Abstract: The invention relates to a luminaire comprising a housing, at least two radiation sources and at least one directing means. The directing means is used to direct the emission of electromagnetic radiation emitted by the radiation sources. According to the invention, the radiation sources are all located in the center of the directing means such that the radiation sources are arranged concentrically with respect to one another. The radiation sources can be switched on and off individually, jointly, or in combination. Each radiation source emits electromagnetic radiation within a constant wavelength range when switched on, wherein different radiation sources can emit electromagnetic radiation within different wavelength ranges.

Abstract: An analogue output signal of a sensor which comprises a carrier signal with a carrier frequency ?C which is modulated by a measurement size is sampled with a sampling frequency ?A to receive a sampled sensor output signal. The frequency ?A of the sampling signal is set so that it is an integer divisor n of the carrier frequency ?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.

Abstract: An analogue output signal of a sensor which comprises a carrier signal with a carrier frequency &ohgr;C which is modulated by a measurement size is sampled with a sampling frequency &ohgr;A to receive a sampled sensor output signal. The frequency &ohgr;A of the sampling signal is set so that it is an integer divisor n of the carrier frequency &ohgr;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.