Interference-insusceptible capacitive sensor for use in collision protection device for detecting e.g. body part of person, has frequency generator generating frequency signal with variable predeterminable transmitting frequency

摘要

The sensor (21) has an electrode assembly (25) comprising a transmitting electrode (30) and a receiving electrode (31). A frequency generator is provided upstream of the transmitting electrode for generating a transmitting signal (ST) by direct digital synthesis and a phase locked loop. The frequency generator generates frequency signal with a variable predeterminable transmitting frequency. The frequency generator comprises a microcontroller for generating a digital signal with the transmitting frequency. A smoothing element is provided downstream of the microcontroller.