FIG. 16, the antenna modem 14 inputs a power feeding signal (a power feeding signal on which an AISG signal is superimposed) input from the BS modem 13 via the input side RF connector 31 to the bias T circuit 32, and the bias T circuit. At 32, the AISG signal is separated from the feed signal. The separated feed signal is output from the output-side RF connector 33 to the feed line 12 on the antenna 10 side. The AISG signal separated by the bias T circuit 32 is further separated into a modulation signal and a power supply signal by the separation circuit 34, and the separated modulation signal is demodulated by the modem circuit 35 and returned to the control signal, which is demodulated. The control signal and the power signal separated by the separation circuit 34 are output to the AISG device 17 via the output AISG connector 36.

  In general, the modem circuit 22 of the BS modem 13 and the modem circuit 35 of the antenna modem 14 are of the same configuration. As shown in FIG. 17, the modem circuits 22 and 35 modulate the control signal (RS485 standard signal) input to the RS485 interface 171 by the modulation circuit 172 to generate a modulation signal, and the generated modulation signal has directionality. The modulation signal input to the directional coupler 173 is demodulated by the demodulation circuit 174 and returned to the control signal, and output from the RS485 interface 171 to the outside. It is configured. The power supply circuit 175 of the modem circuits 22 and 35 uses the power supplied from the control device 16 to convert the input power supply voltage to the voltage for the modem circuits 22 and 35, and the RS485 interface 171, the modulation circuit 172, It is configured to output to the demodulation circuit 174.

  By adopting such a coaxial interface method, it is only necessary to lay the feeder line 12 from the upper part to the lower part of the tower, and the total cost of the antenna control system including the construction cost can be greatly suppressed. Become.

Special table 2010-519844 gazette

  However, in the conventional antenna control system 141, when the power supply is supplied from the control device 16 to the BS modem 13, the internal conductor and the external conductor of the feeder line 12 are short-circuited in a direct current manner. There is a problem that current flows.

  The feeder 12 is made of a coaxial cable, and the internal conductor and the external conductor are exposed during the connection work. Therefore, it is fully conceivable that the internal conductor and the external conductor are short-circuited during the connection work. It is also conceivable that an operator mistakenly connects to the antenna 10 without connecting the feeder 12 to the antenna modem 14. In this case, as shown in FIG. 18, if the incorrectly connected antenna 10 has a structure in which the inner conductor and the outer conductor are short-circuited inside, a short circuit between the inner conductor and the outer conductor occurs. .

  Since such a short circuit occurs during the connection work of the feeder line 12, there are many cases where an operator is present in the vicinity when the short circuit occurs. However, in the conventional antenna control system 141, when the internal conductor and the external conductor of the feed line 12 connected to the BS modem 13 are short-circuited, there is no function of immediately recognizing the short-circuit and notifying the operator. In some cases, it takes time to notice the short circuit.

  Usually, a current limiting element that prevents excessive current is often inserted in the power supply line, so there are few cases that cause damage to the circuit etc., but if a short circuit occurs, notify the operator promptly. It is desirable to take measures.

  The present invention has been made in view of the above circumstances, and when an internal conductor and an external conductor of a power supply line connected to a BS modem are short-circuited, the short-circuit is immediately recognized and promptly notified to an operator. An object of the present invention is to provide an antenna control system and a BS modem that can be used.

  The present invention was devised to achieve the above object, and includes an AISG device that controls an antenna in accordance with an AISG standard, a control signal transmitted to the AISG device, and the AISG device that controls the AISG device. Provided in the middle of a power supply line for controlling the antenna and transmitting a power signal to the AISG device and the antenna and a radio for supplying power to the antenna, and connected to the control device The control signal input from the control device is modulated to generate a modulation signal, and the modulation signal and the power supply signal input from the control device are superimposed on the power supply signal input from the wireless device. A BS modem that outputs to the feeder line on the antenna side, and is provided in the middle of the feeder line on the antenna side of the BS modem, and An ISG device is connected, and the modulation signal and the power signal are separated from the power supply signal input from the BS modem, and the modulation signal is demodulated and returned to the control signal. The control signal and the power signal are separated into the AISG device. An antenna control system comprising an antenna modem that outputs a later feed signal to the feed line on the antenna side, wherein the BS modem has a current that flows in the power line in the middle of the power line that transmits the power signal. The antenna control system includes a short-circuit monitoring circuit that detects a short circuit of the feeder line and issues an alarm when the current flowing through the power supply line exceeds a predetermined threshold.

  The short-circuit monitoring circuit is provided in the middle of the power supply line, and restricts the current flowing through the power supply line so as not to exceed the predetermined threshold, and the voltage on the input side and the output side of the current limit element A voltage comparison circuit for comparing the output side voltage and the voltage comparison circuit, wherein the output side voltage is smaller than the input side voltage of the current limiting element, and the difference between the input side voltage and the output side voltage is a predetermined value or more. An alarm means for issuing an alarm when the determination is made.

  The short circuit monitoring circuit is provided in the middle of the power supply line, detects a current flowing through the power supply line, and outputs a voltage corresponding to the detected current, and the current detection circuit includes the predetermined threshold value. A reference voltage generation circuit for generating a reference voltage corresponding to an output voltage when the current of the current is detected, and a voltage comparison circuit for comparing the output voltage of the current detection circuit with the reference voltage generated by the reference voltage generation circuit And an alarm means for issuing an alarm when the voltage comparison circuit determines that the output voltage of the current detection circuit is greater than a reference voltage.

  The voltage comparison circuit may include a comparator, and the short-circuit monitoring circuit may further include input voltage limiting means for limiting the voltage input to the comparator to be equal to or lower than an allowable voltage of the comparator.

  The alarm unit may include a light emitting unit and be configured to emit an alarm by light.

  The alarm means may include an alarm sound generating means, and may be configured to issue an alarm by sound.

  The alarm means may be configured to output a short circuit alarm signal.

  The short-circuit alarm signal may be a no-voltage contact output signal.

  A modem circuit that modulates the control signal input from the control device to generate a modulation signal when the short-circuit alarm signal is received, and a modulation signal cutoff circuit that blocks transmission of the modulation signal between the power supply line; Further, it may be provided.

  When the short-circuit alarm signal is received, it may further comprise a modem power cut-off circuit that cuts off the power to the modem circuit that modulates the control signal input from the control device and generates a modulation signal.

  A surge protection circuit for protecting the internal circuit from a surge voltage generated outside may be further provided.

  The present invention also provides an AISG device that controls the antenna in accordance with the AISG standard, a control signal transmitted to the AISG device, the AISG device that controls the antenna, and the AISG device. A control device that transmits a power signal and a power supply line that connects the antenna and a radio that feeds power to the antenna are provided. The AISG device is connected to the modulation signal and the power from the input power supply signal. An antenna modem that separates the signal and demodulates the modulated signal back to the control signal, outputs the control signal and the power signal to the AISG device, and outputs the separated feed signal to the feed line on the antenna side, The antenna control system is provided, and is provided in the middle of the feeder line on the radio side of the antenna modem. In both cases, the control device is connected, the control signal input from the control device is modulated to generate a modulation signal, and the modulation signal and the power signal input from the control device are input from the radio device. A BS modem that superimposes the power supply signal and outputs the power to the power supply line on the antenna side, and monitors the current flowing through the power supply line in the middle of the power supply line that transmits the power supply signal. The BS modem includes a short-circuit monitoring circuit that detects a short circuit of the power supply line and issues an alarm when a flowing current exceeds a predetermined threshold value.

  According to the present invention, when an internal conductor and an external conductor of a feeder line connected to a BS modem are short-circuited, an antenna control system and a BS capable of immediately recognizing the short-circuit and promptly notifying an operator A modem can be provided.

(A) is a schematic block diagram of the antenna control system which concerns on one embodiment of this invention, (b) is a schematic block diagram of BS modem. (A) is a schematic block diagram of the short circuit monitoring circuit used for BS modem of FIG.1 (b), (b) is a figure which shows an example of the circuit block diagram. It is a figure which shows the modification of the short circuit monitoring circuit of FIG. (A), (b) is a figure which shows the modification of the short circuit monitoring circuit of FIG. (A), (b) is a figure which shows the modification of the short circuit monitoring circuit of FIG. (A), (b) is a figure which shows the modification of the short circuit monitoring circuit of FIG. It is a figure which shows the modification of the short circuit monitoring circuit of FIG. It is a figure which shows the modification of the short circuit monitoring circuit of FIG. (A) is a schematic block diagram which shows other embodiment of a short circuit monitoring circuit, (b) is a figure which shows an example of the circuit block diagram. It is a schematic block diagram which shows an example of the electric current detection circuit used with the short circuit monitoring circuit of FIG. It is a figure which shows the modification of the short circuit monitoring circuit of FIG. (A), (b) is a schematic block diagram which shows the modification of BS modem of FIG.1 (b). It is a schematic block diagram which shows the modification of BS modem of FIG.1 (b). It is a schematic block diagram of the conventional antenna control system. It is a schematic block diagram of the conventional BS modem used for the conventional antenna control system of FIG. It is a schematic block diagram of the antenna modem used for the conventional antenna control system of FIG. It is a schematic block diagram of the modem circuit used for BS modem of FIG. 15, and the antenna modem of FIG. It is a figure explaining short circuit occurring when a feed line extending from a BS modem is mistakenly connected to an antenna.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1A is a schematic configuration diagram of an antenna control system according to the present embodiment, and FIG. 1B is a schematic configuration diagram of a BS modem.

  As shown in FIG. 1 (a), the antenna control system 1 controls the AISG device 17 by transmitting a control signal to the AISG device 17 that controls the antenna 10 according to the AISG standard, and the AISG device 17. The control device 16 that controls the antenna 10 and transmits a power signal to the AISG device 17 and the feeder line 12 that connects the antenna 10 and the radio 11 that feeds power to the antenna 10 are provided in the middle of the present invention. A BS modem 2 and an antenna modem 14 provided in the middle of the feeder line 12 closer to the antenna 10 than the BS modem 2 are provided.

  In the AISG standard, three types of power supplies of + 12V, -48V, and 10-30V are prepared, + 12V power supply and -48V power supply are arbitrarily connected, and 10-30V power supply is essential connection. Here, as an example, a case where a 10-30V power source with essential connection is used will be described.

  The BS modem 2 generates a modulation signal by modulating the control signal input from the control device 16 via the input AISG connector (male connector) 21, and generates the modulation signal and the power signal input from the control device 16. The synthesized signal (referred to as AISG signal) is superimposed on the power feeding signal input from the wireless device 11 via the input side RF connector 25 and output from the output side RF connector 26 to the power feeding line 12 on the antenna 10 side. It is. Details of the BS modem 2 will be described later. The input AISG connector 21 is a general connector (AISG connector) conforming to the AISG standard, and the RF connectors 25 and 26 are general coaxial cable connectors.

  The antenna modem 14 separates the AISG signal from the power feeding signal input from the BS modem 2 via the input-side RF connector 31, separates the AISG signal into a modulation signal and a power supply signal, and demodulates and controls the modulation signal. Returning to the signal, the control signal and the power signal are output from the output AISG connector 36 to the AISG device 17, and the separated power supply signal is output from the output side RF connector 33 to the power supply line 12 on the antenna 10 side. The antenna modem 14 is a general antenna modem conventionally used, and is the same as that described with reference to FIG. The output AISG connector 36 is a general connector (AISG connector) conforming to the AISG standard, and the RF connectors 31 and 33 are general coaxial cable connectors.

  The BS modem 2 is provided in the vicinity of the wireless device 11 (for example, the lower part of the steel tower), and a control device 16 is connected via a control cable 15. The antenna modem 14 is provided in the vicinity of the antenna 10 (for example, at the top of the steel tower), and an AISG device 17 is connected via the control cable 15.

  Although not shown, the control cable 15 includes two control signal lines for transmitting a control signal (RS485 standard signal) and a power line for transmitting a power signal. In this embodiment, since only the 10 to 30 V power supply is used, the control cable 15 that has at least two power supply lines of the 10 to 30 V power supply line and the DC return power supply line may be used. .

  A male connector 15a and a female connector 15b are provided at both ends of the control cable 15, respectively. The control device 16 is provided with an output connector (female connector) 16a, and the AISG device 17 is provided with an input connector (male connector) 17a. These connectors 15a, 15b, 16a, and 17a are general connectors (AISG connectors) conforming to the AISG standard. Although not shown, the AISG device 17 is provided with an output connector (female connector) so that a plurality of AISG devices 17 can be connected in a daisy chain.

  By connecting the male connector 15a of the control cable 15 to the output connector 16a of the control device 16 and connecting the female connector 15b of the control cable 15 to the input AISG connector 21 of the BS modem 2, the control device 16 and the BS modem 2 are connected. Are connected via the control cable 15. The power supply line 12 extending from the wireless device 11 is connected to the input side RF connector 25 of the BS modem 2, whereby the wireless device 11 and the BS modem 2 are connected via the power supply line 12.

  Further, the male connector 15a of the control cable 15 is connected to the output AISG connector 36 of the antenna modem 14, and the female connector 15b of the control cable 15 is connected to the input connector 17a of the AISG device 17, whereby the antenna modem 14 and the AISG device are connected. 17 is connected through a control cable 15. In addition, the power supply line 12 extending to the antenna 10 is connected to the output-side RF connector 33 of the antenna modem 14, whereby the antenna modem 14 and the antenna 10 are connected via the power supply line 12.

  Furthermore, one end of the feed line 12 is connected to the output side RF connector 26 of the BS modem 2, and the other end of the feed line 12 is connected to the input side RF connector 31 of the antenna modem 14. A modem 14 is connected via the feeder line 12.

  Next, the BS modem 2 will be described.

  As shown in FIG. 1B, the BS modem 2 flows to the power line 4 in the middle of a power line 4 (in this case, a 10 to 30 V power line that transmits 10 to 30 V power) that transmits the power signal. A short-circuit monitoring circuit 3 that monitors current and detects a short circuit of the feeder 12 and issues an alarm when the current flowing through the power supply line 4 exceeds a predetermined threshold value is provided.

  More specifically, the BS modem 2 includes a short circuit monitoring circuit 3, a modem circuit 22 that modulates a control signal input from the control device 16 via the input AISG connector 21 and generates a modulation signal, and a control device 16. A combination circuit 23 that combines the power signal input via the input AISG connector 21 and the modulation signal generated by the modem circuit 22, and a signal combined by the combination circuit 23 (referred to as an AISG signal) is input from the wireless device 11. And a bias T circuit 24 that superimposes the power feeding signal input via the side RF connector 25 and outputs the power feeding signal from the output side RF connector 26 to the power feeding line 12 on the antenna 10 side. The short circuit monitoring circuit 3 is provided on the power supply line 4 between the input AISG connector 21 and the synthesis circuit 23.

  The pin terminal (No. 6 (10 to 30 V DC)) of the input AISG connector 21 is electrically connected to the input terminal 5 of the short-circuit monitoring circuit 3 through an internal wiring and also electrically connected to the power supply circuit of the modem circuit 22. The modem circuit 22 is supplied with power. The pin terminal number is a number defined by the AISG standard (the same applies hereinafter). The modem circuit 22 is the same as that described with reference to FIG. The output terminal 6 of the short circuit monitoring circuit 3 is electrically connected to the input of the power supply signal of the synthesis circuit 23 by internal wiring.

  The pin terminals of Nos. 3 and 5 (RS485A and RS485B) of the input AISG connector 21 are electrically connected to the input / output unit (RS485 interface) of the control signal of the modem circuit 22 by internal wiring, and the modulation signal of the modem circuit 22 The input / output unit (directional coupler) is electrically connected to the input of the modulation signal of the synthesis circuit 23 by internal wiring.

  Next, the short circuit monitoring circuit 3 will be described.

As shown in FIG. 2A, the short circuit monitoring circuit 3 is provided in the middle of the power supply line 4 (between the input terminal 5 and the output terminal 6), and the current flowing through the power supply line 4 does not exceed a predetermined threshold value. The current limiting element 7 for limiting the voltage, the voltage comparing circuit 8 for comparing the voltages V _in and V _out on the input side and the output side of the current limiting element 7, and the voltage comparing circuit 8 on the input side of the current limiting element 7. small voltage V _out of _the output side of the voltage V _in, and, when the difference between the voltage V _out of _the output side voltage V _in of the input side is determined to be equal to or higher than a predetermined value, comprising an alarm means 9 for emitting an alarm, the ing. As the current limiting element 7, a polymer PTC (Positive Temperature Coefficient) thermistor (so-called polyswitch) or the like can be used.

  An example of a specific circuit configuration of the short circuit monitoring circuit 3 is shown in FIG.

In the short circuit monitoring circuit 3 shown in FIG. 2B, the voltage comparison circuit 8 includes an open drain type comparator 41 having a field-effect transistor (hereinafter referred to as FET) 42 in the output stage, and a current limiting element. consisting of two resistors R1, R2 Prefecture using a voltage V _in the input side of the 7 to resistance division.

  When the voltage input to the non-inverting input terminal 46 is larger than the voltage input to the inverting input terminal 47, the comparator 41 inputs a low level signal to the gate terminal of the FET 42 and the FET 42 is turned off. When the voltage input to the non-inverting input terminal 46 is smaller than the voltage input to the inverting input terminal 47, a high level signal is input to the gate terminal of the FET 42 and the FET 42 is turned on. In FIG. 2B, only the FET 42 is illustrated separately in the internal circuit of the comparator 41 for easy explanation.

  The positive power supply terminal 43 of the comparator 41 is connected to the positive power supply V +, and the negative power supply terminal 44 is grounded (connected to 0V). The output terminal 45 of the comparator 41 is electrically connected to the positive power source V + via the LED 9a as the alarm means 9 and the resistor R3 for limiting the current flowing through the LED 9a. That is, in this short circuit monitoring circuit 3, the alarm means 9 is composed of an LED 9a that is a light emitting means, and is configured to emit an alarm by light. In addition, it is necessary to mount LED9a so that it may be visible from the outside using the visible light type thing.

Also, the short-circuit monitor circuit 3 receives directly the voltage V _out of _the output side of the current limiting element 7 to the non-inverting input terminal 46 of the comparator 41, the voltage V _in of the input side of the current limiting element 7, resistors R1, R2 Thus, the voltage is divided by resistance and the resistance-divided voltage V _in ′ is input to the inverting input terminal 47 of the comparator 41. The voltage V _in ′ after resistance division is expressed by the following equation (1)
V _in ′ = V _in · R2 / (R1 + R2) (1)
, And becomes lower than the voltage V _in of the input side of the current limiting element 7.

The resistors R1 and R2 are expressed by the following equation (2), where Vd (= V _in −V _out ) is a voltage drop due to the current limiting element 7.
Vd <V _in −V _in ′ (2)
Is set to satisfy. That is, resistors R1, R2, the voltage V _in after resistance division 'is a value obtained by subtracting the voltage drop due to the current limiting element 7 from the voltage V _in of the input side of the current limiting element 7 (i.e. the normal state of the output side The voltage V _out ) is set as appropriate.

The short-circuit monitor circuit 3, at the time of normal short-circuit to the feed line 12 does not occur, because the current limitation by the current limiting element 7 is not performed, the input side of the voltage V _in and the output side of the voltage V _out of _the current limiting element 7 Are almost the same value, and the voltage V _in ′ obtained by resistance-dividing the input side voltage V _in is lower than the output side voltage V _out . As a result, the FET 42 of the comparator 41 is turned off and no current flows through the LED 9a.

On the other hand, at the time of short circuit a short circuit in the feed line 12 occurs, the current limit by the current limiting element 7 takes place, greatly reduced the voltage V _out of _the output side of the current limiting element 7, the voltage V _in of the input-side output The potential difference from the side voltage _Vout increases. As a result, the FET 42 of the comparator 41 is turned on, the drain terminal and the source terminal of the FET 42 are brought into conduction, and the output terminal 45 becomes the ground potential. Therefore, a current flows through the LED 9a, and a light alarm is executed.

Thus, the short-circuit monitor circuit 3, a voltage V _in 'which resisted divided by the input side of the voltage V _in the resistors R1, R2 of the current limiting element 7, the voltage V _out of _the output side of the current limiting element 7, opened When a comparison is made by the drain type comparator 41 and it is detected that the latter is a lower voltage than the former, a current limited by the resistor R3 flows through the LED 9a connected to the output terminal 45 of the comparator 41, and the LED 9a emits light. It is supposed to be.

  Although the case where the LED 9a is directly inserted between the output terminal 45 of the comparator 41 and the positive power source V + has been described here, the present invention is not limited to this, and as shown in FIG. Alternatively, an LED drive circuit 48 that turns on or blinks the LED 9 a may be connected, and the LED 9 a may be turned on or blinked via the LED drive circuit 48.

  Although the case where the LED 9a, which is a light emitting unit, is used as the alarm unit 9, the alarm unit 9 may be any unit as long as a person in the vicinity of the apparatus can recognize an abnormality. For example, as shown in FIG. 4A, the alarm unit 9 may be configured to use a buzzer 9b, which is an alarm sound generating unit, and issue an alarm by sound. Further, as shown in FIG. 4B, the alarm unit 9 may be configured to use both the LED 9a and the buzzer 9b as the alarm unit 9 and emit an alarm by light and sound.

  Furthermore, as shown in FIG. 5A, the output of the comparator 41 may be output to the outside as it is as a short-circuit alarm signal (in this case, the comparator 41 also serves as the alarm means 9). . In addition, as shown in FIG. 5B, a relay (relay circuit) 9c may be provided between the output terminal 45 of the comparator 41 and the positive power source V +, so that the short-circuit alarm signal can be a non-voltage contact output signal. It is.

  By configuring the alarm means 9 to output the short-circuit alarm signal to the outside, it is possible to receive the short-circuit alarm signal at a remote point, so that monitoring at the remote point is possible. In the case where the relay 9c is used, the output side to the input side (between the input and output terminals of the relay 9c so that the current generated in the coil when the contact of the relay 9c is opened does not affect other circuits such as the comparator 41). A diode 9d may be provided so that a current flows from the lower side to the upper side in the drawing.

  When the voltage (allowable voltage) that can be input to the comparator 41 is low, such as when the voltage of the positive power supply V + is low, the voltage input to the comparator 41 is input to the short circuit monitoring circuit 3 as shown in FIGS. However, an input voltage limiting means 49 for limiting the voltage to be equal to or lower than the allowable voltage of the comparator 41 may be further provided.

Short-circuit monitor circuit 3 shown in FIG. 6 (a), and the resistance dividing the voltage V _in of the input side of the current limiting element 7 by the resistors R1, R2, the inverting input terminal of the comparator 41 a voltage V _in 'that the resistance division In addition, the voltage _Vout on the output side of the current limiting element 7 is divided by resistors R3 and R4, and the divided voltage _Vout ′ is input to the non-inverting input terminal 46 of the comparator 41. The input voltage limiting means 49 is configured. In this case, it is necessary to set each of the resistors R1 to R4 so that V _in '<V _out ' when normal.

The short-circuit monitoring circuit 3 shown in FIG. 6B inserts Zener diodes ZD1 and ZD2 instead of the resistors R2 and R4 in FIG. 6A, and the Zener diodes ZD1 and ZD2 change the input voltage to the comparator 41. The input voltage limiting means 49 is configured to limit. In this case, if the Zener voltages of the Zener diodes ZD1 and ZD2 are V _ZD1 and V _ZD2 , it is necessary to satisfy V _ZD1 <V _ZD2 so that V _in ′ <V _out ′ _in a normal state (for example, V _ZD1 = 2V, V _ZD2 = 3V). Incidentally, the Zener voltage V _ZD2 of Zener diode ZD2 is required to be a voltage higher than the voltage V _out of _the output side of the current limiting element 7 during a short circuit of the power supply line 12.

  The short-circuit monitoring circuit 3 shown in FIG. 7 includes the input voltage limiting means 49 configured to input the voltage limited by the Zener diodes ZD1 and ZD2 in FIG. It is.

The short circuit monitoring circuit 3 in FIG. 7 is configured such that the voltage V _in ′ limited by the Zener diode ZD 1 is further divided by resistors R 5 and R 6, and the divided voltage V _in ″ is input to the inverting input terminal 47. In addition, the voltage V _out ′ limited by the Zener diode ZD 2 is further divided by resistors R 7 and R 8, and the divided voltage V _out ″ is input to the non-inverting input terminal 46. In this case, it is necessary to set the Zener diodes ZD1 and ZD2 and the resistors R1, R3, R5 to R8 so that V _in “<V _out ” is obtained _in the normal state. Since V _in ″ and V _out ″ can be adjusted by the resistors R5 to R8, the Zener diodes ZD1 and ZD2 that have the same Zener voltage may be used. However, as in the case of FIG. 6B, the Zener voltage V _ZD2 of the Zener diode ZD2 needs to be higher than the voltage V _out on the output side of the current limiting element 7 when the feeder line 12 is short-circuited.

In FIG. 2-7, or by using the voltage drop due to resistance, or by limiting the voltage by the Zener diode, so as to input to the comparator 41 by reducing the voltage V _in of the input side of the current limiting element 7 However, the present invention is not limited to this, and as shown in FIG. 8, an element B1 that drops a constant voltage is inserted in the middle of the line from the input side of the current limiting element 7 to the inverting input terminal 47 of the comparator 41. Also good.

In this case, when the voltage across the current limiting element 7 (voltage drop, V _in −V _out ) exceeds the drop voltage V _B1 at the element B1, a short circuit is recognized and an alarm is issued. drop voltage V _B1 of the element B1 must be set to be larger than the voltage drop Vd due to the current limiting element 7 (i.e. the voltage across the current limiting element 7 in the normal). As the element B1, for example, a Zener diode or a diode can be used, and a constant voltage can be lowered by utilizing a Zener voltage of the Zener diode or a forward voltage drop of the diode.

  The operation of the present embodiment will be described.

  In the antenna control system 1 according to the present embodiment, the BS modem 2 monitors the current flowing in the power line 4 in the middle of the power line 4 that transmits the power signal, and the current flowing in the power line 4 is a predetermined threshold value. When it becomes above, the short circuit monitoring circuit 3 which detects the short circuit of the feeder 12 and issues an alarm is provided.

  By providing the short-circuit monitoring circuit 3, for example, when the other end of the feeder 12 connected to the BS modem 2 is accidentally connected to the antenna 10 without being connected to the antenna modem 14, When the inner conductor and the outer conductor of the electric wire 12 are short-circuited, it is possible to immediately recognize the short-circuit and notify the operator promptly.

In the antenna control system 1, the short circuit monitoring circuit 3 is provided in the middle of the power supply line 4, and a current limiting element 7 that limits the current flowing through the power supply line 4 from exceeding a predetermined threshold value, and the current limiting element 7. voltage V _in of the input side and the output side of the voltage comparator circuit 8 for comparing V _out, a voltage comparator circuit 8, less voltage V _out of _the output side of the voltage V _in of the input side of the current limiting element 7, And when it is judged that the difference between the input side voltage V _in and the output side voltage V _out is equal to or greater than a predetermined value, the alarm means 9 is configured to issue an alarm.

As a result, when the inner conductor and the outer conductor of the feeder line 12 are short-circuited, the occurrence of a short-circuit can be detected due to a decrease in the voltage _Vout on the output side of the current-limiting element 7 and the current by the current-limiting element 7 can be detected. Due to the restriction, it is possible to suppress an excessive current from flowing in the power supply line 4.

  Furthermore, in the antenna control system 1, the alarm device 9 is composed of light emitting means such as the LED 9 a or warning sound generating means such as the buzzer 9 b, so that when the short circuit of the feeder 12 is detected, the alarm device 9 is close to the BS modem 2. An operator can be immediately notified of the occurrence of a short circuit by light or sound.

  Furthermore, the short-circuit monitoring circuit 3 is further provided with input voltage limiting means 49 for limiting the voltage input to the comparator 41 to be equal to or lower than the allowable voltage of the comparator 41, so that the positive voltage V + applied to the comparator 41 can be obtained. It can be lowered, contributing to power saving.

  Next, another embodiment of the short circuit monitoring circuit will be described.

  A short-circuit monitoring circuit 51 shown in FIG. 9A is provided in the middle of the power supply line 4, detects a current flowing through the power supply line 4, and outputs a voltage Vc corresponding to the detected current. A reference voltage generation circuit 53 that generates a reference voltage Vth corresponding to the output voltage Vc when the current detection circuit 52 detects a current of a predetermined threshold, an output voltage Vc of the current detection circuit 52, and a reference voltage generation circuit 53 A voltage comparison circuit that compares the generated reference voltage Vth, and an alarm means 55 that issues an alarm when the voltage comparison circuit determines that the output voltage Vc of the current detection circuit 52 is greater than the reference voltage Vth. It is a thing.

  An example of a specific circuit configuration of the short circuit monitoring circuit 51 is shown in FIG.

  The short-circuit monitoring circuit 51 shown in FIG. 9B is provided with a current detection circuit 52 in the middle of the power supply line 4, and the output voltage Vc of the current detection circuit 52 is input to the inverting input terminal 47 of the comparator 41. The configuration is the same as that of the short-circuit monitoring circuit 3 in FIG. 2B except that the reference voltage Vth generated by the reference voltage generation circuit 53 is input to the inverting input terminal 46. The reference voltage Vth is set to be larger than the output voltage Vc of the current detection circuit 52 at the normal time.

  The current detection circuit 52 is not particularly limited. For example, as shown in FIG. 10, a coil 56 that generates a magnetic field by a current flowing through the power supply line 4 and a magnetic field generated by the coil 56 are detected and detected. A magnetic field sensor (such as a Hall element) 57 that outputs a voltage corresponding to the intensity of the magnetic field can be used.

  In the short circuit monitoring circuit 51, when a short circuit occurs in the feeder line 12, an excessive current flows through the current detection circuit 52, and the output voltage Vc of the current detection circuit 52 becomes larger than the reference voltage Vth. As a result, the FET 42 of the comparator 41 is turned on, a current limited by the resistor R3 flows through the LED 9a, the LED 9a emits light, and a light warning is executed. During normal operation, since the output voltage Vc of the current detection circuit 52 is smaller than the reference voltage Vth, the FET 42 of the comparator 41 is turned off and no current flows through the LED 9a.

  In the short circuit monitoring circuit 51, an excessive current flows in the power supply line 4 at the time of the short circuit. Therefore, as shown in FIG. 11, a current limiting element 58 is inserted in series with the current detection circuit 52, and the power supply line 4 is connected. You may comprise so that it may suppress that an excessive electric current flows. However, as the current limiting element 58, an element in which the output voltage Vc of the current detection circuit 52 becomes larger than the reference voltage Vth when a short circuit occurs in the feeder line 12 and the current limiting by the current limiting element 58 is performed. It is necessary to use it.

  The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

  For example, although not mentioned in the above embodiment, when a short circuit occurs in the power supply line 12, the transmission of the modulation signal and the power supply signal between the modem circuit 22 and the power supply line 12 is interrupted, and the modem circuit You may comprise so that 22 may be protected.

  Specifically, as shown in FIG. 12A, a short-circuit alarm signal is received from the short-circuit monitoring circuits 3 and 51 between the modulation signal output of the modem circuit 22 and the modulation signal input of the synthesis circuit 23. When a short circuit alarm signal is received from the short circuit monitoring circuits 3 and 51 as shown in FIG. 12B, the modem circuit 22 is provided. A modem power supply cut-off circuit 61 that cuts off the power supply to the modem and stops the operation of the modem circuit 22 may be provided. In addition, what is necessary is just to utilize the output of the comparator 41 as a short circuit alarm signal. Moreover, as the breaker circuits 60 and 61, a voltage control switch such as a relay (relay circuit) that opens a contact when a short-circuit alarm signal is received may be used.

  Further, as shown in FIG. 13, a surge protection circuit 62 is provided in the vicinity of the input AISG connector 21, and an internal circuit (such as a short circuit monitoring circuit 3, 51 or a modem circuit 22) is detected from a surge voltage generated externally such as a lightning surge. The BS modem 2 may be configured to protect it.

DESCRIPTION OF SYMBOLS 1 Antenna control system 2 BS modem 3 Short circuit monitoring circuit 4 Power supply line 10 Antenna 11 Radio | wireless machine 12 Feed line 14 Antenna modem 15 Control cable 16 Control apparatus 17 AISG device

Claims (12)

An AISG device that controls the antenna in accordance with the AISG standard;
A control device that transmits a control signal to the AISG device, controls the AISG device to control the antenna, and transmits a power signal to the AISG device;
Provided in the middle of a feed line connecting the antenna and a radio that feeds the antenna, the control device is connected, and modulates a control signal input from the control device to generate a modulation signal, A BS modem that superimposes the modulation signal and the power supply signal input from the control device on the power supply signal input from the radio, and outputs the signal to the power supply line on the antenna side,
It is provided in the middle of the power supply line on the antenna side of the BS modem, and the AISG device is connected to separate the modulation signal and the power signal from the power supply signal input from the BS modem. An antenna modem that demodulates and returns to the control signal, outputs the control signal and the power signal to the AISG device, and outputs the separated feed signal to the feed line on the antenna side;
In an antenna control system with
The BS modem is
In the middle of the power supply line that transmits the power supply signal, the current flowing through the power supply line is monitored, and when the current flowing through the power supply line exceeds a predetermined threshold, a short circuit of the feeder line is detected and an alarm is generated. An antenna control system comprising a short-circuit monitoring circuit. The short circuit monitoring circuit is:
A current limiting element that is provided in the middle of the power supply line and limits the current flowing through the power supply line so as not to exceed the predetermined threshold;
A voltage comparison circuit for comparing the input side and output side voltages of the current limiting element;
An alarm that issues an alarm when the voltage comparison circuit determines that the voltage on the output side is smaller than the voltage on the input side of the current limiting element and that the difference between the voltage on the input side and the voltage on the output side is equal to or greater than a predetermined value. The antenna control system according to claim 1, further comprising: means. The short circuit monitoring circuit is:
A current detection circuit that is provided in the middle of the power supply line, detects a current flowing through the power supply line, and outputs a voltage corresponding to the detected current;
A reference voltage generation circuit for generating a reference voltage corresponding to an output voltage when the current detection circuit detects a current of the predetermined threshold;
A voltage comparison circuit that compares the output voltage of the current detection circuit with a reference voltage generated by the reference voltage generation circuit;
The antenna control system according to claim 1, further comprising alarm means for issuing an alarm when the voltage comparison circuit determines that the output voltage of the current detection circuit is greater than a reference voltage. The voltage comparison circuit has a comparator,
The antenna control system according to claim 2, wherein the short-circuit monitoring circuit further includes input voltage limiting means for limiting a voltage input to the comparator to be equal to or lower than an allowable voltage of the comparator. The antenna control system according to any one of claims 2 to 4, wherein the alarm unit includes a light emitting unit and is configured to emit an alarm by light. The antenna control system according to claim 2, wherein the alarm unit includes an alarm sound generation unit and is configured to issue an alarm by sound. The antenna control system according to claim 2, wherein the warning unit is configured to output a short-circuit alarm signal. The antenna control system according to claim 7, wherein the short-circuit alarm signal is a no-voltage contact output signal. A modem circuit that modulates the control signal input from the control device to generate a modulation signal when the short-circuit alarm signal is received, and a modulation signal cutoff circuit that blocks transmission of the modulation signal between the power supply line; The antenna control system according to claim 7 or 8, further comprising:   The modem power cut-off circuit further cuts off power to the modem circuit that modulates the control signal input from the control device and generates a modulation signal when the short-circuit alarm signal is received. The antenna control system described in 1. The antenna control system according to claim 1, further comprising a surge protection circuit for protecting an internal circuit from a surge voltage generated outside. An AISG device that controls the antenna in accordance with the AISG standard;
A control device that transmits a control signal to the AISG device, controls the AISG device to control the antenna, and transmits a power signal to the AISG device;
In addition to being provided in the middle of a feed line connecting the antenna and a radio that feeds power to the antenna, the AISG device is connected to separate the modulation signal and the power signal from the input feed signal, and the modulation signal Is used for an antenna control system comprising: an antenna modem that outputs a control signal and a power signal to the AISG device, and outputs a separated feed signal to the feed line on the antenna side;
Provided in the middle of the feeder line on the radio side of the antenna modem, and connected to the control device, modulates a control signal input from the control device to generate a modulation signal, A BS modem that superimposes a power supply signal input from the control device on a power supply signal input from the wireless device and outputs the power signal to the power supply line on the antenna side,
In the middle of the power supply line that transmits the power supply signal, the current flowing through the power supply line is monitored, and when the current flowing through the power supply line exceeds a predetermined threshold, a short circuit of the feeder line is detected and an alarm is generated. A BS modem characterized by comprising a short-circuit monitoring circuit.