JP2006213289A - Vehicle-mounted receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle-mounted receiver with a constitution for improving a noise-resistant performance of wireless signals from a mobile device without misoperations such as receipt of tire air pressure monitoring electric waves of other vehicles when other vehicles pass near one's own parked vehicle, judging frequency of signals received at a common antenna according to an on/off condition of an engine, and demodulating the signals from the mobile device and a transmitter/receiver by a demodulating part corresponding in modulating system, because a modulating system of the mobile device for keyless entry can be differentiated from a modulation system of the transmitter/receiver for monitoring the tire air pressure. <P>SOLUTION: This vehicle-mounted receiver 13 receives wireless signals from a mobile device 13 for keyless entry held by a user and wireless signals from TPMS transmitters/receivers 12A-12D for monitoring the air pressure of the tires mounted to a vehicle C. This receiver comprises a common antenna part 24 receiving wireless signals modulated and transmitted in an ASK modulation system from the TPMS transmitters/receivers 12A-12D, an FSK demodulation part 32 demodulating the signals received by the common antenna part 24 according to the FSK modulation system at the time of stopping the engine, and an ASK demodulation part 33 demodulating the signals received by the common antenna part 24 according to the ASK modulation system at the time of starting the engine. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-vehicle receiver, and more particularly to an apparatus that can demodulate a plurality of radio signals modulated by different methods by a single in-vehicle receiver.

  2. Description of the Related Art Conventionally, a keyless entry system capable of locking and unlocking a vehicle door without inserting and operating a key into a keyhole has been provided. For example, a keyless entry system that has been used since the beginning was put into practical use is one in which a door is unlocked / locked by wirelessly communicating with a vehicle by operating a button on a transmitter attached to a key. This type of system does not require a key to be inserted into the keyhole to unlock the door lock, but requires a button operation on the transmitter.

  Therefore, in recent years, a system called passive keyless entry has begun to be put into practical use. In this system, when a user touches a touch sensor attached to a door, a request signal is transmitted from the vehicle, and a response signal including an ID code is automatically wirelessly transmitted from a portable device that has received the request signal. . The vehicle verifies the ID code of the received response signal, and if the authentication matches, the door lock is released.

  On the other hand, vehicles equipped with a tire pressure monitoring device (TPMS) for ensuring safety during traveling are also becoming popular. In the tire pressure monitoring apparatus, a TPMS transceiver is built in each of the front and rear wheels, and tire pressure information is periodically transmitted from the TPMS transceiver to the TPMS receiver for monitoring during engine operation. In Japanese Patent Application Laid-Open No. 2004-189072, a keyless entry system and a tire pressure monitoring device are integrated, but a keyless entry receiving unit and a tire pressure monitoring receiving unit are provided separately. Since it is useless if there are two wireless reception units in one vehicle, it is efficient if it can be shared by one wireless receiver.

However, considering that keyless entry and TPMS are shared by the same receiver, both use the same modulation method. However, when another vehicle passes near its own parked vehicle, There is a problem that when a TPMS radio wave is received and an attempt is made to get into the vehicle with the keyless entry, noise may be mixed into the keyless entry signal to cause a malfunction. After all, considering noise resistance, the current situation is that separate receivers with different specifications must be installed in the keyless entry system and the TPMS.
JP 2004-189072 A

  The present invention has been made in view of the above problems, and it is an object of the present invention to share a receiver while improving noise resistance.

In order to solve the above-mentioned problems, the present invention is a device for receiving a radio signal from a keyless entry portable device possessed by a user and a radio signal from a transceiver for monitoring the pressure of tires mounted on a vehicle. In-vehicle receiver
A shared antenna unit that receives a radio signal that is modulated and transmitted from the portable device, and a wireless signal that is modulated by a modulation scheme different from that of the portable device and transmitted from the transceiver,
A first demodulator that demodulates a signal received by the shared antenna unit when the engine is stopped according to a modulation method of the portable device;
A vehicle-mounted receiver comprising a second demodulator that demodulates a signal received by the shared antenna unit during engine operation according to a modulation scheme of the transceiver.

While the keyless entry is used when the engine is parked and the engine is stopped, the tire pressure monitoring device is used while the engine is running, and the operation timing of both is not duplicated. The idea was to switch the demodulation method using the engine on / off as a trigger.
That is, with the above configuration, the radio signal modulation scheme is determined based on the on / off state of the engine, and the signal from the portable device is demodulated by the first demodulator, while the signal from the transmitter / receiver is demodulated by the second demodulator. Since the demodulating process is adopted, the receiver can be shared by a single unit, and the cost of parts can be reduced.
Furthermore, by making it possible to differentiate the modulation method of the portable device for keyless entry and the modulation method of the transceiver for tire pressure monitoring, when another vehicle passes near the parked vehicle, The tire pressure monitoring radio wave is not received, and the noise resistance performance of the radio signal from the portable device is improved.

  The first demodulator and the second demodulator connected to the output from the shared antenna unit are connected in parallel to each other, and one of the first demodulator and the second demodulator is selectively connected and the other is connected. It is preferable to provide a switching unit that cuts off the circuit, and the switching unit is configured to switch according to the on / off state of the engine.

In addition, the modulation method of the portable device and the transmitter / receiver may be selected from methods such as FSK, ASK, and PSK so as not to overlap.
For example, although ASK requires simple modulation / demodulation hardware, it has a characteristic that it is weak against amplitude changes such as amplitude noise and fading. Therefore, it is preferable to adopt it as a modulation method for a transceiver for tire pressure monitoring with a short communication distance. .
Since FSK judges binary values based on changes in frequency, it is not easily affected by amplitude fluctuations, and the transmission error rate for transmission quality (C / N ratio) is better than that of ASK. It is preferable to adopt the modulation method for a portable device having a longer communication distance.

The radio signal from the portable device and the radio signal from the transceiver are different in frequency,
When the engine is stopped, the frequency of the signal received by the shared antenna unit is converted to a demodulation frequency according to the radio frequency of the portable device and output to the first demodulating unit side, while when the engine is operating, according to the radio frequency of the transceiver It is preferable to provide frequency conversion means for converting to the demodulation frequency and outputting it to the second demodulator.

  With the above configuration, even if the radio frequency from the portable device for keyless entry and the radio frequency from the transceiver for tire pressure monitoring are different, it can be demodulated by one receiver, and the receiver can be shared. Can be achieved. In addition, by making the radio frequency different between the portable device and the transceiver, the noise resistance performance of both radio signals is further improved.

  As is clear from the above description, according to the present invention, the modulation method of the portable device for keyless entry and the modulation method of the transceiver for tire pressure monitoring can be made different. When other vehicles pass through the vehicle, there is no malfunction by receiving the tire pressure monitoring radio waves of the other vehicles, and the noise resistance performance of the radio signal from the portable device is improved. In addition, the frequency of the signal received by the shared antenna unit is determined according to the on / off state of the engine, and the signal from the portable device and the transceiver is demodulated by the demodulating unit corresponding to the modulation method. Can be shared.

Embodiments of the present invention will be described with reference to the drawings.
1 and 2 show the RKE / TPMS system 10 of the first embodiment, which is incorporated in a passive keyless entry portable device 11 possessed by a user and a four-wheel tire of a vehicle, respectively, and detects tire air pressure. TPMS transceivers 12 </ b> A to 12 </ b> D and an in-vehicle receiver 13 that is mounted on a vehicle and receives radio signals from the portable device 11 and radio signals from the TPMS transceivers 12 </ b> A to 12 </ b> D are provided.

  The vehicle C constructs a body LAN using the wire harness W / H1 as a transmission medium, and controls a door control ECU 35 that drives and controls the door lock device 36, a display device 38, and an alarm device 39 in the LAN. A TPMS control ECU 37 is connected, and the in-vehicle receiver 13 is connected to the LAN via the door control ECU 35. A drive system LAN using the wire harness W / H2 as a transmission medium is also constructed via the gateway device 40, and an engine ECU 41 is connected to the LAN.

  The portable device 11 generates an ID code for performing an authentication operation in the LF receiver 14 that receives a request signal in the LF band wirelessly transmitted from a transmitter (not shown) of the vehicle C and the door control ECU 35 and performs transmission / reception control. And a UHF transmitter 16 that has a crystal unit 17 for transmission and modulates a signal including an ID code by a FSK (Frequency Shift Keying) method and wirelessly transmits it with a UHF charged wave. .

  The TPMS transceivers 12A to 12D include a tire pressure sensor 19, a control unit 20 that performs transmission / reception control, an LF reception unit 21 that receives a request signal in the LF band that is wirelessly transmitted from a transmitter (not shown) of the vehicle C, and a mobile phone. UHF transmission that has a crystal oscillator 23 that transmits the same frequency as the machine 11 and that modulates a signal including tire air pressure information detected by the tire pressure sensor 19 using an ASK (Amplitude Shift Keying) method and wirelessly transmits it using a UHF charged wave Part 22.

  The in-vehicle receiver 13 includes a shared antenna unit 24 that receives radio signals from the portable device 11 and the TPMS transceivers 12A to 12D, an amplifier 25, a bandpass filter unit 26 that filters frequency signals other than the UHF band, The frequency conversion means 29 that converts the frequency of the received signal that has passed through the path filter unit 26 into a demodulation frequency, the A / D conversion unit 30, and demodulation processing according to the modulation method (FSK method) of the portable device 11 when the engine is stopped An FSK demodulator (first demodulator) 32 and an ASK demodulator (second demodulator) connected in parallel with the FSK demodulator 32 and performing demodulation processing according to the modulation scheme (ASK scheme) of the transceivers 12A to 12D when the engine is operating 33, a relay 31 that selectively connects one of the FSK demodulator 32 and the ASK demodulator 33, and door control of the demodulated data And an output unit 34 for outputting the CU35.

The relay 30 is switched and driven by a command from the engine ECU 41, and is controlled to connect the FSK demodulator 32 to the circuit when the engine is stopped and to connect the ASK demodulator 33 to the circuit when the engine is running.
Further, the frequency conversion unit 29 mixes the frequency transmitted from the crystal unit 27 with the frequency of the received signal that has passed through the bandpass filter unit 26 and the crystal unit 27 that generates a constant frequency, and performs demodulation for IF. And a mixer unit 28 for outputting a signal (intermediate frequency signal).

Next, the operation of the in-vehicle receiver 13 will be described.
First, a processing procedure of a signal transmitted from the portable device 11 will be described.
When the LF reception unit 14 of the portable device 11 possessed by the user receives a request signal from the vehicle C in the communication area around the vehicle C while the engine is stopped, the control unit 15 sends data including the ID code to the UHF transmission unit 16. Entered. In the UHF transmission unit 16, data including an ID code is put on a carrier wave (for example, 300.1 MHz) generated by the crystal unit 17 and wirelessly transmitted by the FSK modulation method.

  This wireless signal is received by the shared antenna unit 24 of the in-vehicle receiver 13, passes through the band pass filter unit 26 through the amplifier 25, and is input to the mixer unit 28. A signal having a frequency (for example, 300 MHz) transmitted from the crystal resonator 27 is inserted into the mixer unit 28 with respect to the signal input from the bandpass filter unit 26, and a difference between the signals is obtained. A 100 kHz IF signal is output.

  The IF signal is converted from analog data to digital data in the A / D converter 30. Since the relay 31 is circuit-connected to the FSK demodulator 32 when the engine is stopped, the FSK demodulator 32 performs demodulation processing and outputs demodulated data to the door control ECU 35 via the output unit 34. The door control ECU 34 checks whether the ID code included in the received demodulated data matches its own ID code. If the ID code matches, the door control ECU 34 instructs the door lock device 36 to unlock the door lock.

Next, a processing procedure of signals transmitted from the TPMS transceivers 12A to 12D will be described.
The TPMS control ECU 37 sequentially transmits request signals to each of the four TPMS transmitters / receivers 12A to 12D via an in-vehicle transmitter (not shown) while the engine is running, and the TPMS transmitters / receivers 12A to 12D The signal transmission / reception timing is shifted. The TPMS transmitter / receiver 12 </ b> A that has received the request signal by the LF receiver 21 inputs a signal including air pressure data detected by the tire pressure sensor 19 to the UHF transmitter 22 by the controller 20. In the UHF transmission unit 22, a signal including air pressure data is put on a carrier wave (for example, 300.1 MHz) generated by the second crystal unit 23 and wirelessly transmitted by the ASK modulation method.

  This wireless signal is received by the shared antenna unit 24 of the in-vehicle receiver 13, passes through the band pass filter unit 26 through the amplifier 25, and is input to the mixer unit 28. A signal having a frequency (for example, 300 MHz) transmitted from the crystal resonator 27 is inserted into the mixer unit 28 with respect to the signal input from the bandpass filter unit 26, and a difference between the signals is obtained. A 100 kHz IF signal is output.

  The IF signal is converted from analog data to digital data in the A / D converter 30. Since the relay 31 is circuit-connected to the ASK demodulator 33 when the engine is in operation, the ASK demodulator 33 performs demodulation processing and outputs demodulated data to the door control ECU 35 via the output unit 34. The door control ECU 35 transmits the demodulated data to the destination TPMS control ECU 37 via the LAN. The TPMS control ECU 37 determines that the tire pressure is abnormal when the received tire pressure is less than or equal to a predetermined threshold value, instructs the alarm device 39 to sound an alarm alarm, and instructs the display device 38 to display a warning. Do.

  According to the above configuration, the modulation method from the portable device 11 for keyless entry and the modulation method from the TPMS transceivers 12A to 12D for tire pressure monitoring can be made different. The monitoring radio wave is not received, the noise resistance performance of the radio signal from the portable device 11 is improved, and malfunction can be prevented. Further, by switching the relay 31 by command from the engine ECU 41 according to the on / off of the engine, the FSK demodulator 32 or the ASK demodulator 33 is selected according to the modulation method of the received signal, and the in-vehicle receiver 13 is carried. It can be shared by the machine 11 and the TPMS transceiver 12.

FIG. 3 shows a second embodiment.
The difference from the first embodiment is that the radio frequency of the portable device 11 ′ is different from the radio frequency of the TPMS transceiver 12 ′.

In the portable device 11 ′, the first crystal resonator 50 for transmission is provided in the UHF transmitter 16.
The TPMS transceiver 12 ′ is provided with a second crystal resonator 51 that transmits a frequency different from that of the first crystal resonator 50 to the UHF transmitter 22.

The in-vehicle receiver 13 ′ includes frequency conversion means 56 that converts the frequency of the received signal that has passed through the bandpass filter unit 26 into a demodulation frequency.
The frequency conversion means 56 includes a first crystal resonator 52 corresponding to the transmission frequency of the portable device 11 and a second crystal resonator corresponding to the transmission frequency of the TPMS transceiver 12 with a different transmission frequency from the first crystal resonator 52. 53 and a mixer which outputs a IF signal (demodulation frequency) by mixing and differing the frequency transmitted from the first crystal unit 52 or the second crystal unit 53 to the frequency of the received signal transmitted through the band-pass filter unit 26. And a relay 55 that selectively connects one of the first crystal unit 52 and the second crystal unit 53 to the mixer unit 54.
The relay 55 is switched and driven by a command from the engine ECU 41 so that the first crystal unit 52 is connected to the mixer unit 54 when the engine is stopped, and the second crystal unit 53 is connected to the mixer unit 54 when the engine is operating. It is set as the structure which performs control.
Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.

Next, the operation of the in-vehicle receiver 13 ′ will be described.
First, a processing procedure of a signal transmitted from the portable device 11 ′ will be described.
When the LF reception unit 14 of the portable device 11 ′ possessed by the user receives a request signal from the vehicle C in the communication area around the vehicle C while the engine is stopped, the control unit 15 transmits the data including the ID code to the UHF transmission unit 16. Is input. In the UHF transmission unit 16, data including an ID code is put on a carrier wave (for example, 300.1 MHz) generated by the crystal unit 50 and wirelessly transmitted by the FSK modulation method.

  This radio signal is received by the shared antenna unit 24 of the in-vehicle receiver 13 ′, passes through the band pass filter unit 26 through the amplifier 25, and is input to the mixer unit 54. Since the relay 55 connects the first crystal unit 52 to the mixer unit 54 when the engine is stopped, the mixer unit 54 receives the signal input from the bandpass filter unit 26 from the first crystal unit 52. A signal having a frequency to be transmitted (for example, 300 MHz) is inserted, and a difference between each other is taken to output an IF signal of 100 kHz serving as an intermediate frequency. Since the subsequent operation is the same as that of the first embodiment, description thereof is omitted.

Next, a processing procedure for signals transmitted from the TPMS transceivers 12A ′ to 12D ′ will be described.
The TPMS transceiver 12A ′ that has received the request signal by the LF receiver 21 inputs a signal including the air pressure data detected by the tire pressure sensor 19 to the UHF transmitter 22 by the controller 20. In the UHF transmission unit 22, a signal including air pressure data is put on a carrier wave (for example, 310.1 MHz) generated by the second crystal resonator 51 and wirelessly transmitted by the ASK modulation method.

  This wireless signal is received by the shared antenna unit 24 of the in-vehicle receiver 13 ′, passes through the band-pass filter unit 26 through the amplifier 25, and is input to the mixer unit 54. Since the relay 55 connects the second crystal unit 53 to the mixer unit 54 when the engine is in operation, the mixer unit 54 receives the second crystal unit 53 in response to the signal input from the bandpass filter unit 26. A signal having a frequency (for example, 310 MHz) transmitted from is inserted, and by taking a difference between them, an IF signal of 100 kHz serving as an intermediate frequency is output. Since the subsequent operation is the same as that of the first embodiment, description thereof is omitted.

  With the above configuration, even if the radio frequency from the portable device 11 ′ is different from the radio frequency from the TPMS transceivers 12A ′ to 12D ′, it can be demodulated by one on-vehicle receiver 13 ′. The machine 13 'can be shared. Further, by making the radio frequency different between the portable device 11 ′ and the TPMS transceivers 12 </ b> A ′ to 12 </ b> D ′, the noise resistance performance of both radio signals is further improved.

FIG. 4 shows a third embodiment.
The difference from the second embodiment is that the frequency conversion means 59 of the in-vehicle receiver 13 ″ changes the frequency by the frequency adjustment circuit 58 with one crystal resonator 57 as one.

  The frequency converting means 59 mixes the frequency transmitted from the crystal resonator 57 with the frequency of the crystal resonator 57 that transmits a predetermined frequency and the frequency of the received signal that has passed through the band-pass filter unit 26 to generate an IF signal (for demodulation). Frequency) and a frequency adjustment circuit 58 for adjusting the vibration frequency of the crystal resonator 57. The frequency adjusting circuit 58 is configured to change the frequency transmitted from the crystal unit 57 when the engine is stopped and when the engine is operating according to a command from the engine ECU 41. Since other configurations are the same as those of the second embodiment, the same reference numerals are given and description thereof is omitted.

Hereinafter, a specific example of the frequency adjustment circuit 58 will be shown.
In the frequency adjustment circuit 58 of FIG. 5, a capacitor 60 is connected in parallel to a crystal unit 57 via a relay 61. The switching of the relay 61 is driven by a command from the engine ECU 41, and the relay 61 is closed when the engine is stopped, while the relay 61 is opened when the engine is operating. As a result, the transmission frequency generated by the crystal unit 57 can be made different when the engine is stopped and when the engine is running.
Further, the frequency adjustment circuit 58 of FIG. 6 has a variable capacitor 62 connected in parallel to the crystal unit 57, and controls the capacity of the variable capacitor 62 to be changed between when the engine is stopped and when the engine is operating according to a command from the engine ECU 41. Do. As a result, the transmission frequency generated by the crystal unit 57 can be made different when the engine is stopped and when the engine is running.

1 is a perspective view showing a vehicle according to a first embodiment of the present invention. It is a system configuration figure containing the in-vehicle receiver of a 1st embodiment. It is a system block diagram containing the vehicle-mounted receiver of 2nd Embodiment. It is a system block diagram containing the vehicle-mounted receiver of 3rd Embodiment. It is drawing which shows the specific example of a frequency adjustment circuit. It is drawing which shows another specific example of a frequency adjustment circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Portable machine 12A-12D TPMS transmitter / receiver 13 Car-mounted receiver 24 Shared antenna part 27 Crystal oscillator 28 Mixer part 29,56,59 Frequency conversion means 30 A / D conversion part 31 Relay 32 FSK demodulation part (1st demodulation part)
33 ASK demodulator (second demodulator)
41 Engine ECU
C vehicle

Claims (2)

A vehicle-mounted receiver that receives a radio signal from a portable device for keyless entry possessed by a user and a radio signal from a transceiver for monitoring the pressure of a tire mounted on a vehicle;
A shared antenna unit that receives a radio signal that is modulated and transmitted from the portable device, and a wireless signal that is modulated by a modulation scheme different from that of the portable device and transmitted from the transceiver,
A first demodulator that demodulates a signal received by the shared antenna unit when the engine is stopped according to a modulation method of the portable device;
A vehicle-mounted receiver, comprising: a second demodulator that demodulates a signal received by the shared antenna unit when the engine is operating according to a modulation scheme of the transceiver. The radio signal from the portable device and the radio signal from the transceiver are different in frequency,
When the engine is stopped, the frequency of the signal received by the shared antenna unit is converted to a demodulation frequency according to the radio frequency of the portable device and output to the first demodulator side, while when the engine is operating, according to the radio frequency of the transceiver The in-vehicle receiver according to claim 1, further comprising frequency conversion means for converting to the demodulation frequency and outputting the frequency to the second demodulation unit.

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