Antenna amplifier, reception device, reception system, setting method, and control method

Abstract

To provide a technique capable of reducing time and effort for designing an antenna amplifier in accordance with a vehicle type.SOLUTION: An antenna amplifier connected to an antenna and a receiving device mounted on a vehicle includes a capacitor variable unit interposed between a ground of the antenna amplifier and a heating wire pattern of a defogger provided on a window of the vehicle, the capacitor variable unit being capable of changing presence or absence of a capacitor or a capacitance between the ground and the heating wire pattern, and a setting unit configured to set the presence or absence of the capacitor or the capacitance in the capacitor variable unit based on a control signal received from the receiving device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an antenna amplifier, a receiving device, a receiving system, a setting method, and a control method. [Background technology]

[0002] In order to ensure reception performance, the vehicle glass antenna must be designed to receive radio waves at a wavelength that is 1 / 4 of the wavelength. Since glass antennas are designed to a specific length, such as a specific length, they naturally occupy an area corresponding to the frequency of the radio waves they receive. However, due to vehicle design constraints, there are cases where the glass antenna area is not sufficient and the desired reception performance cannot be ensured. For this reason, there is a technology that electrically connects the earth-side power supply part of the glass antenna to the defogger (DEF) heating wire pattern and uses the heating wire pattern as part of the antenna, thereby reducing the area of ​​the glass antenna while ensuring reception performance.

[0003] Patent Document 1 describes a technology for suppressing a decrease in antenna gain by providing a capacitive coupling section in the path that runs from the defogger through the earth-side power supply section of the glass antenna to the ground on the vehicle body side. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-101191 Summary of the Invention [Problem to be solved by the invention]

[0005] When the earth-side power supply of the glass antenna is connected to the defogger, a DC-blocking capacitor is provided to prevent DC voltage from being applied to the receiving device so that the voltage required to operate the defogger is not applied to the receiving device. Furthermore, depending on the vehicle, the earth-side power supply of the glass antenna may not be connected to the heating wire pattern of the defogger. This creates a problem in that the antenna amplifier must be designed for each vehicle model, for example, so that the antenna amplifier is equipped with a DC-blocking capacitor for vehicle models that connect the glass antenna to the defogger, and the antenna amplifier is not equipped with a DC-blocking capacitor for vehicle models that do not connect the glass antenna to the defogger.

[0006] The present disclosure aims to provide a technology that can reduce the amount of work required to design an antenna amplifier to suit a vehicle model. [Means for solving the problem]

[0007] In order to solve the above problems, the antenna amplifier of the present disclosure includes: It is connected to the antenna and receiving equipment installed in the vehicle, a capacitor variable section that is interposed between its own ground and a heating wire pattern of a defogger provided on a window of the vehicle and that can change the presence or absence of a capacitor between the ground and the heating wire pattern or the capacitance thereof; a setting unit that sets the presence or absence of the capacitor or the capacitance in the capacitor variable unit based on a control signal received from the receiving device; Equipped with. [Effects of the Invention]

[0008] The technology disclosed herein can reduce the effort required to design an antenna amplifier to suit each vehicle model. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a receiving system having an antenna amplifier and a receiving device according to the first embodiment. [Figure 2A]FIG. 2A is a rear view of a window glass equipped with a glass antenna for a vehicle. [Figure 2B] FIG. 2B is a rear view of a window glass provided with a glass antenna on which an earth pattern is formed separately from the defogger. [Figure 3] FIG. 3 is a diagram showing the configuration of the in-vehicle device. [Figure 4] FIG. 4 is an explanatory diagram of a process in which the in-vehicle device controls the antenna amplifier and causes the antenna amplifier to perform initial setting. [Figure 5] FIG. 5 is a diagram showing an example of a data table in which correspondence information is registered. [Figure 6] FIG. 6 is an explanatory diagram of a process in which the in-vehicle device controls the antenna amplifier to change the presence or absence of a capacitor or the capacitance. [Figure 7] FIG. 7 is a schematic diagram of a receiving system having an antenna amplifier and a receiving device according to the second embodiment. [Figure 8] FIG. 8 is an explanatory diagram of a process in which the in-vehicle device controls the antenna amplifier to change the presence or absence of a capacitor or the capacitance in the second embodiment. [Figure 9] FIG. 9 is a diagram showing a modified example of the capacitor variable section and the setting section. [Figure 10] FIG. 10 is a diagram showing the switching state of the switches in the setting section of the modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate within the scope of the gist of the present invention.

[0011] First Embodiment FIG. 1 is a schematic diagram of a receiving system including an antenna amplifier and a receiving device according to a first embodiment. FIG. 2A is a rear view of a window glass 10 equipped with a vehicle glass antenna, and FIG. 2B is a rear view of a window glass 10B equipped with a glass antenna with an earth pattern formed separately from a defogger. The receiving system 100 includes the window glass 10 including the glass antenna, an antenna amplifier 20, and an in-vehicle device (receiving device) 30. In the receiving system 100, radio or television broadcast waves are received by the glass antenna and input as an electrical signal to the antenna amplifier 20. The antenna amplifier 20 amplifies the input signal using an amplifier circuit 21 to a predetermined level and inputs the amplified signal to the in-vehicle device 30. The in-vehicle device 30 detects a signal to be output from the input signal using a tuner 31, and reproduces and outputs the radio or television broadcast using a control unit 301. The in-vehicle device 30 of this embodiment is an example of a receiving device that receives broadcast waves. The in-vehicle device 30 may be a device that has a navigation function and an audio function for reproducing audio signals stored in a storage medium in addition to receiving broadcast waves.

[0012] <Window glass> As shown in FIG. 2A , the window glass 10 includes a glass plate 11 that is shaped to be fitted into a window opening at the rear of a vehicle to form a window at the rear of the vehicle. Note that the glass plate 11 is not limited to being made of glass alone. For example, the glass plate 11 may be laminated glass having a synthetic resin intermediate layer sandwiched between two glass plates. Furthermore, the window glass 10 may be configured to include a plate made of another material, such as a synthetic resin plate, instead of the glass plate 11.

[0013] The glass plate 11 has an antenna 12 and a device mounted along the surface facing the front or rear of the vehicle. A fog light 13 is provided. The antenna 12 has a first glass antenna 121 for receiving FM radio broadcasts and a second glass antenna 122 for receiving television broadcasts. The number of glass antennas is not limited to two. For example, the antenna 12 may be a single glass antenna for receiving either FM radio broadcasts or television broadcasts, or may include three or more glass antennas including an antenna for receiving other broadcasts.

[0014] The first glass antenna 121 includes a power supply portion 51 connected to a signal line 41 connected to the antenna amplifier 20, and an antenna conductor 52 connected to the power supply portion 51. The power supply portion 51 is a so-called feeding point. The antenna conductor 52 is formed with a shape and dimensions suitable for the frequency band of radio waves to be received by the first glass antenna 121. In other words, the shape and dimensions of the first glass antenna 121 only need to be set so as to satisfy the required value of antenna gain necessary for receiving radio waves of FM radio broadcasts.

[0015] For example, if the first glass antenna 121 is for receiving Japanese FM broadcasts, the antenna conductor 52 is formed to have a shape and dimensions suitable for receiving radio waves in the 76 to 95 MHz FM broadcast band. Similarly, if the first glass antenna 121 is for receiving American FM broadcasts, the antenna conductor 52 is formed to be suitable for receiving radio waves in the 88 to 108 MHz FM broadcast band of the United States. Of course, the antenna conductor 52 may also be formed to be suitable for receiving radio waves in the 76 to 108 MHz FM broadcast band, which covers both Japan and the United States.

[0016] 2A, the first glass antenna 121 is disposed on the interior-side surface of the glass sheet 11 in a region between the defogger 13 and the upper edge of the glass sheet 11. However, the position where the first glass antenna 121 is disposed is not particularly limited as long as it is a position where the first glass antenna 121 can receive radio waves in the frequency band that it is intended to receive. Note that the first glass antenna 121 is a monopole-type glass antenna that does not have an earth-side feeding portion, but it may also be a dipole-type glass antenna that has an earth conductor and an earth-side feeding portion.

[0017] The second glass antenna 122 includes a power feeder 53 connected to a signal line 41 connected to the antenna amplifier 20, and an antenna conductor 54 connected to the power feeder 53. The power feeder 53 is a so-called feeding point. The antenna conductor 54 is formed with a shape and dimensions suitable for the frequency band of radio waves to be received by the second glass antenna 122. In other words, the shape and dimensions of the second glass antenna 122 only need to be set so as to satisfy the required value of antenna gain necessary for receiving television broadcast radio waves.

[0018] For example, in the second glass antenna 122, if the radio waves to be received are Japanese terrestrial digital television broadcasts, the antenna conductor 54 is formed to have a shape and dimensions suitable for receiving radio waves in the 470 to 770 MHz frequency band for terrestrial digital television broadcasts. The antenna conductor 54 may also be formed to be suitable for receiving radio waves in a frequency band that combines Japanese and other countries' television broadcasts. The second glass antenna 122 is a monopole-type glass antenna that does not have an earth-side feeding portion, but may also be a dipole-type glass antenna that has an earth conductor and an earth-side feeding portion.

[0019] The defogger 13 includes a heating wire pattern such as a plurality of parallel-running heating wires 131 and bus bars 132, 133 for supplying power to the heating wires 131. The plurality of heating wires 131 are arranged on the window glass 10 so as to run parallel to a horizontal plane (ground plane) when the window glass 10 is attached to a vehicle, for example.

[0020] The bus bar 132 is connected to a ground portion of the vehicle body or the like via a coil 134, and the bus bar 133 is connected to the positive electrode side of the DC power supply 60 via a coil 135 and a switch 69. When a user turns on the switch 69 to use the defogger 13, power is supplied from the DC power supply 60 to the heater wire 131. The coils 134, 135 have high impedance at frequencies equal to or higher than the frequencies of the radio waves received by the first glass antenna 121 or the second glass antenna 122, thereby suppressing the passage of electrical signals of those frequencies. When power is supplied between the bus bars 132, 133, the defogger 13 removes condensation on the window glass 10 by the heater wire 131 generating heat.

[0021] Conductive patterns such as the power supplying portion 51 and antenna conductor 52 of the first glass antenna 121, the power supplying portion 53 and antenna conductor 54 of the second glass antenna 122, and the heater wire 131 and bus bars 132, 133 of the defogger 13 are formed on the surface of the window glass 10. For example, these conductive patterns are formed by printing a paste containing a conductive metal such as silver paste on the interior surface of the glass sheet 11 and baking it. However, the conductive pattern is not limited to this, and may be a linear or foil-shaped member made of a conductive material such as copper formed on the interior surface or exterior surface of the glass sheet 11, attached to the glass sheet 11 with an adhesive or the like, or provided inside the glass sheet 11.

[0022] <Antenna amplifier> The antenna amplifier 20 includes an amplifier circuit 21, a capacitor variable unit 22, and a setting unit 23. The input terminal of the amplifier circuit 21 is connected to a connector 241 via a signal line 211. A signal line (an inner conductor of a coaxial line) 41 is connected to the connector 241, and the other end of the signal line 41 is connected to a power feeder 51 of the first glass antenna 121 and a power feeder 53 of the second glass antenna 122. The output terminal of the amplifier circuit 21 is connected to a tuner 31 of the in-vehicle device 30 via a signal line 212, and the amplifier circuit 21 inputs an amplified signal to the tuner 31. The ground terminal of the amplifier circuit 21 is connected to a ground 25 that is electrically connected to the vehicle body or the like.

[0023] The capacitor variable unit 22 is interposed between the ground 25 of the antenna amplifier 20 and the heating wire patterns (131, 132, 133) of the defogger 13 provided on the window glass 10 of the vehicle. The capacitor variable unit 22 includes electric paths 62 and 63 including a capacitor, and an electric path (through pattern) 61 not including a capacitor. Furthermore, the capacitor variable unit 22 of this embodiment includes a plurality of electric paths 62 and 63 including a capacitor (two in the example of FIG. 2A ). The electric path 62 includes capacitors 621 and 622 connected in series, and the electric path 63 includes capacitors 631 and 632 connected in series. The electric paths 62 and 63 have different capacitances, which are set according to the frequency band of a signal (broadcast wave) selected by the user to be viewed (output target) as described below. The capacitor variable unit 22 selectively connects one of the electrical circuits 61 to 63 between the heating wire pattern of the defogger 13 and the ground 25, thereby making it possible to change the presence or absence of a capacitor or the capacitance between the heating wire pattern and the ground 25.

[0024] The setting unit 23 includes a first switch 231 and a second switch 232. The first switch 231 is provided between the capacitor variable unit 22 and a signal line 42 connected to the heating wire pattern of the defogger 13. The first switch 231 is a selector switch that can be externally controlled by the in-vehicle device 30. The first switch 231 selectively connects the signal line 42 to one of the electric circuits 61 to 63 in the capacitor variable unit 22.

[0025] The second switch 232 is provided between the capacitor variable section 22 and the ground 25, i.e., between the capacitor variable section 22 and the ground terminal of the amplifier circuit 21. The second switch 232 is a selector switch that can be externally controlled by the in-vehicle device 30. The second switch 232 selectively connects the ground 25 and the ground terminal of the amplifier circuit 21 to one of the electric paths 61 to 63 in the capacitor variable section 22. Note that, although the setting section 23 of this embodiment includes the first switch 231 and the second switch 232, the present invention is not limited to this, and one of the switches may be omitted. Alternatively, the other switch may be used to selectively connect the electric paths 61 to 63 of the capacitor variable section 22.

[0026] <In-vehicle equipment> FIG. 3 is a diagram showing the configuration of the in-vehicle device 30. FIGS. 1 to 3 mainly show components necessary for explaining the features of this embodiment, and some of the general components are omitted. In other words, the components shown in FIGS. 1 to 3 are functional concepts and do not necessarily have to be physically configured as shown. For example, the specific form of distribution and integration of each functional block is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0027] As shown in FIG. 3, the in-vehicle device 30 is an information processing device (computer) having a control unit 301, a memory 302, an input / output interface (IF) 303, and a communication IF 304, which are interconnected by a connection bus 310.

[0028] The control unit 301 controls the entire in-vehicle device and includes, for example, a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), a main memory, etc. The control unit 301 is also referred to as a controller or a processor circuit. The control unit 301 is not limited to a configuration including a single processor, but may have a multiprocessor configuration. Furthermore, a single control unit 301 connected via a single socket may have a multi-core configuration. The main memory is a storage medium used, for example, as a working area for the control unit 301, a storage area for programs and data, and a buffer area for communication data. The main memory includes, for example, a random access memory (RAM) or a combination of a RAM and a read only memory (ROM).

[0029] The memory 302 is an auxiliary storage device that stores programs executed by the control unit 101, operation setting information, etc. The memory 302 is not limited to an internal storage device built into the in-vehicle device 30, but may also be an external storage device such as an external storage device or a NAS (Network Attached Storage). The memory 302 may be, for example, a hard-disk drive (HDD), a solid-state drive (SSD), an EPROM (Erasable Programmable ROM), a flash memory, a USB Memory, memory cards, etc.

[0030] The input / output IF 303 is an interface for inputting and outputting data to and from peripheral devices. The input / output IF 303 inputs and outputs data to and from devices such as a disk drive that reads data from a storage medium such as a CD or a DVD, an operation unit that receives user operations, and a display device that displays information to the user. The input / output IF 303 may also input and output data to and from devices such as a tuner 31 that receives radio or television broadcast waves, a reader / writer that reads and writes data from and to a storage medium such as a memory card, a microphone, and a sensor. In this embodiment, the input / output IF 303 is connected to the antenna amplifier 20 and transmits a control signal to the antenna amplifier 20. Note that the in-vehicle device 30 may transmit a control signal to the antenna amplifier 20 via a network such as a CAN using the communication IF 304 instead of the input / output IF 303. The operation unit is input means that receives an operation by a user and inputs operation information indicating the operation to the control unit 301. The operation unit may be, for example, a button, a switch, a dial (rotary knob), a lever, or the like. The operation unit may also be a touch panel that is provided over the display surface of the display device.

[0031] The communication IF 304 is an interface that communicates with other devices via a communication line, and communicates with an external data server or the like using, for example, a wireless communication system.

[0032] In the in-vehicle device 30, the control unit 301 executes an application program to function as a processing unit that performs predetermined information processing. However, at least a part of the processing of each of the above processing units may be provided by a DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), etc. The above-described processing units may be implemented by dedicated large-scale integration (LSI) such as a field-programmable gate array (FPGA) or other digital circuits. The in-vehicle device 30 may also be configured to include analog circuits in at least some of the above-described processing units.

[0033] <Initial settings> 4 is an explanatory diagram of a process in which the in-vehicle device 30 performs initial setting by controlling the antenna amplifier 20. The in-vehicle device 30 executes the process in FIG. 4 when power is supplied, for example, when an accessory power source of the vehicle is turned on.

[0034] In step S10, the control unit 301 determines whether or not this is the first startup, i.e., whether or not initial settings have already been completed. If this is not the first startup after the in-vehicle device 30 is installed in the vehicle, the control unit 301 makes a negative determination and ends the processing in Fig. 4, whereas if this is the first startup, the control unit 301 makes a positive determination and proceeds to step S20.

[0035] In step S20, the control unit 301 acquires vehicle model information. For example, the control unit 301 acquires vehicle model information indicating the vehicle model from an ECU (Electronic Control Unit) of the vehicle. Furthermore, the control unit 301 may acquire vehicle model information input by the user operating the operation unit.

[0036] In step S30, the control unit 301 determines whether a capacitor is present based on the vehicle model information acquired in step S20. For example, the control unit 301 references a data table such as that shown in FIG. 5 to determine whether a capacitor is present corresponding to the vehicle model information. FIG. 5 is a diagram showing an example of a data table that registers correspondence information indicating the correspondence between the presence or absence of a capacitor or capacitance, which differs for each vehicle model, and each vehicle model. In FIG. 5, vehicle model information that identifies the vehicle model, the presence or absence of a capacitor, and information on electrical circuits 62, 63 corresponding to the signal (broadcast wave) received by the in-vehicle device 30 are registered in association with each other. For example, in the window glass 10B shown in FIG. 2B, the antenna 12 includes an antenna conductor 55 and an earth pattern 56, and the antenna conductor 55 is connected to the signal line 41, and the earth pattern 56 is connected to the signal line 42. In this way, if the antenna 12 itself has its own earth pattern 56 and the earth pattern 56 is not connected to the heating wire pattern of the defogger 13, a capacitor is not required, and therefore the presence or absence of a capacitor is displayed as "No." Furthermore, for vehicle models in which the heating wire pattern of the defogger 13 is connected to the antenna amplifier 20, a capacitor is connected between the ground 25 and the heating wire pattern to cut DC power, so the presence or absence of a capacitor is marked "present." In Fig. 5, the capacitor for vehicle model A is marked "absent," and the capacitors for vehicle models B to D are marked "present."

[0037] 5, when a capacitor is "present," information indicating corresponding electric circuits 62 and 63 is registered for each signal received by the in-vehicle device 30. For example, in the example of FIG. 5, when the signal received by the in-vehicle device 30 is an FM radio broadcast (frequency band: 76 to 90 MHz), the electric circuit 62 is found as the corresponding electric circuit. When the signal received by the in-vehicle device 30 is a television broadcast (frequency band: 470 to 770 MHz), the electric circuit 63 is found as the corresponding electric circuit.

[0038] In step S40, the control unit 301 stores the presence or absence of the capacitor determined in step S30 as setting information in the memory 302. In addition, when the capacitor is "present" as in the vehicle models B, C, and D in FIG. 5, information on the electrical path corresponding to the frequency band of the signal (broadcast wave) received by the in-vehicle device 30 is stored as setting information in the memory 302. Here, in the case of the vehicle model B, When the signals (broadcast waves) received by the in-vehicle device 30 have a plurality of frequency bands, information on a plurality of electrical circuits corresponding to each frequency band is stored as setting information in the memory 302. When the signals received by the in-vehicle device 30 are only FM radio broadcasts, as in the case of vehicle model C, information on electrical circuit 62 corresponding to this frequency band is stored as setting information in the memory 302. When the signals received by the in-vehicle device 30 are only television broadcasts, as in the case of vehicle model D, information on electrical circuit 63 corresponding to this frequency band is stored as setting information in the memory 302.

[0039] In step S50, if the setting information determined in step S40 indicates that a capacitor is "absent," the control unit 301 transmits a control signal to the antenna amplifier 20 to set the electric path 61. In response to this, the antenna amplifier 20 switches the first switch 231 and the second switch 232 based on the control signal so that no capacitor is interposed between the ground 25 and the heating wire pattern, i.e., so that the electric path 61 (through pattern) is connected.

[0040] Also, in step S50, if the setting information determined in step S40 includes only one electrical path, the control unit 301 transmits a control signal to the antenna amplifier 20 to set that electrical path. For example, if the vehicle model is C, it receives only FM radio broadcasts and does not switch to television broadcasts, so it transmits a control signal to the antenna amplifier 20 to set it to electrical path 62 corresponding to FM radio broadcasts. Also, if the vehicle model is D, it receives only television broadcasts and does not switch to FM radio broadcasts, so it transmits a control signal to the antenna amplifier 20 to set it to electrical path 63 corresponding to television broadcasts. Note that if the setting information determined in step S40 includes multiple electrical paths, the control unit 301 may end the processing of FIG. 4 without transmitting a control signal to the antenna amplifier 20.

[0041] <Control method> 6 is an explanatory diagram of a process in which the in-vehicle device 30 controls the antenna amplifier 20 to change the presence or absence of a capacitor or its capacitance. The in-vehicle device 30 executes the process of FIG. 6 when a user operates the in-vehicle device 30 to output broadcast waves, i.e., when the in-vehicle device 30 receives an instruction to start listening to an FM radio broadcast or watching a television broadcast. Hereinafter, listening to an FM radio broadcast or watching a television broadcast is also simply referred to as "viewing." After starting viewing, the in-vehicle device 30 repeatedly executes the process of FIG. 6 even if the process of FIG. 6 has ended until the in-vehicle device 30 receives an instruction to end viewing.

[0042] In step S100, control unit 301 acquires setting information from memory 302. In step S110, control unit 301 determines whether or not a capacitor is "absent" based on the setting information acquired in step S100. If the capacitor is "absent" and the determination is affirmative in step S110, control unit 301 ends the processing in FIG. 6. On the other hand, if the capacitor is "present" and the determination is negative in step S110, control unit 301 proceeds to step S120.

[0043] In step S120, the control unit 301 determines whether the setting information acquired in step S100 contains only one electrical circuit. If the setting information contains only one electrical circuit and the determination is affirmative in step S120, electrical circuit switching is unnecessary, and the control unit 301 terminates the processing in Fig. 6. If the setting information contains multiple electrical circuits and the determination is negative in step S120, the control unit 301 proceeds to step S130.

[0044] In step S130, the control unit 301 identifies the broadcast wave that the user has selected to view, obtains information about the electrical path corresponding to the broadcast wave from the setting information, and generates a control signal to cause the antenna amplifier 20 to set the electrical path. For example, if the user has selected an FM radio broadcast, the control unit 301 generates a control signal to cause the antenna amplifier 20 to set electrical path 62, and if the user has selected a television broadcast, the control unit 301 generates a control signal to cause the antenna amplifier 20 to set electrical path 63.

[0045] In step S140, the control unit 301 transmits the control signal generated in step S130 to the antenna amplifier 20 to control the antenna amplifier 20. The antenna amplifier 20, which has received the control signal, selects the first switch 231 and the second switch 232 to connect the electric circuit 62 or the electric circuit 63 between the ground 25 and the heating wire pattern. That is, when the user selects FM radio broadcasting and the in-vehicle device 30 receives signals in the range of 76 to 90 MHz, the setting unit 23 of the antenna amplifier 20 sets the electric circuit 62 and interposes capacitors 621 and 622 between the heating wire pattern and the ground 25. On the other hand, when the user selects television broadcasting and the in-vehicle device 30 receives signals in the range of 470 to 770 MHz, the setting unit 23 of the antenna amplifier 20 sets the electric circuit 63 and interposes capacitors 631 and 632 between the heating wire pattern and the ground 25.

[0046] As described above, in the receiving system 100 of this embodiment, by inserting a capacitor between the heating wire pattern and the ground 25, even when power for heating is supplied to the heating wire pattern, the capacitor prevents DC power from passing through, thereby reducing the impact on the in-vehicle device. In this case, the signal (broadcast wave) received by the in-vehicle device 30 is AC and can pass through the capacitor. However, to efficiently pass the signal, it is desirable to set the capacitance of the capacitor according to the frequency band of the signal. Therefore, the capacitors 621 and 622 of the electric circuit 62 are set to have a capacitance corresponding to the FM radio broadcast frequency band of 76 to 90 MHz. Furthermore, the capacitors 631 and 632 of the electric circuit 63 are set to have a capacitance corresponding to the television broadcast frequency band of 470 to 770 MHz.

[0047] In step S150, the control unit 301 determines whether a DC voltage has been applied to the heating wire pattern of the defogger 13. The control unit 301 acquires information about the defogger 13, for example, from the vehicle's ECU, and determines that a DC voltage has been applied to the heating wire pattern if the defogger 13 is in an operating state, and determines that a DC voltage has not been applied if the defogger 13 is not in an operating state. Furthermore, if a sensor that detects the power supplied to the heating wire pattern or a sensor that detects the state of a switch or the like of the defogger 13 is provided, the control unit 301 may determine whether a DC voltage has been applied to the heating wire pattern based on the detection result of the sensor. If the determination in step S150 is positive, the control unit 301 ends the processing of FIG. 6, and if the determination in step S150 is negative, the control unit 301 proceeds to step S160.

[0048] In step S160, the control unit 301 generates a control signal that causes the antenna amplifier 20 to set the electric path 61 and transmits it to the antenna amplifier 20. Upon receiving the control signal, the antenna amplifier 20 switches the first switch 231 and the second switch 232 based on the control signal so that no capacitor is interposed between the ground 25 and the heating wire pattern, i.e., so that the electric path 61 (through pattern) is connected. If it is determined in step S150 that a DC voltage is being applied to the heating wire pattern, the control unit 301 keeps the capacitor interposed between the ground 25 and the heating wire pattern as set in step S140 and cuts off the DC voltage. On the other hand, if it is determined in step S150 that a DC voltage is not being applied to the heating wire pattern, there is no need to cut off the DC voltage, so the electric path (through pattern) 61 is set.

[0049] <Effects of the embodiment> (1) The antenna amplifier 20 of this embodiment is connected to an antenna 12 mounted on a vehicle and an in-vehicle device (receiving device) 30. The antenna amplifier 20 is also provided with a capacitor variable unit 22 that is inserted between its own ground 25 and a heating wire pattern of a defogger 13 provided on a vehicle window and that can change the presence or absence of a capacitor or the capacitance between the ground 25 and the heating wire pattern. Furthermore, the antenna amplifier 20 sets the presence or absence of a capacitor or the capacitance in the capacitor variable unit 22 based on a control signal received from the in-vehicle device 30. The antenna amplifier 20 of this embodiment is equipped with a setting unit 23 that sets the capacitance and presence of a capacitor. In this way, the antenna amplifier 20 of this embodiment can change the capacitance and presence of a capacitor. Therefore, the antenna amplifier 20 can be installed in both vehicle models that require a capacitor between the heating wire pattern of the defogger 13 and the ground 25 of the antenna amplifier 20 and vehicle models that do not require such a capacitor. In other words, the antenna amplifier 20 of this embodiment can reduce the effort required to design different antenna amplifiers for different vehicle models.

[0050] (2) In the antenna amplifier 20 of this embodiment, the setting unit 23 sets the presence or absence of a capacitor or the capacitance based on a control signal that differs for each vehicle model and is transmitted from the in-vehicle device 30. This allows the antenna amplifier 20 of this embodiment to set the capacitance of the capacitor according to the frequency band of the signal received by the in-vehicle device 30, and can maintain good sensitivity even when receiving broadcasts of different frequency bands.

[0051] (3) In the antenna amplifier 20 of this embodiment, the capacitor variable unit 22 includes a capacitor connectable between the ground 25 and the heating wire pattern, and a through pattern connectable between the ground 25 and the heating wire pattern in place of the capacitor. In addition, the setting unit 23 of the antenna amplifier 20 switches the through pattern or capacitor to be connected between the ground 25 and the heating wire pattern based on a control signal. This allows the antenna amplifier 20 of this embodiment to switch between the presence or absence of a capacitor with a simple configuration.

[0052] (4) In the antenna amplifier 20 of this embodiment, the capacitor variable unit 22 includes a plurality of capacitors with different capacitances, and the setting unit 23 switches the capacitance of the capacitors according to the frequency band of the signal received by the in-vehicle device 30 via the antenna 12. As a result, the antenna amplifier 20 of this embodiment can set the capacitance of the capacitors according to the frequency band of the signal received by the in-vehicle device 30, and can maintain good sensitivity even when receiving broadcasts of different frequency bands.

[0053] (5) In this embodiment, the setting unit 23 of the antenna amplifier 20 inserts a capacitor between the ground 25 and the heating wire pattern when it detects that a DC voltage is applied to the heating wire pattern. On the other hand, the antenna amplifier 20 sets the capacitor not to be inserted between the ground 25 and the heating wire pattern when it detects that no DC voltage is applied to the heating wire pattern. As a result, the antenna amplifier 20 uses the capacitor to block the DC voltage when a DC voltage is applied to the heating wire pattern, and does not insert the capacitor when no DC voltage is applied, thereby maintaining good sensitivity.

[0054] Second Embodiment Fig. 7 is a schematic diagram of a receiving system having an antenna amplifier and a receiving device according to the second embodiment, and Fig. 8 is an explanatory diagram of a process in which an in-vehicle device 30 controls the antenna amplifier 20 to change the presence or absence of a capacitor or its capacitance in the second embodiment. This embodiment differs from the first embodiment in that the antenna amplifier 20A detects whether a DC voltage is applied to the heating wire pattern of the defogger 13 and sets the capacitor variable unit 22, but the other configurations are the same. For this reason, the same elements as those in the first embodiment are designated by the same reference numerals, and repeated description will be omitted.

[0055] 7, compared to the antenna amplifier 20 of the first embodiment, the antenna amplifier 20A of the present embodiment further includes a detection unit 26 that detects whether or not a DC voltage is applied to the heating wire pattern of the defogger 13. When the detection unit 26 detects that a DC voltage is not being applied to the heating wire pattern, the setting unit 23A switches the first switch 231 and the second switch 232 so that the electric path 61 (through pattern) is connected between the ground 25 and the heating wire pattern.

[0056] The process of FIG. 8 differs from the process of FIG. 6 in that steps S150 and S160 for controlling the antenna amplifier 20 depending on whether a DC voltage is applied to the heating wire pattern are omitted. Other steps S100 to S140 in FIG. 8 are the same as those in FIG. 6. As described above, when receiving FM radio broadcasts or television broadcasts, the in-vehicle device 30 transmits a control signal to the antenna amplifier 20 in step S140. In response to this control signal, the in-vehicle device 30 interposes a capacitor between the heating wire pattern of the defogger 13 and ground 25, so that even if a DC voltage is applied to the heating wire pattern of the defogger 13, the capacitor blocks the DC voltage. Even when receiving FM radio broadcasts or television broadcasts with the in-vehicle device 30, there is no need to block the DC voltage if no DC voltage is applied to the heating wire pattern. Therefore, when the detection unit 26 detects that no DC voltage is being applied to the heating wire pattern, the setting unit 23A disables the control signal from the in-vehicle device 30 and sets the capacitor variable unit 22 to select the electric circuit 61. On the other hand, when the detection unit 26 detects that a DC voltage is being applied to the heating wire pattern, the setting unit 23A switches the first switch 231 and the second switch 232 based on the control signal received from the in-vehicle device 30, as in the first embodiment described above.

[0057] In this way, the antenna amplifier 20A of this embodiment can maintain good sensitivity by not inserting a capacitor between the heating wire pattern and ground 25 when no DC voltage is applied to the heating wire pattern.

[0058] <Modification> FIG. 9 is a diagram showing a modified example of the capacitor variable section 22B and the setting section 23B, and FIG. 10 is a diagram showing the switching states of the switches 633 to 636 in the setting section 23B of this modified example. This modified example differs from the second embodiment described above in the configuration of the capacitor variable section 22B and the setting section 23B. Since the other configurations are the same as those of the second embodiment, the same elements are given the same reference numerals, and a repeated description will be omitted. Note that the configuration of this modified example may be the same as that of the first embodiment, except for the capacitor variable section 22B and the setting section 23B.

[0059] The capacitor variable unit 22B of this modified example includes a through pattern 64 with no capacitor inserted therein, and a plurality of (four in the example of FIG. 9) capacitors 623-626. The setting unit 23B of this modified example also includes a plurality of (four in the example of FIG. 9) switches 633-636. The switch 633 of the setting unit 23B is a three-way switch having one terminal on one side and two terminals on the other side, and selectively connecting one terminal to either of the other two terminals. In other words, the switch 633 of the setting unit 23B is a two-notch selector switch. The switches 634-636 are single-pole switches that can be switched between an on state and an off state. All of the switches 633-636 are configured to be externally controllable by the in-vehicle device 30.

[0060] The switch 633 of the setting unit 23B has two alternatively switchable terminals, one of which is connected to the through pattern 64, and the other of which is connected to the capacitor 623 and the switch 634. The switch 634 has one terminal connected to the capacitor 623 and the switch 633, and the other terminal connected to the capacitor 624 and the switch 635. The switch 635 has one terminal connected to the capacitor 624 and the switch 634, and the other terminal connected to the capacitor 625 and the switch 636. The switch 636 has one terminal connected to the capacitor 625 and the switch 635, and the other terminal connected to the capacitor 626.

[0061] In the example of Figure 9, the switch 633 of the setting unit 23B is switched to the through pattern 64 side, so that the heating wire pattern and the ground 25 are connected via the through pattern 64, and no capacitor is interposed between the heating wire pattern and the ground 25.

[0062] 10A, the switch 633 of the setting unit 23B is switched to the capacitor 623 side, and the other switches 634 to 636 are in the OFF state. In this case, the capacitor 623 is interposed between the heating wire pattern and the ground 25.

[0063] 10B, switch 633 of setting unit 23B is switched to the capacitor 623 side, switch 634 is on, and switches 635 and 636 are off. In this case, capacitors 623 and 624 are inserted in parallel between the heating wire pattern and ground 25.

[0064] 10(C), switch 633 of setting unit 23B is switched to the side of capacitor 623, switches 634 and 635 are on, and switch 636 is off. In this case, capacitors 623 to 625 are inserted in parallel between the heating wire pattern and ground 25.

[0065] 10(D), the switch 633 of the setting unit 23B is switched to the capacitor 623 side, and the switches 634 to 636 are in the ON state. In this case, the capacitors 623 to 626 are inserted in parallel between the heating wire pattern and the ground 25.

[0066] As described above, in this modification, the number of capacitors inserted between the heating wire pattern and ground 25 is changed by switching the switches 633 to 636 in the setting unit 23. That is, the antenna amplifier 20B of this modification can change the capacitance between the heating wire pattern and ground 25. In this case, the in-vehicle device 30 stores the switching states of the switches 633 to 636 corresponding to the broadcast waves received by the in-vehicle device 30, as in FIG. 5. Then, when the user specifies a broadcast wave to be viewed, the in-vehicle device 30 controls the antenna amplifier 20 so that the capacitance between the heating wire pattern and ground 25 becomes a value corresponding to the broadcast wave.

[0067] In this way, the antenna amplifier 20B of this modification can set the capacitance between the heating wire pattern and the ground 25 or the presence or absence of a capacitor according to the frequency band of the signal (broadcast wave) received by the in-vehicle device 30, thereby reducing the effort required to design an antenna amplifier to suit the vehicle model. Furthermore, the antenna amplifier 20B of this modification can set the capacitance of the capacitor according to the frequency band of the signal received by the in-vehicle device 30, and can maintain good sensitivity even when receiving broadcasts of different frequency bands.

[0068] <Other> Although the embodiments of the present invention have been described above, these are merely examples, and the present disclosure is not limited to these, and various modifications based on the knowledge of those skilled in the art are possible as long as they do not deviate from the spirit of the claims. For example, the receiving system of the present disclosure can receive signals from a vehicle keyless entry system (frequency band: 300 to 450 MHz), signals for car telephones (frequency band: 810 to 960 MHz), signals for car telephones (frequency band: 1.429 to 1.501 GHz), and signals for GPS (Global Positioning System) (frequency band: 1.429 to 1.501 GHz). It may be configured to perform communication in a band of 1176.45 to 1575.42 MHz or the like. [Explanation of symbols]

[0069] 10: Window glass 11: Glass plate 12: Antenna 13: Defogger 20: Antenna amplifier 20A, 20B: Antenna amplifier 21: Amplifier circuit 22, 22B: Variable capacitor section 23,23A,23B: Setting section 25: Ground 26:Detection unit 30: In-vehicle device 31: Tuner 41, 42: Signal line 51, 53: Power supply unit 52, 54, 55: Antenna conductor 56: Earth pattern 60: DC power supply 61~63:Electric circuit 64:Through pattern 69: Switch 100: Receiving system 101: Control unit 121: First Glass Antenna 122: Second Glass Antenna 131: Heater wire 132, 133: Busbar 134, 135: Coil 211, 212: Signal lines 231: First Switch 232: Second switch 241: Connector 301: Control unit 302: Memory 310: Connection bus 621~626: Capacitor 631~636: Switch 303: Input / output interface 304: Communication IF

Claims

1. An antenna amplifier connected to an antenna and a receiving device mounted on a vehicle, a capacitor variable section that is interposed between its own ground and a heating wire pattern of a defogger provided on a window of the vehicle and that can change the presence or absence of a capacitor between the ground and the heating wire pattern or the capacitance thereof; a setting unit that sets the presence or absence of the capacitor or the capacitance in the capacitor variable unit based on a control signal received from the receiving device; An antenna amplifier comprising:

2. 2. The antenna amplifier according to claim 1, wherein the setting unit sets the presence or absence of the capacitor or the capacitance based on the control signal transmitted from the receiving device, which differs for each vehicle model.

3. the variable capacitor unit includes a capacitor connectable between the ground and the heating wire pattern, and a through pattern connectable between the ground and the heating wire pattern in place of the capacitor, The setting unit switches the through pattern or the capacitor to be connected between the ground and the heating wire pattern based on the control signal.

2. The antenna amplifier according to claim 1.

4. the capacitor variable unit includes a plurality of capacitors having different capacitances, 4. The antenna amplifier according to claim 3, wherein the setting section switches the capacitance of the capacitor in accordance with a frequency band of a signal received by the receiving device via the antenna.

5. 2. The antenna amplifier according to claim 1, wherein the setting unit is configured to insert the capacitor between the ground and the heating wire pattern when it detects that a DC voltage has been applied to the heating wire pattern, and to not insert the capacitor between the ground and the heating wire pattern when it detects that a DC voltage has not been applied to the heating wire pattern.

6. An antenna amplifier connected to an antenna and a receiving device mounted on a vehicle, a capacitor variable section that is interposed between its own ground and a heating wire pattern of a defogger provided on a window of the vehicle and that can change the presence or absence of a capacitor between the ground and the heating wire pattern; a setting unit that sets whether or not the capacitor is present in the capacitor variable unit based on a signal indicating that a DC voltage has been applied to the heating wire pattern; An antenna amplifier comprising:

7. A receiving device connected to the antenna amplifier according to any one of claims 1 to 5, A receiving device that has correspondence information indicating the correspondence between the presence or absence or capacitance of the capacitor, which differs for each vehicle model, and each vehicle model, and transmits the control signal to the antenna amplifier to set the presence or absence or capacitance of the capacitor corresponding to the vehicle model based on the correspondence information.

8. A system including the antenna amplifier according to any one of claims 1 to 5 and a receiving device that receives a signal via the antenna and the antenna amplifier, The receiving device has correspondence information indicating the correspondence between the presence or absence or capacitance of the capacitor, which differs for each vehicle model, and each vehicle model, and transmits the control signal to the antenna amplifier based on the correspondence information to set the presence or absence or capacitance of the capacitor corresponding to the vehicle model.

9. A method performed by an antenna amplifier connected to an antenna and a receiving device mounted on a vehicle, comprising: the antenna amplifier has a capacitor variable section that is interposed between its own ground and a heating wire pattern of a defogger provided on a window of the vehicle and that can change the presence or absence of a capacitor between the ground and the heating wire pattern or the capacitance, and a setting section that sets the presence or absence of the capacitor or the capacitance in the capacitor variable section, A setting method in which the antenna amplifier sets the presence or absence of the capacitor in the capacitor variable section or the capacitance based on a control signal received from the receiving device.

10. A method executed by a receiving device connected to the antenna amplifier according to any one of claims 1 to 5, A control method in which the receiving device has correspondence information indicating the correspondence between the presence or absence or capacitance of the capacitor, which differs for each vehicle model, and each vehicle model, and transmits the control signal to the antenna amplifier based on the correspondence information to set the presence or absence or capacitance of the capacitor corresponding to the vehicle model.

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