A device for measuring a periodic signal includes: a first control unit for generating an electrical input signal (V1) of the period T a light source for generating an optical input signal directed to an object being measured from the electrical input signal (V1) an optical receiver for detecting and converting the signal reflected from the object being measured, the signal corresponding to the optical input signal altered in terms of phase and amplitude, into an electrical measurement signal (V2) and a plurality of measurement channels connected in parallel between the optical receiver and a second control unit, each measurement channel being connected in series to a switching element, a filter element, and an analog-to-digital converter, wherein the second control unit is suitable for evaluating the measurement signals from the plurality of measurement channels, and in which the electrical measurement signal (V2) is applied to each of the plurality of measurement channels, the first control unit is connected to the plurality of switching elements and is suitable for actuating the switching elements for different time intervals in each case, and the analog-to-digital converters have a maximum sampling rate of less than 2×1/T.
