Abstract: A start-up routine for a brushless sensor-less DC motor inductively measures motor position angle rather than motor start phase and inductively calculates an acceleration trajectory based on motor position rather than motor parameters. Motor position angle is determined by measuring the rise time of each phase, computing sinusoidal components for each phase, then calculating the angular position based on the sinusoidal components. The acceleration trajectory is determined by computing time delays for each phase. To do this, angular acceleration of the motor is calculated by determining the change in angular position of the motor between two predetermined time intervals. The motor may then be spun up with a start-up routine that is not dependent on motor parameters, resulting in a more efficient and consistent performance.

Abstract: A switch mode sine wave driver circuit selectively sources and sinks driving currents to and from a DC brushless motor in accordance with the substantially sinusoidal switched driving signals. A signal waveform monitoring circuit monitors electrical signals appearing the motor windings and puts out motor phase reference signals. A phase clock generator provides a motor-synchronized clock signal. A phase counter is clocked by the motor clock signal and is reset by the motor phase reference signals. The phase counter counts predetermined phase intervals and generates phase counts and phase polarity signals. A motor state decoder responds to the phase polarity signals by generating state control signals. Sine wave logic circuitry is addressed by the phase counts and puts out digital polyphase sine values for each one of the polyphases. A polyphase pulse width modulator circuit responds to the polyphase sine values by generating phase pulses having duty cycle duration controlled by the sine values.

Abstract: Shown is a disk drive arrangement with servo-mechanism for controlling (thin-film) head position, etc.; the servo having a disk face dedicated to servo tracks, rendered in "Quad" code, with special timing indicia to separate position indicia, with position signals being deployed to follow, and to be terminated by, like, distinct timing sequences.

Abstract: Described is a novel technique and associated arrangement for determining the noise-free value of a system parameter (e.g., head position in a disk drive) which is time variable and (usually) has a noise component as detected. The technique involves processing the (as detected) noise-including value and passing it through "Second Order/Summing" filter means.For instance, the technique is described as particularly useful with the "track-following servo" (part of the transducer positioning means) in a high density disk file (where track density is higher than usual) to secure superior head-displacement error values which are more noise-free. Thus, (see FIG. 4), a pair of first values V.sub.a, V.sub.b are secured by detecting motor current sense voltage V.sub.i, integrating it with respect to time and passing the result through a pair of novel "second order filter" means--one hand-pass (F.sub.1) the other low-pass (F.sub.2); while also securing a third value V.sub.

Abstract: Described is a novel technique and associated arrangement for determining the noise-free value of a system parameter (e.g., head position in a disk drive) which is time variable and (usually) has a noise component as detected. The technique involves processing the (as detected) noise-including value and passing it, plus a "Time-derivative version" thereof, through "Second Order/Summing" filter means.For instance, the technique is described as particularly useful with the "track-following servo" (part of the transducer positioning means) in a high density disk file (where track density is higher than usual) to secure superior head-displacement error values which are more noise-free. Thus, (see FIG. 4), a pair of first values V.sub.a, V.sub.b are secured by detecting motor current sense voltage V.sub.i, integrating it with respect to time and passing the result through a pair of novel "second order filter" means--one band-pass (F.sub.1), the other low-pass (F.sub.2); while also securing a third value V.sub.

Abstract: Described is a novel technique and associated arrangement for determining the noise-free value of a system parameter (e.g., head position in a disk drive) which is time variable and (usually) has a noise component as detected. The technique involves processing the (as detected) noise-including value and passing it through "Second Order/Summing" filter means.For instance, the technique is described as particularly useful with the "track-following servo" (part of the transducer positioning means) in a high density disk file (where track density is higher than usual) to secure superior head-displacement error values which are more noise-free. Thus, (see FIG. 4), a pair of first values V.sub.a, V.sub.b are secured by detecting motor current sense voltage V.sub.i, integrating it with respect to time and passing the result through a pair of novel "second order filter" means--one hand-pass (F.sub.1), the other low-pass (F.sub.2); while also securing a third value V.sub.