High sample rate dPES to improve contact detection signal to noise ratio
AssigneeSeagate Technology LLC
InventorsLin Zhou, Juil Lee, Dongming Liu, Huazhou Lou
Life of this patent
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Abstract
Using a high sample rate dPES, together with pulsed heater and lock-in technique, to improve dPES SNR for contact detection between the head and media surface. Steps of powering a transducing head actuator with pulsed input signal at a select data track offset from a previously-written to data track of the storage medium, where the pulsed input signal has select amplitude and duty cycle to simulate a response signal, and further locking in an amplitude with respect to the heater frequency, can lead to a determination of level of heater power for initiating contact between the transducing head and the storage medium.
Claims17
A method of detecting initial contact between a transducing head and a storage medium, the method comprising:
- providing a pulsed input signal to an actuator of the transducing head, wherein a sampling frequency of the input signal is at least four times higher than a heater frequency;
- sampling amplitudes of the input signal;
- determining a lock-in amplitude from the sampled amplitudes, wherein the lock-in amplitude is determined through use of an algorithm with respect to the response signal at the sampled amplitudes;
- generating a curve of the lock-in amplitude against varied heater power;
- and
- determining a turning point of the curve.
A method of determining heater power requisite to initiate contact between a transducing head and a storage medium, the method comprising:
- powering a heater of the transducing head with pulsed input signal at a select data track of the storage medium, the pulsed input signal having select amplitude and duty cycle to simulate a response signal at the select data track, the select data track being offset from a single data track of the storage medium previously written to;
- sampling amplitudes of the input signal at a frequency higher than frequency of the heater;
- determining a lock-in amplitude from the sampled amplitudes;
- generating a curve of the lock-in amplitude against varied heater power;
- and
- determining a turning point of the curve.
Dependencies are inferred from the claim text.