JP2010056704A - On-vehicle receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle receiver for excellently receiving a desired signal even in a region where a desired signal is mixed with an interference wave. <P>SOLUTION: The on-vehicle receiver includes: an antenna for receiving broadcast waves; an RF amplifier for amplifying the broadcast signals received by the antenna; a selecting means for selecting a desired signal of a desired station from the amplified broadcast signals; an AGC control circuit which includes a suppression start point S for adjusting gain of an RF signal and controls the RF amplifier so that a suppression quantity is changed into a linear shape in accordance with an electric field intensity when the electric field intensity of a broadcast signal is the suppression start point S or smaller and the suppression is constant when the electric field intensity is over the suppression start point S; and a determining means for determining whether its own vehicle is approaching the desired station. The AGC control circuit is changed to a start point S1 where the suppression start point S becomes large when its own vehicle is determined to be approaching the desired station, and is changed to a start point S2 where the suppression start point S becomes small when its own vehicle is determined to drive away from the desired station. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an in-vehicle receiver having a function of receiving broadcast waves such as terrestrial digital broadcasting, satellite broadcasting, and radio broadcasting, and in particular, the influence of interference waves when receiving a plurality of broadcast signals having different electric field strengths. The present invention relates to a method for reducing the above.

  In-vehicle electronic devices are receiving multimedia terrestrial digital TV broadcasts and radio broadcasts, and using GPS satellites, etc. in addition to video and audio data playback and recording functions recorded on CDs, DVDs, etc., due to multimediaization. It has a navigation function.

  The in-vehicle electronic device can change the reception environment of the radio wave depending on the position of the vehicle, and if the received intensity of the desired wave is weak or there is an interference wave with a large received intensity around the desired wave, the video and audio of the desired station will be displayed. Cannot watch accurately. For example, Patent Document 1 discloses a technique for reducing reception errors by increasing the gain of an AGC circuit when there is an interference signal with a high reception level adjacent to a desired signal. Patent Document 2 relates to a mobile reception terminal device. When the received level of the desired wave is low, the AGC sensitivity (attenuation amount) is reduced, and when the desired wave reception level is high, the AGC sensitivity (attenuation amount) is increased. The technology is disclosed.

JP 2006-197633 A JP 2007-129576 A

  The frequency used for terrestrial digital television broadcasting is 470 to 770 MHz, and since the existing analog broadcasting frequency band is used, digital broadcasting and analog broadcasting may be mixed in a specific area or the like. For example, when watching digital TV broadcasts, if the reception strength of digital TV broadcasts is low and the reception strength of analog TV broadcasts is high, the effects of jamming waves will be large, resulting in unclear video and audio, or reception errors. It will occur.

  In the conventional in-vehicle receiver, for example, when the electric field strength (S meter) of the intermediate frequency (IF) signal of the broadcast signal becomes smaller than a certain value, the radio frequency (RF) signal is amplified by the AGC circuit, and the electric field strength becomes smaller than the certain value. Becomes larger, the RF signal is suppressed. As shown in FIG. 6, in the AGC circuit of the conventional receiver, when the electric field strength is equal to or lower than the suppression start point S, the RF signal is amplified according to the electric field strength, and when the electric field strength becomes larger than the suppression start point S, The RF signal is suppressed to a constant level regardless of the magnitude of the intensity.

  For example, when the vehicle approaches the desired station and travels away from the jamming station, the electric field strength P1 of the desired wave increases and the electric field strength P2 of the jamming wave decreases. When the electric field intensity P1 of the desired wave is larger than the suppression start point S, the sensitivity of the desired wave is sufficient, but if the suppression start point S is small, the interference wave may be unnecessarily amplified.

  On the other hand, when the host vehicle travels away from the desired station and approaches the jamming station, the electric field strength P1 of the desired wave decreases and the electric field strength P2 of the jamming wave increases. When the desired electric field strength P1 is smaller than the suppression start point S, it is necessary to improve the sensitivity of the desired wave, and the desired wave is amplified. When the suppression start point S is large, the interference wave is amplified. End up.

  As described above, the AGC circuit of the conventional in-vehicle receiver cannot receive the desired wave in an area where the desired wave and the interference wave are mixed because the suppression amount or the AGC effect amount is fixed, or There was a problem that the reception state deteriorated.

  An object of the present invention is to solve such a conventional problem and provide an in-vehicle receiver that can receive a desired wave satisfactorily even in an area where a desired wave and an interference wave can be mixed. And

  An in-vehicle receiving apparatus according to the present invention includes an antenna that receives a broadcast wave, an amplification unit that amplifies a broadcast signal received by the antenna, a selection unit that selects a desired wave of a desired station from the amplified broadcast signal, Including a suppression start point for adjusting the gain of the broadcast signal, when the electric field strength of the broadcast signal is equal to or less than the suppression start point, the suppression amount is linearly changed according to the electric field strength, and is suppressed when exceeding the suppression start point Amplifying control means for controlling the amplifying means so that the amount is constant; and a judging means for determining whether or not the own vehicle is approaching the desired station. When it is determined that the vehicle is approaching the station, the suppression start point is changed to the high electric field side. When it is determined that the vehicle is moving away from the desired station, the suppression start point is changed to the low electric field side.

  Furthermore, the vehicle-mounted receiving device according to the present invention includes an antenna that receives a broadcast wave, an amplification unit that amplifies a broadcast signal received by the antenna, and a selection unit that selects a desired wave of a desired station from the amplified broadcast signal; , Including a suppression start point for adjusting the gain of the broadcast signal, when the electric field strength of the broadcast signal is equal to or less than the suppression start point, when the suppression amount is linearly changed according to the electric field strength, exceeds the suppression start point, Amplification control means for controlling the amplification means so that the amount of suppression is constant, and determination means for determining whether or not the own vehicle is approaching the desired station, the amplification control means When it is determined that the vehicle is approaching the desired station, the linear inclination is increased, and when it is determined that the vehicle is moving away from the desired station, the linear is decreased.

  Furthermore, the vehicle-mounted receiving device according to the present invention includes an antenna that receives a broadcast wave, an amplification unit that amplifies a broadcast signal received by the antenna, and a selection unit that selects a desired wave of a desired station from the amplified broadcast signal; , Including a suppression start point for adjusting the gain of the broadcast signal, when the electric field strength of the broadcast signal is equal to or less than the suppression start point, when the suppression amount is linearly changed according to the electric field strength, exceeds the suppression start point, Amplification control means for controlling the amplification means so that the amount of suppression is constant, and determination means for determining whether or not the own vehicle is approaching the desired station, the amplification control means When it is determined that it is approaching the desired station, the suppression start point is changed to the high electric field side and the linear gradient is increased, and when it is determined that the vehicle is moving away from the desired station, the suppression start point is Change to low electrolysis side and tilt the linear It is reduced.

  Preferably, the in-vehicle receiving apparatus further includes own vehicle position detecting means for detecting the own vehicle position, and storage means for storing broadcast antenna information relating to the location of the broadcast antenna and the broadcast station relayed by the broadcast antenna, and the determination means Determines whether the vehicle is approaching the desired station based on the detected vehicle position and the broadcast antenna information. Preferably, the determining means approaches the desired station when the own vehicle travels forward, when the desired station is located on the front side of the own vehicle, and when the desired station is located on the rear side of the own vehicle. It is determined to move away from. In addition, when the desired station is within a certain angle centered on the traveling direction of the own vehicle, the determination means is that the own vehicle approaches the desired station, and the desired vehicle is desired when there is a desired station other than the certain angle. It may be determined that the user is moving away from the station.

  Furthermore, the vehicle-mounted receiving device according to the present invention is attached to at least the left side and the right side of the own vehicle, and includes a plurality of antennas that respectively receive broadcast waves, and amplification means that amplifies broadcast signals received by the plurality of antennas A selection means for selecting a desired wave of a desired station based on the broadcast signal amplified by the amplification means, and a suppression start point for adjusting the gain of the broadcast signal, and the electric field strength of the broadcast signal is less than or equal to the suppression start point When the suppression amount is linearly changed according to the electric field strength and exceeds the suppression start point, the amplification control means for controlling the amplification means so that the suppression amount becomes constant, and the own vehicle approaches the desired station Determining means for determining whether the vehicle is approaching the desired station, the amplification control means is configured to suppress the broadcast signal from the antenna closer to the desired station. Change the point to the high electric field side, it changes the suppression start point of the broadcasting signal from the far side of the antenna to a desired station in the low electric field side.

  Alternatively, when it is determined that the own vehicle is approaching the desired station, the amplification control means increases the inclination of the broadcast signal from the antenna closer to the desired station and broadcasts from the antenna farther from the desired station. Reduce the slope of the signal. The amplification control means further increases the inclination of the broadcast signal from the antenna closer to the desired station when it is determined that the vehicle is approaching the desired station, and broadcasts from the antenna far from the desired station. You may make it make the said inclination of a signal small.

  Preferably, the plurality of antennas are attached to the left and right positions of the windshield or rear glass of the vehicle, and when the suppression start point of the broadcast signal from the left antenna is changed to the high electric field side, The suppression start point of the broadcast signal is changed to the low electric field side. Preferably, the amplification means includes an amplification circuit that amplifies the RF signal, and the amplification control means includes an AGC circuit that adjusts amplification of the amplification circuit.

  According to the present invention, since the suppression start point of the amplifier control means and / or the linear gradient of the electric field strength and the suppression amount are varied depending on whether or not the own vehicle approaches the desired station, Even in a region where jamming waves are mixed, the influence of the jamming waves can be suppressed and the desired wave can be received with high accuracy.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings. In this preferred embodiment, it is assumed that terrestrial digital television broadcasts are received as desired waves or desired stations, and analog television broadcasts or other broadcasts are received as interference waves. Further, the in-vehicle receiving device of the present embodiment is included in an in-vehicle electronic device having a multimedia data reproduction and recording function and a navigation function, and constitutes a receiving function of the in-vehicle electronic device.

  FIG. 1 is a block diagram showing a configuration of an in-vehicle electronic device according to an embodiment of the present invention. The in-vehicle electronic device 1 according to the present embodiment uses a broadcast wave receiving unit 10 that receives broadcast waves for terrestrial digital TV broadcast, analog TV broadcast, AM / FM radio broadcast, and the like, and a GPS receiver or a self-contained navigation sensor. The navigation function unit 20 having the function of detecting the position of the vehicle and searching for and guiding the route to the destination is reproduced, and audio data and video data recorded on a medium such as a CD, a DVD, and a semiconductor memory are reproduced. An AV playback unit 30, a storage unit 40 for storing road map data and programs, an input unit 50 for inputting instructions from a user, a speaker 60, a display 70, a bus 80 for connecting the units, and a program And a control unit 90 that controls each unit of the in-vehicle electronic device 1.

  The broadcast wave receiving unit 10 includes a tuner that receives terrestrial digital TV broadcast, analog TV broadcast, radio broadcast, and the like, and a signal processing circuit that decodes a signal received by the tuner. The decoded audio signal and video signal are output to the speaker 60 and the display 70.

  Next, the configuration of the broadcast wave receiving unit will be described. FIG. 2 shows an example of a terrestrial digital television receiver (tuner). As shown in FIG. 2, the terrestrial digital television receiver 10A includes an antenna 100, an RF amplifier 102, an RF tuning circuit 104, a mixer 106, a local oscillator 108, a PLL circuit 110, a filter 112, an IF amplifier 114, an LPF 116, An AGC control circuit 118 is included.

  The antenna 100 receives an RF signal obtained by modulating a digital broadcast transmitted from a broadcasting station, and outputs the RF signal to the RF amplifier 102. The RF amplifier 102 amplifies the RF signal and adjusts the gain (amplification) of the RF signal in response to the control signal from the AGS control circuit. The RF signal amplified by the RF amplifier 102 is output to the RF tuning circuit 104, and the RF tuning circuit 104 changes the tuning frequency and selects the RF signal of the desired station.

  The RF signal output from the RF tuning circuit 104 is supplied to one input of the mixer 106, and the frequency signal from the local oscillator 108 is supplied to the other input of the mixer 106 to generate an IF frequency signal. . The local oscillator 108 generates a local oscillation frequency signal based on the variable frequency signal from the PLL circuit 110.

  The IF signal is amplified and then supplied to a filter 112 that passes a specific frequency signal such as a SAW filter, where a desired wave is extracted and other frequency signals are removed. The output signal of the filter 112 is amplified by the IF amplifier 114, and an S meter output signal indicating the reception intensity of the IF signal is supplied to the AGC control circuit 118 via the LPF 116.

  The AGC control circuit 118 outputs an AGC control signal to the RF amplifier 102 based on the output signal from the LPF 116, the output signal from the mixer 106, and the positional relationship between the own vehicle and the broadcast antenna as will be described later. The amplification (gain) of the amplifier 102 is controlled. The AGS control circuit 118 can include, for example, a microcomputer, and the microcomputer executes a program stored in the storage unit 40.

  Next, the AGC control circuit 118 of this embodiment will be described. FIG. 3 shows a functional configuration of the AGC control circuit. The AGC control circuit 118 searches for the own vehicle position information acquisition unit 120 that acquires the own vehicle position information from the navigation function unit 20 and the broadcast antenna that relays the broadcast wave of the broadcast station selected by the user. Unit 122, positional relationship determination unit 124 that determines the positional relationship between the antenna attached to the vehicle and the broadcast station antenna, and the suppression start point and / or the amount of suppression based on the positional relationship determined by positional relationship determination unit 124 And a suppression determining unit 126 that determines the slope of the.

  The own vehicle position information acquisition unit 120 acquires own vehicle position information such as the current position of the own vehicle and the traveling direction of the own vehicle from the navigation function unit 20 in response to the start of reception of the broadcast wave. Furthermore, if the guidance route to the destination is being guided, the guidance route information may be acquired together.

  The broadcast station antenna search unit 122 searches, for example, position information of a broadcast station (desired station) being viewed. Preferably, the storage unit 40 stores a broadcast station antenna database (DB) related to the broadcast station antenna, and the broadcast station antenna search unit 122 searches for a broadcast station that is a desired station with reference to this database. FIG. 4 shows an example of the broadcast station antenna DB. As shown in the figure, the broadcast station antenna DB includes broadcast station antenna identification information, channel information relayed by each broadcast station antenna, and address or longitude / latitude information where the broadcast station antenna is located. For example, the broadcast station antenna # 1 relays a 4-channel broadcast signal, and the location is represented by the longitude and latitude of (X1, Y1). When the in-vehicle electronic device has a data communication function for transmitting / receiving data to / from an external device, the broadcast station antenna search unit 122 accesses an external server that distributes information related to the broadcast station antenna, and the like. The information of the desired station may be acquired from.

  The positional relationship determination unit 124 determines the positional relationship between the vehicle position and the desired station antenna. One preferable determination is to determine whether the vehicle is approaching the desired station antenna. As this determination method, when the desired station antenna is in the traveling direction of the own vehicle or in front of the own vehicle, the own vehicle approaches the desired station antenna, and the desired station antenna is opposite to the traveling direction of the own vehicle or behind the own vehicle. It is determined that the vehicle is moving away from the desired station antenna. In this case, for example, as shown in FIG. 5A, if the desired station antenna 140 is located within a range of a certain angle α around the traveling direction M of the own vehicle, the own vehicle approaches the desired station antenna. If it is outside the range, it may be determined that it is away.

  As another method, the distance between the current position of the vehicle and the position of the desired station antenna is measured, and it is determined whether or not the own vehicle is approaching the desired station antenna from the temporal change in distance. May be. For example, as shown in FIG. 5B, when a distance D1 from the vehicle position at time t1 to the desired station antenna 140 and a distance D2 from the vehicle position at time t2 to the desired station antenna 140, D1-D2 When the difference is positive, the vehicle is moving away from the desired station antenna 140. On the contrary, when the difference is negative, it is determined that the vehicle is approaching the desired station antenna 140.

  Further, the positional relationship determination unit 124 may determine the distance from the own vehicle to the desired station antenna 140 in a plurality of stages in determining the approach or separation between the own vehicle and the desired station antenna 140. For example, when it is determined that the own vehicle is approaching the desired station antenna 140, if the distance D3 from the own vehicle position to the desired station antenna is smaller than the predetermined distance A, stage 1, the distance D3 is equal to or greater than the predetermined distance A If the distance D3 is smaller than the predetermined distance B, the step 2 is determined. If the distance D3 is equal to or larger than the predetermined distance B, the step 3 is determined (distance A <distance B, and the distances in the order of step 1 <step 2 <step 3). large). Similarly, when it is determined that the vehicle is moving away from the desired station antenna 140, the distance D3 is classified into stage 1, stage 2, and stage 3. In this way, the distance from the desired station antenna 140 to the host vehicle can be divided into a plurality of stages, and the suppression characteristic can be changed for each stage.

  The suppression determination unit 126 changes the suppression start point according to the result of the positional relationship determination unit 124. That is, when the vehicle is approaching the desired station antenna 140, the suppression start point is set earlier than the preset start point, and conversely, when the vehicle is moving away from the desired station antenna, the suppression start point is set. Set later than the preset starting point.

  6A is an example in which the operation at the suppression start point is accelerated, and FIG. 6B is an example in which the operation at the suppression start point is delayed. The suppression start point S is a point connecting a linear region where the electric field strength and the suppression amount increase with a positive slope and a saturated region where the suppression amount becomes constant regardless of the magnitude of the electric field strength. The field strength preferably corresponds to the S meter from LPF 116. When the own vehicle is approaching the desired station antenna, the electric field strength of the desired wave is increased, so the suppression start point S (broken line portion) is changed to a higher electric field side start point S1. Thereby, the influence of noise other than the desired wave can be reduced.

  When the host vehicle is moving away from the desired station antenna, the electric field strength of the desired wave is small, so the suppression start point S is changed to a start point S2 on the lower electric field side. By delaying the start point of AGC, it is possible to improve the reception sensitivity of a desired wave having a weak electric field.

  For example, as shown in FIG. 6A, the electric field strength of the desired wave is P1, the electric field strength of the disturbing wave is P2, and P1> S1, P2 <S, and S <S1. When the suppression start point S is not changed, the electric field strength P2 of the disturbing wave is amplified if it is in the linear region. However, by changing to the suppression start point S1, the electric field strength P2 of the disturbing wave is changed from the linear region. It will not be amplified. When the suppression start point S is as shown in FIG. 6B, the electric field intensity P1 of the desired wave is out of the linear region and is not amplified, but the desired wave is changed to the suppression start point S2. The signal is amplified according to the electric field intensity P1.

  Next, an example in which the suppression determination unit 126 changes the slope of the suppression amount in the linear region will be described. FIG. 7A shows a change in inclination when the own vehicle approaches the desired station antenna. The inclination V1 of the suppression amount set in advance (broken line portion) is changed to a larger or steep slope V1. By strengthening the suppression in this way, when the desired wave is a strong electric field, the suppression is strengthened and it is difficult to be affected by noise such as an interference wave other than the desired station.

  On the other hand, when the own vehicle moves away from the desired station antenna, as shown in FIG. 7 (b), the slope V2 of the suppression amount is changed to a slope V2 that becomes smaller or relaxed. When the desired wave is a weak electric field, the reception sensitivity of the desired wave can be improved by reducing the suppression.

  Further, the suppression determination unit 126 may change both the suppression start point and the inclination according to whether or not the own vehicle approaches the desired station antenna. FIG. 8A is an example in the case where the vehicle is approaching the desired station antenna, that is, the suppression start point S is changed to a higher electric field side start point S1, and the slope of the linear region is changed. V is changed to a gradient V1 that is steeper. FIG. 8B shows an example in which the vehicle moves away from the desired station antenna. The suppression start point S is changed to a start point S2 on the lower electric field side, and the slope V of the linear region becomes gentler. The inclination is changed to V2 such that

  Further, when the positional relationship determination unit 124 determines the distance from the own vehicle to the desired station antenna 140 in a plurality of steps, the suppression determination unit 126 determines the suppression start point and / or the slope of the linear region according to the step. It may be changed. For example, when the host vehicle is approaching the desired station, the suppression start point S1 is set to the high electric field side in the order of stage 1, stage 2, and stage 3, and when the host vehicle is moving away from the desired station, stage 3, The suppression start point S2 is set on the low electric field side in the order of stage 2 and stage 1. Similarly, in the case of FIGS. 7 and 8, the suppression determining unit 126 can change the suppression start point and / or the slope of the suppression amount of the linear region according to the stage 1, the stage 2, and the stage 3. .

  Next, another modification of the present embodiment will be described. In the above embodiment, an example of controlling the gain based on the relationship between the own vehicle and the desired station antenna has been described. However, the relationship with the disturbing station antenna may be further considered.

  FIG. 9 is an example of the area-specific jamming wave database showing the relationship between the desired wave channel and the jamming wave channel for each area. The area can be set in units of prefectures and municipalities, and when the desired wave channel is received in these areas, it is specified in advance whether the channel becomes an interference wave. For example, if it is determined from the acquired own vehicle position that the vehicle is traveling in area # 1, if the desired wave channel is one channel, the channels that become the interference wave are the third channel and the fifth channel. . The area may be set so as to correspond to the boundary where the channel of the broadcasting station changes.

  The broadcast station antenna search unit 122 can search for the broadcast station antenna that relays the interference wave channel with reference to the area-specific interference wave database shown in FIG. The positional relationship determination unit 124 can determine the positional relationship between the vehicle position and the jamming station antenna, and can determine whether the vehicle is approaching the jamming station antenna. Then, when the own vehicle is approaching the jamming station antenna, the suppression determining unit 126 uses a strong electric field as the jamming wave, so that the suppression start point S is set to the low electric field side start point S2 (see FIG. 6B). Or the slope V of the suppression amount may be changed to a gentle slope V2 (see FIG. 7B). Also, when the vehicle is moving away from the jamming station antenna, the jamming wave becomes a weak electric field, so that the suppression start point S is changed to the high electric field side start point S1 (see FIG. 6A) or is suppressed. The amount gradient V may be changed to a steep gradient V1 (see FIG. 7A).

  Further, the suppression determination unit 126 considers both whether the own vehicle is approaching the desired station antenna and whether the own vehicle is approaching the interfering wave antenna, and the suppression start point and the slope of the suppression amount. May be changed. For example, when the own vehicle approaches the desired station antenna and moves away from the disturbing station antenna, the suppression start point S is changed to the start point S1, or the inclination is changed from V to V1, and the own vehicle is moved from the desired station antenna. When moving away and approaching the interfering station antenna, the suppression start point S may be changed to the start point S2, or the slope V may be changed to V2.

  Next, a second embodiment of the present invention will be described. In the second embodiment, the broadcast wave receiving unit 10 performs diversity reception using a plurality of antennas. FIG. 10A shows an example in which four antennas 100A, 100B, 100C, and 100D are attached to the windshield of the own vehicle. FIG. 10B shows an example in which the antennas 100E and 100F are attached to the left and right of the windshield, and the antennas 100G and 100H are attached to the rear glass.

  FIG. 11 is a block diagram showing a part of the configuration of the diversity receiver, and the same reference numerals are assigned to the same components as those in FIG. As shown in the figure, RF signals received by antennas 100A (100E), 100B (100F), 100C (100G), and 100D (100H) are amplified by RF amplifiers 102A, 102B, 102C, and 102D, respectively. The amplification factors of the RF amplifiers 102A to 102D are controlled by the control signals from the AGC control circuit 118A.

  An IF signal is extracted from RF signals received by a plurality of antennas, and a signal corresponding to the S meter obtained from the IF signal is output to the AGC control circuit 118A. In diversity reception, an antenna having a high reception strength is selected, and a desired signal broadcast signal is obtained based on an RF signal from the selected antenna, or a signal obtained from each antenna is synthesized to generate a desired signal broadcast signal. Obtainable.

  In this embodiment, the positional relationship between the plurality of antennas and the desired station antenna is determined, and the amplification factors of the RF amplifiers 102A to 102D are controlled based on the determination result. The positional relationship determination unit 124 of the AGC control circuit 118A determines the positional relationship between the own vehicle and the desired station and the disturbing station antenna based on the own vehicle position information and the positional information of the desired station and the disturbing station antenna. When the positional relationship determination unit 124 determines that the desired station antenna is present on the right side of the traveling direction of the host vehicle and the interfering station antenna is present on the left side, the suppression determination unit 126 determines that the right antennas 100C and 100D (100F, The suppression start point S of 100H) is shifted to the start point S1 on the high electric field side, and the suppression start point S of the left antennas 100A and 100B (100E, 100G) is shifted to the start point S2 on the low electric field side. FIG. 12A shows the state of this AGC effect amount. Thereby, the right antennas 100C and 100D (100F and 100H) close to the desired station antenna start AGC earlier, and the influence of noise other than the desired station can be reduced. In addition, the left antennas 100A and 100B (100E and 100G) far from the desired station antenna can delay the start of AGC and improve the reception sensitivity of the desired station.

  On the other hand, when the desired station antenna is present on the left side of the traveling direction of the host vehicle and the interfering station antenna is present on the right side, the AGC adjustment is reversed as in FIG. .

  In the above example, the suppression determination unit 126 changes the suppression start point, but the suppression determination unit 126 can change the slope of the suppression amount. When it is determined by the positional relationship determination unit 124 that the desired station antenna is present on the right side of the traveling direction of the host vehicle and the interfering station antenna is present on the left side, the suppression determining unit 126, as shown in FIG. The slopes of the right antennas 100C and 100D (100F and 100H) are made steep (increase suppression), and the inclinations of the left antennas 100A and 100B (100E and 100G) are made smooth (suppression is weakened). As a result, the right antennas 100C and 100D close to the desired station antenna can strengthen the suppression and reduce noise other than the desired station. Further, the left antennas 100A and 100C far from the desired station antenna can weaken the suppression and improve the reception sensitivity of the desired station. When the desired station antenna is on the left side and the disturbing station antenna is on the right side, an AGC operation opposite to the above is performed.

  Further, the suppression determining unit 126 may change both the suppression start point and the slope of the suppression amount for the gains of the RF signals from the left and right antennas. This is particularly effective when the desired station antenna and the disturbing station antenna are present obliquely with respect to the traveling direction.

  Further, as shown in FIG. 10 (b), when antennas are attached to the front and rear windshields of the host vehicle, when there is a desired station antenna in front of the traveling direction, suppression of RF signals from the front antennas 100E and 100F starts. The point may be changed to the high electric field side, and the suppression start point of the rear antennas 100G and 100H may be changed to the low electric field side. When the desired station antenna is behind the direction of travel, the AGC operation opposite to the above may be performed.

  The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the specific embodiment, and various modifications can be made within the scope of the present invention described in the claims. Deformation / change is possible. For example, in the above-described embodiment, an example in which terrestrial television broadcasting is received has been described. However, the present invention can also be applied to reception of other broadcast waves. Furthermore, the mounting positions and number of the plurality of antennas can be changed as appropriate. Further, in the above embodiment, the gain of the RF amplifier is controlled by using the reception intensity of the IF signal, but the RF amplifier is further utilized by using the output signal from the mixer 106 and the output signal from the RF tuning circuit 104. The gain may be controlled.

It is a block diagram which shows the structure of the vehicle-mounted electronic device which concerns on the Example of this invention. It is a block diagram which shows the structure of the terrestrial digital television receiver of the vehicle-mounted electronic apparatus shown in FIG. It is a block diagram which shows the functional structure of an AGC control circuit. It is an example of a broadcast station antenna database. It is a figure explaining the method to determine the positional relationship of the own vehicle and a desired station antenna. It is a figure explaining the example which changes the suppression start point of AGC in a present Example. It is a figure explaining the example which changes the inclination of the suppression amount of AGC in a present Example. It is a figure explaining the example which changes both the suppression start point of AGC, and the inclination of the suppression amount. It is a figure which shows the example of the jamming station antenna database classified by area. It is a figure which shows the attachment position of a some antenna. It is a figure which shows the example of 1 structure of the diversity receiver which concerns on the 2nd Example of this invention. It is a figure explaining operation | movement of the suppression determination part which concerns on 2nd Example of this invention.

Explanation of symbols

1: vehicle-mounted electronic device 10: receiving unit 20: navigation function unit 30: AV playback unit 40: storage unit 50: input unit 60: speaker 70: display 80: path 90: control unit

Claims (11)

A vehicle-mounted receiving device having a function of receiving broadcast waves,
An antenna for receiving broadcast waves;
Amplifying means for amplifying the broadcast signal received by the antenna;
A selection means for selecting a desired wave of a desired station from the amplified broadcast signal;
Including a suppression start point for adjusting the gain of the broadcast signal, when the electric field strength of the broadcast signal is equal to or less than the suppression start point, the suppression amount is linearly changed according to the electric field strength, and is suppressed when exceeding the suppression start point Amplification control means for controlling the amplification means so that the amount is constant;
Determination means for determining whether or not the own vehicle is approaching the desired station,
When it is determined that the own vehicle is approaching the desired station, the amplification control unit changes the suppression start point to a high electric field side, and when the own vehicle is determined to move away from the desired station, the suppression start point is determined. Vehicle-mounted receiving device that changes to the low electric field side. A vehicle-mounted receiving device having a function of receiving broadcast waves,
An antenna for receiving broadcast waves;
Amplifying means for amplifying the broadcast signal received by the antenna;
A selection means for selecting a desired wave of a desired station from the amplified broadcast signal;
Including a suppression start point for adjusting the gain of the broadcast signal, when the electric field strength of the broadcast signal is equal to or less than the suppression start point, the suppression amount is linearly changed according to the electric field strength, and is suppressed when exceeding the suppression start point Amplification control means for controlling the amplification means so that the amount is constant;
Determination means for determining whether or not the own vehicle is approaching the desired station,
The amplification control means increases the linear inclination when it is determined that the vehicle is approaching the desired station, and decreases the linear when it is determined that the vehicle is moving away from the desired station. Receiver device. A vehicle-mounted receiving device having a function of receiving broadcast waves,
An antenna for receiving broadcast waves;
Amplifying means for amplifying the broadcast signal received by the antenna;
A selection means for selecting a desired wave of a desired station from the amplified broadcast signal;
Including a suppression start point for adjusting the gain of the broadcast signal, when the electric field strength of the broadcast signal is equal to or less than the suppression start point, the suppression amount is linearly changed according to the electric field strength, and is suppressed when exceeding the suppression start point Amplification control means for controlling the amplification means so that the amount is constant;
Determination means for determining whether or not the own vehicle is approaching the desired station,
When it is determined that the own vehicle is approaching the desired station, the amplification control means determines that the own vehicle moves away from the desired station by changing the suppression start point to the high electric field side and increasing the linear inclination. When this is done, the on-vehicle receiving device changes the suppression start point to the low electrolysis side and reduces the linear slope. In-vehicle receivers
Own vehicle position detecting means for detecting the own vehicle position;
Storage means for storing broadcast antenna information relating to the location of the broadcast antenna and a broadcast station relayed by the broadcast antenna,
The in-vehicle receiver according to any one of claims 1 to 3, wherein the determination unit determines whether the vehicle is approaching a desired station based on the detected vehicle position and the broadcast antenna information. . The determining means approaches the desired station when the own vehicle travels forward, when the desired station is located on the front side of the own vehicle, and moves away from the desired station when the desired station is located on the rear side of the own vehicle. The vehicle-mounted receiving device according to claim 4, which is determined as follows. The determination means is configured such that when the desired station is within a certain angle centered on the traveling direction of the own vehicle, the own vehicle approaches the desired station, and when the desired station is other than the certain angle, the own vehicle is the desired station. The in-vehicle receiving device according to claim 4, wherein the receiving device is determined to be away from the vehicle. A vehicle-mounted receiving device having a function of receiving broadcast waves,
A plurality of antennas mounted at least on the left side and the right side of the own vehicle respectively for receiving broadcast waves,
Amplifying means for amplifying broadcast signals received by a plurality of antennas;
Selection means for selecting a desired wave of a desired station based on the broadcast signal amplified by the amplification means;
Including a suppression start point for adjusting the gain of the broadcast signal, when the electric field strength of the broadcast signal is equal to or less than the suppression start point, the suppression amount is linearly changed according to the electric field strength, and is suppressed when exceeding the suppression start point Amplification control means for controlling the amplification means so that the amount is constant;
Determination means for determining whether or not the own vehicle is approaching the desired station,
When it is determined that the own vehicle is approaching the desired station, the amplification control means changes the suppression start point of the broadcast signal from the antenna closer to the desired station to the high electric field side, and moves to the side far from the desired station. A vehicle-mounted receiving device that changes the suppression start point of the broadcast signal from the antenna to the low electric field side. A vehicle-mounted receiving device having a function of receiving broadcast waves,
A plurality of antennas mounted at least on the left side and the right side of the own vehicle respectively for receiving broadcast waves,
Amplifying means for amplifying broadcast signals received by a plurality of antennas;
Selecting means for synthesizing the amplified broadcast signal and selecting a desired wave of the desired station from the synthesized broadcast signal;
Including a suppression start point for adjusting the gain of the broadcast signal, when the electric field strength of the broadcast signal is equal to or less than the suppression start point, the suppression amount is linearly changed according to the electric field strength, and is suppressed when exceeding the suppression start point Amplification control means for controlling the amplification means so that the amount is constant;
Determination means for determining whether or not the own vehicle is approaching the desired station,
When it is determined that the vehicle is approaching the desired station, the amplification control means increases the inclination of the broadcast signal from the antenna closer to the desired station, and the broadcast signal from the antenna far from the desired station. A vehicle-mounted receiving device that reduces the inclination of the vehicle. The amplification control means further increases the inclination of the broadcast signal from the antenna closer to the desired station when it is determined that the vehicle is approaching the desired station, and broadcasts from the antenna far from the desired station. The in-vehicle receiver according to claim 7, wherein the inclination of the signal is reduced. The plurality of antennas are attached to the left and right positions of the windshield or rear glass of the own vehicle, and when the suppression start point of the broadcast signal from the left antenna is changed to the high electric field side, the broadcast from the right antenna The in-vehicle receiver according to any one of claims 7 to 9, wherein the suppression start point of the signal is changed to a low electric field side. The in-vehicle receiver according to claim 1, wherein the amplifying unit includes an amplifying circuit that amplifies an RF signal, and the amplifying control unit includes an AGC circuit that adjusts amplification of the amplifying circuit.

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