JP4768568B2 - Antenna module and receiver - Google Patents

Description

  The present invention relates to a technique for controlling the directivity of an antenna element using an antenna element capable of controlling directivity so that a received signal level becomes high.

  An antenna element capable of controlling directivity is known. For example, the antenna element disclosed in Patent Document 1 is called an electronically controlled waveguide array antenna (ESPAR antenna), and is provided at a predetermined distance from a radiating element to which a wireless signal is fed. And at least one non-excited element to which no wireless signal is supplied, and a variable reactance element connected to the non-excited element. By changing the reactance value of the variable reactance element, the directivity of the antenna element can be changed.

JP 2001-24431 A

  By the way, each component provided in the antenna element has frequency characteristics, and the antenna element as a whole has different characteristics for each frequency. Therefore, the characteristics of the antenna element at a specific frequency are the same at other frequencies as well. Not necessarily. Therefore, in radio broadcast receivers and the like that need to receive radio waves of different frequencies, the change in directivity pattern with respect to the reactance value is measured and stored as a table for each frequency that may be set. When a frequency to be received is designated, it is necessary to control directivity using a corresponding table.

  As such a receiving apparatus, for example, a configuration as shown in FIG. 5 is conceivable. The receiving device 50 includes an antenna module 60 and a receiver 70. The receiver 70 demodulates the signal received from the antenna module 60 by, for example, a heterodyne method, and indicates reception level information indicating a signal level at an intermediate frequency and a frequency obtained by adding the intermediate frequency to a frequency set as a local oscillation. The reception frequency information is supplied to the antenna module 60.

  The antenna module 60 is provided with an electronic control waveguide array antenna 61 and a directivity control circuit 62 that controls the directivity of the electronic control waveguide array antenna 61. The directivity control circuit 62 stores in advance information indicating the change in directivity of the electronically controlled waveguide array antenna 61 with respect to the reactance value for each frequency as a table, and the received frequency information supplied from the receiver 70 is stored in the received frequency information. Based on this, one piece of information indicating a change in directivity of the electronically controlled waveguide array antenna 61 with respect to the reactance value is selected from the table. Then, the directivity control circuit 62 changes the reactance value of the electronic control waveguide array antenna 61 so that the signal level indicated by the reception level information supplied from the receiver 70 becomes higher based on the selected information. Let

  By the way, an antenna module and a receiver may be sold separately. The antenna module with fixed directivity has existed as a single unit, and the specifications of the interface with the receiver (antenna input signal) are shared among multiple manufacturers, but directivity can be controlled. Since the antenna itself is a relatively new technology, the specifications of control signals such as reception level information and reception frequency information may differ depending on the design manufacturer. Therefore, an antenna module manufactured by one manufacturer may not be used with a receiver manufactured by the other manufacturer.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to appropriately control antenna directivity in an antenna module without supplying reception frequency information and reception level information from the receiver to the antenna module. There is to be able to do it.

  In order to solve the above problems, the antenna module of the present invention estimates a reception channel set in the receiver from a local signal leaking from the antenna input terminal of the receiver.

  The first aspect of the present invention is, for example, an antenna module that receives a radio wave and supplies it to a receiver, and an antenna element whose directivity changes according to a given signal, and an input received signal level The directivity control circuit that controls the directivity of the antenna element by controlling the signal given to the antenna element for the specified frequency, and the signal output from the antenna element via the cable A directional coupler that is provided between the output terminal for output to the antenna element and the output terminal and attenuates a signal flowing from the output terminal to the antenna element more than a signal flowing from the antenna element to the output terminal; First level measuring means for measuring and outputting a signal level of a designated frequency for a signal flowing between the antenna element and the directional coupler; A second level measuring means for measuring and outputting a signal level of a designated frequency for a signal flowing between the directional coupler and the output terminal; a first level measuring means; and a second level measuring means. The frequency of the signal to be measured is indicated, and when the signal level output from the second measuring unit is higher than the signal level output from the first measuring unit, the signal level is set to the measured frequency. The received frequency detection means for outputting to the directivity control circuit as the reception frequency that is the frequency to which the value is to be received and the signal flowing between the antenna element and the directional coupler are output from the local frequency determination means. And third level measuring means for measuring the signal level of the received frequency and inputting the measured signal level as the received signal level to the directivity control circuit. To provide an antenna module to be.

  Further, a second aspect of the present invention is a receiving device including, for example, an antenna module that receives radio waves and a receiver that demodulates a signal received by the antenna module, and the antenna module responds to a given signal. Directivity control circuit that controls the directivity of the antenna element by controlling the signal given to the antenna element at a specified frequency so that the input received signal level becomes higher And an output terminal for outputting a signal output from the antenna element to the receiver via a cable, and a signal flowing from the output terminal to the antenna element between the antenna element and the output terminal. A directional coupler that attenuates more than the signal flowing to the output terminal, and a flow between the antenna element and the directional coupler. A first level measuring means for measuring and outputting a signal level of a specified frequency for the signal to be output, and a signal level of the specified frequency for the signal flowing between the directional coupler and the output terminal. The second level measuring means to output, the first level measuring means and the second level measuring means to instruct the frequency of the signal to be measured, and the signal level output from the second measuring means is the first level When the signal level is higher than the signal level output from the measuring means, the received signal level is detected and output to the directivity control circuit as a received frequency that is a frequency to which the predetermined value is added to the measured frequency. The signal level of the received frequency output from the local frequency determining means is measured for the signal flowing between the means, the antenna element and the directional coupler, and the measured signal level is measured. And a third level measuring means for inputting the signal to the directivity control circuit as a received signal level, and the receiver demodulates the signal received from the antenna module via the cable by a heterodyne method. Providing equipment.

  According to the present invention, it is possible to appropriately control the antenna directivity in the antenna module without supplying reception frequency information and reception level information from the receiver to the antenna module.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a system configuration diagram showing a configuration of a receiving apparatus 10 according to an embodiment of the present invention. The receiving device 10 is mounted on a vehicle, for example, and includes an antenna module 20 and a receiver 30. The antenna module 20 and the receiver 30 are connected via the cable 11.

  The antenna module 20 is attached to, for example, the outer surface of the vehicle, receives radio waves and converts them into electrical signals, and outputs the converted electrical signals to the receiver 30 via the cable 11. The receiver 30 is attached to a dashboard of a vehicle, for example, and outputs information included in the signal received from the antenna module 20 by demodulating the signal received from the antenna module 20 via the cable 11. In the present embodiment, the receiver 30 is an FM radio receiver.

  FIG. 2 is a block diagram illustrating an example of a detailed functional configuration of the receiver 30. The receiver 30 includes an input terminal 31, an LNA (Low Noise Amplifier) 32, a mixer 33, a BPF (Band-Pass Filter) 34, a detector 35, an amplifier 36, a local oscillator 37, a control unit 38, and an input unit 39. Prepare.

  The input unit 39 is, for example, a keypad or a touch panel, and receives frequency information indicating a frequency channel to be received from the user of the receiving device 10. In the present embodiment, the input unit 39 receives, for example, 80.0 MHz as frequency information of an FM broadcast station to be received.

  The control unit 38 generates a control signal such as a PLL (Phase Locked Loop) setting signal included in the local oscillator 37 based on the frequency information received from the user via the input unit 39, and the generated control signal is This is supplied to the oscillator 37. In the present embodiment, for example, the control unit 38 sends a control signal for generating a local oscillation signal of 69.3 MHz to the local oscillation oscillator 37 for 80.0 MHz which is frequency information of the FM broadcast station to be received. Supply.

  The local oscillator 37 has, for example, a VCO (Voltage Controlled Oscillator) and a PLL, generates a local oscillator signal having a frequency corresponding to the control signal supplied from the control unit 38, and sends the generated local oscillator signal to the mixer 33. Supply.

  The cable 11 is connected to the input terminal 31. The LNA 32 amplifies the electric signal received from the antenna module 20 via the input terminal 31 and supplies the amplified signal to the mixer 33. The mixer 33 mixes the signal supplied from the LNA 32 and the local signal supplied from the local oscillator 37, converts the signal into a sum and difference signal of both frequencies, and supplies the converted signal to the BPF 34. To do.

  The BPF 34 attenuates a signal having a frequency other than a predetermined frequency band. In the present embodiment, the BPF 34 passes a signal in a predetermined band whose center frequency is 10.7 MHz, and attenuates signals of other frequencies. The detector 35 detects the signal that has passed through the BPF 34 using, for example, quadrature detection. The amplifier 36 amplifies the signal detected by the BPF 34 and outputs it as an audio signal through an external speaker.

  The LNA 32 amplifies the signal transmitted from the input terminal 31 to the mixer 33, but attenuates the signal transmitted from the mixer 33 to the input terminal 31. However, since the signal level of the local oscillation signal supplied to the mixer 33 by the local oscillation oscillator 37 is high, the local oscillation signal leaks from the input terminal 31 as shown by the dotted line in FIG. The local signal leaking from the input terminal 31 is transmitted to the antenna module 20 via the cable 11.

  FIG. 3 is a block diagram illustrating an example of a detailed functional configuration of the antenna module 20. The antenna module 20 includes an antenna element 21, a directivity control circuit 22, a third DSP 23, a first DSP 24, a reception frequency detection unit 25, a second DSP 26, a directional coupler 27, and an output terminal 28.

  The antenna element 21 changes its directivity according to the input control signal. In the present embodiment, the antenna element 21 is, for example, an electronically controlled waveguide array antenna. The antenna element 21 may be an antenna element other than the electronically controlled waveguide array antenna as long as the antenna element can control directivity.

  The directivity control circuit 22 holds in advance as a table information indicating a change in directivity of the antenna element 21 with respect to a control signal applied to the antenna element 21 for each frequency. The directivity control circuit 22 selects one piece of information indicating a change in directivity of the antenna element 21 with respect to the control signal based on the reception frequency information supplied from the reception frequency detection unit 25, and based on the selected information. Thus, the control signal applied to the antenna element 21 is changed so that the signal level indicated by the reception level information supplied from the third DSP 23 is increased.

  The cable 11 is connected to the output terminal 28. The input terminal of the directional coupler 27 is connected to the antenna element 21, and the output terminal of the directional coupler 27 is connected to the output terminal 28. The directional coupler 27 attenuates the electrical signal transmitted from the output terminal 28 to the antenna element 21 more than the electrical signal transmitted from the antenna element 21 to the output terminal 28 (for example, 20 dB).

  The first DSP 24 measures the level of the signal on the signal line between the antenna element 21 and the directional coupler 27 at the frequency specified by the reception frequency detection unit 25 and supplies it to the reception frequency detection unit 25. In the present embodiment, the first DSP 24 is used by the receiver 30 to receive, for example, a signal on a signal line between the antenna element 21 and the directional coupler 27 and a signal from an FM radio broadcasting station. Obtained via a BPF that passes the frequency band of the local oscillation signal (for example, 65.3 MHz to 79.3 MHz).

  Then, the first DSP 24 converts the acquired signal into a predetermined frequency by mixing the acquired signal with the local oscillation signal of the frequency specified from the reception frequency detection unit 25, and converts the level of the converted signal to the predetermined level. By measuring, the level of the signal on the signal line between the antenna element 21 and the directional coupler 27 is measured at the frequency specified by the reception frequency detector 25. The function realized by the first DSP 24 is the same as the technology used by a normal spectrum analyzer or the like, and thus detailed description thereof is omitted.

  The second DSP 26 measures the level of the signal on the signal line between the directional coupler 27 and the output terminal 28 at the frequency specified by the reception frequency detection unit 25 and supplies it to the reception frequency detection unit 25. The function of the second DSP 26 is the same as that of the first DSP 24.

  The reception frequency detection unit 25 is a signal for instructing the first DSP 24 and the second DSP 26 on the frequency of the signal to be measured, and the signal level output from the second DSP 26 as a signal output from the first DSP 24. And processing for determining whether or not the level is higher than the level. When the signal level output from the second DSP 26 is higher than the signal level output from the first DSP 24, the frequency at which the signal level is measured is used as the local signal used by the receiver 30. presume.

  The reception frequency detection unit 25 generates reception frequency information indicating a frequency obtained by adding an intermediate frequency (10.7 MHz in the present embodiment) used in the receiver 30 to the frequency estimated as the local oscillation signal. The received frequency information is supplied to the directivity control circuit 22 and the third DSP 23.

  Although not present between the antenna element 21 and the directional coupler 27 in the frequency band of the local signal used by the receiver 30 to receive a signal from the FM radio broadcast station, the directional coupler 27 The signal existing between the output terminal 28 is likely to be a local signal leaking from the receiver 30. The reception frequency detection unit 25 according to the present embodiment uses the frequency at which the signal level higher than the signal level output from the first DSP 24 is output from the second DSP 26 as a local signal leaking from the receiver 30. By estimating, it is possible to specify the frequency of the local signal without receiving information indicating the local signal from the receiver 30.

  The third DSP 23 measures the level of the signal on the signal line between the antenna element 21 and the directional coupler 27 at the frequency indicated by the reception frequency information supplied from the reception frequency detector 25 to control the directivity. Supply to circuit 22. In the present embodiment, for example, the third DSP 23 converts the signal on the signal line between the antenna element 21 and the directional coupler 27 into the frequency band (for example, 76.0 MHz to 90.0 MHz) of the FM radio broadcasting station. Acquired through the BPF to be passed.

  Then, the third DSP 23 converts the acquired signal into a predetermined frequency by mixing the acquired signal with a local oscillation signal having the frequency indicated by the reception frequency information supplied from the reception frequency detection unit 25, and converts the acquired signal. By measuring the level of the received signal, the level of the signal on the signal line between the antenna element 21 and the directional coupler 27 is measured at the frequency indicated by the reception frequency information supplied from the reception frequency detector 25. To do. The function realized by the third DSP 23 is the same as the technique used by a normal spectrum analyzer or the like, and thus detailed description thereof is omitted.

  FIG. 4 is a flowchart illustrating an example of the reception frequency detection process executed by the reception frequency detection unit 25. For example, at a predetermined timing such as when the antenna module 20 is turned on, the reception frequency detection unit 25 executes the reception frequency detection process shown in this flowchart.

  First, the reception frequency detection unit 25 sets a local frequency corresponding to the lower limit of the frequency band to be received as a designated frequency (S100), and supplies the set designated frequency to the first DSP 24 and the second DSP 26. In the present embodiment, the reception frequency detector 25 sets 65.3 MHz as the local frequency corresponding to the lower limit of the frequency band to be received.

  Next, the reception frequency detection unit 25 acquires information indicating the signal level from each of the first DSP 24 and the second DSP 26 (S101), and the signal level output from the second DSP 26 is obtained from the first DSP 24. It is determined whether or not the output signal level is higher (S102).

  When the signal level output from the second DSP 26 is equal to or higher than the signal level output from the first DSP 24 (S102: Yes), the reception frequency detection unit 25 currently supplies the first DSP 24 and the second DSP 26. The designated frequency is estimated as the local frequency currently used by the receiver 30. The reception frequency detection unit 25 generates reception frequency information including a frequency obtained by adding a predetermined value (10.7 MHz in the present embodiment) to the current designated frequency, and supplies the reception frequency information to the directivity control circuit 22 and the third DSP 23. (S105), the reception frequency detection unit 25 executes the process shown in step S103.

  When the signal level output from the second DSP 26 is lower than the signal level output from the first DSP 24 (S102: No), the reception frequency detection unit 25 selects the next higher frequency as the designated frequency (S103). ). In step S103, the reception frequency detection unit 25 selects, as the designated frequency, a frequency that is, for example, 100 kHz higher than the previous time.

  Next, the reception frequency detection unit 25 determines whether or not the frequency selected as the designated frequency has exceeded the local frequency corresponding to the upper limit of the frequency band to be received (S104). In the present embodiment, the reception frequency detection unit 25 sets 79.3 MHz as the local frequency corresponding to the upper limit of the frequency band to be received.

  When the frequency selected as the designated frequency exceeds the local frequency corresponding to the upper limit of the frequency band to be received (S104: Yes), the reception frequency detection unit 25 executes the process shown in step S100 again. When the frequency selected as the designated frequency does not exceed the local frequency corresponding to the upper limit of the frequency band to be received (S104: No), the reception frequency detection unit 25 selects the frequency selected as the designated frequency as the first DSP 24. And the second DSP 26, and the process shown in step S101 is executed again.

  The embodiment of the present invention has been described above.

  As is clear from the above description, according to the antenna module 20 of the present invention, the directivity of the antenna element 21 can be appropriately controlled without receiving the reception frequency information and the reception level information from the receiver 30. .

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in embodiment mentioned above. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above-described embodiment. Furthermore, it is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

It is a figure which shows the structure of the receiver 10 which concerns on one Embodiment of this invention. 3 is a block diagram illustrating an example of a detailed functional configuration of a receiver 30. FIG. 3 is a block diagram illustrating an example of a detailed functional configuration of an antenna module 20. FIG. 5 is a flowchart illustrating an example of a reception frequency detection process executed by a reception frequency detection unit 25. It is a figure which shows an example of a structure of the conventional receiver 50. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Receiver, 11 ... Cable, 20 ... Antenna module, 21 ... Antenna element, 22 ... Directivity control circuit, 23 ... Third DSP, 24 ... First 1 DSP, 25 ... reception frequency detector, 26 ... second DSP, 27 ... directional coupler, 28 ... output terminal, 30 ... receiver, 31 ... input Terminal, 32 ... LNA, 33 ... Mixer, 34 ... BPF, 35 ... Detector, 36 ... Amplifier, 37 ... Local oscillator, 38 ... Control unit, 39. ..Input unit, 50... Receiving device, 60... Antenna module, 61... Electronically controlled waveguide array antenna, 62 .about. Directivity control circuit, 70. LNA, 72 ... mixer, 73 ... BPF, 74 ... detector, 75 ... Width unit, 76 ... local oscillation oscillator, 77 ... controller, 78 ... input unit

Claims (2)

An antenna module that receives radio waves and supplies them to a receiver,
An antenna element whose directivity changes according to a given signal;
A directivity control circuit that controls the directivity of the antenna element by controlling a signal applied to the antenna element with respect to a specified frequency so that an input received signal level becomes high;
An output terminal for outputting a signal output from the antenna element to the receiver via a cable;
A directional coupler that is provided between the antenna element and the output terminal and attenuates a signal flowing from the output terminal to the antenna element more than a signal flowing from the antenna element to the output terminal;
First level measuring means for measuring and outputting a signal level of a designated frequency for a signal flowing between the antenna element and the directional coupler;
Second level measuring means for measuring and outputting a signal level of a specified frequency for a signal flowing between the directional coupler and the output terminal;
The first level measuring means and the second level measuring means are instructed of the frequency of the signal to be measured, and the signal level output from the second measuring means is output from the first measuring means. A reception frequency detection means for outputting to the directivity control circuit as a reception frequency that is a frequency to be received when a frequency obtained by adding a predetermined value to the measured frequency when the signal level is higher than the signal level;
For the signal flowing between the antenna element and the directional coupler, the signal level of the reception frequency output from the local frequency determination means is measured, and the directivity control circuit is set with the measured signal level as the reception signal level. And a third level measuring means for inputting to the antenna module. A receiving device comprising an antenna module for receiving radio waves and a receiver for demodulating a signal received by the antenna module,
The antenna module is
An antenna element whose directivity changes according to a given signal;
A directivity control circuit that controls the directivity of the antenna element by controlling a signal applied to the antenna element with respect to a specified frequency so that an input received signal level becomes high;
An output terminal for outputting a signal output from the antenna element to the receiver via a cable;
A directional coupler that is provided between the antenna element and the output terminal and attenuates a signal flowing from the output terminal to the antenna element more than a signal flowing from the antenna element to the output terminal;
First level measuring means for measuring and outputting a signal level of a designated frequency for a signal flowing between the antenna element and the directional coupler;
Second level measuring means for measuring and outputting a signal level of a specified frequency for a signal flowing between the directional coupler and the output terminal;
The first level measuring means and the second level measuring means are instructed of the frequency of the signal to be measured, and the signal level output from the second measuring means is output from the first measuring means. A reception frequency detection means for outputting to the directivity control circuit as a reception frequency that is a frequency to be received when a frequency obtained by adding a predetermined value to the measured frequency when the signal level is higher than the signal level;
For the signal flowing between the antenna element and the directional coupler, the signal level of the reception frequency output from the local frequency determination means is measured, and the directivity control circuit is set with the measured signal level as the reception signal level. And third level measuring means for inputting to
The receiver
A receiving apparatus for demodulating a signal received from the antenna module via a cable by a heterodyne method.

Images