Abstract: Some of the embodiments of the present disclosure provide a method for operating a disc drive system, the method comprising based at least in part on a first injector signal, oscillating a focusing apparatus of the disc drive system; while oscillating the focusing apparatus of the disc drive system and rotating a disc placed within the disc drive system, estimating an amplitude of a track crossing speed signal; generating a second injector signal having a frequency that is substantially the same as a frequency of the first injector signal; and based at least in part on the estimated amplitude of the track crossing speed signal and the second injector signal, estimating a sign of the track crossing speed signal.

Abstract: An optical disc drive having a lens position motor (24) for control of a lens position relative to a track on a disc (10) and a second (“sledge”) motor (25) for control of the position of the first motor and of the lens radially relative to the disc. An alternating signal is generated (56) and applied to the lens position motor to modulate the control of the lens position motor. In this manner, the control loop that controls the lens position motor can have higher bandwidth and therefore greater responsiveness during rough searching or at initialization. For example, where the control circuit controlling the first motor has a lowpass filter (65) with a cut-off frequency, this cut-off frequency can be selected relative to the frequency of the alternating signal.