JPH0328568Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an antenna switching device in a device in which the receiving function portion of a radio transmitter/receiver is commonly used for a direction finder.

[Conventional technology]

This type of device is equipped with a transmitting/receiving antenna and a direction finding antenna, as well as a configuration for connecting either of these antennas to the wireless transmitter/receiver, thereby making it possible to replace the receiving function part of the wireless transmitter/receiver. The one that was designed to be used commonly for direction finders was Utility Model 57-164479 (Utility Model 57-164479)
-3081) and others.

In addition, the direction finder used for the above uses four dipole antennas as direction finding antennas, and each dipole antenna is sequentially switched by a diode switch to obtain an induced voltage including the Doppler effect. An antenna coupler is provided to obtain a direction signal using a switched scanning frequency modulated wave, and this direction signal is amplified and detected by the receiving function part of the wireless transceiver, and the signal is included in the low frequency output obtained. A so-called switched scanning Doppler direction finder is known in which a signal for direction indication is obtained by comparing the phase shift of the above-mentioned frequency modulated wave with the above-mentioned switching phase.

Furthermore, in the wireless transceiver, the antenna can be connected to the transmitting circuit during transmission, and the antenna can be turned off during reception by inputting a manual switch attached to the transmitting microphone or using the transmitting input of the transmitting microphone. It is well known to provide a switching function connected to the receiving circuit, and in a device in which the receiving function part of the wireless transmitter/receiver is shared as a direction finder, when the wireless transmitter/receiver is set to the transmitting state, It is well known to provide a switching function for interrupting the input circuit between the direction-finding antenna and the receiver, and such switching function is also referred to as a B-K relay function.

[The problem that the idea aims to solve]

In a device in which the receiving function part of the radio transceiver described above is shared for a direction finder,
In the case where the switch is operated for transmitting/receiving and for direction finding, if you want to automatically detect the direction of the communication partner while making a short communication with the other party, the switch can be made more complex accordingly. In addition to the inconvenience of having to operate quickly, a similar inconvenience occurs when an emergency contact is received from the person on the other end of the radio waves whose direction is being detected.

For this reason, a method can be considered in which the switching function for transmitting and receiving in the wireless transceiver is linked with the switching function for direction finding, but this method does not add the direction finding function to the existing wireless transceiver. In the case of adding such a function, as in the above-mentioned case of Utility Model Application No. 57-164479, there arises the problem that the relevant functional circuit inside the wireless transceiver must be modified.

Therefore, there is a problem in that it is desired to provide a simple external additional device that eliminates the above-mentioned disadvantages.

[Means to solve the problem]

This invention is based on a relay circuit that is installed outside the radio transmitter/receiver and selects either the transmitting/receiving antenna or the direction finding antenna and connects it to the antenna terminal of the radio transmitter/receiver in the above device. , a detection circuit that is provided outside the radio transceiver and that detects the carrier wave signal during transmission output from the above antenna terminal and obtains a detection output, and a relay circuit that transmits and receives while the above detection output is obtained. and a relay operation circuit that connects the direction finding antenna to the side that selects the direction finding antenna while the above detection output is not obtained. This system is designed to solve the above problems.

〔Example〕

Examples will be described below with reference to the drawings.

In FIG. 1, the connection line from the antenna terminal 11 of the radio transceiver 10 is connected to the circuit side formed by the relay 5 and switched and connected by the relay circuit provided outside the radio transceiver 10, that is, the switching side c It is connected to.

The input/output connection line for the transmitting/receiving antenna 1 is connected to one circuit side, that is, the transmitting/receiving side a, which is switched and connected by a relay circuit formed by a relay 5.

The connection line for the output from the direction finding antenna 2 is
It is connected to the other circuit side which is switched and connected by a relay circuit formed by the relay 5, ie to the direction finding side b.

The excitation circuit 51 of the relay 5 is a circuit for causing the relay circuit to perform a switching operation, and is operated by a carrier wave detection circuit 6, which will be described later.

In the case of the figure, the movable contact 52 on the switching side c of the relay 5
is shifted to the transmitting/receiving side contact point by a spring 53, and the antenna terminal 11 is normally connected to the transmitting/receiving antenna 1.

The carrier wave detection circuit 6 is a circuit for detecting whether or not a carrier wave signal at the time of transmission is output to the connection line from the antenna terminal 11, and specifically has a configuration example as shown in FIG. It is a circuit.

In FIG. 2, power supply terminals 20 and 21 are circuits to which DC power for operation is supplied, and are also circuits to which signals from the antenna terminal 11 of the radio transceiver 10 are supplied, and are output when the radio transceiver 10 transmits. This circuit is designed to detect a carrier wave signal and provide an output to the excitation circuit 51 of the relay 5.

The carrier wave signal appearing at the antenna terminal 11 passes through a coupling capacitor 22, is rectified by diodes 22 and 23, and is then connected to a resistor 25 and a time constant capacitor 2.
It is applied to the time constant circuit formed by 6 and 6 to create a DC voltage.

This DC voltage is applied to the base of the transistor 27, current flows to the collector, and the voltage drop across the resistor 28 increases, causing the voltage at the collector to drop significantly, resulting in the voltage at the base of the transistor 29 to drop significantly.

In the state before this voltage drop occurs, the transistor 29 has a current flowing through its collector due to the voltage applied from the power supply terminal 21 via the resistor 28, and this current causes an exciting current to flow through the exciting circuit 51. , a movable contact 52 of the relay 5 in FIG. 1 is connected to the direction-finding side b against a spring 53.

As described above, when the voltage at the base of the transistor 29 drops significantly due to the carrier wave signal during transmission, the current at the collector of the transistor 29 becomes extremely small, and the attractive force of the excitation circuit 51 to the movable contact 52 decreases. Because of the decrease, the movable contact 5
2 is transferred to the transmitting and receiving side a by the spring 53.

That is, the antenna terminal 11 of the wireless transceiver 10
When the carrier wave signal at the time of transmission does not appear and no detection output is obtained from the carrier wave detection circuit 6, the connection line from the antenna terminal 11 is connected to the direction finding antenna 2 by the relay 5 of the relay circuit. Also, only when a carrier wave signal during transmission appears at the antenna terminal 11 and a detection output is obtained from the carrier wave detection circuit 6, the connection from the antenna terminal 11 is made by the relay 5 of the relay circuit. The cable is configured to be connected to a connection line for the transmitting/receiving antenna 1.

When the direction finding function part is configured as a Doppler direction finder function that obtains a well-known switching scanning type frequency modulated wave, the direction finding antenna 2 is, for example, four dipole antennas, and each The wireless transmitter/receiver 10 is constructed by providing an antenna coupler 3 which obtains an induced voltage including the Doppler effect by sequentially switching dipole antennas using a diode switch to obtain a direction signal 4. The output obtained from the low frequency output terminal 12 of the wireless transmitter/receiver 10 is provided to a direction indicating circuit 7 provided outside the wireless transmitter/receiver 10.

Then, the direction indicating circuit 7 has a low frequency output terminal 1
The phase of the above-mentioned frequency modulated wave appearing at 2 is compared with the phase of switching by the above-mentioned diode switch to obtain a direction indication.

[Effect of idea]

According to this invention, as described above, the antenna terminal of the radio transceiver 10 is connected to Since the connection line from the transmitting/receiving antenna to 11 and the connection line from the direction finding antenna are switched, the switching operation is performed only when a carrier wave at the time of transmission appears.

Since the carrier wave signal during transmission is very strong, in order to operate the carrier wave detection circuit 6 so that it will not be switched by other signals, it is necessary to adjust the conditions of the transistor, time constant circuit, excitation circuit, etc. as appropriate. This is a good thing and can be done within the range of well-known technology, so there is probably no need to explain it.

According to this switching device, the connection line of the antenna terminal 11 of the wireless transceiver 10 and the transmitting/receiving antenna 1
It is only necessary to connect a switching device between the connection line of the direction-finding antenna 2 and the connection line of the direction-finding antenna 2, and there is no need to make any modifications related to the switching function between transmitting and receiving inside the radio transceiver. It has the advantage of being able to provide products.

[Brief explanation of the drawing]

The drawings show an embodiment, and FIG. 1 is a block diagram, and FIG. 2 is a diagram of the main circuit. DESCRIPTION OF SYMBOLS 1... Transmission/reception antenna, 2... Direction finding antenna, 3... Antenna coupler, 4... Direction signal, 5... Relay, 6... Carrier wave detection circuit, 7...
... Direction indicating circuit, 8 ... Antenna switching device, 10
...Radio transceiver, 11...Antenna terminal, 12
...Low frequency output terminal, 20, 21...Power terminal,
22... Coupling capacitor, 23, 24... Diode, 25, 28... Resistor, 26... Time constant capacitor, 27, 29... Transistor.

Claims (1)

[Claims for Utility Model Registration] A direction-finding antenna is connected to the antenna terminal of the radio transceiver in place of the transmitting/receiving antenna, and a direction-finding direction indicating circuit is connected to the low frequency output terminal of the wireless transceiver. An antenna switching device for a device in which the wireless transmitter/receiver can be used commonly for direction finding, comprising: (a) provided outside the wireless transmitter/receiver, and configured to connect either the transmitting/receiving antenna or the direction finding antenna; a relay circuit that selects and connects to the antenna terminal; b. a detection circuit that is provided outside the wireless transmitter/receiver and that detects a carrier signal during transmission output from the antenna terminal and obtains a detection output; c. While the detection output is obtained, the relay circuit is connected to the side that selects the transmitting/receiving antenna, and while the detection output is not obtained, the relay circuit is connected to the side that selects the direction finding antenna. An antenna switching device characterized by comprising a relay operation circuit.