JPS54161307A - Magnetic recording and reproducing apparatus - Google Patents

Abstract

PURPOSE: To provide a recording and reproducing apparatus, which has its recording bias current automatically adjusted, by controlling the preset level ratio of such reproduction reference signals of an attenuator for interchanging the input reference signal frequencies and for adjusting the bias current as have different frequencies through a control circuit.

CONSTITUTION: When an input is interchanged by a change-over switch 8 in response to the control signals from a control circuit 17, the reference signals having different frequencies and generated from a reference signal generator 6 are recorded in a magnetic tape by the different bias currents, which are generated by a bias signal generator 1 and which have passed through a variable attenuator 2 controlled by the circuit 17, and then are reproduced. The integrated signals of the reproduced signals, which respond to the reproduced reference signal levels detected by an integrating circuit 15, are compared by a comparating circuit 16, and the attenuator 2 is controlled, until the reproduced reference signal levels having different frequencies become a preset ratio, so that the recording bias current is automatically adjusted to the most proper level having preset frequency characteristics. If a compensating circuit is used, a higher bias adjustment than the reference signals having the highest frequency can be performed even for the input.

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