Magnetic recording and reproducing apparatus automatically adjustable to

Abstract

A magnetic recording and reproducing apparatus comprises a source for producing test signals, a variable-gain amplifier, an equalizer, a recording bias generating circuit, a control unit for supplying control signals to the amplifier, equalizer and recording bias generating circuit, a memory and an operating circuit unit. The apparatus is automatically adjusted to each individual magnetic tape in use in such a manner that: a first test signal from the source is recorded on a magnetic tape with a preset bias control signal, the recorded first test signal is reproduced, the bias control signal is adjusted to provide a maximum HF saturation level and a minimum distortion to thereby determine an optimum bias control signal, and the proper bias control signal is fixed for said bias generating circuit; another test signal from the source is recorded on the magnetic tape with a preset gain control signal, the recorded other test signal is reproduced and is compared with a reference value at the operating circuit unit to provide an error signal, and the resulting error signal is fed through the memory to the control unit to renew the preset gain control signal for said amplifier. The adjustment of the frequency response control signal for the equalizer is effected in the same manner as the adjustment of the gain control signal.