1. Calibration device for a signal processing device comprising an input stage, a signal processing stage and an output stage, comprising: an output stage calibrator comprising a test signal source adapted to be coupled to the output stage, a feedback channel connectable between output of the output stage and input of the input stage, and a signal analyzer adapted to be coupled to the input stage, wherein the test signal source is implemented to provide a test signal to the output stage, which can be supplied to the input stage via the feedback channel after processing by the output stage, wherein the signal analyzer is implemented to analyze the test signal after processing by the input stage and to determine, based on the analysis, deviations of an actual output amplification of the output stage at a set output amplification of the output stage and/or deviations of an actual input amplification of the input stage at a set input amplification of the input stage, wherein the calibration device comprises an input stage calibrator, which comprises a calibration signal source adapted to be coupled to the input of the input stage and the signal analyzer adapted to be coupled to the input stage, wherein the calibration signal source is implemented to provide a calibration signal to the input stage, wherein the signal analyzer is implemented to analyze the calibration signal after processing by the input stage and determine, based on the analysis, deviations of an actual input amplification of the input stage at a set input amplification of the input stage.