| 摘要 |
PURPOSE:To make the pulse width of a unipolar signal constant after the conversion by changing the setting of an identification level in response to the level fluctuation of a bipolar input signal so as to bring the identification point into the positive of negative amplitude median of an input signal. CONSTITUTION:A bipolar input signal 1' fed to the primary side of a transformer 1 is converted into a position phase signal 12, a negative phase signal 13, a divided negative phase signal 18 and a divided negative phase signal 19, which are fed to two comparators 4, 5 respectively. The comparators 4, 5 compare the signals and output a pulse signal respectively. The pulsive comparison outputs are combined by an OR circuit 8 and converted into a unipolar signal. A parallel circuit comprising a variable resistor 7 and a capacitor 8 is connected to a midpoint of voltage division signal generating resistors 21-32. A variable resistor 7 is adjusted if an input signal level is fluctuated. The identification point is changed through the adjustment without changing the signal level, that is, without changing the attenuation of an AC signal.
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