摘要 |
<p>IOM-8112 An improved servo encoding scheme and demodulation circuit for control of the position of a read/write head with respect to a magnetic recording disk is disclosed. First and second signals of like polarity are recorded preceding each data field on the sector of the disk. The signals are summed to provide automatic gain control to the servo loop to compensate for variations in read-back amplitude, while the difference between the two signals is measured and used to provide an indication of departure of the head from the center of the disk track.</p> |