JPH0730461A - Transmitter-receiver for testing automobile telephone system - Google Patents

Abstract

PURPOSE:To prevent the sneak path of signal to a transmitter-receiver for testing an automobile telephone system and to make the transmitter-receiver small in size and economical in constitution. CONSTITUTION:A transmitting/receiving shared equipment 1 separates a receiving signal received through an antenna AT from a transmitting signal outputted from a transmitting part TX and a variable attenuator 2 attenuates the separated receiving signal and outputs the attenuated signal to either one of receiving parts RX1, RX2 through a change-over switch SW. Since the signal separated by the equipment 1 and the transmitting signal are prevented from respective sneak paths to the transmitting side and the receiving side, accurate transmitting/reception can be attained and a transmitting/receiving shared equipment or the like for resynthesizing the separated transmitting and receiving signals is unnecessitated, so that the transmitter-receiver is made small in size and economical in constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test transmitter / receiver for testing a car telephone system, and more particularly to a car based on a signal communicated between a car, which is a mobile unit, installed in a base station. The present invention relates to a transmitter / receiver for a test of a car telephone system that tests a telephone system.

[0002]

2. Description of the Related Art Conventionally, a test transmitter / receiver for testing an automobile telephone system transmits a test signal to the automobile telephone system via one antenna (antenna) AT as shown in FIG. The signal transmitted between the base station of the car telephone system and the mobile unit is transmitted to the antenna A.
It is received via T to check whether the system is right or wrong. This test transceiver uses one antenna AT for signal transmission / reception, and attenuates a high-level signal input from the antenna AT, so that the transmission signal and the reception signal must be separated. Therefore, a duplexer 1 for separating the transmission signal and the reception signal, and a variable attenuator 2 for attenuating the separated reception signal having a high level are provided. A transmitter / receiver 3 for synthesizing the separated reception signal and transmission signal is provided, and a test mobile unit 5 is connected to the transmitter / receiver 3. The test mobile unit 5 is composed of one transmission unit TX and two reception units RX1 and RX2 provided for diversity reception. Of these, the transmission unit TX and the reception unit RX1 are connected to the duplexer 6. Further, the duplexer 6 is the duplexer 3 described above.
It is connected to the. The duplexer 6 is for synthesizing and separating the signals of the transmitter TX and the receiver RX1.

[0003]

In the conventional test transmitter / receiver, the reception signal from the antenna AT and the transmission signal to be transmitted to the system via the antenna AT are temporarily separated by the duplexer 1, and the separated reception signal is obtained. And a transmission signal
Since they are re-synthesized by the method, there is a possibility that the signals may wrap around during this time, and there is a problem that the signals cannot be transmitted and received accurately. Further, in addition to the duplexer 1, the duplexer 3 and the duplexer 6 on the side of the mobile device 5 are also required, which causes a problem that the test transceiver becomes large and expensive.

Therefore, it is an object of the present invention to prevent signals from sneaking around in a test transceiver and to make the test transceiver compact and economical.

[0005]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention is provided in a car telephone system and is provided with a transmitter for transmitting signals and a plurality of receivers for performing diversity reception, which are commonly used for transmission and reception. In a car telephone system test transceiver that tests the correctness of a car telephone system based on the received signal from the antenna, a transceiver that is connected to the antenna and separates the transmitted signal from the received signal via the antenna, and the transceiver And an attenuator for attenuating the reception signal separated by the duplexer and outputting the attenuated reception signal to one of the plurality of receiving units. Also,
A switch is provided between the attenuator and the plurality of receiving units to selectively connect the attenuator and the receiving unit. Also,
The selective connection operation of the switch is controlled by a remote control signal.

[0006]

In the duplexer, the reception signal via the antenna and the transmission signal from the transmission unit are separated, and the separated reception signal is attenuated by the attenuator and output to one of the plurality of reception units. . As a result, it is possible to prevent the reception signal separated by the duplexer from sneaking into the transmission unit side and the transmission signal from sneaking into the reception unit side, so that transmission and reception can be performed accurately. Further, the attenuator and each receiving unit are selectively connected by a switch provided between the attenuator and the plurality of receiving units. Therefore, for example, when one receiving unit fails, it is possible to connect to another receiving unit and receive a signal. Further, since the selective connection operation of the switch is controlled by the remote control signal, this test transceiver can be installed in, for example, an unmanned base station.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a test transceiver of a car telephone system according to the present invention. In the figure, this test transceiver 10 is a transmitter / receiver in the test mobile unit 5 in which the duplexers 3 and 6 are removed from the conventional test transceiver shown in FIG. The TX is directly connected to the transmission side of the duplexer 1 via the transmission dedicated terminal 7, and either one of the two reception units RX1 and RX2 provided for diversity reception is connected via the reception dedicated terminal 8 to the variable attenuator. 2 is configured to be connected.

By the way, the test transceiver 10 is a base station (BS) (not shown) which constitutes a car telephone system.
It is provided inside. Here, the transmission signal of the test transceiver 10 is transmitted from the transmission unit TX in the test mobile unit 5 to the mobile unit such as a car having a base station or a radio telephone via the duplexer 1 and the antenna AT. At the same time, a signal communicated between the base station and the mobile unit is input as a reception signal via the same antenna AT. Then, the correctness of the system is confirmed based on this reception result. That is, when the radio signal communicated between the base station and the mobile body arrives at the duplexer 1 via the antenna AT, the duplexer 1 separates this radio signal from the transmission signal from the transmitter TX side. To receive.
Since this received signal is excessive, the variable attenuator 2
It is attenuated by the
Is output to the receiving unit RX1 via. The receiving unit RX1 confirms the correctness of the system based on this received signal.

As described above, in the duplexer 1, the transmission signal is separated from the reception signal to be transmitted, and the transmission path of the reception signal separated from the transmission signal can be formed independently of the transmission side path. Is completely prevented from sneaking into the transmitting unit TX side or from sneaking into the receiving unit RX1 side of a transmission signal from the transmitting unit TX side, and as a result, accurate communication can be performed. Further, since the changeover switch SW is provided between the reception units RX1 and RX2 used for diversity reception and the variable attenuator 2 and either one of the reception units RX1 and RX2 is switched and used, the reception unit RX.
If any one of RX1 and RX2 fails, it can be received using a normal receiving unit, and the normality of each receiving unit can also be confirmed.

Further, the changeover of the changeover switch SW can be controlled by the remote control signal a. That is, since the test transceiver 10 is provided in the base station, the remote control signal a can be transmitted to the test transceiver 10 via a wire such as a telephone line or a dedicated line. It becomes possible to perform switching control of the changeover switch SW. As a result, the test transceiver 10
Can be installed in an unattended base station.

[0011]

As described above, according to the present invention, the duplexer separates the reception signal from the antenna from the transmission signal from the transmission section, and the attenuator attenuates the separated reception signal to obtain a plurality of signals. Since it is output to either one of the receiving units of the above, the sneak of the received signal separated by the duplexer to the transmitting unit side and the sneak of the transmitting signal to the receiving unit side are prevented, and accurate transmission / reception is performed. In addition, it becomes unnecessary to use a duplexer or the like for synthesizing separated reception signals and transmission signals, so that the apparatus can be made compact and economical. Further, since a switch is provided between the attenuator and the plurality of receiving units and the switch is used to selectively connect the attenuator and each receiving unit, for example, when a certain receiving unit fails, another switch is provided. The signal can be received by connecting to the receiver. Further, since the selective connection operation of the switch is controlled by the remote control signal, the test transceiver can be installed in, for example, an unmanned base station.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a test transceiver of a car telephone system according to the present invention.

FIG. 2 is a block diagram of a conventional test transceiver.

[Explanation of symbols]

 1 Transmitter / receiver 2 Variable attenuator 5 Test mobile device 7 Transmission dedicated terminal 8 Reception dedicated terminal 10 Test transmitter / receiver SW switch TX transmitter RX1, RX2 Receiver AT antenna (antenna) a Remote control signal

Claims (3)

[Claims] 1. A vehicle telephone system is provided with a transmitter for transmitting signals and a plurality of receivers for performing diversity reception, and the vehicle telephone system is tested for correctness based on a received signal from an antenna that is commonly used for transmission and reception. In a test transceiver of a car telephone system, a duplexer connected to the antenna for separating a transmission signal and a reception signal via the antenna, and a reception signal separated by the duplexer are attenuated and attenuated. An attenuator for outputting the received signal to any one of the plurality of receiving units, a test transceiver for a car telephone system. 2. The test transceiver of the car telephone system according to claim 1, wherein a switch is provided between the attenuator and the plurality of receiving units to selectively connect the attenuator and the receiving units. A transmitter / receiver for testing a car telephone system. 3. The test transceiver of the car telephone system according to claim 2, wherein the selective connection operation of the switch is controlled by a remote control signal.