摘要 |
A gain controller changes a gain of a read amplifier depending on whether a head reads out servo data or user data. Further, a heater setting unit changes the temperature of a heater and a reading gain when detecting touchdown performed by the head. Accordingly, a dynamic range of AGC in a read-write channel is increased, so that error detection is prevented for touchdown that occurs because an AGC gain converged value remains at 0.
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