Please choose your delivery country and your customer group
A flying height measurement scheme based on the servo pattern recorded in the servo sectors was developed and simulated using a read back signal model. The two proposed flying height measurement methods show excellent agreement within a large flying height range while being insensitive to off-track motion of the read write head. In the proposed method, the off-track sensitivity is a function of the radial servo burst spacing, i.e., the cross-track spacing between the A and B burst in each servo sector. The proposed method was tested experimentally to identify the dynamics of a resistance heater element capable of modifying the flying height at the read/write element. Based on the current data that uses a servo sector-based signal at a sampling rate of approximately 15.36 kHz it can be concluded that the response of the thermal actuator can be approximated by a first order system with a time-delay. It was found that the time delay was negligible and the time constant was found to be very small at around 65 micros. This promises feasible solutions to real-time flying height adjustment up the 15-20 kHz-regime. The gain or actuator efficiency (input power vs flying height reduction) decreases as the flying height decreases which might be due to the push-back effect or the air-bearing cooling effect.