INTERFERENCE REDUCTION CHARACTERISTICS CIRCUIT

摘要

1. Circuit for improving the reduction characteristic in the audible range of frequencies of systems for active reduction protection comprising an operational amplifier (5) which is used as power amplifier and which feeds the primary winding (4) of a transformer (3) which is used as coupling section and via one secondary winding (2) of which, which is used as control winding, the pilot wire (1) is passed from which the interference signal remaining after the coupling section is picked up, characterized in that the reduced interference signal is fed both to the input of a summing amplifier (14) and to an inverting low-pass filter (13) the cut-off frequency of which allows optimization in the audible range and the output of which is also fed to the input of the summing amplifier (14) whilst the output of the summing amplifier is connected to the input of the power amplifier (5).