JP2006214240A - On-vehicle receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver to be used in common while improving its noise resistance. <P>SOLUTION: One on-vehicle receiver 10 receives a radio signal from a keyless entry portable machine 11 and a radio signal from a TPMS transceiver 12 mounted on a vehicle C for monitoring pneumatic pressure in a tire. It comprises a common antenna part 24 for receiving the radio signal modulated and transmitted from the portable machine 11 and the radio signal modulated with a frequency different from that of the portable machine 11 and transmitted from the TPMS transceiver 12, a frequency converting means 31 for converting the frequency of the signal received by the common antenna part 24 into a demodulation frequency (an IF frequency) in accordance with the radio frequency of the portable machine 11 when stopping an engine and for converting the frequency of the signal received by the common antenna part 24 into a demodulation frequency in accordance with the radio frequency of the TPMS transceiver 12 when operating the engine, and a demodulating part 33 for demodulating the signal whose frequency is converted by the frequency converting means 31. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle-mounted receiver, and more particularly to a device that can demodulate a plurality of radio signals modulated at different frequencies with a single 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 disclosed in Japanese Patent Application Laid-Open No. 2000-352243 has been put into practical use. In the passive keyless entry system, a request signal is transmitted from the vehicle when the user touches a touch sensor attached to the door, and a response signal including an ID code is automatically wirelessly transmitted from the portable device that has received the request signal. Is done. 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 will use the same frequency band, but 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 2000-352243 A 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 radio signal that is modulated at a frequency different from that of the portable device and transmitted from the transceiver,
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, while the frequency of the signal received by the shared antenna unit is operated according to the radio frequency of the transceiver when the engine is operating. Frequency conversion means for converting to the demodulation frequency;
A vehicle-mounted receiver comprising a demodulator that demodulates a signal frequency-converted by the frequency converter.

While the keyless entry is used when the parked 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 reception frequency with the engine on / off as a trigger.
That is, with the above configuration, the radio frequency from the portable device for keyless entry and the radio frequency from the transceiver for tire pressure monitoring can be made different so that another vehicle has passed near the parked vehicle. Occasionally, the tire pressure monitoring radio waves of other vehicles are not received, and the noise resistance performance of radio signals from portable devices is improved.
In addition, the frequency conversion means can determine the frequency of the radio signal before conversion using the engine on / off as a trigger, and convert the signal of both the portable device and the transceiver to a demodulation frequency that can be processed by the demodulator. Therefore, the receiver can be shared by a single unit and resources can be effectively used.

  The frequency conversion means includes a first crystal resonator, a second crystal resonator having a different transmission frequency from the first crystal resonator, and the frequency of the signal received by the shared antenna unit. A mixer unit for mixing and differing frequencies transmitted from the second crystal unit and outputting the demodulation frequency; and connecting the first crystal unit to the mixer unit when the engine is stopped while the engine unit is operating. It is preferable that a connection switching unit for connecting two crystal units to the mixer unit is provided.

  With the above configuration, by mixing the frequency generated by the crystal resonator in the mixer unit and taking the difference, the signal received by the shared antenna unit is converted to a demodulation frequency that can be processed by the demodulation unit. At this time, a first crystal unit having a frequency corresponding to the portable device is prepared, and a second crystal unit having a frequency corresponding to the transmitter / receiver is prepared. By switching by the connection switching unit, it is possible to uniformly convert signals of different frequencies received by the shared antenna unit into specific demodulation frequencies. In other words, the frequency of the signal from the portable device and the frequency of the signal from the transceiver are different from each other, but by switching the connection to the mixer unit of the crystal resonator, it is appropriately converted to the required demodulation frequency. Can be output.

  The frequency converting means includes a crystal unit, a mixer unit that mixes a frequency transmitted from the crystal unit with a frequency of a signal received by the shared antenna unit, and outputs the demodulation frequency, and the crystal unit A configuration including a frequency adjusting unit that makes the frequency transmitted from the child different between when the engine is stopped and when the engine is operating is also preferable.

With the above configuration, even if two types of crystal resonators are not provided as described above, the frequency can be changed by switching the frequency of the transmission frequency from one crystal resonator by using the frequency adjustment unit as an on / off of the engine as a trigger. Thus, it is possible to appropriately convert signals from portable devices or transmitters / receivers having different frequencies into a required demodulation frequency.
As the frequency adjusting unit, for example, a configuration in which a capacitor is connected in parallel so as to be able to be cut off with respect to a crystal resonator, and the cut-off / connection of the circuit is switched using the on / off of the engine as a trigger is suitable. Or it is suitable also as a structure which changes the capacity | capacitance of a variable capacitor by connecting a variable capacitor with a crystal oscillator in parallel and triggering on / off of an engine as a trigger.

  As is clear from the above description, according to the present invention, the radio frequency from the keyless entry portable device and the radio frequency from the tire pressure monitoring transceiver can be made different, so that the self-parked vehicle When another vehicle passes near the vehicle, it does not malfunction by receiving a tire pressure monitoring radio wave of the other vehicle, and the noise resistance performance of the wireless signal from the portable device is improved. In addition, the frequency conversion means can determine the frequency of the signal received by the shared antenna unit using the engine on / off as a trigger, and can convert the signals of both the portable device and the transceiver to the demodulation frequency processed by the demodulation unit. Therefore, the receiver 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. The LAN controls a door control ECU 36 that drives and controls a door lock device 37, a display device 39, and an alarm device 40. A TPMS control ECU 38 is connected, and the in-vehicle receiver 13 is connected to the LAN via the door control ECU 36. In addition, a drive system LAN using the wire harness W / H2 as a transmission medium is also constructed via the gateway device 41, and an engine ECU 42 is connected to the LAN.

  The portable device 11 generates an ID code for performing an authentication operation between the LF receiving unit 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 34 and performs transmission / reception control. And a UHF transmitter 16 that has a first crystal resonator 16 for transmission and modulates a signal including an ID code in the UHF band and wirelessly transmits the signal.

  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 an LF band request signal wirelessly transmitted from a transmitter (not shown) of the vehicle C, A UHF transmission unit 22 that has a second crystal unit 23 having a transmission frequency different from that of the one crystal unit 17 and that wirelessly transmits a signal including tire pressure information detected by the tire pressure sensor 19 in the UHF band. It has.

  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, A frequency converter 31 that converts the frequency of the received signal that has passed through the path filter unit 26 into a demodulation frequency, an A / D converter 32, and a demodulator that performs demodulation processing according to the modulation schemes of the portable device 11 and the TPMS transceiver 12 33 and an output unit 36 that outputs demodulated data to the door control ECU 36.

The frequency conversion means 31 includes a first crystal resonator 28 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 28. 29 and a mixer that outputs a IF signal (demodulation frequency) by mixing and differing the frequency transmitted from the first crystal resonator 27 or the second crystal resonator 28 to the frequency of the received signal transmitted through the band-pass filter unit 26. And a relay 30 (connection switching unit) that selectively connects either the first crystal unit 27 or the second crystal unit 28 to the mixer unit 29.
The switching of the relay 30 is driven by a command from the engine ECU 42, and the first crystal unit 27 is connected to the mixer unit 29 when the engine is stopped, and the second crystal unit 28 is connected to the mixer unit 29 when the engine is operating. In this way, the switching control is performed.

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 receiver 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 transmitter 16. Entered. The UHF transmitter 16 wirelessly transmits data including an ID code on a carrier wave (for example, 300.1 MHz) generated by the first crystal unit 17.

  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 29. Since the relay 30 connects the first crystal unit 27 to the mixer unit 29 when the engine is stopped, the mixer unit 29 receives the signal input from the bandpass filter unit 26 from the first crystal unit 27. 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.

  The IF signal is converted from analog data to digital data by the A / D conversion unit 32, demodulated by the demodulation unit 33 according to the modulation method of the portable device 11, and input to the door control ECU 36 via the output unit 34. The door control ECU 36 checks whether the ID code included in the received demodulated data matches its own ID code, and if it matches, instructs the door lock device 37 to unlock the door lock.

Next, a processing procedure of signals transmitted from the TPMS transceivers 12A to 12D will be described.
While the engine is running, the TPMS control ECU 36 sequentially transmits a request signal to each of the four TPMS transceivers 12A to 12D via an in-vehicle transmitter (not shown), and the TPMS transceivers 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. The UHF transmitter 22 wirelessly transmits a signal including air pressure data on a carrier wave (for example, 310.1 MHz) generated by the second crystal unit 23.

  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 29. Since the relay 30 connects the second crystal unit 28 to the mixer unit 29 when the engine is in operation, the mixer unit 29 receives the second crystal unit 28 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.

  The IF signal is converted from analog data to digital data in the A / D converter 32, demodulated in the demodulator 33 according to the modulation scheme of the transceiver 12, and input to the door control ECU 36 via the output unit 34. The door control ECU 36 transmits the demodulated data to the TPMS control ECU 38 that is the destination via the LAN. The TPMS control ECU 38 determines that it is abnormal when the received tire pressure is less than or equal to a predetermined threshold value, and instructs the alarm device 40 to sound an alarm alarm and also instructs the display device 39 to display a warning. Do.

  According to the above configuration, the radio frequency from the keyless entry portable device 11 and the radio frequency from the tire pressure monitoring TPMS transceiver 12 can be made different. , The noise resistance performance of the radio signal from the portable device 11 is improved, and malfunction can be prevented. In addition, by switching from the relay 30 by commanding from the engine ECU 42 according to the on / off state of the engine, the frequency conversion can be performed into an IF signal that can be processed by the demodulator 33 according to the frequency of the received signal. The device 13 can be shared by the portable device 11 and the TPMS transceiver 12.

FIG. 3 shows a second embodiment.
The difference from the first embodiment is that the frequency conversion means 52 of the in-vehicle receiver 13 ′ changes the frequency by the frequency adjustment circuit 51 with one crystal resonator 50 as one.

  The frequency conversion means 52 mixes the frequency transmitted from the crystal resonator 50 with the frequency of the crystal resonator 50 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). A frequency adjustment circuit 51 that adjusts the vibration frequency of the crystal unit 50. The frequency adjustment circuit 51 is configured to change the frequency transmitted from the crystal unit 50 when the engine is stopped and when the engine is operating according to a command from the engine ECU 42. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.

Hereinafter, a specific example of the frequency adjustment circuit 51 will be shown.
In the frequency adjustment circuit 51 of FIG. 4, a capacitor 54 is connected in parallel to the crystal unit 50 via a relay 55. The switching of the relay 55 is driven by a command from the engine ECU 42, and the relay 55 is closed when the engine is stopped and the relay 55 is opened when the engine is operating. As a result, the transmission frequency generated by the crystal unit 50 can be made different between when the engine is stopped and when the engine is running.
In addition, the frequency adjustment circuit 51 of FIG. 5 connects the variable capacitor 57 in parallel to the crystal unit 50, and performs control to change the capacity of the variable capacitor 57 when the engine is stopped and when the engine is operating according to a command from the engine ECU. Do. As a result, the transmission frequency generated by the crystal unit 50 can be made different between 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 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, 13 'Car-mounted receiver 24 Shared antenna part 27 1st crystal oscillator 28 2nd crystal oscillator 29 Mixer part 30 Relay (connection switching part)
31, 52 Frequency conversion means 33 Demodulator 42 Engine ECU
50 Crystal unit 51 Frequency adjustment circuit C Vehicle

Claims (3)

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 radio signal that is modulated at a frequency different from that of the portable device and transmitted from the transceiver,
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, while the frequency of the signal received by the shared antenna unit is operated according to the radio frequency of the transceiver when the engine is operating. A frequency converting means for converting to the demodulation frequency;
A vehicle-mounted receiver comprising: a demodulator that demodulates a signal frequency-converted by the frequency converter.   The frequency conversion means includes a first crystal resonator, a second crystal resonator having a different transmission frequency from the first crystal resonator, and the frequency of the signal received by the shared antenna unit. A mixer unit for mixing and differing frequencies transmitted from the second crystal unit and outputting the demodulation frequency; and connecting the first crystal unit to the mixer unit when the engine is stopped while the engine unit is operating. The in-vehicle receiver according to claim 1, further comprising a connection switching unit that connects two crystal units to the mixer unit.   The frequency converting means includes a crystal unit, a mixer unit that mixes a frequency transmitted from the crystal unit with a frequency of a signal received by the shared antenna unit, and outputs the demodulation frequency, and the crystal unit The on-vehicle receiver according to claim 1, further comprising: a frequency adjusting unit that makes a frequency transmitted from the child different between when the engine is stopped and when the engine is operating.

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