| 摘要 |
The World Wide Theft alerter has a very small size transmitter located in the car to be protected, with a half wavelength antenna. The transmitter operates at 401.65 MHz and has a power level of between 30 and 37 dBm. A biphase modulation is produced. The transmitter box is fed from a 12 volt supply. The calculation of the position of the transmitter is based on the doppler effect. The transmitter is set into operation at a distance by a radiomessage receiver integrated in the transmitter, or located with it, which is remotely activated.
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