CONVERTER CIRCUIT FOR CONVERTING SINUSOIDAL AC VOLTAGE SIGNAL SUPERIMPOSED ON DC OFFSET VOLTAGE INTO SQUARE-WAVE VOLTAGE

摘要

An output signal of a magnetoelectrical transducer of a capstan DC motor used in a magnetic tape recorder includes a DC offset voltage. The output signal of the transducer is coupled to a non-inverting input of a first operational amplifier. The output signal is also coupled to an inverting input of a second operational amplifier, operating as a comparator. The non-inverting input of the second operational amplifier is coupled to an output terminal of the first operational amplifier that amplifies an AC voltage component of the transducer output signal. By means of two anti-parallel coupled diodes in a negative feedback branch of the first operational amplifier, a DC amplification of unity is obtained as soon as a first peak of the output signal of the transducer is reached.