Pioneer Electronic Corporation

Koki Aizawa

Akira Haeno

Yoshiyuki Takizawa

Tadahiro Yamaguchi

Akira Motoyama

A pickup level control device for a system for reading out recorded information which has a pickup element producing a pickup output signal. The device detects a dc component of the pickup output signal and produces a level control signal. A voltage level of the pickup output signal is controlled in response to the level control signal produced by the dc level detection operation. The control of the voltage level of the pickup output signal is performed by a variable impedance element connected to a terminal of the pickup element, so that a peak level of an ac component of the pickup output signal is controlled below a predetermined level.

Pickup level control device for a system for reading out recorded

A level-shifting circuit is arranged such that the amount of level-shifting is controlled so that the DC requirement of a succeeding circuit may be satisfied. In particular, negative feedback control of the amount of level shift results in a constant zero DC potential being maintained at the circuit output.

Level shifting circuit

A stereo signal demodulation for obtaining left and right channel signals from an input stereo signal. A differential amplifier is coupled to a constant current source and first and second multipliers are coupled to the differential amplifier. A dividing circuit is coupled to the amplifier and the resulting channel signals are obtained in full wave rectified form.

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Tokorozawa, Japan

Koki Aizawa