HIGH SAMPLE RATE DPES TO IMPROVE CONTACT DETECTION SIGNAL TO NOISE RATIO

摘要

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.

主权项

1. 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 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 a heater of the transducing head; determining a lock-in amplitude from the sampled amplitudes so as to limit response signal to noise not attributed from position of the heater; generating a curve of the lock-in amplitude against varied heater power; and determining turning point of the curve, wherein the turning point comprises a point at which curve initially deviates from what is expected, the curve point characterizing initial contact between the transducing head and the storage medium.