The invention relates to a method for determining and/or evaluating a differential, optical signal. According to the invention, at least two first light sources (S1, S2) which are sequentially clocked in terms of light and emitted in a phased manner are provided, in addition to at least one receiver (E) which is used to receive at least the alternating light portion arising from the first light sources (S1, S2). The light intensity radiating through at least one light source (S1, S2) in the measuring arrangement is controlled in such a manner that the clock synchronous alternating light portion, which occurs between different phases, is zero in the receiver (E). By determining the reception signal in the receiver (E) in relation to the phase position in order to regulate the radiated light intensity and by producing an adjustable variable (R) directly or by adding current in the receiver, it is possible to simplify digital implementation of the method with as little sensitivity loss as possible.