Automatic Voltage Offset Zeroing for Multiple Servo Loop Disk Files
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
The method for automatically zeroing out voltage offsets on multiple servo loop disk files eliminates the need for using operational amplifiers with low input offset voltages, which are expensive, or potentiometers, which require manual adjustments. The figure shows a portion of an electronic tachometer. The tachometer generates a velocity signal by differentiating the "+position" signal and integrating the "+current sense in" signal. These two outputs are then combined based on frequency content. In the figure, only those portions of the tachometer that were changed or added to for zeroing offsets are labeled. The zeroing of offsets depends on two conditions: one, that the seek mode only lasts a finite maximum time, and two, that the electronic tachometer is not used during tack follow. Both of these condition are met.