Patent ID: 8619924

Claim:
A circuit comprising: a receiver circuit configured to receive a modulated signal; a control unit configured to control the receiver circuit, the receiver circuit configured to output a phase difference between a phase of a complex baseband signal and a phase precalculated from previous sampled values; an evaluation circuit, which for evaluating the phase difference is connectable to the receiver circuit and the control unit, the evaluation circuit being configured to compare the phase difference with a first threshold and configured to output an output signal based on a number of exceedances of the first threshold by the phase difference, wherein the control unit is configured to turn off the receiver circuit based on the output signal of the evaluation circuit; wherein: the evaluation circuit has a control input for setting the first threshold; and the evaluation circuit has a first comparator, which is formed with the receiver circuit or with the output of a subtractor for comparing the phase difference with the first threshold, wherein the evaluation circuit has a counter configured to determine the number of exceedances, the counter being configured to count a clock signal as a function of an output signal of the first comparator, and wherein the evaluation circuit has a second comparator, which is configured to compare the number determined by the counter with a second threshold and an output of the output signal based on the comparison result of the evaluation circuit.