| 摘要 |
PURPOSE:To dispense with a magnetic recording medium and a recording head for recording a signal on said medium, by superposing the signal corresponding to the signal recorded on a conventional magnetic recording medium to an exciting element for generating a bias magnetic field. CONSTITUTION:A comb tooth wave signal of frequency fs is generated by the first signal generator 1 and a bias signal of frequency fb is generated by the second signal generator 9. These two signals are superposed to drive an exciting element 13 consisting of a magnetic core 11 and a coil 12 by an amplifier 10 and an MR element 6 to be measured is excited. A constant current flows to the MR element 6 from a constant current source 5 and the resistance change of the MR element 6 is applied to a regeneration amplifier 7 as voltage to obtain regeneration output Vout. This output is passed through BPF 8a taking out a fundamental wave component having the first signal frequency and BPF 8b taking out a secondary higher harmonic component to obtain signals V1(fs), V2(2fs). These two signals V1, V2 and the voltage VH proportional to the bias magnetic field obtained from the signal generator 9 are used to obtain a bias characteristic.
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