The transmission signal of the car key is mainly carried out by radio waves. Smart car keys are usually equipped with a small transmitter that can send a radio signal, which is decoded and processed by the receiver in the car, so as to realize the control of the car to start, lock, and open the door.
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Specifically, each smart car key is equipped with a unique identification code, which can be regarded as the fingerprint of the key. When the button on the key is pressed, the transmitter sends an encrypted signal to the car, which is transmitted wirelessly to the receiver and decoded after receiving it. If the decoded code matches the stored code of the car, the door opens or closes.
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It should be noted that the frequency and programming method of the launch key signal are customized according to the requirements of the automobile manufacturer, so the transmission signal between different car brands and different models is not the same. In addition, with the development of radio technology, more and more cars are adopting more advanced key technologies, such as dynamic codes, challenge response methods, etc., to improve the security of cars.
Car keys are transmitted by a signal transmitter, the key has a signal transmitter, there is a code. And the vehicle has a receiving device, if the signal code matches, then it will automatically unlock
A weak radio wave is emitted from the owner's side, which is received by the car antenna, identified by the signal code of the electronic controller ECU, and then the actuator of the system (motor or electromagnetic manager circle) performs the opening\/closing action. The system is mainly composed of two parts: transmitter and receiver:
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1. Transmitter The transmitter is composed of a transmitting switch, a transmitting antenna (key plate), an integrated circuit, etc. It is integrated with the signal sending circuit on the key plate. From the identification code storage loop to the FSK modulation loop, which is miniaturized by the use of a single-chip integrated circuit, a lithium battery with a snap button type is installed on the opposite side of the circuit. The transmission frequency is selected according to the radio wave goodness of the country of use, and the 27, 40, and 62MHz frequency bands can be generally used. The transmitting switch transmits signals once every time the press button is pressed.
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2. The receiver transmitter sends out the identification code using FM modulation, receives it through the FM antenna of the car, and demodulates it using the FM high-frequency increase processor entering the receiver ECU to compare with the identification code of the decoded regulator; If the code is correct, input the control circuit and make the actuator work.