摘要 |
A head IC adjusts an amplitude level of a read signal of a head to adjust dispersion of the output characteristic of the head and to adjust the read signal within the input dynamic range of the AGC of a read channel. An AGC amplifier is installed in a head IC connected to a read channel and a feedback response speed of an AGC circuit of the head IC is set to be sufficiently slower than a feedback response speed of an AGC circuit of the read channel. Also a peak hold circuit and an amplitude limiting circuit are installed in the head IC, and gain is adjusted with a holding value of the peak hold circuit. An initial gain can therefore be stably adjusted at high-speed without being influenced by signals having a small amplitude on the medium.
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