JPH09224289A - Remote control signal transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a transmitter with a simple circuit structure to generate a transmission signal spread over a wide frequency band and to simplify the circuit structure of a receiver. SOLUTION: The remote control signal transmitter uses a vibrator 31 to send a modulated signal in air as a radio wave. The vibrator 31 has plural surface acoustic wave elements 311, 312. The resonance frequencies f1, f2 of the surface acoustic wave elements 311, 312 differ from each other but are close to each other. Thus, the transmission signal diffused over a wide frequency band is generated with a simple circuit configuration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote control signal transmitter for remotely controlling a load such as a door lock actuator of a vehicle by using a radio signal, and more particularly to a surface acoustic wave element (SAW / Surface Acoustic).
The present invention relates to a technique for improving a remote control signal transmission device that uses a vibrator formed of Wave Device or the like and sends a modulation signal modulated by the vibrator into a radio wave and sends it to the air.

[0002]

2. Description of the Related Art A conventional remote control signal transmitter of this type is disclosed in Japanese Utility Model Laid-Open No. 7-14787.
This conventional remote control signal transmitting device has a vibrator having a surface acoustic wave element as in the present invention, and has a circuit structure in which a modulation signal modulated by the vibrator is transmitted as an electric wave and sent to the air. This type of unlicensed remote control signal transmitter that transmits weak radio waves must have an electric field strength of 500 [μV / m] or less at a position 3 [m] away from the radio wave transmission source according to the radio regulations in Japan. There is a regulation such that the oscillation frequency must be 322 [MHz] or less.

[0003]

However, when transmitting a weak radio wave like this type of remote control signal transmitting device, the signal level of external noise, white noise, etc. and the transmission signal level are close to each other, and noise is generated. The transmission could be adversely affected. When the noise signal level and the transmission signal level are close to each other in this way, as a general communication method for reducing the influence of noise, for example, a spread spectrum communication method or a direct spread (Direct Sequence) communication method is used.
Spread communication system and frequency modulation (Freq)
uency Modulation) communication method and the like. These communication systems are communication systems in which the influence of noise is reduced by widely spreading the frequency band, but require a complicated circuit structure. In particular, when incorporating such a complicated circuit structure into a radio key carried by a vehicle occupant on the transmitter side, it is necessary to develop a dedicated IC or the like in order to accommodate electronic components in a limited narrow space. In addition to the high cost of the device, the receiving device also requires a special circuit structure such as a despread demodulator.

The present invention solves the above-mentioned problems, and it is possible to generate a transmission signal diffused in a wide frequency band by a transmitter having a simple circuit structure and simplify the circuit structure of a receiver. An object of the present invention is to provide a remote control signal transmitting device that can be used.

[0005]

In order to solve the above-mentioned problems, first of all, the invention according to claim 1 is a remote-control signal transmitting apparatus for transmitting a modulated signal, which is modulated by using a vibrator, to the air and sends it to the air. The oscillator has multiple elements, and the resonance frequency of each element is set to be different so that at least some of the frequency spectrum distributions of the oscillation frequency determined by each element overlap each other, and the remote control signal transmission is set close to each other. Provide a device.

Further, the invention according to claim 2 provides a remote control signal transmitting apparatus in which the vibrator has a plurality of surface acoustic wave elements.

According to a third aspect of the present invention, there is provided a remote control signal transmitting device in which the plurality of surface acoustic wave elements are formed on the surface of a crystal piece of one piezoelectric medium.

Further, the invention according to claim 4 provides a remote control signal transmitting device in which a vibrator having the plurality of elements is built in a radio wave key carried by an occupant of a vehicle.

[0009]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described with reference to FIGS. The remote control signal transmitting device A shown in FIG. 1 is called a radio wave key carried by a vehicle occupant, and has a built-in operation switch 1, a signal generating circuit 3, a modulating circuit 3, an antenna 4, and a DC power supply 5.

First, the operation switch 1 is a switch operated by an occupant of a vehicle carrying the remote control signal transmission device A. For example, the lock operation switch 11 operated when the vehicle door is to be locked, and the vehicle door is unlocked. An unlocking operation switch 12 that is operated when it is desired to lock is provided.
The operation switch 1 is connected to the signal generating circuit 2.

The signal generation circuit 2 is a circuit composed of, for example, a microcomputer, and outputs a coded signal in response to the operation of the operation switch 1 to a PWM (Pulse W).
It is programmed to derive by an appropriate method such as the idth Modulation method. For example, when the occupant carrying the remote control signal transmitter A operates the lock operation switch 11, the signal generation circuit 2 derives a coded signal in which a unique ID code and a command code indicating the lock operation are combined. Further, for example, when an occupant operates the unlock operation switch 12, the signal generating circuit 2 derives a coded signal in which a unique ID code and a command code indicating the unlock operation are combined. The signal generation circuit 2 is connected to the modulation circuit 3.

The modulation circuit 3 is a circuit which modulates and derives a coded signal derived by the signal generation circuit 2 using the oscillator 31, and includes first and second surface acoustic wave elements 311 and 312.
And a first and second transistor 32
1, 331, capacitors 322, 323, 332, 33
3, 342, the resistors 324, 325, 334, 335 and the coil 341 are connected as shown in FIG.

Here, in the vibrator 31, the first and second surface acoustic wave elements 311 and 312 are integrally formed on the surface of a crystal piece of one piezoelectric medium (eg, quartz) by using a thin film deposition technique. The space occupied by the vibrator 31 itself can be reduced. In this case, the first in one housing,
The second surface acoustic wave elements 311 and 312 are housed. Further, the first and second surface acoustic wave elements 311 and 312 can be separately provided on the surface of each piezoelectric medium, but in that case, the first and second surface acoustic wave elements 311 and 312 can be formed. Each of the 312 is housed in an individual casing, so that it is necessary to secure a large occupied space for the vibrator 31 itself, and the size of the radio wave key carried by a vehicle occupant becomes large.

The modulation circuit 3 can perform Colpitts oscillation or Hartley oscillation operation by the above connection configuration. The oscillation frequency at this time matches the resonance frequencies f1 and f2 of the first and second surface acoustic wave elements 311 and 312.

The resonance frequency f1 of the first surface acoustic wave device 311 connected to the first transistor 321 is, for example, 30.
The resonance frequency f2 of the second surface acoustic wave element 312 connected to the second transistor 331 is set to 0 [MHz], for example, 301 [MHz] close to the resonance frequency f1 of the surface acoustic wave element 311. . Thereby, the first
At least a part of the frequency spectrum distribution of the oscillation frequency on the side of the transistor 321 and the frequency spectrum distribution of the oscillation frequency on the side of the second transistor 331 are overlapped with each other so that two frequencies f1 as shown by a solid line a in FIG.
The mountain-shaped electric characteristics having the peak at f2 are obtained. still,
The characteristic indicated by the solid line b in FIG. 2 is white noise. Further, the coil 341 and the capacitor 342 constitute a spurious removal file. The modulation circuit 3 is connected to the antenna 4.

The antenna 4 is a portion for converting the modulated signal derived by the modulating circuit 3 into a radio wave and transmitting it into the air.
The first and second surface acoustic wave elements 311 and 312 of the first antenna are the same in number as the first and second pattern antennas 41 and 42. The first and second pattern antennas 41,
42 is a shape suitable for emitting a radio wave, for example, an arc shape, by processing a part of the conductor pattern on the substrate on which the operation switch 1, the signal generating circuit 2 and the modulating circuit 3 are mounted. doing.

Next, the operation of the first embodiment will be described. First, when a vehicle occupant operates the operation switch 1, the signal generation circuit 2 outputs a coded signal corresponding to the operation of the operation switch 1 to the modulation circuit 3. The modulation circuit 3 oscillates at the "1" level portion of the coded signal input from the signal generation circuit 2. The oscillation frequency f1 on the side of the first transistor 321 at this time is, for example, 300 [MHz],
The oscillation frequency f2 on the second transistor 331 side is, for example, 301 [MHz]. Therefore, the first and second transistors connected to the first and second transistors 321 and 331, respectively.
The pattern antennas 41 and 42 send out radio waves of, for example, oscillation frequencies f1, f2 = 300, 301 [MHz], which are interrupted by the coded signal output from the signal generation circuit 2, into the air.

Next, a second embodiment of the present invention will be described with reference to FIGS. The basic configuration of the remote control signal transmitting apparatus A shown in FIG. 3 is similar to that of the first embodiment shown in FIG. 1, and only the different configuration will be described here. In the case of the second embodiment, the oscillator 31 has the third surface acoustic wave element 313 in addition to the first and second surface acoustic wave elements 311 and 312, and accordingly, the third transistor 351, the capacitor 342, and the like. 353, resistors 354, 355, and a third
The pattern antenna 43 is added to that of the first embodiment. The coil 341 is patterned on the substrate similarly to the antenna 4. Here, the oscillator 31
Is similar to the oscillator 31 of the first embodiment, the first, the second, and the third are formed on the surface of the crystal piece of one piezoelectric medium (for example, quartz crystal).
The surface acoustic wave elements 311, 312, 313 can be integrally formed by using a thin film deposition technique.

The resonance frequency f3 of the third surface acoustic wave element 313 connected to the third transistor 351 is the resonance frequency f1 of each of the first and second surface acoustic wave elements 311 and 312.
At a resonance frequency close to f2, for example, f3 = 302 [MH
z] is set. As a result, each transistor 32
The frequency spectrum distributions of the oscillating frequencies of 1,331,351 are overlapped with each other, and as shown by the solid line a in FIG.
The mountain-shaped electrical characteristics having the peaks at the two frequencies f1, f2, and f3 are obtained. The operation is basically the same as that of the first embodiment, and the description thereof will be omitted.

Next, a third embodiment of the present invention will be described with reference to FIGS. The basic configuration of the remote control signal transmitting apparatus A shown in FIG. 5 is similar to that of the first embodiment shown in FIG. 1, and only different configurations will be described here. In the case of the third embodiment, a transistor 361, coils 362, 363 and a capacitor 364 are added to the circuit shown in the first embodiment.
To 366, resistors 367 to 370, and a variable resistor 371 are added. However, antenna 4
Is one. With this buffer circuit, the electric field strength of the radio wave emitted from the antenna 4 can be finely adjusted as shown by virtual lines c and d in FIG. The operation is basically the same as that of the first embodiment, and the description is omitted.

[0021]

Since the present invention has the above-mentioned configuration and operation, it is possible to generate a transmission signal diffused in a wide frequency band by a transmission device having a simple circuit structure,
Since it is not necessary to develop a dedicated IC or the like to generate a transmission signal diffused in a wide frequency band, the transmission device becomes inexpensive. Further, the receiving device does not need a special circuit structure such as a despreading demodulator, and the circuit structure of the receiving device can be simplified, and the receiving device can be inexpensive.

[Brief description of drawings]

FIG. 1 is an electrical circuit diagram showing a first embodiment of the present invention.

FIG. 2 is an electrical characteristic diagram of what is shown in FIG.

FIG. 3 is an electric circuit diagram showing a second embodiment of the present invention.

FIG. 4 is an electrical characteristic diagram of what is shown in FIG.

FIG. 5 is an electric circuit diagram showing a third embodiment of the present invention.

FIG. 6 is an electrical characteristic diagram of what is shown in FIG.

[Explanation of symbols]

 A remote control signal transmission device 1 operation switch 2 signal generation circuit 3 modulation circuit 4 antenna 5 DC power supply 31 oscillator

Claims (4)

[Claims] 1. A remote control signal transmitting apparatus for transmitting a modulated signal, which is modulated by using a vibrator (31), to a radio wave and transmitting the signal to the air, wherein the vibrator (31) has a plurality of elements (311, 321, ...
.. and each element (311, 312, ...
.) Resonant frequencies (f1, f) of the elements (311, 312, ...) To the extent that at least a part of each frequency spectrum distribution of the oscillation frequency overlaps with each other.
2, ...) are set differently and close to each other. 2. The invention according to claim 1, wherein the vibrator (31) has a plurality of surface acoustic wave elements (311,
Remote control signal transmitting device having 312, ... 3. The remote control signal transmitting device according to claim 1 or 2, wherein the plurality of surface acoustic wave devices (311, 312, ...) Are formed on the surface of a crystal piece of one piezoelectric medium. 4. The invention according to claim 1, 2 or 3, wherein a vibrator (31) having the plurality of elements (311, 312, ...) Is incorporated in a radio wave key carried by a vehicle occupant. Remote control signal transmitter.