Patent ID: 8654465

Claim:
A method for implementing data detection with spin-torque oscillator (STO) sensing with a demodulator for hard disk drives comprising: receiving an input signal from a STO read sensor having an oscillation frequency ω(t) related to magnetic field varying in time in response to a varying applied magnetic field; providing a mixer for mixing said readback signal with a quadrature reference frequency signal producing a complex baseband readback signal; said quadrature reference frequency signal having a frequency approximately equal to said STO read sensor in a quiescent bias state; providing a phase detector for measuring an instantaneous phase of said complex baseband a readback signal from said STO read sensor; and providing a finite difference function coupled to said phase detector converting said processed readback signal into a converted signal proportional to the magnetic field affecting frequency of said STO read sensor during a bit time; said converted signal being used for processing by data detection electronics.