HEAD-POSITIONING ERROR SIGNAL GENERATOR for MAGNETIC DISK DRIVE
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
In a magnetic small disk drive wherein the data track is accessed using a head drive motor equipped with an encoder which produces pseudo sine- wave encoder signals of one cycle per track, the encoder signals are uniquely combined to form plural composite signals which are selectively switched to form a substantially sawtoothed head positioning error signal. This signal can be used to precisely position the magnetic head in the conventional manner. (Image Omitted) Referring to Fig. 1(A), two phases of the pseudo sine-wave encoder signals are shown in which the B phase signal Vb crosses a reference voltage Vc (e.g., 5V) at a track position T. The A phase signal Va is shifted with a constant voltage Vr (e.g., 2V) to form two kinds of voltage signals of Va+Vr and 10-(Va+Vr), as shown in Fig. 1(B).