JP2010004451A - Noise reduction device for on-vehicle radio device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise reduction device for an on-vehicle radio device, which has a simple structure and efficiently reduces influence of radio waves (noise signal) generated in a vehicle interior. <P>SOLUTION: Radio waves outside a vehicle is received by a first external antenna 10 having directivity for receiving the radio waves outside the vehicle, and radio waves in a vehicle interior is received by a first vehicle interior antenna 20 having directivity for receiving the radio waves in the vehicle interior. The amplitude and phase of the radio waves received by the first vehicle interior antenna 20 is controlled by an amplitude and phase control part 30, and its output is added to the radio waves received by the first external antenna 10. Added power is detected by a first power detecting part 50, and the first amplitude and phase control part 30 is controlled by a demodulation control part 60, and power detected by the first power detecting part 50 is thereby minimized. This reduces influence of radio waves (noise signal) generated in a vehicle interior on the on-vehicle radio device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a noise reduction device for an in-vehicle wireless device that reduces a noise component mixed in a received wireless signal.

  Conventionally, a main antenna that receives a radio signal and a noise scan antenna for scanning noise generated in the vicinity of a device equipped with the main antenna, and a signal received by a noise scan antenna from a radio signal received by the main antenna There is a noise device that reduces the noise component of the radio signal received by the main antenna by performing anti-phase addition.

In this noise reduction device, the optimum attenuation rate of the attenuation circuit is set from the distance between the main antenna and the noise scan antenna or the level difference of the peak value of the received signal, and the received signal from the noise scan antenna is determined from the received signal from the main antenna. Reverse phase addition is performed (for example, see Patent Document 1)
JP 2004-173063 A

  However, in the above-described noise reduction device, if the phase of the noise received by the noise scan antenna is not in phase with the received signal from the main antenna, it is not possible to perform anti-phase addition, so a sufficient noise reduction effect may not be obtained There is sex.

  Also, since the same radio signal as the main antenna is mixed in the noise scan antenna, if the received signal from the noise scan antenna is simply reversed-phase added from the received signal from the main antenna, not only the noise component but also the level of the radio signal There is also a possibility that the signal quality deteriorates.

  Furthermore, since the anti-phase addition is performed after the receiving circuit section of each of the main antenna and the noise scan antenna, a receiving circuit is required for each antenna. Therefore, since the circuit scale becomes large, there is a problem that it is difficult to reduce the size of the apparatus and the cost increases.

  Conventionally, many noise sources in the vehicle interior are fixed in the vehicle interior such as audio devices, but in recent years, they have moved in the vehicle interior such as personal computers and mobile phones. Therefore, it is necessary to perform noise reduction by adaptively controlling the phase of the noise received by the noise scan antenna according to the movement of the noise source in the vehicle interior.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a noise reduction device for an in-vehicle wireless device that efficiently reduces the influence of radio waves (noise signals) generated in a vehicle interior with a simple configuration. .

  The noise reduction device for an in-vehicle wireless device according to claim 1, which has been made to solve such a problem (1: In this column, in order to facilitate understanding of the invention, as needed, The reference numeral used in the “best mode” column is attached, but does not mean that the scope of claims is limited by the reference numeral). The first vehicle exterior antenna (10) and the first vehicle interior antenna (20 ), First amplitude phase control means (30), first addition means (40), first power detection means (50), and optimum control means (60).

  The first vehicle exterior antenna (10) receives radio waves outside the vehicle, and the first vehicle interior antenna (20) receives radio waves inside the vehicle interior. The first amplitude phase control means (30) controls and outputs the amplitude and phase of the radio wave received by the first vehicle interior antenna (20), and the first addition means (40) is the first amplitude phase. The output of the control means (30) and the radio wave received by the first external antenna (10) are added and output.

  The first power detection means (50) detects the output power of the first addition means (40), and the optimum control means (60) controls the first amplitude / phase control means (30), thereby The power detected by the power detection means (50) is minimized.

  In the noise reduction device for an in-vehicle wireless device configured as described above, radio waves (mainly including noise signals) received by the first vehicle interior antenna (20) are transmitted to the first vehicle exterior antenna by the first addition means (40). It is added to the radio wave received in (10). At that time, the amplitude and phase of the radio wave (mainly including the noise signal) received by the first vehicle interior antenna (20) are controlled so that the power of the added radio wave is minimized.

  That is, the radio wave (mainly including a noise signal) received by the first vehicle interior antenna (20) is simply added to the radio wave (mainly including a signal to be originally received) received by the first vehicle exterior antenna (10). Rather than performing anti-phase addition, the amplitude and phase of the radio wave received by the first vehicle interior antenna are controlled, so that the radio wave received by the first vehicle exterior antenna (10) and the first vehicle interior antenna (20 ) To reduce the intensity of the noise component of the radio wave added to the radio wave received in (1).

  Accordingly, a sufficient noise reduction effect can be obtained even if the noise signal received by the first vehicle interior antenna (20) and the noise signal received by the first vehicle interior antenna (20) are not in phase.

  Further, even if a signal that should be originally received is mixed into the first vehicle interior antenna (20), the amplitude ratio and phase difference between the signal that should be received and the noise signal are different from those of the first vehicle antenna (10). Since it is different from the received radio wave, only the noise component can be reduced, and the level of the signal to be originally received is not lowered more than necessary, so that the possibility that the signal quality is deteriorated is also reduced.

  Furthermore, since the addition can be performed after the receiving circuit portion of each of the first vehicle exterior antenna (10) and the first vehicle interior antenna (20), a reception circuit for each antenna becomes unnecessary. Therefore, since the circuit scale can be reduced, the apparatus can be reduced in size and the cost can be reduced.

  Moreover, even if the noise source in the vehicle interior moves within the vehicle interior such as a personal computer or a mobile phone, the amplitude of the radio wave (mainly including the noise signal) received by the first vehicle interior antenna (20). Since the phase is adaptively controlled according to the movement of the noise source in the vehicle interior, noise can be appropriately reduced even if the noise source moves.

  By the way, the first vehicle exterior antenna (10) is for receiving radio waves transmitted from outside the vehicle, and the first vehicle interior antenna (20) is for receiving radio waves generated in the vehicle interior. It is.

  Therefore, as described in claim 2, the first exterior antenna (10) has directivity for receiving radio waves outside the vehicle, and the first interior antenna (20) Having directivity for receiving radio waves in the passenger compartment can efficiently receive radio waves according to each purpose, and it is difficult to receive radio waves other than the intended purpose. Reduction can be performed.

  Further, as described in claim 3, when the first vehicle exterior antenna (10) is installed outside the ceiling of the vehicle and the first vehicle interior antenna (20) is installed on the vehicle interior side of the vehicle. Compared with the case where the first vehicle antenna (10) is installed in the passenger compartment, the ceiling of the vehicle body does not become an obstacle when receiving radio waves transmitted from the outside.

  Further, compared to the case where the first vehicle interior antenna (20) is installed outside the vehicle compartment on the ceiling, the ceiling portion of the vehicle body does not become an obstacle when receiving radio waves generated in the vehicle interior. Therefore, an optimal radio wave reception environment can be obtained by making use of the directivity of each antenna, and the noise reduction effect can be improved.

  Further, the first vehicle exterior antenna (10) and the first vehicle interior antenna (20) may be arranged as described in claim 4. That is, the first vehicle exterior antenna (10) and the first vehicle interior antenna (20) are arranged on the rear or upper ceiling as viewed from the vehicle interior side of the room mirror installed at the front of the ceiling portion in the vehicle interior. It is.

  With this arrangement, although the reception capability of the first external antenna (10) is somewhat inferior, the two antennas are arranged on the rear or upper ceiling of the room mirror so that each antenna is not conspicuous in the vehicle interior. can do.

  Incidentally, there are various types of noise in the passenger compartment having different characteristics. Therefore, as described in claim 5, the second vehicle interior antenna (22) and the second vehicle interior antenna for suppressing radio waves in the vehicle interior of a radiation source different from the first vehicle interior antenna (20). Second amplitude phase control means (32) for controlling and outputting the amplitude and phase of the radio wave received by the antenna (22) is provided.

  In addition, the first addition means (40) adds the output of the first amplitude phase control means (30) and the output of the second amplitude phase control means (32) to the radio wave received by the first external antenna (10). The first power detection means (50) detects the first amplitude phase control means (30) and the second amplitude phase control means (32) by the optimum control means (60). It is advisable to minimize power.

  In this case, the first vehicle interior antenna (20) receives radio waves (mainly including noise signals), and the amplitude ratio and phase difference differ from the radio waves received by the first vehicle interior antenna (20). Can be received by the second vehicle interior antenna (22). The first amplitude phase control means (30) and the second amplitude phase control means (32) can control the amplitude and phase shift of each received noise signal to minimize the influence of each noise signal. .

That is, since the influence can be minimized with respect to the noise signal of different radiation sources generated in the vehicle interior, the noise reduction effect can be improved.
In addition, when receiving radio waves from outside the vehicle, a plurality of radio waves with different propagation paths may be received. For example, when performing vehicle-to-vehicle communication for data communication between multiple vehicles or road-to-vehicle communication for data communication between a roadside base station and a vehicle, multiple propagation paths occur due to ground and surrounding reflectors. It is.

  In this case, as described in claim 6, the second external antenna (12), the distribution means (70), the third amplitude phase control means (34), the second addition means (42), and the second power The detection means (52) may be provided.

  The second vehicle exterior antenna (12) receives a radio wave outside the vehicle at a position and directivity different from that of the first vehicle exterior antenna (10), and the distribution means (70) includes the first vehicle interior antenna (20 ) Received radio waves. The third amplitude phase control means (34) controls and outputs the amplitude and phase of one of the received radio waves distributed by the distribution means (70).

  Further, the second addition means (42) adds the output of the third amplitude phase control means (34) to the radio wave received by the second vehicle exterior antenna (12) and outputs it, and the second power detection means (52) Detects the output power of the second addition means (42).

  Further, the optimum control means (60) controls the first amplitude phase control means (30) and the third amplitude phase control means (34), so that the first power detection means (50) and the second power detection means ( 52) to minimize the power detected.

  In this case, the first vehicle exterior antenna (10) and the second vehicle exterior antenna (12) can receive radio waves from outside the vehicle on a plurality of different propagation paths in different phase relationships, so that a plurality of different propagations can be received. Communication quality can be improved by synthesizing radio waves that arrive along the route.

  In addition, the distribution means (70) distributes vehicle interior radio waves (mainly including noise signals) received by the first vehicle interior antenna (20) to each of a plurality of radio waves, and then sets the amplitude and phase thereof. Control and add. The added radio wave power is controlled to be minimum.

  Therefore, for each radio wave received by the first vehicle exterior antenna (10) and the second vehicle exterior antenna (12), a radio wave (mainly including a noise signal) received by the first vehicle interior antenna (20). Therefore, noise can be reduced for each radio wave received by the first vehicle exterior antenna (10) and the second vehicle exterior antenna (12).

  By the way, when controlling and outputting the amplitude and phase of the received radio wave by the first vehicle interior antenna (20), the control is performed in the process of converting to the intermediate frequency in addition to the method of directly controlling the amplitude and phase of the received radio wave. There is a way to do it. That is, as described in claim 7, a reference signal generator (90) that outputs a clock signal having a predetermined reference frequency, and a radio wave that is input from outside the vehicle based on the clock signal that is output from the reference signal generator (90). The first local oscillator (92) that outputs a local oscillation signal in the vicinity of the frequency of the signal and the frequency of the radio wave input from the outside of the vehicle based on the frequency input from the outside of the vehicle based on the local oscillation signal output from the first local oscillator (92) A first frequency converter (94) that converts the frequency to a lower intermediate frequency is provided between the first vehicle antenna (10) and the first adding means (40).

  Further, the first amplitude phase control means (30) shifts the phase of the clock signal output from the reference signal generator (90) and outputs the first phase shifter (100) and the first phase shifter (100). ) Output a local oscillation signal in the vicinity of the frequency of the radio wave input from the vehicle interior, and the frequency of the radio wave input from the vehicle interior based on the signal output from the vehicle interior. The second frequency converter (104) converts the frequency to an intermediate frequency lower than the frequency input from the vehicle interior based on the local oscillation signal output from the vehicle.

  In this way, the phase control of the radio wave received by the first vehicle interior antenna (20) can be accurately realized by the clock signal of the predetermined reference frequency output from the reference signal generator (90). Therefore, compared with the case where the phase of the radio wave received by the first vehicle interior antenna (20) is phase-shifted using an analog phase shifter, phase control can be performed over a wide range with high accuracy, resulting in high noise reduction. An effect can be obtained.

  By the way, if the power detected by the first power detection means (50) is minimized while the signal that should be originally received is received by the first external antenna (10), the signal that should be originally received may be suppressed. is there. This is likely to occur when the rate of change of the amplitude and phase of the noise signal to be suppressed is comparable to the rate of change of the amplitude and phase of the signal to be originally received.

  Therefore, as described in claim 8, the optimum control means (60) determines whether or not the signal of the radio wave received by the first vehicle antenna (10) is a predetermined signal, and As long as it is determined that the signal is not a predetermined signal, the first amplitude phase control means (30) is dynamically controlled to minimize the power detected by the first power detection means (50), and the received radio wave When it is determined that the signal is a predetermined signal, the control of the first amplitude phase control means (30) is stopped so that the power is not minimized.

  In this way, even when the amplitude and phase change rates of the noise signal to be suppressed are approximately the same as the amplitude and phase change rates of the signal to be originally received, the signal to be originally received is not suppressed.

  If the change rate of the amplitude and phase of the noise signal to be suppressed is significantly lower than the change rate of the amplitude and phase of the signal to be originally received, the response speed of the optimum control means is reduced to reduce the noise signal. It is possible to avoid suppressing the signal to be received.

  Here, “dynamically controlled” means that the amplitude and phase of the first amplitude phase control means (30) are controlled based on the change rate of the amplitude and phase of the noise signal.

Embodiments to which the present invention is applied will be described below with reference to the drawings. The embodiment of the present invention is not limited to the following embodiment, and can take various forms as long as they belong to the technical scope of the present invention.
[First Embodiment]
FIG. 1 is a block diagram illustrating a schematic configuration of a noise reduction device 1 for an in-vehicle wireless device to which the present invention is applied, and FIG. 2 is a diagram illustrating an attachment position and directivity of an antenna attached to a vehicle. .

  The on-vehicle wireless device noise reduction device 1 includes a first vehicle exterior antenna 10, bandpass filters (hereinafter referred to as BPF) 200, 204, an amplifier 202, a first vehicle interior antenna 20, a first amplitude phase control unit 30, A first adder 40, a first power detection unit 50, a demodulation control unit 60, and a first reception circuit 80 are provided.

  The first vehicle exterior antenna 10 is an antenna for receiving radio waves outside the vehicle, and is installed outside the vehicle on the ceiling at the rear of the vehicle, as shown in FIG. The first vehicle exterior antenna 10 is a monopole antenna having directivity for receiving radio waves outside the vehicle, and the directivity is a plane on which the vehicle exists above the vehicle as shown in FIG. It spreads in a donut shape centering on the pole part of the antenna on a plane parallel to.

  The BPF 200 is a high-frequency bandpass filter having a predetermined bandwidth, and among the radio waves received by the first vehicle antenna 10, only radio waves for a predetermined frequency band are passed from the center frequency of the radio wave to be originally received. It is a filter that does not pass high-frequency and low-frequency radio waves other than.

The amplifier 202 is a low-noise high-frequency amplifier, amplifies the radio wave filtered by the BPF 200 at a predetermined magnification, and outputs the amplified signal to the first adder 40.
The first adder 40 adds the output of the first amplitude phase control unit 30 to the radio wave received by the first vehicle antenna 10, filtered by the BPF 200, and further amplified by the amplifier 202, and outputs it. This is a high-frequency adder (2 inputs and 1 output in the first embodiment).

  The first power detection unit 50 is a high-frequency wattmeter that detects the output power of the first adder 40. The first receiving circuit 80 is a converter that converts the frequency of the output of the first adder 40 into baseband, and includes a local oscillator, a mixer, a gain controller, and the like, and the output of the first adder 40 Is converted to a baseband signal.

  The first vehicle interior antenna 20 is an antenna for receiving radio waves in the vehicle interior, and is installed on the vehicle interior side of the vehicle ceiling as shown in FIG. The first vehicle interior antenna 20 is a microstrip antenna having directivity for receiving radio waves in the vehicle interior of the vehicle. As shown in FIG. 2, the first vehicle interior antenna 20 extends from the antenna portion to the vehicle interior side in a substantially spherical shape. .

  The BPF 204 is a high-frequency bandpass filter having a predetermined bandwidth, and among the radio waves received by the first vehicle interior antenna 20, only radio waves for a predetermined frequency band are passed from the center frequency of the radio wave to be originally received, It is a filter that does not allow other high-frequency and low-frequency radio waves to pass through.

  The first amplitude / phase control unit 30 controls and outputs the amplitude and phase of the radio wave received by the first vehicle interior antenna 20 and filtered by the BPF 204. As shown in FIG. A variable amplifier 30a that amplifies the amplitude of the radio wave according to a command signal from the demodulation control unit 60, and a variable phase shifter 30b that changes (phase shifts) the phase of the input radio wave according to the command signal from the demodulation control unit 60. It consists of.

  The demodulation control unit 60 demodulates the radio wave output from the first receiving circuit 80 and controls the first amplitude phase control unit 30 to minimize the power detected by the first power detection unit 50. is there.

  The demodulation control unit 60 includes an ADC that performs analog-to-digital conversion on the baseband signal output from the first receiving circuit 80, a demodulator (such as an FPGA) that demodulates the digitized baseband signal, and the first amplitude phase shift control unit 30. It is composed of a CPU, ROM, RAM, and I / O for control, and receives a power value detected by the first power detection unit 50, and a variable amplifier 30a and a variable phase shifter of the first amplitude phase control unit 30 A control signal is output to 30b, and an optimization process for minimizing the power detected by the first power detection unit 50 is performed.

(Optimization process)
Next, optimization processing executed in the demodulation control unit 60 will be described with reference to FIG. FIG. 3 is a flowchart showing the flow of optimization processing. The optimization process starts after the demodulation control unit 60 is turned on, and, as shown in FIG. 3, the gain control voltage Vg (hereinafter simply referred to as Vg) and the phase shift control voltage Vp ( Hereinafter, initial values are set to Vp step width ΔVg (hereinafter simply referred to as ΔVg) and Vp step width ΔVp (hereinafter simply referred to as ΔVp).

  In subsequent S105, the received power value is acquired from the first power detection unit 50, and the acquired received power value is substituted into the variable F0. However, this received power value is an average of received power values when received for a predetermined time in a state where there is no signal to be originally received, that is, in a state where packets are not being received (the same applies hereinafter).

  In subsequent S110, the step width ΔVp is added to Vp. In subsequent S115, the received power value is acquired again from the first power detection unit 50, and the acquired received power value is substituted into the variable F1.

  In subsequent S120, the value of F0 obtained in S105 is compared with the value of F1 obtained in S115. If the F1 value is not smaller than the F0 value within a predetermined time set in advance (S120: Yes), the process proceeds to S125, and the F1 value is equal to or greater than the F0 value or is predetermined. If the time has elapsed (S120: No), the process proceeds to S150.

  In S150, the difference between the value of F1 and the value of F0 is compared with the threshold value Lm (hereinafter simply referred to as Lm) of the received power value change. If the difference is smaller than Lm (S150: Yes), the process proceeds to S155. If the difference is greater than or equal to Lm (S150: No), the process proceeds to S160.

  In S155, ΔVp is divided by k, which is a step width adjustment constant, and the sign is inverted to be a new ΔVp. In S160, ΔVpi, which is the initial step width of ΔVp, is substituted into ΔVp, and processing is performed. Is returned to S110.

  On the other hand, in S125, the value of F1 is substituted for F0, and in subsequent S130, the step width ΔVg is added to Vg. In subsequent S135, the received power value is acquired again from the first power detection unit 50, and the acquired reception is obtained. The power value is substituted into F1.

  In subsequent S140, the value of F0 obtained in S125 is compared with the value of F1 obtained in S135. If the value of F1 is not smaller than the value of F0 within the predetermined time set in advance (S140: Yes), the process proceeds to S145, and the value of F1 is equal to or greater than the value of F0 or is predetermined. When the time has elapsed (S140: No), the process proceeds to S165.

  In S165, the difference between the values of F1 and F0 is compared with the threshold value Lm of the received power value change. If the difference is smaller than Lm (S165: Yes), the process proceeds to S170, and the difference is greater than or equal to Lm. (S165: No), the process proceeds to S175.

  In S170, ΔVg divided by k and inverted in sign is set as a new ΔVg. In S175, ΔVgi which is the initial step width of ΔVg is substituted into ΔVg, and the process returns to S130.

On the other hand, in S145, after the value of F1 is assigned to F0, the process returns to S110, and the optimization process is repeated.
(Characteristics of noise reduction device 1 for in-vehicle wireless device)
In the vehicle-mounted radio apparatus noise reduction apparatus 1 described above, vehicle interior radio waves (including mainly noise signals) received by the first vehicle interior antenna 20 are transmitted by the first adder 40 to the first vehicle exterior antenna 10. It is added to the received radio wave. At that time, the amplitude and phase of the radio waves (mainly including noise signals) received by the first vehicle interior antenna 20 are controlled so that the power of the added radio waves is minimized.

  In other words, the amplitude and phase of the radio wave received by the first vehicle interior antenna 20 are not simply added to the radio wave received by the first vehicle interior antenna 20 instead of simply adding the opposite phase to the radio wave received by the first vehicle interior antenna 20. Are controlled so that the intensity of the noise component of the radio wave obtained by adding the radio wave received by the first vehicle exterior antenna 10 and the radio wave received by the first vehicle interior antenna 20 is minimized.

  Therefore, a sufficient noise reduction effect can be obtained even if the noise signal received by the first vehicle interior antenna 20 and the noise signal received by the first vehicle interior antenna 20 are not in phase.

  In addition, even if a signal that should be originally received is mixed into the first vehicle interior antenna 20, the amplitude ratio and phase difference between the signal that should be received and the noise signal are different from the received radio wave of the first vehicle antenna 10. Therefore, only the noise component can be reduced, and the level of the signal that should be received is not lowered more than necessary, so that the possibility that the signal quality is deteriorated is also reduced.

  Furthermore, since the addition can be performed after the receiving circuit portion of each of the first vehicle exterior antenna 10 and the first vehicle interior antenna 20, a reception circuit for each antenna becomes unnecessary. Therefore, since the circuit scale can be reduced, the apparatus can be reduced in size and the cost can be reduced.

  Furthermore, even if the noise source in the vehicle interior moves within the vehicle interior, such as a personal computer or a mobile phone, the amplitude and phase of the noise signal received by the first vehicle interior antenna 20 can be determined as the noise source in the vehicle interior. Since the adaptive control is performed according to the movement, the noise can be appropriately reduced even if the noise source moves.

  The first vehicle antenna 10 has directivity for receiving radio waves outside the vehicle, and the first vehicle interior antenna 20 has directivity for receiving radio waves inside the vehicle cabin. is doing. Therefore, it is possible to efficiently receive radio waves according to the respective purposes, and it is difficult to receive radio waves other than the intended purpose, so that noise can be reduced efficiently.

  Furthermore, the first vehicle exterior antenna 10 is installed outside the ceiling of the vehicle, and the first vehicle interior antenna 20 is installed on the vehicle interior side of the vehicle. Therefore, compared with the case where the first vehicle antenna 10 is installed in the vehicle interior, the ceiling portion of the vehicle body does not become an obstacle when receiving radio waves transmitted from the outside. In addition, compared to the case where the first vehicle interior antenna 20 is installed outside the vehicle compartment on the ceiling, the ceiling portion of the vehicle body does not become an obstacle when receiving radio waves generated in the vehicle interior.

Therefore, an optimal radio wave reception environment can be obtained by making use of the directivity of each antenna, and the noise reduction effect can be improved.
[Second Embodiment]
Next, with respect to the noise reduction device 2 for in-vehicle wireless device according to the second embodiment in which a plurality of antennas mainly receiving vehicle interior noise are provided, compared to the noise reduction device 1 for in-vehicle wireless device according to the first embodiment. Based on FIG. 4 is a block diagram showing a schematic configuration of the in-vehicle wireless device noise reduction device 2.

  In addition, since the noise reduction apparatus 2 for vehicle-mounted wireless devices of 2nd Embodiment has many the same components as the noise reduction device 1 for vehicle-mounted wireless devices of 1st Embodiment, the same code | symbol is attached | subjected to the same components, and the Description is omitted.

  As shown in FIG. 4, the in-vehicle wireless device noise reduction device 2 is different from the in-vehicle wireless device noise reduction device 1 (see FIG. 1) in the vehicle interior of a vehicle having a radiation source different from the first vehicle interior antenna 20. Radio waves received by the second vehicle interior antenna 22, the BPF 206 that passes only radio waves of a predetermined frequency band among the radio waves received by the second vehicle interior antenna 22, and the second vehicle interior antenna 22. Is provided with a second amplitude phase control unit 32 for controlling and outputting the amplitude and phase.

  As described in the first embodiment, the first vehicle interior antenna 20 is a microstrip antenna and is installed on the vehicle interior side of the vehicle ceiling. Since it receives radio waves having different amplitude ratios and phase differences from the vehicle interior antenna 20, an antenna having a directivity different from that of the first vehicle interior antenna (for example, a loop antenna, a microstrip antenna having a different shape, etc.) ) In different positions (for example, different positions on the vehicle interior side of the vehicle ceiling, dashboard, side surfaces on the vehicle interior side, etc.).

  Then, the first adder 40 is a high frequency adder with three inputs and one output, and the first vehicle exterior antenna 10, the output of the first amplitude phase control unit 30 and the output of the second amplitude phase control unit 32 are added as inputs. Output. That is, the output of the first amplitude phase control unit 30 and the output of the second amplitude phase control unit 32 are added to the radio wave received by the first vehicle exterior antenna 10 and output.

  The second amplitude / phase control unit 32 controls and outputs the amplitude and phase of the radio wave received by the second vehicle interior antenna 22 and filtered by the BPF 206. As shown in FIG. A variable amplifier 32a that amplifies the amplitude of the radio wave according to a command signal from the demodulation control unit 60, and a variable phase shifter 32b that changes (phase shifts) the phase of the input radio wave according to the command signal from the demodulation control unit 60. It consists of.

The demodulation control unit 60 minimizes the power detected by the first power detection unit 50 by controlling the second amplitude phase control unit 32 in addition to the first amplitude phase control unit 30.
In the optimization process for minimizing the power detected by the first power detection unit 50, the first amplitude phase control unit 30 is optimized, and then the same process as the optimization process of the first amplitude phase control unit 30 is performed. The second amplitude phase control unit 32 is optimized.

  In the on-vehicle wireless device noise reduction device 2 described above, the noise signal is received by the first vehicle interior antenna 20 and the noise signal having an amplitude and phase different from the radio wave received by the first vehicle interior antenna 20 is received. It can be received by the second vehicle interior antenna 22.

The first amplitude phase control unit 30 and the second amplitude phase control unit 32 can control the amplitude and phase shift of each received noise signal, thereby minimizing the influence of each noise signal.
That is, since the influence can be minimized with respect to the different radiation noise signals generated in the passenger compartment, the noise reduction effect can be improved.
[Third Embodiment]
Next, with respect to the noise reduction device 3 for the in-vehicle wireless device according to the third embodiment, a plurality of antennas that mainly receive radio waves from outside the vehicle are provided for the noise reduction device 1 for the in-vehicle wireless device according to the first embodiment. 5 will be described. FIG. 5 is a block diagram showing a schematic configuration of the noise reduction device 3 for in-vehicle wireless device.

  In addition, since the noise reduction apparatus 3 for vehicle-mounted radio | wireless apparatuses of 3rd Embodiment has many same components as the noise reduction apparatus 1 for vehicle-mounted radio | wireless apparatuses of 1st Embodiment, the same code | symbol is attached | subjected to the same component, Description is omitted.

  As shown in FIG. 5, the in-vehicle wireless device noise reduction device 3 is different from the in-vehicle wireless device noise reduction device 1 (see FIG. 1) in that the second vehicle exterior antenna 12, the BPF 208, the amplifier 210, the distributor 70, A three-amplitude phase controller 34, a second adder 42, a second receiver circuit 82, and a second power detector 52 are provided.

  The second vehicle antenna 12 is an antenna that mainly receives radio waves outside the vehicle at any position and directivity different from that of the first vehicle antenna 10. For example, the first vehicle antenna 10 is a ceiling on the rear of the vehicle. If the monopole antenna is installed on the outside of the vehicle, the second external antenna 12 is a monopole antenna installed on the outside of the vehicle on the ceiling at the front of the vehicle, or installed near the rearview mirror. It may be a loop antenna.

  The BPF 208 is a high-frequency bandpass filter having a predetermined bandwidth, and passes only radio waves of a predetermined frequency band from the center frequency of the radio wave that is originally intended to be received among the radio waves received by the second vehicle exterior antenna 12. It is a filter that does not pass high-frequency and low-frequency radio waves other than.

The amplifier 210 is a low-noise high-frequency amplifier, amplifies the radio wave filtered by the BPF 208 at a predetermined magnification, and outputs the amplified signal to the second adder 42.
The distributor 70 is a one-input multi-output high-frequency distributor. In the third embodiment, the received radio wave of the first vehicle interior antenna 20 is sent to the first amplitude phase control unit 30 and the third amplitude phase control unit 34. Distribute.

  The third amplitude phase control unit 34 amplifies the amplitude of the input radio wave according to the command signal from the demodulation control unit 60 and the phase of the input radio wave according to the command signal from the demodulation control unit 60. And a variable phase shifter 34 b that changes (phase shifts), controls the amplitude of one of the received radio waves distributed by the distributor 70, and outputs it to the second adder 42.

The second adder 42 adds the output of the third amplitude phase controller 34 to the radio wave received by the second vehicle exterior antenna 12 and outputs the result to the first receiving circuit 80.
The second power detector 52 detects the output power of the second adder 42. The demodulation control unit 60 controls the third amplitude phase control unit 34 in addition to the first amplitude phase control unit 30 to minimize the power detected by the first power detection unit 50 and the second power detection unit 52. Turn into.

  In the optimization process for minimizing the power detected by the first power detection unit 50, the first amplitude phase control unit 30 is optimized, and then the same process as the optimization process of the first amplitude phase control unit 30 is performed. The third amplitude phase control unit 34 is optimized.

  In the on-vehicle wireless device noise reducing device 3 described above, the first vehicle exterior antenna 10 and the second vehicle exterior antenna 12 can receive radio waves from outside the vehicle at any of a plurality of different positions and directivities. Therefore, communication quality can be improved by synthesizing radio waves arriving through a plurality of different propagation paths.

  Further, a noise signal generated in the vehicle interior received by the first vehicle interior antenna 20 is distributed to each of the plurality of radio waves by the distributor 70, and the amplitude and phase thereof are controlled and added. The added radio wave power is controlled to be minimum.

Therefore, the amplitude and phase of the noise signal received by the first vehicle interior antenna 20 are controlled and added to each radio wave received by the first vehicle exterior antenna 10 and the second vehicle exterior antenna 12. Noise can be reduced for each radio wave received by the first vehicle antenna 10 and the second vehicle antenna 12.
[Fourth Embodiment]
Next, the noise reduction device 4 for the vehicle-mounted wireless device according to the fourth embodiment in which phase control is performed based on the clock signal of the reference frequency with respect to the noise reduction device 1 for the vehicle-mounted wireless device of the first embodiment. This will be described with reference to FIG. FIG. 6 is a block diagram showing a schematic configuration of the in-vehicle wireless device noise reduction device 4.

  In addition, since the noise reduction apparatus 4 for vehicle-mounted radio | wireless apparatuses of 4th Embodiment has many the same components as the noise reduction apparatus 1 for vehicle-mounted radio | wireless apparatuses of 1st Embodiment, the same code | symbol is attached | subjected to the same component, Description is omitted.

  As shown in FIG. 6, the vehicle-mounted wireless device noise reduction device 4 is arranged between the first vehicle exterior antenna 10 and the first adder 40 with respect to the vehicle-mounted wireless device noise reduction device 1 (see FIG. 1). A reference signal generator 90, a first local oscillator 92, and a first frequency converter 94 are provided.

The reference signal generator 90 outputs a clock signal having a predetermined reference frequency. The first local oscillator 92 generates a local oscillation in the vicinity of the frequency of a radio wave input from outside the vehicle based on the clock signal output from the reference signal generator 90. The first frequency converter 94 that outputs the signal changes the frequency of the radio wave input from outside the vehicle to an intermediate frequency that is lower than the frequency input from outside the vehicle based on the local oscillation signal output from the first local oscillator 92. Convert.

Further, the first amplitude phase control unit 30 includes a first phase shifter 100, a second local oscillator 102, a second frequency converter 104, and a first variable amplifier 106.
The first phase shifter 100 shifts and outputs the phase of the clock signal output from the reference signal generator 90. The second local oscillator 102 outputs the vehicle based on the signal output from the first phase shifter 100. The second frequency converter 104 that outputs a local oscillation signal in the vicinity of the frequency of the radio wave input from the interior of the vehicle based on the local oscillation signal output from the second local oscillator 102 Conversion to an intermediate frequency lower than the frequency input from the passenger compartment.

  The first variable amplifier 106 is an amplifier that can change the amplification factor according to the command voltage from the demodulation control unit 60, and the output of the second frequency converter 104 is first added by the demodulation control unit 60 with a predetermined amplification factor. To the device 40.

  In the on-vehicle wireless device noise reduction device 4 described above, the phase control of the radio wave received by the first vehicle interior antenna 20 is accurately realized by the clock signal of the predetermined reference frequency output from the reference signal generator 90. be able to. Accordingly, the phase control can be performed over a wide range with high accuracy compared to the case where the phase of the radio wave received by the first vehicle interior antenna 20 is shifted using an analog phase shifter. Obtainable.

[Other Embodiments]
As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, A various aspect can be taken as follows.

  (1) In the embodiment described above, the first vehicle exterior antenna 10 is attached to the outside of the vehicle interior ceiling, and the first vehicle interior antenna 20 is attached to the vehicle interior ceiling (see FIG. 2). As described above, the first vehicle exterior antenna 10 and the first vehicle interior antenna 20 may be arranged on the rear or upper ceiling as viewed from the vehicle interior side of the room mirror installed at the front of the ceiling portion in the vehicle interior. Good.

  If arranged in this way, the reception capacity of the first vehicle antenna 10 is somewhat inferior, but the two antennas are arranged on the back or upper ceiling of the rearview mirror, so that each antenna is arranged inconspicuously in the vehicle interior. Can do.

(2) In the above embodiment, the amplitude control unit, the adder, and the power detection unit are configured by analog circuits, but may be configured as shown in FIG.
That is, functions such as the first amplitude phase control unit 30, the first adder 40, and the first power detection unit 50 are built in the demodulation control unit 60, and the output of the amplifier 212 is converted into a baseband signal by the second receiving circuit 82. And input to the demodulation control unit 60. That is, the combination of the radio wave received by the first vehicle exterior antenna 10 and the radio wave received by the first vehicle interior antenna 20 is performed by digital signal processing.

  In this way, a signal before synthesis of radio waves received by each antenna is obtained, so optimization using a known digital processing optimization method (steepest descent method, direct solution method, recursive least square method, etc.) Since the required time can be shortened, the response of noise reduction can be improved. In addition, since the accuracy of the amplitude control unit can be increased, the effect of noise reduction can also be increased.

  In the present embodiment (see FIG. 8), the first vehicle exterior antenna 10 and the first vehicle interior antenna 20 are used. However, as shown in the first to third embodiments, even if each antenna is increased, they are used. The same effect can be obtained by independently processing.

  (3) In the first embodiment, the BPFs 200 and 204 are arranged immediately after the antennas 10 and 20, and the amplifiers 202 and 210 are arranged immediately after them. However, as shown in FIG. You may make it arrange | position in the back | latter stage of 1 adder 40. FIG.

  In this way, the receiver sensitivity as a receiver is somewhat inferior, but when the receiver sensitivity may be low, it is applicable, and there is an advantage that the structure is simple and the cost can be reduced.

It is a block diagram which shows the schematic structure of the noise reduction apparatus 1 for vehicle-mounted radio | wireless apparatuses in 1st Embodiment. It is a figure which shows the attachment position and directivity of the antenna in 1st Embodiment. It is a flowchart which shows the flow of an optimization process. It is a block diagram which shows the structure of the outline of the noise reduction apparatus 2 for vehicle-mounted radio | wireless apparatuses in 2nd Embodiment. It is a block diagram which shows the schematic structure of the noise reduction apparatus 3 for vehicle-mounted radio | wireless apparatuses in 3rd Embodiment. It is a block diagram which shows the schematic structure of the noise reduction apparatus 4 for vehicle-mounted radio | wireless apparatuses in 4th Embodiment. It is a figure which shows the attachment position and directivity of an antenna at the time of arrange | positioning an antenna in a vehicle interior. It is a block diagram which shows the schematic structure at the time of changing the circuit structure of the noise reduction apparatus 4 for vehicle-mounted radio | wireless apparatuses in 4th Embodiment. It is a block diagram which shows the schematic structure at the time of changing the arrangement position of BPF200,204 and amplifier 202,210 in the noise reduction apparatus 1 for vehicle-mounted radio | wireless apparatuses.

Explanation of symbols

  1, 2, 3, 4, noise reducing device for in-vehicle wireless device, 10, first antenna for outside the vehicle, 12, antenna for the second vehicle, 20, antenna for the first vehicle interior, 22, antenna for the second vehicle interior, DESCRIPTION OF SYMBOLS 30 ... 1st amplitude phase control part, 30a, 32a, 34a ... Variable amplifier, 30b, 32b, 34b ... Variable phase shifter, 32 ... 2nd amplitude phase control part, 34 ... 3rd amplitude phase control part, 40 ... 1st DESCRIPTION OF SYMBOLS 1 adder, 42 ... 2nd adder, 50 ... 1st electric power detection part, 52 ... 2nd electric power detection part, 60 ... Demodulation control part, 70 ... Distributor, 80 ... 1st receiving circuit, 82 ... 2nd reception Circuit 90... Reference signal generator 92... First local oscillator 94... First frequency converter 100... First phase shifter 102 .. second local oscillator 104 ... second frequency converter 106. 1 variable amplifier, 200, 204, 206, 208 ... band pass fill (BPF), 202,210,212 ... amplifier.

Claims (8)

A first external antenna for receiving radio waves outside the vehicle;
A first vehicle interior antenna for receiving radio waves in the vehicle interior;
First amplitude and phase control means for controlling and outputting the amplitude and phase of the radio wave received by the first vehicle interior antenna;
First addition means for adding the output of the first amplitude phase control means to the radio wave received by the first vehicle antenna;
First power detection means for detecting the output power of the first addition means;
Optimal control means for minimizing the power detected by the first power detection means by controlling the first amplitude phase control means;
A noise reduction device for an in-vehicle wireless device. The noise reduction device for in-vehicle wireless device according to claim 1,
The first vehicle exterior antenna has directivity for receiving radio waves outside the vehicle of the vehicle,
The in-vehicle wireless device noise reduction device, wherein the first vehicle interior antenna has directivity for receiving radio waves in the vehicle interior of the vehicle. In the noise reduction device for in-vehicle wireless device according to claim 1 or 2,
The first vehicle exterior antenna is installed outside the ceiling of the vehicle,
The first vehicle interior antenna is installed on a vehicle interior side of the vehicle. In the noise reduction device for in-vehicle wireless device according to claim 1 or 2,
The first vehicle exterior antenna and the first vehicle interior antenna are:
A noise reduction device for an in-vehicle wireless device, which is disposed on a back or upper ceiling of a rearview mirror installed at a front portion of a ceiling portion of the vehicle interior as viewed from the vehicle interior side. In the on-vehicle wireless device noise reduction device according to any one of claims 1 to 4,
A second vehicle interior antenna for receiving radio waves in the vehicle interior with a different amplitude ratio and phase difference from the first vehicle interior antenna;
Second amplitude and phase control means for controlling and outputting the amplitude and phase of the radio wave received by the second vehicle interior antenna;
With
The first adding means adds the output of the first amplitude phase control means and the second amplitude phase control means to the radio wave received by the first vehicle antenna, and outputs the result.
The optimum control means is:
An on-vehicle wireless device noise reduction device characterized in that the power detected by the first power detection means is minimized by controlling the first amplitude phase control means and the second amplitude phase control means. In the noise reduction device for in-vehicle wireless device according to any one of claims 1 to 5,
A second vehicle antenna for receiving radio waves outside the vehicle at a position and directivity different from the first vehicle antenna;
Distributing means for distributing received radio waves of the first vehicle interior antenna;
Third amplitude phase control means for controlling and outputting the amplitude and phase of one of the received radio waves distributed by the distribution means;
Second addition means for adding the output of the third amplitude phase control means to the radio wave received by the second vehicle antenna;
Second power detection means for detecting the output power of the second addition means;
With
The optimum control means is:
An in-vehicle wireless device characterized in that the power detected by the first power detection means and the second power detection means is minimized by controlling the first amplitude phase control means and the third amplitude phase control means. Noise reduction device. In the noise reduction device for in-vehicle wireless device according to any one of claims 1 to 5,
A reference signal generator that outputs a clock signal of a predetermined reference frequency;
A first local oscillator that outputs a local oscillation signal in the vicinity of a frequency of a radio wave input from outside the vehicle, based on a clock signal output from the reference signal generator;
A first frequency converter that converts a frequency of a radio wave input from outside the vehicle into an intermediate frequency that is lower than a frequency input from outside the vehicle based on a local oscillation signal output from the first local oscillator;
Between the first vehicle antenna and the first adding means,
The first amplitude phase control means includes:
A first phase shifter that shifts and outputs the phase of the clock signal output by the reference signal generator;
A second local oscillator that outputs a local oscillation signal in the vicinity of a frequency of a radio wave input from the vehicle interior based on a signal output by the first phase shifter;
A second frequency converter for converting a frequency of a radio wave input from the vehicle interior to an intermediate frequency lower than a frequency input from the vehicle interior based on a local oscillation signal output from the second local oscillator; ,
The noise reduction apparatus for vehicle-mounted radio | wireless apparatuses characterized by comprising. In the on-vehicle wireless device noise reduction device according to any one of claims 1 to 7,
The optimum control means is:
It is determined whether or not the radio wave signal received by the first antenna for outside the vehicle is a predetermined signal, and as long as it is determined that the received radio wave signal is not the predetermined signal, the first amplitude phase control means When the signal detected by the first power detection means is minimized and the received radio wave signal is determined to be a predetermined signal, the first amplitude phase control means The noise reduction device for in-vehicle wireless devices is characterized by stopping the control of the vehicle and not minimizing the power.

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