| 摘要 |
PURPOSE:To obtain a setting level possible for proper signal processing without giving effect on variation of a waveform by discriminating whether or not a signal waveform inputted via an input terminal is larger than an output from an adder circuit so as to obtain a proper level at an output terminal. CONSTITUTION:A discrimination circuit 41 discriminates whether an AC signal waveform from the input terminal 40 is larger or smaller than a reference level. Detection circuits 42, 43 detect the moment that the signal waveform of the output of the circuit 41 is larger or smaller than the reference level. A detection circuit 44 detects a maximum value of the input signal waveform and is reset by an output of the circuit 42. A sample and hold circuit 45 inputs the output of the circuit 44 to sample and hold the output of the circuit 43. A detection circuit 46 detects a minimum value of the signal waveform from the circuit 45. The detection circuit 47 detects the maximum value of the output of the circuit 44 or the input signal waveform. An adder circuit 48 adds outputs of the circuits 46, 47. A discrimination circuit 49 discriminates whether the input AC signal waveform is larger or smaller than the output of the circuit 48, a prescribed setting level is obtained at an output terminal 50.
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