Patent ID: 7675706

Claim:
A hard-disk drive system, comprising: a hard-disk drive platter storing information; a hard-disk drive read system to actuate a read head, the read head forming a first signal having information from the hard-disk drive platter; a a proximity detector to receive the first signal and form a second signal indicative of a distance from the read head to the hard-disk drive platter, a frequency of the second signal being based on the distance from the read head to the hard-disk drive platter; and a hard-disk drive controller to adjust the distance of the read head from the hard-disk drive platter in response to the second signal, wherein the proximity detector comprises: a first filter operative for filtering an information signal and transmitting a first signal having a first amplitude and a first offset voltage; a second filter coupled to receive the first signal, the second filter operative for filtering the first signal and transmitting a second offset voltage substantially equal to the first offset voltage; an amplifier coupled to receive the first signal and the second offset voltage, the amplifier operative for amplifying the first amplitude around the second offset voltage so as to form an amplified signal having a second amplitude, wherein the second amplitude is greater than the first amplitude; and a comparator coupled to receive the second offset voltage and the amplified signal, the comparator operative for comparing the second offset voltage and the amplified signal, wherein the comparator detects the location of the read head.