Track centering servo pulse noise filter
AssigneeMagnetic Peripherals Inc.
InventorGuss L. Krake
Life of this patent
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Abstract
A track centering servo pulse noise filter is provided. Prerecorded pulses on a disk track's even and odd half tracks are sensed by the disk's read head, preamplified, DC biased, peak detected, and stored on a FIFO basis into a noise filter comprising two sets of N analog sample and hold cells, one set for the even pulses and one set for the odd pulses. The output of each even-pulse sample and hold cell is input to a summing junction to form an average of the last N pulses. The same is done with the outputs of the odd-pulse sample and hold cells. The two summing junctions are then input to a differential amplifier to form a position error signal to the disk head track centering servo system for keeping the head centered on the track.
Claims7
In a disk track centering servo system having even pulses written on one servo track and odd pulses written on an adjacent servo track, a read head for reading information, including said pulses, means for preamplifying said pulses, and means for distinguishing between odd and even pulses, the improvment comprising:
- first and second pluralities of analog sample and hold circuits, each having an output;
- means for inputting even pulses, one pulse per circuit, into said first plurality of said circuits;
- said first circuits holding the latest received N pulses, where N is a predetermined number;
- means for inputting odd pulses, one pulse per circuit, into said second plurality of said circuits;
- said second circuits holding the latest received N pulses, where N is a predetermined number;
- means for analog summing the outputs of said first plurality of circuits to form a first sum;
- means for analog summing the outputs of said second plurality of circuits to form a second sum;
- and
- means for deriving the difference between said first sum and said second sum to form a position error signal.
Dependencies are inferred from the claim text.