JP3148058B2 - Keyless entry system device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a keyless entry system mainly used for automobiles.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. Conventionally, a keyless entry system of this type is provided with a transmitter 2 having an oscillation circuit 5 for generating an airborne signal and a power supply 6 independent of the automobile 1 as shown in FIG. And a storage unit 8 containing the only coded signal b, and the received coded signal a
And a receiver 3 having a comparator 9 for comparing
When both the coded signals a and b match, a door lock / unlock signal is output to the controller 4. In the transmitter 2 in the figure,
2b is an operation switch, 13 is a transistor driven by an oscillation output, 14 is an infrared light emitting diode for outputting a transmission signal, and 15 in the receiver 3 is a light receiving section.

An example of the structure of the coded signal a or b will be described with reference to FIGS. 8A to 8C. The coded signal is composed of 24 bits, and the width t of one pulse is t.
Is modulated at 0.6 [msec] at a frequency of about 38 [kHz]. "0" when the interval of each pulse is 2t, 4
At the time of t, it is set to "1", converted into a coded signal by a binary number of 0 and 1, and transmitted as a coded signal a.

[0004]

However, in the above-mentioned conventional keyless entry system device, since the coded signal a is simple, the coded signal is easily copied by a commercially available device, and there is a problem in security.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an excellent keyless entry system device capable of keeping a security by preventing a coded signal from being copied. Things.

[0006]

According to the present invention, in order to solve the above-mentioned problems, the first stage of the transmission signal is a baseband signal or a signal different from the normal modulation frequency, and the second stage is a normal coded signal of the normal modulation frequency. It consists of.

[0007]

As described above, since the baseband signal or a signal different from the normal modulation frequency is used before the transmission signal, the equipment to be copied uses the baseband system instead of the modulation frequency system for transmission. Alternatively, the modulation frequency is erroneously recognized, so that the copy of the legitimate coded signal is prevented, and the security of the keyless entry system can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. It should be noted that the same components as those described as the related art will be described with the same reference numerals. 1 and 2,
Reference numeral 1 denotes an automobile, 2a denotes a transmitter, 3a denotes a receiver, 4 denotes a controller, and the transmitter 2a includes a switch 2b, an oscillation circuit 5a, a power supply 6, and the like. 7, a storage unit 8a, a comparator 9a and the like.

FIG. 3 shows an entire transmission signal according to the present embodiment. The coded signal 10 is modulated at a normal carrier frequency, and a baseband signal inserted before the coded signal 10 (no radio signal). (Modulated signal) 11.

Next, the details of the configuration of the above embodiment will be described together with the operation. When the operation switch 2b of the transmitter 2a is pressed,
The oscillation circuit 5a operates, the transistor 13 is driven by the oscillation output, and a transmission signal is output from the infrared light emitting diode (hereinafter, referred to as LED) 14. The transmission signal from the LED 14 is received by the light receiving unit 15 of the receiver 3a, this optical signal is converted into an electric signal, and the signal stored in the storage unit 8a is compared by the comparator 9a. If so, a door lock or unlock signal is output. If the compared signals are different, lock,
It is configured not to output the unlock signal.

Next, an example of the transmission signal transmitted from the oscillation circuit 5a of the transmitter 2a will be described. As shown in FIG. 4, the normal coded signal 10 is a 25-pulse, 24-bit signal having 25 pulses of "0", By distinguishing “1”, 10
When each pulse is generated, it is transmitted as a pulse modulated at a modulation frequency of 38 [kHz]. The baseband signal 11 is inserted before this as shown in FIG. The baseband signal 11 has a pulse width and a pulse interval different from those of the normal coded signal, and considering the life of the battery (the keyless entry system transmitter mainly uses a button battery). 10 [μsec], the pulse interval is set to 200 [μsec] in consideration of the response speed, the number of pulses is set to 300 bits, and as shown in FIG.
The number of it is 372 bits.

As described above, according to the above-described embodiment, the whole transmission signal is used as the baseband signal 11 and the coded signal 10 at the beginning of the transmission signal, which is the front part of the transmission signal. , Remote control signal to RA
In the procedure for storing the transmission signal in M, the function of determining whether the transmission signal is a baseband signal or a modulation signal is determined to be a baseband signal, and then a normal coded modulation signal is transmitted. It can prevent copying on the device. Even if the copy device can store both the baseband signal and the modulation signal, the storage capacity of the learning remote controller overflows by transmitting the leading baseband signal of 300 bits at the front stage (generally, The capacity of the learning remote controller having the copy function is about 150 bits), and copying of the regular coded signal becomes extremely difficult, thereby eliminating the possibility of unlocking the door and improving security. .

FIG. 5 (a) shows an entire transmission signal according to another embodiment of the present invention, in which a coded signal 10 modulated at a regular modulation frequency is inserted before the coded signal. It is composed of a coded signal 12 modulated at a frequency different from the modulation frequency of the normalized coded signal 10. In this embodiment, focusing on the fact that only one modulation frequency is stored in the method of storing the remote control signal in the copying machine (there is only one modulation frequency of the normal remote control signal), it is the preceding stage of the transmission signal. For example, by transmitting a dummy modulation frequency 56 [kHz] higher than the modulation frequency 38 [kHz] of the normal coded signal 10 to the head portion, all reproduction signals of the copy device after being copied by the copy device are 56 [kHz]. If the receiver 3a is configured to receive only a signal with a modulation frequency of 38 [kHz], there is no possibility that the door will be unlocked, and security will be improved. improves.

The modulation frequency of the dummy is 56 [kHz].
z] is set higher than the normal modulation frequency because the dummy modulation frequency is easily produced by frequency division when producing the dummy modulation frequency from the clock signal built in the transmitter.

[0015]

According to the present invention, as is apparent from the above embodiment, a baseband signal (unmodulated signal) different from a normal coded signal or a normal By transmitting a modulation frequency signal different from the above modulation frequency signal, the storage function of the copying apparatus is confused and the security of the keyless entry system device of the vehicle can be improved.

[Brief description of the drawings]

FIG. 1A is a block diagram of a transmitter which is a main part of one embodiment of a keyless entry system device of the present invention. FIG.

FIG. 2 is an explanatory diagram illustrating an outline of the system.

FIG. 3A is an overall view of the transmission signal. FIG. 3B is a baseband signal diagram of the transmission signal. FIG. 3C is a coded signal diagram of a transmission signal.

FIG. 4 is a pulse waveform diagram of the coded signal.

FIG. 5A is an overall view of a transmission signal according to another embodiment of the present invention. FIG. 5B is a diagram showing a coded signal of a dummy modulation frequency having a different modulation frequency, which is a main part of the transmission signal. Coded signal diagram that is the main part

FIG. 6 is an explanatory diagram illustrating an outline of a conventional keyless entry system device.

FIG. 7A is a block diagram of the transmitter. FIG. 7B is a block diagram of the receiver.

8A is an overall view of the transmission signal. FIG. 8B is a coded signal diagram as a main part of the transmission signal.

[Explanation of symbols]

 2a transmitter 3a receiver 4 controller 5a oscillation circuit 6 power supply 8a memory 9a comparator 10 coded signal 11 baseband signal 12 dummy modulation signal

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masafumi Kamiya 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Tomonori Suzuki 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation ( 56) References JP-A-2-296495 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04Q 9/00-9/16

Claims (3)

(57) [Claims] 1. A transmitting means for transmitting a coded signal and a transmitter provided with the power supply, a receiving means for receiving a coded signal from the transmitter, a power supply device and the coded coding A storage device for storing the signal, and a receiver having a comparator for comparing the coded signal received by the receiving means and outputting a signal when the two match each other. A keyless entry system device characterized in that, in a transmission signal, a leading signal at a preceding stage is a baseband signal, and a rear signal is a regular coded modulation signal. 2. A transmitting means for transmitting a coded signal and a transmitter provided with the power supply, a receiving means for receiving a coded signal from the transmitter, a power supply and the coded coding A storage device for storing a signal, and a receiver having a comparator for comparing the coded signal received by the receiving means and outputting a signal when the two match, and transmitting the signal from the transmitter. A keyless entry system device in which the modulation frequency of a signal is a non-regular modulation frequency on the first stage and a regular modulation frequency receivable by the receiver on the second stage. 3. The keyless entry system device according to claim 2, wherein the non-regular modulation frequency on the preceding stage is set higher than the regular modulation frequency.