JP2014158208A - Vehicle communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle communication device which enhances reproduction quality in a reproduction device or communication quality between ECUs.SOLUTION: Determination means 40 of a specific ECU 30 in a vehicle communication device 12 determines whether communication signals at a prescribed frequency f1 between ECUs 30 and 32a to 32d become noise for signals at a reception frequency fr acquired from a reproduction device 22. When it is determined that the communication signals at the prescribed frequency f1 become noise for signals at the reception frequency fr, the specific ECU 30 changes the prescribed frequency f1.

Description

  The present invention relates to a vehicle communication device in which a plurality of electronic control devices are connected to a common communication line and communicate with each other using a communication signal of a specified frequency.

In Patent Document 1, the drive frequency of a PWM drive signal for driving an electric motor such as an electric power steering device or a power window device is changed according to the channel frequency of the car radio, and the car radio is caused by the harmonic component of the PWM drive frequency. The purpose is to prevent noise jumping in ([0002], [0008]). Therefore, in Patent Document 1, the control unit 15 changes the drive frequency of the PWM control signal for the electric motor according to the external specific information J _G (channel frequency received by the car radio ([0035])), and the PWM drive frequency. Is set to a frequency far from the channel frequency of the radio, thereby preventing noise from entering the car radio ([0069]).

  Moreover, the vehicle information communication system which applied power line communication (PLC) to the vehicle is examined from needs, such as harness wire-saving (patent document 2). In Patent Document 2, it is introduced as a prior art that a PLC is used for communication in a master controller 74 (master 74) and a slave controller 75 (slave 75) that control a plurality of loads 73 constituting an electrical equipment ([0003 ]). Patent Document 2 discloses a plurality of PLC networks 20 (20A, 20B, 20C,...) Each having a master 40 that performs master-slave communication ([0014], [0017]).

JP-A-10-327597 JP 2005-278087 A

As described above, in Patent Document 1, the control unit 15 changes the drive frequency of the PWM control signal for the electric motor in accordance with the external identification information _JG . In other words, Patent Document 1 only considers the case where the control means 15 for driving a certain electric motor (actuator) alone changes the drive frequency of the PWM control signal. For this reason, when the technique of patent document 1 is incorporated in the communication system of patent document 2, master-slave communication in each PLC network 20 or communication between a plurality of PLC networks 20 (in other words, between a plurality of electronic control units (ECUs)). Communication).

  Note that the above problem applies not only to car radios (radio receivers) but also to other playback devices (for example, television receivers).

  The present invention has been made in consideration of the above-described problems, and an object of the present invention is to provide a vehicle communication device that improves reproduction quality in a reproduction device.

  A vehicle communication device according to the present invention is such that a plurality of electronic control devices are connected to a common communication line and communicate with each other using a communication signal of a specified frequency. A content signal obtained by selecting and receiving at least one of a plurality of fixed-frequency radio waves transmitted from, and demodulating the received radio wave among the plurality of radio waves and including at least audio information or video information Is reproduced in the vehicle, and a predetermined electronic control device among the plurality of electronic control devices receives one or more of the radio waves that the reproduction device is receiving or is likely to receive. A determination unit that specifies a reception frequency that is a frequency and determines whether or not the communication signal of the specified frequency becomes noise with respect to the signal of the specified reception frequency; When it is determined that the communication signal of the specified frequency becomes noise with respect to the signal of the received frequency, the change notification of the specified frequency is transmitted to all electronic control devices other than the predetermined electronic control device, and the predetermined electronic All the electronic control devices other than the control device change the prescribed frequency sequentially or simultaneously based on the change notification, and the predetermined electronic control device receives from all electronic control devices other than the predetermined electronic control device. On the condition that the response signal is received, the subsequent communication is performed at the specified frequency after the change.

  According to the present invention, when it is determined that a communication signal of a specified frequency (a signal used between a plurality of electronic control units (hereinafter also referred to as “ECUs”)) becomes noise with respect to a reception frequency signal of the playback device, the ECU Change the frequency used for communication (specified frequency). For this reason, the fixed frequency radio signal selected by the playback apparatus or the demodulated signal of the radio wave is prevented from affecting the communication signal of the specified frequency used for communication between the ECUs from the viewpoint of frequency. It becomes possible. Therefore, it is possible to improve the reproduction quality in the reproduction apparatus.

  When the communication method performed between the plurality of electronic control devices is a baseband method in which a substantially rectangular wave signal is transmitted at the specified frequency, the determination means includes a basic component of frequency components included in the substantially rectangular wave. The specified frequency after the change may be set so that a frequency that is a harmonic component with respect to the frequency and the fundamental frequency does not coincide with the reception frequency.

  When a rectangular wave such as a pulse is transmitted by the baseband, many harmonic components are included. For this reason, when communication between ECUs is performed in the baseband method, a communication signal of a specified frequency used for communication between ECUs is generated with respect to a fixed-frequency radio wave selected by the playback device or a demodulated signal of the radio wave. It becomes easy to influence from the viewpoint of frequency. In the present invention, the changed specified frequency is set in consideration of the characteristics of the baseband system as described above. For this reason, it becomes possible to prevent the above effects.

  Alternatively, a communication method performed between the plurality of electronic control devices is a method (for example, orthogonal frequency division multiplexing (OFDM) or spread spectrum (SS)) that modulates the carrier wave of the specified frequency with a signal of a predetermined communication frequency. In some cases, the determination unit may set the changed specified frequency so that a center frequency of the carrier wave frequency and a frequency of a bandwidth of the communication frequency with respect to the center frequency do not coincide with the reception frequency. .

  When a method for modulating a carrier wave is used, a frequency band centered on the center frequency of the carrier wave is used. In the present invention, the changed specified frequency is set in consideration of such characteristics. For this reason, when using a method of modulating a carrier wave, between a fixed frequency radio wave selected by the playback device or a demodulated signal of the radio wave and a communication signal of a specified frequency used for communication between ECUs It becomes possible to prevent the influence.

  The communication line also serves as a power line for supplying power from the power source of the vehicle to the plurality of electronic control devices, and communication performed between the plurality of electronic control devices is a communication signal of the specified frequency to the power line. May be power line communication that performs communication by superimposing. Thereby, when using power line communication (PLC), the influence between the fixed frequency radio wave selected by the playback device or the demodulated signal of the radio wave and the communication signal of the specified frequency used for communication between ECUs Can be prevented.

  The reception frequency is a plurality of receivable frequencies that are frequencies of broadcast stations or broadcast channels that can be received corresponding to the current position of the vehicle. It may be determined whether or not the communication signal becomes noise. This makes it unnecessary to change the specified frequency when changing the broadcast station or broadcast channel. Accordingly, it is possible to more surely prevent the generation of temporary noise when the broadcast station or the broadcast channel is changed.

  According to the present invention, when it is determined that a communication signal of a specified frequency (a signal used between ECUs) becomes noise with respect to a signal of a reception frequency of the playback device, the frequency (specified frequency) used for communication between ECUs is changed. To do. For this reason, the fixed frequency radio signal selected by the playback apparatus or the demodulated signal of the radio wave is prevented from affecting the communication signal of the specified frequency used for communication between the ECUs from the viewpoint of frequency. It becomes possible. Therefore, it is possible to improve the reproduction quality in the reproduction apparatus.

1 is a schematic block diagram of a vehicle including a vehicle communication device according to a first embodiment of the present invention. It is a block diagram which shows a part of said vehicle communication apparatus in detail. It is a flowchart which shows the process of the master for setting a baud rate in 1st Embodiment. It is a flowchart which shows the process of the slave for setting the said baud rate in 1st Embodiment. It is a figure which shows the result of having carried out the FFT analysis of the waveform of the sine wave, and the said sine wave. It is a figure which shows the result of carrying out the FFT analysis of the waveform of a rectangular wave, and the said rectangular wave. It is a schematic block diagram of a vehicle provided with the vehicle communication apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the process of the master for setting a baud rate in 2nd Embodiment.

A. First Embodiment 1. FIG. Explanation of overall configuration [1-1. overall structure]
FIG. 1 is a block diagram of a schematic configuration of a vehicle 10 including a vehicle communication device 12 according to the first embodiment of the present invention. FIG. 2 is a block diagram showing a part of the vehicle communication device 12 in more detail. The vehicle communication device 12 (hereinafter also referred to as “communication device 12”) includes a communication network 20 and a radio receiver 22 (hereinafter referred to as “radio 22”) as a playback device.

[1-2. Communication network 20]
(1-2-1. Overall Communication Network 20)
As shown in FIG. 1, the communication network 20 includes a plurality of electronic control devices 30, 32 a to 32 d (hereinafter referred to as “ECU 30, 32 a to 32 d”) and communication for communication between the ECUs 30, 32 a to 30 d. Line 34. The ECUs 30, 32a to 32d are connected to a common communication line 34 and communicate with each other at a specified frequency (hereinafter referred to as “specified frequency f1”) [Hz]. The communication method here is a baseband method in which a substantially rectangular wave signal is transmitted at a specified frequency f1. As will be described later, other communication methods may be used. Further, the specified frequency f1 here is synonymous with the baud rate [bps]. Hereinafter, the baud rate used in the present embodiment is referred to as “baud rate Rb”.

  Further, the communication network 20 of the present embodiment uses so-called power line communication (PLC) as a communication technique. For this reason, the communication line 34 also serves as a power line for supplying power from the battery 36 as a power source of the vehicle 10 to the plurality of ECUs 30, 32 a to 32 d. In power line communication, communication is performed by superimposing a predetermined signal on the communication line 34 that also serves as a power line.

  As the communication network 20, for example, a configuration described in JP 2012-129742 A can be used.

  The ECUs 30, 32a to 32d include a master ECU 30 (hereinafter also referred to as “master 30”) functioning as a master node and slave ECUs 32a to 32d (hereinafter referred to as “slave 32a to 32d”) functioning as slave nodes. Are collectively referred to as “.”. Note that the ECUs 30 and 32a to 32d are not necessarily all incorporated in the vehicle 10, and may be included in mobile terminals such as mobile phones and smartphones.

(1-2-2. Master ECU 30)
The master 30 of this embodiment manages the control of the entire communication network 20 through communication with each slave 32. In addition, the part that the master 30 is in charge of may be controlled. For example, when the vehicle 10 includes an engine (not shown), the master 30 may control the engine. Alternatively, when the vehicle 10 includes a travel motor (not shown), the master 30 may control the travel motor.

  As shown in FIG. 2, the master 30 includes a microcomputer 40 (hereinafter also referred to as “master side microcomputer 40”), a phase synchronization circuit 42 (hereinafter referred to as “master side PLL 42” or “PLL 42”), and a power line. And a communication modem 44 (hereinafter referred to as “master modem 44” or “modem 44”). In FIG. 2, “MCOM” is an abbreviation for microcomputer.

  The microcomputer 40 executes predetermined processing based on the program stored in the storage unit 46. The predetermined process includes a determination function for determining whether or not to change the baud rate Rb (specified frequency f1). For this reason, the microcomputer 40 also functions as a determination unit. Details of the processing of the microcomputer 40 will be described later with reference to FIG.

  The PLL 42 changes the baud rate Rb (specified frequency f1) according to a command from the microcomputer 40. The specific configuration of the PLL 42 is the same as a phase synchronization circuit 52 (hereinafter referred to as “slave-side PLL 52” or “PLL 52”) of the slave 32 described later. As the configuration of the PLL 42, not only the configuration of the PLL 52 in FIG. 2 but also other existing configurations can be used.

  The modem 44 performs modulation and demodulation when communicating with the other ECUs 32a to 32d (slave 32). As described above, since the communication network 20 of this embodiment uses power line communication, the modem 44 is a power line communication modem.

(1-2-3. Slave ECUs 32a to 32d)
The slaves 32a to 32d communicate with the master 30 and the other slaves 32a to 32d, and control the parts that they are in charge of. The control targets of the slaves 32a to 32d may be parts such as a transmission, a brake, and an air conditioner, for example.

  As shown in FIG. 2, each of the slaves 32 a to 32 d has a microcomputer 50 (hereinafter also referred to as “slave side microcomputer 50”) and a phase synchronization circuit 52 (hereinafter referred to as “slave side PLL 52” or “PLL 52”). And a power line communication modem 54 (hereinafter referred to as "slave modem 54" or "modem 54").

  The microcomputer 50 executes predetermined processing based on the program stored in the storage unit 56. The predetermined processing includes a function of changing the baud rate Rb (specified frequency f1) based on a command from the master 30. For this reason, the microcomputer 50 also functions as a baud rate changing means or a specified frequency changing means. Details of the processing of the microcomputer 50 will be described later with reference to FIG.

  The PLL 52 changes the baud rate Rb (specified frequency f1) according to a command from the microcomputer 50. As shown in FIG. 2, the PLL 52 includes a phase frequency comparator 60 (hereinafter referred to as “PFD 60”), a charge pump 62 (hereinafter referred to as “CP62”), and a loop filter 64 (hereinafter referred to as “LPF 64”). , A voltage controlled oscillator 66 (hereinafter referred to as “VCO 66”) and a frequency divider 68.

  The PFD 60 compares the phase or frequency of the reference signal Sref from the microcomputer 50 and the feedback signal Sfb from the frequency divider 68, and outputs the comparison result as an error signal Ser (digital signal). The CP 62 converts the error signal Ser from the PFD 60 into an analog signal and outputs it to the LPF 64.

  The LPF 64 smoothes the analog signal from the CP 62 and converts it into a control voltage for the VCO 66. The VCO 66 changes the oscillation frequency according to the input voltage from the LPF 64.

  The frequency divider 68 divides the input signal from the VCO 66 and outputs it as a lower frequency signal. The frequency division ratio (= output frequency / input frequency) in the frequency divider 68 changes according to a command from the microcomputer 50. Note that a prescaler (not shown) may be disposed in front of the frequency divider 68 to divide the frequency into two stages.

  As described above, the specific configuration of the slave side PLL 52 is the same as that of the master side PLL 42. As the configuration of the PLL 52, not only the configuration of FIG. 2 but also other existing configurations can be used.

  The modem 54 performs modulation and demodulation when communicating with the master ECU 30 and the other ECUs 32a to 32d (slave 32). As described above, since the communication network 20 of the present embodiment uses power line communication, the modem 54 is a power line communication modem.

[1-3. Radio 22]
The radio 22 can receive radio waves having a predetermined frequency (hereinafter referred to as “reception frequency fr”) [Hz] transmitted from the outside of the vehicle 10. The radio 22 reproduces a signal (content signal) including audio information obtained by demodulating the received radio wave in the vehicle 10. The audio information mentioned here can also include music information. Further, the content signal may include video information. The video information here can include character information.

  The radio 22 notifies the microcomputer 40 of the reception frequency fr in response to a request from the master side microcomputer 40. Alternatively, the radio 22 may notify the microcomputer 40 of the reception frequency fr at a predetermined timing without a request from the microcomputer 40. The predetermined timing includes, for example, the time when the radio 22 is activated, the time when the selected channel is changed in the radio 22, and a specific time (fixed time) (for example, one of several seconds to several tens of seconds). At least one of the time points can be used.

  As will be described later, in addition to the radio 22 or in place of the radio 22, a television receiver (not shown) (hereinafter referred to as “TV”) may be used. The television reproduces in the vehicle 10 a signal (content signal) including at least audio information or video information obtained by demodulating the received radio wave.

2. Setting of baud rate Rb [2-1. Processing of master 30]
FIG. 3 is a flowchart showing processing of the master 30 for setting the baud rate Rb (specified frequency f1) in the first embodiment. Each process of FIG. 3 is executed by the master microcomputer 40. In step S <b> 1, the microcomputer 40 acquires the reception frequency fr from the radio 22. The reception frequency fr here is the reception frequency fr of the broadcast station or broadcast channel selected by the radio 22 and is a frequency at which a signal for reproduction by the radio 22 is received.

  In step S2, the microcomputer 40 determines whether or not a value obtained by multiplying the baud rate Rb by n (hereinafter referred to as “multiplied value nRb”) (n is a natural number) is equal to the reception frequency fr. More precisely, after comparing the units of both numerical values, it is determined whether or not they are equal. Thereby, the microcomputer 40 determines whether or not the baud rate Rb (specified frequency f1) becomes noise with respect to the acquired reception frequency fr. For this reason, “the multiplication value nRb is equal to the reception frequency fr” here means not only when the multiplication value nRb is exactly the same value as the reception frequency fr (after aligning the units), but substantially both May be the same value. Instead of the above, the multiplied value nf1 of the prescribed frequency f1 may be compared with the reception frequency fr.

  When the multiplied value nRb is not equal to the reception frequency fr (S2: NO), that is, when it is determined that the baud rate Rb does not become noise of the reception frequency fr, the current process is terminated without changing the baud rate Rb. When the multiplied value nRb is equal to the reception frequency fr (S2: YES), that is, when it is determined that the baud rate Rb becomes noise of the reception frequency fr, the process proceeds to step S3.

  In step S3, the microcomputer 40 selects the baud rate Rb so that the multiplied value nRb is different from the reception frequency fr. For example, in the case of baseband communication as in the first embodiment, the frequency (baud rate Rb (specified frequency f1)) that is the fundamental frequency among the frequency components included in the substantially rectangular wave and the frequency (baud rate Rb × 2 or more) transmits a change notification of the baud rate Rb so as not to coincide with the reception frequency fr.

  In step S4, the microcomputer 40 notifies each slave 32 of the change in the baud rate Rb.

  In step S <b> 5, the microcomputer 40 determines whether or not there is a reception confirmation (response signal) from all the slaves 32. If there is no reception confirmation from any of the slaves 32 (S5: NO), the process returns to step S4. However, when a state in which there is no reception confirmation from any of the slaves 32 continues for a predetermined time, the process may proceed to step S6 as a timeout process.

  If reception has been confirmed from all slaves 32 (S5: YES), in step S6, the microcomputer 40 changes the baud rate Rb. Thereby, subsequent communication between the master 30 and each slave 32 is performed using the changed baud rate Rb. As described above, communication between the master 30 and each slave 32 is performed in a baseband manner. A method of setting the baseband frequency fbase used here will be described later.

  The microcomputer 40 repeats the process of FIG. 3 at predetermined intervals (for example, every few seconds to several minutes).

[2-2. Processing of slave 32]
FIG. 4 is a flowchart showing processing of the slave 32 for setting the baud rate Rb in the first embodiment. In step S <b> 11, the slave microcomputer 50 determines whether or not a change notification of the baud rate Rb has been received from the master 30. If the change notification has not been received (S11: NO), step S11 is repeated. When the change notification is received (S11: YES), in step S12, the microcomputer 50 transmits a reception confirmation (response signal) to the master 30.

  In step S13, the microcomputer 50 changes the baud rate Rb after a predetermined time from the transmission of the reception confirmation (S12).

  The microcomputer 50 repeats the process of FIG. 4 at predetermined intervals (for example, every few seconds to several minutes).

[2-3. Setting method of baseband frequency fbase]
FIG. 5 is a diagram showing the waveform of the sine wave 70 and the result of FFT analysis of the sine wave 70. FIG. 6 is a diagram illustrating the waveform of the rectangular wave 72 and the result of FFT analysis of the rectangular wave 72.

  As shown as a sine wave 70 in FIG. 5, if the baseband signal is a perfect sine wave, the frequency is one. For this reason, if the baseband frequency fbase is not equal to the reception frequency fr, the communication signal in the communication network 20 does not affect the reception of the radio 22.

  However, there are disadvantages to baseband communication with a perfect sine wave. For example, the amplitude modulation (AM) communication is vulnerable to noise. Therefore, in order to increase the communication success rate, it is required to perform communication with a waveform closer to a rectangular wave.

  As shown as a rectangular wave 72 in FIG. 6, when the baseband signal is brought close to a rectangular wave, harmonic components increase. As a result, if the harmonic component becomes equal to the multiplied value nRb of the reception frequency fr, reception of the radio 22 is affected.

  Therefore, in the present embodiment, the base frequency communication reference frequency and its harmonic component (that is, the multiplied value nRb of the baud rate Rb) are not equal to the reception frequency fr or the communication signal in the communication network 20 affects the radio 22. The baud rate Rb is changed so that becomes smaller.

3. Effects of the First Embodiment As described above, according to the first embodiment, the signal of the reception frequency fr of the radio 22 (playback device) (the fixed frequency radio wave selected by the radio 22 or received by the radio 22 or the radio wave) When it is determined that the communication signal (the signal used between the ECUs 30 and 32) of the baud rate Rb (specified frequency f1) becomes noise with respect to the demodulated signal (S2 in FIG. 3: YES), the communication between the ECUs 30 and 32 is performed. The baud rate Rb (specified frequency f1) to be used is changed (S3 to S6). For this reason, it becomes possible to prevent the communication signal of the baud rate Rb (specified frequency f1) used for communication between the ECUs 30 and 32 from affecting the signal of the reception frequency fr from the viewpoint of frequency. Therefore, the reproduction quality on the radio 22 can be improved.

  In the first embodiment, the communication system performed between the ECUs 30 and 32 is a baseband system that transmits a substantially rectangular wave signal (see FIG. 6) at a baud rate Rb (specified frequency f1). The determination unit sets the changed baud rate Rb (specified frequency f1) so that the baud rate Rb (fundamental frequency) and the multiplied value nRb (frequency that becomes a harmonic component) do not coincide with the reception frequency fr (S3). . When a rectangular wave 72 such as a pulse is transmitted by baseband, a large number of harmonic components are included (see FIG. 6). For this reason, when communication between the ECUs 30 and 32 is performed in the baseband method, communication between the ECUs 30 and 32 is performed with respect to a fixed-frequency radio wave selected by the radio 22 (reproducing device) or a demodulated signal of the radio wave. The communication signal of the baud rate Rb (specified frequency f1) used for the above is likely to have an influence from the viewpoint of frequency. In the first embodiment, the changed baud rate Rb (specified frequency f1) is set in consideration of the characteristics of the baseband method as described above. For this reason, it becomes possible to prevent the above effects.

B. Second Embodiment 1. FIG. Description of overall configuration (difference from the first embodiment)
[1-1. overall structure]
FIG. 7 is a schematic block diagram of a vehicle 10A including the vehicle communication device 12a according to the second embodiment of the present invention. Constituent elements similar to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The vehicle communication device 12a (hereinafter also referred to as “communication device 12a”) according to the second embodiment includes a navigation device 90 as current position detection means in addition to the communication network 20 and the radio 22.

  The hardware configuration of the second embodiment includes a navigation device 90 in addition to the configuration of the first embodiment. Further, the reception frequency fr of the radio 22 is not input to the master side microcomputer 40 (however, the reception frequency fr may be input to the master side microcomputer 40). Furthermore, the processing in the microcomputer 40 of the master 30 is different from that in the first embodiment.

[1-2. Navigation device 90]
The navigation device 90 can detect the current position Pc of the vehicle 10A using a GPS (Global Positioning System) or the like, and includes a map database 92 (hereinafter referred to as “map DB 92”) that stores map information Im. .

  The navigation device 90 notifies the microcomputer 40 of the current position Pc in response to a request from the master side microcomputer 40. Alternatively, the navigation device 90 may notify the microcomputer 40 of the current position Pc at a predetermined timing without a request from the microcomputer 40. The predetermined timing includes, for example, when the navigation device 90 is activated, when the current position Pc moves a predetermined distance according to the travel of the vehicle 10A, and for a specific time (fixed time) (for example, several seconds to several tens of seconds). At least one of the points when any) has elapsed can be used. As will be described later, the information transmitted from the navigation device 90 to the microcomputer 40 may be other information.

[1-3. Master 30]
The master 30 of the second embodiment is different from the first embodiment in the processing when setting the baud rate Rb (specified frequency f1) in the communication network 20. Details will be described later with reference to FIG.

2. Setting of baud rate Rb [2-1. Processing of master 30]
FIG. 8 is a flowchart showing processing of the master 30 for setting the baud rate Rb in the second embodiment. Each process of FIG. 8 is executed by the master microcomputer 40. In step S <b> 21, the microcomputer 40 acquires the current position Pc from the navigation device 90.

  In step S22, the microcomputer 40 confirms the receivable frequencies fr1 to frx on the radio 22 according to the current position Pc. The receivable frequencies fr1 to frx are frequencies that can be selected or received by the radio 22 in relation to the current position Pc among the frequencies assigned to the broadcast station or the broadcast channel. “X” in “frx” means a positive integer other than 1. Further, the storage unit 46 (see FIG. 2) of the microcomputer 40 of the second embodiment stores a map in which the position information (current position Pc) and the receivable frequencies fr1 to frx are associated with each other. For this reason, the microcomputer 40 can specify the receivable frequencies fr1 to frx based on the current position Pc.

  As will be described later, the processing up to the specification of the receivable frequencies fr1 to frx can also be performed by the navigation device 90. In order to improve the reliability of the receivable frequencies fr1 to frx, the reception frequency fr may be input from the radio 22 to the master microcomputer 40 and collated with the receivable frequencies fr1 to frx. That is, if one of the receivable frequencies fr1 to frx matches the reception frequency fr, the reliability of the receivable frequencies fr1 to frx can be increased.

  In step S23, the microcomputer 40 determines whether or not the value (multiplied value nRb) obtained by multiplying the baud rate Rb by n is equal to any of the receivable frequencies fr1 to frx. More precisely, after comparing the units of both numerical values, it is determined whether or not they are equal. Thereby, the microcomputer 40 performs the baud rate Rb (specified frequency f1) on the confirmed signals of the receivable frequencies fr1 to frx (a plurality of radio waves that the radio 22 may select and receive or a demodulated signal of the radio waves). ) Determines whether or not the communication signal becomes noise. For this reason, the “multiplied value nRb is equal to any of the receivable frequencies fr1 to frx” here means that the multiplied value nRb is the same numerical value as any of the receivable frequencies fr1 to frx (after aligning the units). It can include not only a case but also a case where both values are substantially equal.

  When the multiplication value nRb is not equal to any of the receivable frequencies fr1 to frx (S23: NO), that is, when it is determined that the communication signal of the baud rate Rb does not become noise in any of the signals of the receivable frequencies fr1 to frx. The current process is terminated without changing the baud rate Rb. If the multiplied value nRb is equal to any of the receivable frequencies fr1 to frx (S23: YES), that is, if it is determined that the communication signal of the baud rate Rb becomes noise of any of the signals of the receivable frequencies fr1 to frx, step Proceed to S24.

  In step S24, the microcomputer 40 selects the baud rate Rb so that the multiplied value nRb is different from any of the receivable frequencies fr1 to frx.

  Steps S25 to S27 are the same as steps S4 to S6 of the first embodiment (FIG. 3).

  The microcomputer 40 repeats the process of FIG. 8 at predetermined intervals (for example, every several seconds to several minutes).

[2-2. Processing of slave 32]
The processing of the slave 32 in the second embodiment is the same as that in the first embodiment (FIG. 4).

3. Effects of Second Embodiment As described above, according to the second embodiment, the following effects can be obtained in addition to or instead of the effects of the first embodiment.

  That is, in the second embodiment, the master-side microcomputer 40 (determination means) has a plurality of receivable frequencies fr1 to frx that are frequencies of broadcast stations or broadcast channels that can be received corresponding to the current position Pc of the vehicle 10A. It is determined whether or not the communication signal having the baud rate Rb (specified frequency f1) becomes noise with respect to the signal (S23 in FIG. 8). This makes it unnecessary to change the baud rate Rb (specified frequency f1) when changing the broadcast station or broadcast channel. Accordingly, it is possible to more surely prevent the generation of temporary noise when the broadcast station or the broadcast channel is changed.

C. Modifications Note that the present invention is not limited to the above-described embodiments, and various configurations can be adopted based on the description of the present specification. For example, the following configuration can be adopted.

1. Vehicle 10 (application target)
In each said embodiment, although the communication apparatus 12 was mounted in the vehicle 10, it is applicable not only to this but for another use. For example, the communication device 12 may be applied to a moving body such as an aircraft or a ship. Alternatively, the communication device 12 can be used for devices such as industrial machines and home appliances.

2. Communication network 20
In each of the above-described embodiments (FIG. 1, FIG. 7, etc.), one communication network 20 is shown, and the baud rate Rb (specified frequency f1) in communication within the one communication network 20 (communication between the master 30 and the slaves 32a to 32d). ), But is not limited to this. For example, as in Patent Document 2 (FIG. 1), a plurality of communication networks 20 are provided, and the processing in the first and second embodiments (see FIGS. 3, 4, and 8) in communication between these communication networks 20 is performed. Can be used. In this case, the relationship between the master and the slave is replaced with the relationship between the masters 30 of each network 20.

3. Radio 22 (playback device)
In each of the embodiments described above, the radio 22 is used as a playback device that plays back content (sound or video) in the vehicle 10. For example, from the viewpoint of a playback device that plays back content (sound or video) in the vehicle 10. If so, other playback devices may be used. For example, a television receiver (not shown) can be used instead of the radio 22 or together with the radio 22. When both the radio 22 and the television are received, the baud rate Rb or the specified frequency f1 in which the multiplied value nRb or nf1 is set so as to avoid the respective reception frequencies fr may be used.

4). Communication Method In each of the above embodiments, the baseband method is used as the communication method between the ECUs 30 and 32. However, a viewpoint other than the communication method (for example, the reception frequency fr of the radio 22 and the baud rate Rb between the ECUs 30 and 32 are different). In view of the above, a method other than the baseband method may be used. As such a communication method, for example, a method (for example, orthogonal frequency division multiplexing (OFDM) or spread spectrum (SS)) that modulates a carrier wave having a baud rate Rb (specified frequency f1) with a signal of a predetermined communication frequency is used. Is possible.

  When the above method (OFDM, SS, etc.) is used as a communication method between the ECUs 30 and 32, the master microcomputer 40 (determination means) has a center frequency of the carrier frequency and a frequency of the bandwidth of the communication frequency with respect to the center frequency. The changed baud rate Rb (specified frequency f1) may be set so as not to coincide with the reception frequency fr or the receivable frequencies fr1 to frx. When a method for modulating a carrier wave (OFDM, SS, etc.) is used, a frequency band centered on the center frequency of the carrier wave is used. Therefore, the changed baud rate Rb (specified frequency f1) is set in consideration of such characteristics. For this reason, in the case of using a method for modulating a carrier wave, one or a plurality of radio waves selected by the radio 22 (reproducing device) or possibly received, or a demodulated signal of the radio wave, an ECU 30, It is possible to prevent the influence between the communication signal of the baud rate Rb (specified frequency f1) used for communication between 32.

5. Setting of Receivable Frequency fr1-frx In the second embodiment, when setting the receivable frequencies fr1-frx, the navigation device 90 transmits the current position Pc to the master microcomputer 40, and the microcomputer 40 receives the received current position Pc. Was used to identify the receivable frequencies fr1 to frx (S22 in FIG. 8). However, the receivable frequencies fr1 to frx can be specified by other methods.

  For example, the navigation device 90 may identify the receivable frequencies fr1 to frx and notify the microcomputer 40 of the receivable frequencies fr1 to frx from the navigation device 90. In this case, the map DB 92 of the navigation device 90 may include a map that defines the relationship between the current position Pc and the receivable frequencies fr1 to frx.

  Alternatively, the following processing may be performed. That is, the navigation device 90 identifies the area code Cz based on the current position Pc, and notifies the microcomputer 40 of the area code Cz. The microcomputer 40 notified of the area code Cz specifies the receivable frequencies fr1 to frx from the area code Cz. Here, the area code Cz can be, for example, a code assigned to each area obtained by dividing the map into a grid, or a code assigned to an area divided for each administrative division (such as a municipality). In this case, a map defining the relationship between the current position Pc and the area code Cz is included in the map DB 92 of the navigation device 90, and the area code Cz and the receivable frequencies fr1 to frx are stored in the storage unit 46 of the master side microcomputer 40. Just include a map that defines the relationship.

  The timing at which the receivable frequencies fr1 to frx or the area code Cz are transmitted from the navigation device 90 to the microcomputer 40 is, for example, the timing when the master side microcomputer 40 requests the navigation device 90 or the timing from the microcomputer 40. It can be a predetermined timing without a request. As the predetermined timing, for example, when the navigation device 90 is activated, when the current position Pc moves a predetermined distance according to the travel of the vehicle 10A, the receivable frequencies fr1 to frx or the area code according to the travel of the vehicle 10A At least one of the time when Cz is changed and the time when a specific time (fixed time) (for example, one of several seconds to several tens of seconds) has elapsed can be used.

6). Control of the baud rate Rb (specified frequency f1) between the ECUs 30 and 32 In the first embodiment, the process of FIG. 3 is executed as the process of the master 30, and the process of FIG. 8 is executed in the second embodiment. Therefore, the processes shown in FIGS. 3 and 8 may be used in combination. 3 and FIG. 8, when receiving the reception frequency fr from the radio 22 (see FIG. 1), the master side microcomputer 40 receives the current position Pc (or the receivable frequencies fr1 to frx) from the navigation device 90. Alternatively, the area code Cz) may be input.

  In each of the above embodiments, each of the slaves 32a to 32d has changed the baud rate Rb (specified frequency f1) at the same time after a predetermined time has elapsed since the transmission of the reception confirmation to the master 30 (S13 in FIG. 4). However, the timing for changing the baud rate Rb in each of the slaves 32a to 32d is not limited to this. For example, the baud rate Rb may be sequentially changed in each of the slaves 32a to 32d immediately after the reception confirmation is transmitted to the master 30.

7). Others In each of the above embodiments, the master 30 is configured such that the reception frequency fr of the radio 22 (including the receivable frequencies fr1 to frx) and the baud rate Rb (specified frequency f1) in the communication network 20 are aligned (units are aligned). ) Although the specified frequency f1 is set so as not to match, the baud rate Rb (specified frequency f1) may be set so as to avoid the drive frequency for the electric motor as in Patent Document 1. In this case, the baud rate Rb (specified frequency f1) and the drive frequency are set so as to avoid the reception frequency fr of the radio 22, and the specified frequency f1 and the drive frequency are set so that the specified frequency f1 and the drive frequency are not equal to each other. .

  In the first embodiment, the reception frequency fr is input from the radio 22 to the master microcomputer 40. However, as in Patent Document 1, the reception frequency fr (pseudo signal) may be input from an external diagnostic device.

DESCRIPTION OF SYMBOLS 10 ... Vehicle 12 ... Communication apparatus 22 ... Radio (reproducing apparatus)
30 ... Master ECU (predetermined electronic control unit)
32a to 32d ... Slave ECU 34 ... Communication line 40 ... Master side microcomputer (determination means)
f1 ... Specified frequency fr ... Reception frequency nRb ... Multiplication value of baud rate (frequency that becomes a high frequency component)
Rb ... Baud rate (specified frequency, fundamental frequency)

Claims (5)

A vehicle communication device in which a plurality of electronic control devices are connected to a common communication line and communicate with each other with a communication signal of a specified frequency,
The vehicle communication device is obtained by selecting and receiving at least one of a plurality of fixed-frequency radio waves transmitted from the outside of the vehicle, and demodulating the received radio wave among the plurality of radio waves; A playback device that plays back at least the content signal including audio information or video information in the vehicle;
The predetermined electronic control device among the plurality of electronic control devices specifies and specifies a reception frequency that is one or a plurality of the radio waves that the reproduction device is receiving or may receive. Determination means for determining whether or not the communication signal of the specified frequency becomes noise with respect to the signal of the reception frequency;
When the determination unit determines that the communication signal of the specified frequency becomes noise with respect to the signal of the reception frequency, the determination unit transmits a change notification of the specified frequency to all electronic control devices other than the predetermined electronic control device. ,
All electronic control devices other than the predetermined electronic control device change the prescribed frequency sequentially or simultaneously based on the change notification,
The predetermined electronic control device performs subsequent communication at the specified frequency after the change, on condition that response signals from all electronic control devices other than the predetermined electronic control device have been received. Vehicle communication device. The vehicle communication device according to claim 1,
The communication method performed between the plurality of electronic control devices is a baseband method for transmitting a substantially rectangular wave signal at the specified frequency,
The determination unit sets the changed specified frequency so that a fundamental frequency and a frequency that becomes a harmonic component with respect to the fundamental frequency among frequency components included in the substantially rectangular wave do not coincide with the reception frequency. A vehicular communication device. The vehicle communication device according to claim 1,
The communication method performed between the plurality of electronic control devices is a method of modulating a carrier wave of the specified frequency with a signal of a predetermined communication frequency,
The determination means sets the specified frequency after the change so that the center frequency of the carrier wave and the frequency of the bandwidth of the communication frequency with respect to the center frequency do not coincide with the reception frequency. Communication equipment. The vehicle communication device according to any one of claims 1 to 3,
The communication line also serves as a power line for supplying power from the power source of the vehicle to the plurality of electronic control devices,
The communication performed between the plurality of electronic control devices is power line communication for performing communication by superimposing a communication signal of the specified frequency on the power line. The vehicle communication device according to any one of claims 1 to 4,
The reception frequency is a plurality of receivable frequencies that are frequencies of broadcast stations or broadcast channels that can be received corresponding to the current position of the vehicle,
The vehicle communication apparatus according to claim 1, wherein the determination unit determines whether or not the communication signal having the specified frequency becomes noise with respect to the signal having the reception frequency.

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