device to identify a maximum financing in excess of a predetermined frequency spurious dose and

摘要

To detect the occurrence of interference signals of a predetermined frequency and having an unacceptably high level in a circuit, two test signals of the predetermined frequency are generated with a phase shift of 90 DEG with respect to one another. The test signals are in each case superimposed on the interference signals. It is only when the two superimposed signals are within a permissible tolerance range that no interference message is output.