JPH11261455A - Signal transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the transmitter in which a monitor cable is omitted by providing a low frequency signal generating means to one end of a high frequency coaxial cable, providing a low frequency signal reception means to the other end of the cable by applying high frequency isolation to them, and sending a low frequency signal through a high frequency coaxial cable. SOLUTION: On the occurrence of a fault in a transmission reception amplifier 2B, a state detection section 2b detects the fault state and provides an output of a state signal denoting it. The state signal 20 is given to a state/pulse signal conversion circuit 14, where the signal is converted into a low frequency pulse signal, and the signal is outputted to a high frequency coaxial cable 18 via a buffer 15 and an inductance 16. A fault state discriminated and detected by the state detection section 2b is outputted as a prescribed pulse signal. In this case, the pulse signal is outputted in a form that is superimposed on a signal through the high frequency coaxial cable 18. The pulse signal superimposed on a signal through the high frequency coaxial cable 18 reaches a pulse/ state signal conversion circuit 12 via an inductance 10 and a buffer 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a signal transmission device that transmits a low-frequency signal using a high-frequency coaxial cable provided between points, and particularly uses a high-frequency coaxial cable that connects a transmission / reception amplifier and a modem in a base station such as a mobile phone. Further, the present invention relates to a signal transmission device in a state monitoring device or the like that transmits a state signal for monitoring an abnormal state of a transmission / reception amplifier as a low-frequency pulse signal.

[0002]

2. Description of the Related Art In a general base station such as a cellular phone, a transmission / reception amplifier is provided near an antenna disposed outdoors, and a signal processing device such as a modem is installed indoors far from the transmission / reception amplifier. Is arranged. As described above, in the base station, the antenna is disposed outdoors, and the transmission / reception amplifier is disposed at a position distant from the modem or the like. Therefore, a state monitoring device for monitoring the normal / abnormal state of the transmission / reception amplifier. Is installed to transmit the status signal of the transmission / reception amplifier to the indoor side. Conventionally, signal transmission in such a state monitoring device is performed by laying a cable dedicated to monitoring between the modem and the transmission / reception amplifier, and transmitting a state signal by this cable.

FIG. 3 is a block diagram showing a conventional signal transmission device in a base station such as a mobile phone. In FIG. 3, reference numeral 1 denotes a transmitting / receiving antenna which is disposed outdoors and 2A denotes a transmitting / receiving amplifier connected to the transmitting / receiving antenna 1 in the vicinity of the transmitting / receiving antenna 1 outdoors. Is provided with a state detection unit 2a for monitoring.

The state detector 2a detects, for example, a potential state of a predetermined section of the transmission / reception amplifier 2A, determines whether the transmission / reception amplifier 2A is normal or abnormal based on the potential state, and outputs a state signal as a determination result. This is output to a state monitoring device (not shown) provided on the indoor side. The status signal is a low-frequency analog signal or a logic signal for serial communication.

[0005] Reference numeral 3 denotes a reception signal cable for transmitting the reception signal amplified by the transmission / reception amplifier 2A to the indoor modem 6, and 4 denotes a transmission signal cable for transmitting the transmission signal from the modem 6 to the transmission / reception amplifier 2A. 5 is a monitoring cable for transmitting the status signal of the transmission / reception amplifier 2A to the modem 6 side (status monitoring device), 6 is the above-described modem, and 7 is connected to the modem 6 to connect the modem 6 to a telephone line. The exchanger.

[0006] As described above, the transmitting and receiving antenna 1 to the monitoring cable 5 are usually installed outdoors, and the modem 6,
The exchange 7 is installed indoors. In a base station such as a mobile phone, a transmission / reception amplifier 2A is installed immediately below the transmission / reception antenna 1 in order to reduce the influence on the transmission / reception signal due to the cable loss to the transmission / reception antenna 1.

[0007]

As described above, conventionally, a monitoring cable 5 is laid from outside to inside to monitor the state of the transmission / reception amplifier 2A. Thus, in a signal transmission device in a conventional state monitoring device or the like,
There is a problem in that a cable dedicated to monitoring must be laid, which requires a lot of labor for laying work, and also requires a space for laying the cable.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a signal transmission device capable of omitting a monitoring cable conventionally required.

[0009]

In order to solve the above-mentioned problems, the present invention provides a high-frequency coaxial cable for transmitting a high-frequency signal by providing high-frequency insulation at one end and providing a low-frequency signal generating means. The other end of the cable is provided with high-frequency insulation to provide low-frequency signal receiving means, and the low-frequency signal is transmitted by the high-frequency coaxial cable.

According to such a configuration, a high-frequency coaxial cable for transmitting a high-frequency signal can be used as a cable for transmitting a low-frequency signal. This high-frequency coaxial cable can be used as, for example, a monitoring cable for transmitting a low-frequency state signal. Can also be used as

In the first embodiment, the signal transmission device according to the present invention is applied as a signal transmission device of a state monitoring device in a transmission / reception amplifier 2B provided in a base station or the like. A state detection unit 2b for detecting the state of the transmission / reception amplifier 2B, a state / pulse signal conversion circuit 14 for converting a state signal detected by the state detection unit 2b into a low-frequency pulse signal, and transmitting one of the transmission / reception signals The high-frequency coaxial cable 18, the inductance 16 as means for connecting the state / pulse signal conversion circuit 14 and the high-frequency coaxial cable 18 by performing high-frequency insulation, and transmission from the state / pulse signal conversion circuit 14 via the high-frequency coaxial cable 18. A pulse / state signal conversion circuit 12 for converting the obtained low-frequency pulse signal into a state signal;
High-frequency coaxial cable 18 and pulse / state signal conversion circuit 1
2 and an inductance 10 which is means for connecting by performing high-frequency insulation. Further, in the first embodiment, the transmission / reception amplifier 2B and the modem 13 connected to the transmission / reception amplifier 2B are each provided between the high-frequency coaxial cable 18 and the capacitor 17 for performing low-frequency insulation with the cable 18. 19 are provided.

In the second embodiment, the signal transmission device according to the first embodiment is provided bidirectionally so that the low-frequency pulse signal according to the first embodiment can be transmitted bidirectionally. In this case, bidirectional transmission can be performed using two high-frequency coaxial cables 24 and 25 for transmission and reception, or bidirectional transmission can be performed using one high-frequency coaxial cable using time division. You can also.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a block diagram showing a signal transmission device according to Embodiment 1. In FIG. 1, reference numeral 1 denotes a shared transmitting / receiving antenna disposed outdoors, and 2B denotes a shared transmitting / receiving antenna.
, A transmission / reception amplifier 2b is built in the transmission / reception amplifier 2B, a state detection unit 13 having the same configuration as the conventional state detection unit 2a, and 13 is disposed indoors and connected to an exchange (not shown). , A transmission / reception amplifier 18
B is a high-frequency coaxial cable that connects B to the modulator / demodulator 13 and transmits any of high-frequency signals transmitted and received.

In FIG. 1, reference numeral 14 denotes a state detector 2
b, a state / pulse signal conversion circuit for converting the state signal into a low-frequency pulse signal, and a pulse 12 for receiving the pulse signal from the state / pulse signal conversion circuit 14 and converting it into a state signal again / State signal conversion circuit. Reference numeral 17 denotes a capacitor for connecting the transmission / reception amplifier 2B and the high-frequency coaxial cable 18; 15, a buffer connected to the output side of the state / pulse signal conversion circuit 14;
Is an inductance connected between the output side of the buffer 15 and a connection point between the capacitor 17 and the high-frequency coaxial cable 18.

Further, in FIG. 1, reference numeral 19 denotes a modem 1
3 and a high-frequency coaxial cable 18
10 is an inductance whose one end is connected to a connection point between the high-frequency coaxial cable 18 and the capacitor 19, 11 is an input connected to the other end of the inductance 10, and an output is connected to an input of the pulse / state signal conversion circuit 12. Buffer. Note that, in FIG.
The exchanges connected to are not shown.

In the above configuration, when an abnormality occurs in the transmission / reception amplifier 2B, the state detection section 2b determines an abnormal state and outputs a state signal 20 indicating the abnormal state. Status signal 20
Is converted into a low-frequency pulse signal by the state / pulse signal conversion circuit 14 and output to the high-frequency coaxial cable 18 via the buffer 15 and the inductance 16. The abnormal states determined and detected by the state detecting unit 2b include, for example, abnormal temperatures of the transmitting / receiving amplifier 2B, abnormalities of the power supply voltage, abnormal rotation of the cooling fan, and abnormalities of the control state, and these are output as predetermined pulse signals. This pulse signal is formed by combining high (H) and low (L) voltages of a general TTL level or RS-232C level.

In this case, the pulse signal is output in a form superimposed on the high-frequency coaxial cable 18. The pulse signal superimposed on the high-frequency coaxial cable 18 has an inductance of 1
0, pulse / state signal conversion circuit 1 through buffer 11
Reach 2. At this time, since the pulse signal is a low-frequency pulse, the pulse signal representing the state signal is not input to the transmission / reception amplifier 2B and the modem 13 by the capacitors (capacitors) 17 and 19. Further, the high-frequency signal which is a transmission or reception signal is converted by the inductances 10 and 16 into a state / pulse signal conversion circuit 14.
Is not input to the pulse / state signal conversion circuit 12.

Therefore, the state / pulse signal conversion circuit 1
4 and the pulse / state signal conversion circuit 12 are in a signal-insulated state (high-frequency insulation state) with respect to the transmission / reception amplifier 2B and the modem 13 by the inductances 10 and 16 for the high-frequency signal. In this way, the status signal indicating the status of the transmission / reception amplifier 2B can be transmitted via the existing high-frequency coaxial cable 18 without using a dedicated monitoring cable as in the related art.

In the first embodiment, the state / pulse signal conversion circuit 14, the buffer 15, the inductance 16, and the capacitor 17 include the transmission / reception amplifier 2B.
It may be built in or outside. Further, the pulse / state signal conversion circuit 12, the inductance 10, the buffer 11, and the capacitor 19 may be built in the modem 13.

Embodiment 2 In the first embodiment described above,
The embodiment in which the state signal is transmitted by one-way communication from the state / pulse signal conversion circuit 14 (transmission / reception amplifier 2B) to the pulse / state signal conversion circuit 12 (indoor side) has been described. In the second embodiment, the state / pulse signal conversion circuit (state detection unit 2c) and the pulse / state signal conversion circuit 12
A mode in which two-way communication is performed by an (indoor state monitoring device not shown) will be described.

FIG. 2 is a block diagram showing a signal transmission device according to the second embodiment. In FIG. 2, reference numeral 22 denotes a serial communication circuit provided on the transmission / reception amplifier 2C side instead of the state / pulse signal conversion circuit 14 of FIG. 1, and reference numeral 23 denotes an indoor side, instead of the pulse / state signal conversion circuit 12 of FIG. Is a serial communication circuit provided in the system. Also, 2
Reference numerals 4 and 25 denote high-frequency coaxial cables, respectively.
Used as a cable for transmitting a high-frequency reception signal to the serial communication circuit 22 and transmitting a status signal from the serial communication circuit 22 to the serial communication circuit 23 as a pulse signal.
Is used, for example, as a cable for transmitting a high-frequency transmission signal from the modem 26 to the transmission / reception amplifier 2C and transmitting a control signal from the serial communication circuit 23 to the serial communication circuit 22 as a pulse signal.

The state detector 2c performs various state monitoring based on a control signal input from a state monitoring device (not shown), and sends a result of the state determination to the state monitoring device. In this case, the control signal is converted into a low-frequency pulse signal by the serial communication circuit 23, and the buffer 41, the inductance 40, the high-frequency coaxial cable 25, the inductance 34,
The signal is transmitted to the serial communication circuit 22 via the buffer 35, where it is converted into a control signal and input to the state detection unit 2c. As the control signal, a low-frequency analog signal, a logic signal for serial communication, or the like is used. As the serial data, a combination of high (H) and low (L) voltages of the RS-232C level is used.

On the other hand, the state signal 21 output from the state detector 2c is converted into a low-frequency pulse signal by the serial communication circuit 22, and the buffer 37, the inductance 3
6, transmitted to the serial communication circuit 23 via the high-frequency coaxial cable 24, the inductance 38, and the buffer 39,
Here, the signal is converted into a state signal and input to a state monitoring device (not shown). As this state signal, a low-frequency analog signal or a logic signal for serial communication or the like is used as in the case of the above-described control signal, and the serial data is an RS-232C level signal as described above. A combination of high (H) and low (L) voltages is used.

The capacitor 30 is a high-frequency coaxial cable 24
And a transmission / reception amplifier 2C, and is a capacitor that prevents a low-frequency pulse signal from the serial communication circuit 22 from being input to the transmission / reception amplifier 2C. Capacitor 3
Reference numeral 2 denotes a capacitor provided between the high-frequency coaxial cable 24 and the modulator / demodulator 26 to prevent a low-frequency pulse signal from the serial communication circuit 22 from being input to the modem 26. The capacitor 31 is provided between the high-frequency coaxial cable 25 and the transmission / reception amplifier 2C, and is connected to the serial communication circuit 23.
This is a capacitor for preventing a low-frequency pulse signal from being input to the transmission / reception amplifier 2C. The capacitor 33 is provided between the high-frequency coaxial cable 25 and the modem 26 and is a capacitor that prevents a low-frequency pulse signal from the serial communication circuit 23 from being input to the modem 26.

The inductance 34 is provided between the high-frequency coaxial cable 25 and the buffer 35, and prevents a high-frequency reception signal from being input to the serial communication circuit 22. The inductance 36 is provided between the high-frequency coaxial cable 24 and the buffer 37, and prevents the high-frequency transmission signal voltage from being applied to the output terminal of the buffer 37. The inductance 38 is connected to the high-frequency coaxial cable 24 and the buffer 3.
9, and prevents a high-frequency transmission signal from being input to the serial communication circuit 23. The inductance 40 is provided between the high-frequency coaxial cable 25 and the buffer 41, and prevents the high-frequency reception signal voltage from being applied to the output terminal of the buffer 41.

Also in the above-described configuration, the high-frequency coaxial cables 24 and 25 for transmitting transmission / reception signals are used to transmit the status signal (serial data) from the status detection unit 2c and the control signal from the status monitoring device to the status detection unit 2c. (Serial data) can be transmitted, and bidirectional serial communication can be performed between them without attaching a separate cable for status monitoring. By transmitting serial data from the state monitoring device to the transmission / reception amplifier side, the transmission / reception amplifier can be remotely controlled.

In the above, a case has been described in which bidirectional communication is performed using two high-frequency coaxial cables. However, half-duplex bidirectional communication is performed by performing time division or the like using one high-frequency coaxial cable. You may do so.

[0028]

As is apparent from the above description, according to the present invention, the condition monitoring cable between two points which are required at a distance from each other can be omitted by also using the high-frequency coaxial cable. It is possible to reduce the cable installation cost and the cable installation space.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a signal transmission device of a state monitoring device according to a first embodiment.

FIG. 2 is a block diagram illustrating a signal transmission device of a state monitoring device according to a second embodiment.

FIG. 3 is a block diagram illustrating a signal transmission device of a conventional state monitoring device.

[Explanation of symbols]

 2B, 2C transmission / reception amplifier 2b, 2c state detector 12 pulse / state signal converter 13 modulator / demodulator 14 state / pulse signal converter 10, 16, 34, 36, 38, 40 inductance 18, 24, 25 high-frequency coaxial cable 30, 31, 32, 33 Capacitor

Claims (1)

[Claims] 1. A high-frequency coaxial cable for transmitting a high-frequency signal is provided with a high-frequency insulation at one end and a low-frequency signal generating means is provided at the other end of the high-frequency coaxial cable. Means for transmitting a low-frequency signal through the high-frequency coaxial cable.