A method for the control of a phase shift between a transmission signal and a received signal of an electromechanical transducer unit to a predetermined value in an oscillatory circuit. The received signal is sampled at discrete points in time predetermined based on the transmission signal. Sampled voltage values are compared with desired values, which the received signal assumes at the respective points in time, when the predetermined phase shift is present, and, in the case of a deviation of a voltage value from its desired value, based on the sign of the deviation, the frequency of the transmission signal is decreased or increased.