| 摘要 |
PURPOSE:To make accurate positioning control of a head to a track even if an off-track amount exceeds the specific track width, by switching a head positioning control from the control with an address signal to that with a head positioning control signal. CONSTITUTION:An address signal outputted from a sector signal demodulation circuit 3 is given to one input of a track detecting circuit 9 via a line 4 and an objective track signal (objective track number) is applied to another input of the circuit 9 via a bus 10. The circuit 9 has 5 output signals lines 11-14, and 15, generates a signal on the line 11 displaying that the signal on the line 4 is smaller than the objective track signal, produces a signal on the line 12 displaying that the signal on the line 4 is smaller than the objective track signal by 1, that is, smaller than the address of the objective track by 1, and generates a signal on the line 13 displaying that the address signal is coincident with the objective signal. |
