Abstract: A device is disclosed. The device includes a. at least one radiation emitting element configured for emitting a modulated thermal radiation as a result of its temperature; where the radiation emitting element includes at least one incandescent lamp; and b. at least one electronic circuit configured for applying a periodic time-dependent voltage to the radiation emitting element, wherein where the electronic circuit is configured for controlling one or more of an amplitude, a duty cycle and a frequency of the periodic time-dependent voltage, where a temperature of the radiation emitting element and a frequency of the modulated thermal radiation depend on the applied periodic time-dependent voltage controlled by the electronic circuit.

Abstract: Described herein is a spectral sensing device that includes at least one photosensitive detector, where the at least one photosensitive detector has at least one photosensitive region designated for receiving optical radiation, where at least one detector signal as generated by the at least one photosensitive detector is dependent on an illumination of the at least one photosensitive region; at least one radiation emitting element; at least one optical element; and at least one evaluation unit, where the at least one evaluation unit is configured to perform a calibration of the spectral sensing device by using at least one first detector signal as generated by the at least one photosensitive detector upon the illumination of the at least one photosensitive region by a first portion of the optical radiation. Also described herein is a method for measuring optical radiation with a spectral sensing device.