Method and device for processing analogue output signals from capacitive sensors

摘要

An analogue output signal of a sensor which comprises a carrier signal with a carrier frequency omega_C which is modulated by a measurement size is sampled with a sampling frequency omega_A to receive a sampled sensor output signal. The frequency omega_A of the sampling signal is set so that it is an integer divisor n of the carrier frequency omega_C, wherein the phase of the sampling signal is set so that the sampling signal is synchronous to the sensor output signal. The sampled sensor output signal is filtered now to remove periodically repeated signal components from the sampled sensor output signal. Then a filtered useful signal is received, wherein its amplitude is proportional to the measurand detected by the sensor.