Patent ID: 8508876

Claim:
A proximity sensing system for determining proximity of a head to a magnetic media, comprising: A. input circuitry having input leads, output leads, and bias circuitry connected between the input leads and output leads; B. a bias digital to analog converter (DAC) having outputs coupled to the bias circuitry; C. an offset DAC having an output; D. subtractor circuitry having inputs coupled to the outputs of the input circuitry and to the output of the offset DAC and having difference outputs; E. an amplifier having inputs coupled to the outputs of the difference outputs and an amplified signal output; F. a filter having an input coupled to the amplified signal output and having a filtered signal output; G. a track and hold circuit having an input coupled to the filtered signal output and having an output; and H. a decision circuit having an input coupled to the output of the track and hold circuit and an offset output coupled to an input of the offset DAC.