A measuring device for measuring a power of a measurement signal comprises an analog-processing unit (1) and a calibration unit (5) for the implementation of a calibration procedure. The analog-processing unit (1) provides two detector diodes (14, 15) connected in an antiparallel manner relative to a signal input (10) and an amplifier (50) for the amplification of signals which are derived from output signals of the detector diodes (14, 15). The analog-processing unit (1) further provides a chopper unit (28) which is connected at two terminals in series between the detector diodes (14, 15) and the amplifier (50). In this context, the calibration unit (5) comprises at least one current source, wherein the current sources (46, 47) is connected to at least one input terminal of the amplifier (50).