PURPOSE: To stably replay also a high-speed recorded signal by a method wherein one out of two write current generation means which are provided with different current values is selected by a selection means according to recorded data.
CONSTITUTION: A data conversion circuit 1 holds an output when write data is set at '0' and inverts the output when the data is at '1'. A selection circuit 4 selects a write current circuit 2 when the output of the data conversion circuit 1 is at '0', it selects a write current circuit 3 when the output is at '1', and it makes an electric current flow to a write head 5. When an electric current value is large, a large magnetic field is recorded on a recording medium. For example, when electric current values iW1, iW2 are set so as to match the magnetic-field-to-resistance value conversion characteristic of an MR head 8, a change in a resistance value whose upper and lower amplitude values are equal is caused with reference to an operating point decided by a bias magnetic field generated by a bias conductor 7 and a bias current circuit 9. A constant current (is) from a sense current circuit 10 is read out, it is made to flow to a head 6, it is input to an amplifier 11 as voltage signal, and a replayed waveform is obtained. Thereby, a replay circuit by the high-speed inversion of a bias current in conventional cases is not required.
IWABUCHI KAZUNORI
YAMAKAWA HIDEYUKI
ISHIDA YOSHITERU
