Patent ID: 8537487

Claim:
A circuit for use with a memory storage device including a magnetic storage medium and a write head operative to subject the magnetic storage medium to a magnetic field in response to an application of current to the write head, the circuit comprising: a write circuit operative to generate a write current supplied to the write head, the write current characterized by a current waveform that reverses polarity in accordance with data to be stored on the magnetic medium; and a degauss circuit operative to generate a degaussing current supplied to the write head, the degaussing current characterized by a current waveform that oscillates between opposite polarities with an amplitude that changes over time and a frequency that changes over time, wherein the degauss circuit comprises: a first signal generator operative to generate a first control signal as a function of a first set of parameters supplied to the first signal generator; a second signal generator operative to generate a second control signal as a function of a second set of parameters supplied to the second signal generator; a voltage-controlled oscillator (VCO) operative to generate an output signal having a frequency which varies as a function of the first control signal; and a mixer connected with the VCO and second signal generator, the mixer operative to generate the degaussing current having a frequency which varies with a function of the first control signal and having an amplitude which varies as a function of the second control signal.