JP7038483B2 - Antenna amplifier unit and receiving system - Google Patents

Description

The disclosed embodiments relate to antenna amplifier units and receiving systems.

Conventionally, there is a receiving circuit that amplifies a signal received by an antenna by an amplifier and outputs it to a circuit in a subsequent stage. Such a receiving circuit is generally provided with a matching circuit that matches the input impedance of the amplifier with the output impedance of the antenna (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-223742

However, since the conventional receiving circuit assumes an antenna having one type of output impedance, it cannot support a plurality of types of antennas having different output impedances.

One aspect of the embodiment is made in view of the above, and an object thereof is to provide an antenna amplifier unit and a receiving system capable of supporting a plurality of types of antennas having different output impedances.

The antenna amplifier unit according to one embodiment includes a connection unit, an amplification unit, and a matching unit. A receiving antenna is connected to the connection portion. The amplification unit amplifies the reception signal received by the reception antenna connected to the connection unit. The matching unit is connected between the connection unit and the amplification unit, and matches the input impedance of the amplification unit with the output impedance of the reception antenna connected to the connection unit according to the type of the reception antenna.

The antenna amplifier unit according to one embodiment can correspond to a plurality of types of antennas having different output impedances.

FIG. 1 is an explanatory diagram showing a configuration of a receiving system according to an embodiment. FIG. 2 is an explanatory diagram showing a configuration of a receiving system according to the first modification of the embodiment. FIG. 3 is an explanatory diagram showing the configuration of the receiving system according to the second modification of the embodiment. FIG. 4A is an explanatory diagram showing an example of a partial circuit configuration of the receiving system according to the second modification of the embodiment. FIG. 4B is an explanatory diagram showing an example of a partial circuit configuration of the receiving system according to the second modification of the embodiment. FIG. 5A is an explanatory diagram showing an example of a partial other circuit configuration of the receiving system according to the second modification of the embodiment. FIG. 5B is an explanatory diagram showing an example of a partial other circuit configuration of the receiving system according to the second modification of the embodiment. FIG. 6 is an explanatory diagram showing the configuration of the receiving system according to the third modification of the embodiment.

Hereinafter, embodiments of the antenna amplifier unit and the receiving system disclosed in the present application will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments shown below. Further, in the following description, duplicate description will be omitted by assigning the same reference numerals to the same components shown in the drawings.

Hereinafter, a case where the receiving system according to the embodiment is mounted on a vehicle to receive an AM (Amplitude Modulation) radio broadcast will be described as an example. The receiving system according to the embodiment can be applied to a broadcast receiving system that receives an arbitrary broadcast such as an FM (Frequency Modulation) radio broadcast or a digital television broadcast. Further, the receiving system according to the embodiment can be applied to any broadcast receiving device capable of receiving broadcasts.

FIG. 1 is an explanatory diagram showing a configuration of a receiving system according to an embodiment. As shown in FIG. 1, the receiving system according to the embodiment includes a first receiving antenna 21 or a second receiving antenna 22 having different output impedances, and an antenna amplifier unit 1.

The first receiving antenna 21 is, for example, a pole antenna provided on the roof of a vehicle. The second receiving antenna 22 is, for example, a film antenna provided on the glass of a vehicle.

The first receiving antenna 21 and the second receiving antenna 22 have a common connector connected to the antenna amplifier unit 1, and one of the receiving antennas is connected to the antenna amplifier unit 1.

The antenna amplifier unit 1 includes a connection unit 4, a matching unit 5, an amplification unit 6, and an output unit 7, and is connected to the in-vehicle device 3. The in-vehicle device 3 is, for example, a car navigation device including a tuner 31 for receiving AM radio broadcasting and a microcomputer (hereinafter, referred to as “microcomputer 32”). In FIG. 1, components other than the tuner 31 and the microcomputer 32 included in the in-vehicle device 3 are not shown.

A plurality of types of receiving antennas having different output impedances (here, one of the first receiving antenna 21 and the second receiving antenna 22) is connected to the connecting portion 4.

The matching unit 5 is connected between the connecting unit 4 and the amplifying unit 6, and matches the input impedance of the amplifying unit 6 with the output impedance of the receiving antenna connected to the connecting unit 4 according to the type of the receiving antenna.

Specifically, the matching unit 5 includes a plurality of matching circuits having different input impedances for each type of receiving antenna. In the example shown in FIG. 1, the matching unit 5 has a first matching circuit 51 whose input impedance is equal to the output impedance of the first receiving antenna 21, and a second matching whose input impedance is equal to the output impedance of the second receiving antenna 22. The circuit 52 is provided.

Further, the matching unit 5 includes changing units 53 and 54 that change the input impedance of the amplification unit 6 by selecting a matching circuit connected between the connecting unit 4 and the amplification unit 6 from a plurality of matching circuits.

The matching unit 5 connects the connecting unit 4 and the first matching circuit 51 by the changing unit 53, and connects the first matching circuit 51 and the amplifying unit 6 by the changing unit 54 to obtain the input impedance of the amplifying unit 6. It can be matched to the output impedance of the first receiving antenna 21.

Further, the matching unit 5 connects the connecting unit 4 and the second matching circuit 52 by the changing unit 53, and connects the second matching circuit 52 and the amplifying unit 6 by the changing unit 54, thereby inputting the amplification unit 6. The impedance can be matched to the output impedance of the second receiving antenna 22.

The amplification unit 6 is an amplifier that amplifies the reception signal input from the first reception antenna 21 or the second reception antenna 22 and outputs the reception signal to the output unit 7 via the connection unit 4 and the matching unit 5. The output unit 7 includes a filter that removes a noise component from the received signal input from the amplification unit 6, a matching circuit that matches the output impedance of the output unit 7 to the input impedance of the tuner 31, and the like, and receives the noise component removed. The signal is output to the tuner 31 of the vehicle-mounted device 3. The tuner 31 demodulates the received signal input from the antenna amplifier unit 1 and outputs sound from a speaker (not shown).

Here, the type of vehicle to be mounted on the vehicle-mounted device 3 is predetermined. That is, it is known whether the in-vehicle device 3 is mounted on the vehicle provided with the first receiving antenna 21 or on the vehicle provided with the second receiving antenna 22.

Therefore, for example, when the antenna amplifier unit 1 is connected to the in-vehicle device 3 mounted on the vehicle provided with the first receiving antenna 21, the low level control signal is transmitted from the microcomputer 32 to the changing units 53 and 54. The software to output is incorporated.

Then, when the Low level control signal is input from the microcomputer 32, the change units 53 and 54 connect the first matching circuit 51 between the connection unit 4 and the amplification unit 6. As a result, the antenna amplifier unit 1 can match the input impedance of the amplification unit 6 with the output impedance of the first receiving antenna 21.

Further, for example, when the antenna amplifier unit 1 is connected to the vehicle-mounted device 3 mounted on the vehicle provided with the second receiving antenna 22, a high-level control signal is transmitted from the microcomputer 32 to the changing units 53 and 54. The software to output is incorporated.

Then, when the high level control signal is input from the microcomputer 32, the change units 53 and 54 connect the second matching circuit 52 between the connection unit 4 and the amplification unit 6. As a result, the antenna amplifier unit 1 can match the input impedance of the amplification unit 6 with the output impedance of the second receiving antenna 22.

As described above, the antenna amplifier unit 1 has the first receiving antenna 21 or the first receiving antenna 21 in which the input impedance of the amplification unit 6 is connected to the connection unit 4, depending on the types of the first receiving antenna 21 and the second receiving antenna 22. A matching unit 5 that matches the output impedance of the second receiving antenna 22 is provided. As a result, the antenna amplifier unit 1 can support a plurality of types of receiving antennas having different output impedances.

The configuration of the receiving system according to the embodiment is not limited to the configuration shown in FIG. Next, the configuration of the receiving system according to the first modification of the embodiment will be described with reference to FIG. FIG. 2 is an explanatory diagram showing a configuration of a receiving system according to the first modification of the embodiment.

As shown in FIG. 2, the receiving system according to the first modification is different from the receiving system shown in FIG. 1 in that the tuner 31a is provided in the antenna amplifier unit 1a instead of the in-vehicle device 3a. In the antenna amplifier unit 1a, for example, a control signal is input to the tuner 31a from the microcomputer 32 of the vehicle-mounted device 3a via the GPIO (General Purpose Input Output) port.

The tuner 31a outputs the control signal input from the microcomputer 32 to the changing units 53 and 54 of the matching unit 5. Similar to the change units 53 and 54 shown in FIG. 1, the change units 53 and 54 connect the first matching circuit 51 between the connection unit 4 and the amplification unit 6 when a Low level control signal is input. Let me. As a result, the antenna amplifier unit 1a can match the input impedance of the amplification unit 6 with the output impedance of the first receiving antenna 21.

Further, the change units 53 and 54 connect the second matching circuit 52 between the connection unit 4 and the amplification unit 6 when a high level control signal is input. As a result, the antenna amplifier unit 1a can match the input impedance of the amplification unit 6 with the output impedance of the second receiving antenna 22.

As described above, the antenna amplifier unit 1a is a plurality of types of receiving antennas having different output impedances by changing the input impedance of the amplification unit 6 based on the control signal input from the in-vehicle device 3a via the tuner 31a. Can be accommodated.

Further, the antenna amplifier unit 1a is provided at a position closest to the first receiving antenna 21 or the second receiving antenna 22 which is separated from the in-vehicle device 3a and connected. As a result, the antenna amplifier unit 1a can suppress the noise generated by the in-vehicle device 3a and the electronic device provided in the vicinity of the in-vehicle device 3a from being mixed in the received signal demodulated by the tuner 31a.

Until now, the input impedance of the amplification unit 6 has been changed to the output impedance of the first receiving antenna 21 or the second receiving antenna 22 based on the control signals input from the in-vehicle devices 3 and 3a of the antenna amplifier units 1 and 1a. The case of matching to the above was explained.

However, this is just one example. The receiving system according to the embodiment detects the types of the first receiving antenna 21 and the second receiving antenna 22 by the antenna amplifier unit 1b described with reference to FIGS. 3 to 4B, and amplifies the connection unit 41 and the amplifier. The configuration may be such that a matching circuit to be connected between the units 6 is selected.

FIG. 3 is an explanatory diagram showing the configuration of the receiving system according to the second modification of the embodiment. 4A and 4B are explanatory views showing an example of a partial circuit configuration of the receiving system according to the second modification of the embodiment.

As shown in FIG. 3, in the receiving system according to the modification 2, the point that the microcomputer 32b of the in-vehicle device 3b does not output the control signal to the antenna amplifier unit 1b and the point that the antenna amplifier unit 1b includes the detection unit 8 are shown in FIG. It is different from the receiving system shown in 1.

Further, in the receiving system according to the second modification, the configuration of the connecting portion 41 is different from that of the connecting portion 4 shown in FIG. 1, and the connector 23 of the first receiving antenna 21 connected to the connecting portion 41 and the second receiving antenna The configuration of the connector 24 of 22 is different from that shown in FIG.

In the detection unit 8, the connector 23 of the first receiving antenna 21 having no connection terminal to which the connector connected to the connection unit 41 is connected to the outside other than the output terminal of the reception signal, or the second connector having a connection terminal. The type of the antenna is detected based on the connector 24 of the receiving antenna 22 of the above.

Then, the detection unit 8 outputs a control signal according to the type of the detected receiving antenna to the change units 53 and 54 of the matching unit 5. The matching unit 5 changes the input impedance of the amplification unit 6 according to the type of the receiving antenna detected by the detection unit 8.

For example, the detection unit 8 applies a predetermined voltage to the connection unit 41, and when the connector 23 of the first reception antenna 21 is connected to the connection unit 41, the detection unit 8 detects the connection of the first reception antenna 21. The Low level control signal indicating that this is output to the change units 53 and 54.

Similar to the change units 53 and 54 shown in FIG. 1, the change units 53 and 54 connect the first matching circuit 51 between the connection unit 41 and the amplification unit 6 when a Low level control signal is input. Let me. As a result, the antenna amplifier unit 1b can match the input impedance of the amplification unit 6 with the output impedance of the first receiving antenna 21.

Further, the detection unit 8 applies a predetermined voltage to the connection unit 41, and when the connector 24 of the second reception antenna 22 is connected to the connection unit 41, the detection unit 8 detects the connection of the second reception antenna 22. A high level control signal indicating that this is output to the change units 53 and 54.

The change units 53 and 54 connect the second matching circuit 52 between the connection unit 41 and the amplification unit 6 when a high level control signal is input. As a result, the antenna amplifier unit 1b can match the input impedance of the amplification unit 6 with the output impedance of the second receiving antenna 22.

As described above, according to the antenna amplifier unit 1b, the input impedance of the amplification unit 6 is automatically matched with the output impedance of the connected receiving antenna without incorporating software for outputting the control signal to the microcomputer 32b of the in-vehicle device 3b. Can be made to. Such a receiving system can be realized, for example, by the circuit configurations shown in FIGS. 4A and 4B.

Specifically, as shown in FIG. 4A, the connector 23 of the first receiving antenna 21 includes an output terminal 25 for outputting a received signal and a dummy terminal 26 not connected to the outside. The dummy terminal 26 may not be provided. As described above, the connector 23 of the first receiving antenna 21 is a connector that does not have a connection terminal 27 (see FIG. 4B) connected to the outside, which is different from the output terminal 25.

Further, as shown in FIG. 4B, the connector 24 of the second receiving antenna 22 includes an output terminal 25 for outputting a received signal and a connection terminal 27 connected to the outside (for example, the body ground of the vehicle). As described above, the connector 24 of the second receiving antenna 22 is a connector having a connection terminal 27 connected to the outside, which is different from the output terminal 25.

Further, as shown in FIGS. 4A and 4B, the connection unit 41 is detected to be connected to an input terminal 42 to which a received signal is input and a dummy terminal 26 provided in the connector 23 or a connection terminal 27 provided in the connector 24. A terminal 43 is provided.

Further, the detection unit 8 includes a detection circuit composed of a diode D, a first resistance R1, a second resistance R2, a third resistance R3, a transistor T, and an output port P. The transistor T is, for example, a PNP type bipolar transistor.

The collector of the transistor T is connected to the ground via the third resistance R3 and is connected to the output port P. Further, the emitter of the transistor T is connected to a reference voltage line to which a predetermined positive reference voltage Vcc is applied, and is also connected to the base of the transistor T via the second resistor R2. Further, the base of the transistor T is connected to the detection terminal 43 via the first resistance R1 and the diode D connected in series.

As shown in FIG. 4A, when the connector 23 of the first receiving antenna 21 is connected to the connection unit 41, the detection unit 8 applies a positive voltage to the base of the transistor T to turn off the transistor T. Become. As a result, the detection unit 8 outputs a Low level control signal from the output port P to the change units 53 and 54. As a result, the changing units 53 and 54 can connect the first matching circuit 51 between the connecting unit 41 and the amplification unit 6 and input the received signal from the input terminal 42 to the first matching circuit 51.

Further, as shown in FIG. 4B, in the detection unit 8, when the connector 24 of the second receiving antenna 22 is connected to the connection unit 41, the base of the transistor T is connected to the ground and the transistor T is turned on. .. As a result, the detection unit 8 outputs a high level control signal from the output port P to the change units 53 and 54. As a result, the changing units 53 and 54 can connect the second matching circuit 52 between the connecting unit 41 and the amplification unit 6 and input the received signal from the input terminal 42 to the second matching circuit 52.

In this way, the antenna amplifier unit 1b automatically matches the input impedance of the amplification unit 6 with the output impedance of the connected receiving antenna without incorporating software for outputting the control signal to the microcomputer 32b of the in-vehicle device 3b. Can be done.

The receiving system shown in FIG. 3 can also be realized by, for example, the circuit configurations shown in FIGS. 5A and 5B. 5A and 5B are explanatory views showing an example of a partial other circuit configuration of the receiving system according to the second modification of the embodiment.

As shown in FIGS. 5A and 5B, one end of the detection unit 8a is connected to a reference voltage line to which a predetermined positive reference voltage Vcc is applied, and the other end is connected to the detection terminal 43 and the output port P. A fourth resistor R4 is provided.

Further, as shown in FIG. 5B, the connector 24a of the second receiving antenna 22 is connected to the outside (for example, the body ground of the vehicle) via the fifth resistor R5 separately from the output terminal 25 of the receiving signal. A connection terminal 27a is provided. Here, the resistance value of the fifth resistor R5 and the resistance value of the fourth resistor R4 are the same. As shown in FIG. 5A, the connector 23 of the first receiving antenna 21 has the same configuration as that shown in FIG. 4A.

In the case of such a configuration, the changing units 53 and 54 amplify with the connecting unit 41, for example, when a control signal whose signal level is higher than half (Vcc / 2) of the reference voltage Vcc is input from the detection unit 8a. The first matching circuit 51 is connected to the unit 6. Further, the changing units 53 and 54 connect the second matching circuit 52 between the connecting unit 41 and the amplification unit 6 when a control signal having a signal level of Vcc / 2 or less is input.

In such a receiving system, as shown in FIG. 5A, when the connector 23 of the first receiving antenna 21 is connected to the connecting unit 41, the detection unit 8a does not allow current to flow to the detection terminal 43 side. Therefore, the detection unit 8a outputs a control signal having the same signal level as the reference voltage Vcc from the output port P to the change units 53 and 54. As a result, the changing units 53 and 54 can connect the first matching circuit 51 between the connecting unit 41 and the amplification unit 6 and input the received signal from the input terminal 42 to the first matching circuit 51.

Further, as shown in FIG. 5B, when the connector 24a of the second receiving antenna 22 is connected to the connection unit 41, the detection unit 8a has a reference voltage Vcc of 1 / due to the fourth resistance R4 and the fifth resistance R5. The voltage is divided into two. Therefore, the detection unit 8a outputs a control signal having a signal level of the reference voltage Vcc / 2 from the output port P to the change units 53 and 54. As a result, the changing units 53 and 54 can connect the second matching circuit 52 between the connecting unit 41 and the amplification unit 6 and input the received signal from the input terminal 42 to the second matching circuit 52.

As described above, according to the other circuit configuration of the receiving system according to the modification 2, the type of the receiving antenna connected to the connecting unit 41 can be detected by the detecting unit 8a having a simpler circuit configuration.

Further, in the example shown in FIG. 5B, the resistance value of the fifth resistance R5 and the resistance value of the fourth resistance R4 are the same, but when there are three or more types of receiving antennas having different output impedances, the antennas are used. A fifth resistance R5 having a different resistance value for each type is provided in the connector of each receiving antenna. As a result, the detection unit 8a can output control signals having different voltage values to the change units 53 and 54 according to the type of the receiving antenna connected to the connection unit 41.

Therefore, when the detection unit 8a is configured as such, the matching unit 5 is configured to include the same number of matching circuits as the number of types of receiving antennas. Each matching circuit is configured to match the input impedance of the amplification unit 6 with the output impedance of different types of receiving antennas.

Further, the change units 53 and 54 are configured to connect a matching circuit previously associated with the voltage value of the control signal input from the detection unit 8a between the connection unit 41 and the amplification unit 6. As a result, the matching unit 5 can match the input impedance of the amplification unit 6 with the output impedance of the receiving antenna connected to the connection unit 41.

In this way, the antenna amplifier unit 1b is provided with a fifth resistance R5 having a resistance value different for each type of antenna at the connector of each receiving antenna, and the type of the receiving antenna, the voltage value of the control signal, and the matching circuit. The type may be associated with each other in advance. Thereby, the antenna amplifier unit 1b can correspond to all the receiving antennas when there are three or more types of receiving antennas having different output impedances.

In the above-described embodiment, the case where the matching unit 5 includes a plurality of matching circuits having different input impedances for each type of receiving antenna has been described, but the matching unit 5 includes one matching circuit whose input impedance can be changed. It may be provided.

In such a case, the matching circuit includes, for example, a plurality of reactance elements such as a capacitive element, an inductance element, and a resistance element, and the input impedance of the amplification unit 6 is changed by switching the connection mode of the plurality of reactance elements. And.

As a result, the matching unit 5 can match the input impedance of the amplification unit 6 with the output impedance of a plurality of types of receiving antennas by switching the connection mode of the plurality of reactance elements in one matching circuit.

Further, the receiving system according to the embodiment can be further modified. Next, the receiving system according to the third modification of the embodiment will be described with reference to FIG. FIG. 6 is an explanatory diagram showing the configuration of the receiving system according to the third modification of the embodiment.

As shown in FIG. 6, the receiving system according to the modified example 3 differs from the receiving system shown in FIG. 3 in the configuration of the changing units 53c and 54c provided in the matching unit 5c of the antenna amplifier unit 1c and the operation of the detecting unit 8c. .. Note that FIG. 6 shows the configuration of the changed units 53c and 54c at the time of initial startup.

Specifically, the change unit 53c includes a first fuse H1 that connects the connection unit 41 and the first matching circuit 51, and a second fuse H2 that connects the connection unit 41 and the second matching circuit 52. Further, the change unit 54c includes a third fuse H3 that connects the first matching circuit 51 and the amplification unit 6, and a fourth fuse H4 that connects the second matching circuit 52 and the amplification unit 6.

Then, for example, the detection unit 8c disconnects the second fuse H2 and the fourth fuse H4 when the antenna amplifier unit 1c is started for the first time after the first receiving antenna 21 is connected to the connection unit 41. The control signal is output to the change units 53c and 54c. As a result, the connection between the connection unit 41, the first matching circuit 51, and the amplification unit 6 is fixed thereafter.

Further, the detection unit 8c cuts the first fuse H1 and the third fuse H3, for example, when the antenna amplifier unit 1c is started for the first time after the second receiving antenna 22 is connected to the connection unit 41. The control signal is output to the change units 53c and 54c. As a result, thereafter, the connection between the connection unit 41, the second matching circuit 52, and the amplification unit 6 is fixed.

According to the antenna amplifier unit 1c, for example, after the second receiving antenna 22 is connected to the connection unit 41, the matching circuit connected between the connection unit 41 and the amplification unit 6 is connected from the second matching circuit 52. It is possible to prevent switching to the first matching circuit 51.

Specifically, the antenna amplifier unit 1c has a connection unit 41 even if a connection failure between the connection terminal 27 (see FIG. 4B) and the detection terminal 43 occurs due to vibration of the vehicle or deterioration of the connector 24 over time. And the connection between the second matching circuit 52 and the amplification unit 6 can be maintained.

Therefore, according to the antenna amplifier unit 1c, when the second receiving antenna 22 is connected to the connection unit 41, the matching circuit connected between the connection unit 41 and the amplification unit 6 is first matched from the middle. It is possible to prevent the occurrence of reception failure due to switching to the circuit 51.

The antenna amplifier unit 1b shown in FIG. 3 can also obtain the same effect as the antenna amplifier unit 1c shown in FIG. 6 by changing the operation of the detection unit 8. For example, the detection unit 8 shown in FIG. 3 is changed only when the antenna amplifier unit 1b is first activated after the first receiving antenna 21 or the second receiving antenna 22 is connected to the connecting unit 41. The control signal can be output to 53 and 54.

As a result, the antenna amplifier unit 1b shown in FIG. 3 can fix the matching circuit connected between the connecting unit 41 and the amplifying unit 6 to either the first matching circuit 51 or the second matching circuit 52. .. As a result, the antenna amplifier unit 1b can prevent the occurrence of reception failure due to switching between the first matching circuit 51 and the second matching circuit 52 during reception of the received signal.

The detection unit 8 has, for example, the first matching circuit 51 and the second matching circuit 51 when a connection failure between the connection terminal 27 (see FIG. 4B) and the detection terminal 43 occurs due to vibration of the vehicle or deterioration of the connector 24 over time. Both of the matching circuit 52 and the connection unit 41 and the amplification unit 6 may be disconnected.

In this way, when a connection failure between the connection terminal 27 (see FIG. 4B) and the detection terminal 43 occurs, the detection unit 8 intentionally causes a reception failure state to replace the connector 24. You can also urge the user.

Further effects and variations can be easily derived by those skilled in the art. For this reason, the broader aspects of the invention are not limited to the particular details and representative embodiments described and described above. Thus, various modifications can be made without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.

1,1a, 1b, 1c Antenna amplifier unit 3,3a, 3b In-vehicle device 4,41 Connector part 5,5c Matching part 6 Amplification part 7 Output part 8,8a, 8c Detection part 21 First receiving antenna 22 Second Receive antenna 23, 24, 24a Connector 25 Output terminal 26 Dummy terminal 27, 27a Connection terminal 31, 31a Tuner 32, 32b Microcomputer 42 Input terminal 43 Detection terminal 51 First matching circuit 52 Second matching circuit 53, 53c, 54, 54c change part

Claims (6)

The connection part to which the receiving antenna is connected and
An amplification unit that amplifies the received signal of the connection unit,
A detection unit that detects the type of the reception antenna based on whether or not the connector of the reception antenna connected to the connection unit has a connection terminal connected to the outside other than the output terminal of the reception signal. ,
It is characterized by being connected between the connection unit and the amplification unit, and including a matching unit that changes the input impedance of the amplification unit according to the output of the detection unit and matches the output impedance of the receiving antenna. Antenna amplifier unit. The matching part is
The input impedance of the amplification unit is changed by selecting from the plurality of matching circuits a plurality of matching circuits having different input impedances for each type of the receiving antenna and a matching circuit connected between the connection unit and the amplification unit. The antenna amplifier unit according to claim 1, further comprising a change unit. The matching part is
The antenna amplifier unit according to claim 1, further comprising a matching circuit that changes the input impedance of the amplification unit by switching the connection mode of the plurality of reactance elements. The detector is
The connector of the receiving antenna connected to the connection portion is the connector of the first receiving antenna having no connection terminal connected to the outside other than the output terminal of the received signal, or the connector having the connection terminal. The type of the receiving antenna is detected based on the connector of the receiving antenna.
The matching part is
The antenna amplifier unit according to any one of claims 1 to 3, wherein the input impedance of the amplification unit is changed according to the type of the receiving antenna detected by the detection unit. The connection part is
Equipped with a detection terminal connected to the connection terminal
The detector is
A predetermined voltage is applied to the detection terminal, and signals having different levels depending on whether the connector connected to the connection portion has the connection terminal or not is output to the matching unit. The antenna amplifier unit according to any one of claims 1 to 4, wherein the antenna amplifier unit is characterized in that. A first receiving antenna to which a connector having a connection terminal connected to the outside other than the output terminal for outputting a reception signal is connected, or a connector not having the connection terminal is connected to the first receiving antenna. The second receiving antenna, which has a different output impedance from
It is provided with an antenna amplifier unit connected to the first receiving antenna or the second receiving antenna and amplifying the input received signal.
The antenna amplifier unit is
With the connection part to which the first receiving antenna or the second receiving antenna is connected,
An amplification unit that amplifies the reception signal received by the first receiving antenna or the second receiving antenna connected to the connection unit.
The type of the receiving antenna based on whether the connector of the first receiving antenna or the second receiving antenna connected to the connecting portion is the connector of the first receiving antenna or the connector of the second receiving antenna. With a detector that detects
The input impedance of the amplification unit is connected to the connection unit according to the type of the first receiving antenna or the second receiving antenna connected between the connection unit and the amplification unit and detected by the detection unit. A receiving system comprising a matching unit that matches the output impedance of the first receiving antenna or the second receiving antenna.

Images