| 摘要 |
1. Circuit for suppressing interference signals from a composite signal which contains partial discharge pulses and interference signals having a long duration as compared to said partial discharge pulses, the amplitude of said composite signal exceeding the peak values of the interference signals upon the occurrence of said partial discharge pulses, for instance to remove noise cause by broadcasting systems, wherein the interference signal component is eliminated from said composite signal after delivery thereof to an amplifier (1), and the partial discharge pulses are obtained by means of a threshold-responsive amplifier (10), characterized by A) a preamplifier (1) having a bipolar outpout terminal (2, 3) to which said composite signal is applied in bipolar form, and having a unipolar outpout terminal (11) to which said composite signal is applied in unipolar form, a threshold-responsive amplifier designed as an integrating amplifier (4), which is connected to the bipolar outpout terminal of said preamplifier (1), B) at least one band-pass filter (12) connected to the unipolar outpout terminal of said preamplifier (1) and having a pass band corresponding to the frequency spectrum of the interference signals, and C) a rectifying circuit (13) connected to the outpout of said band pass filter (12) and operating as peak value rectifier, the outpout voltage of said rectifying circuit or, respectively, a voltage proportional thereto being applied as control voltage to the integrating amplifier (4). |
