Abstract: A media type detector in a tracking and focus servo system is presented. Operating parameters for a first media type are loaded and a peak-to-peak value of a tracking error signal is calculated. Whether the media type is the first media or a second media can then be determined by comparing the peak-to-peak value with a threshold value.

Abstract: A tracking servo system with a at least one second order digital filter is presented. The servo system calculates an error signal and offsets, amplifies, and filters the error signal before a control signal is calculated. The control signal is then utilized to position an optical pick-up unit which provides signals from which the error signal is calculated. Filters in the servo system can include a low-pass integrator, a phase lead filter, notch filters, or other filters. At least one of the filters is a second order digital filter.

Abstract: A system, method, and apparatus for recovering from performance errors in an optical disc drive is provided for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The system includes instructions operable to detect a problem with at least one of: focus control, tracking control, or spin control when accessing the optical media; instructions operable to save the current state of the disc drive; instructions operable to attempt to recover from the problem; and instructions operable to restore the current state of the disc drive after recovering from the problem.

Abstract: A calibration of input signal offsets for stray light in an optical disk drive is presented. The input signal offsets can be determined by setting a laser power level, receiving digitized input signals, and setting the input signal offsets so that the digitized input signals are zero. The laser power level can be a read power or a write power. In some embodiments, input signal offsets for both read power and write power are determined and stored.

Abstract: A tracking servo system with a feed-forward control loop is presented. Periodic variations in a control signal can be detected. These periodic variations can be added into the control signal to form a new control signal so that on subsequent cycles the control signal does not include the periodic variations.

Abstract: A system and method for controlling spin speed, which includes a module for receiving an indication to make a velocity change from a first RPM to a second RPM. The difference between the first RPM and the second RPM is a predetermined value. The module is operable to rotate an optical medium at a maximum control effort from the first RPM to the second RPM, and rotate the optical medium with a proportional plus integral (P+I) control at the second RPM.

Abstract: A device with an optical disk drive with a digital servo system for controlling tracking or focus in an optical disk driver is presented. A servo system according to the present invention includes an optical pick-up with detectors providing optical signals, an analog processor receiving the optical signals and providing a digital signal, and digital processors receiving the digital signal and providing a control signal that controls the position of the optical pick-up unit. The digital processor executes an algorithm that calculates an error signal, provides amplification and biasing to the error signal, provides filtering for the error signal, and computes the control signal. The error signal can be the focus error signal or the tracking error signal. The device can be any device.

Abstract: A determination of a focus sum threshold in a tracking and focus servo system of an optical disk drive is presented. The focus sum threshold can be determined by moving an optical pick-up unit sinusoidally through a focus position, for example by moving the optical pick-up unit between its closest position to an optical media and its farthest position from the optical media. While moving the optical pick-up unit, a sum signal is monitored. In some embodiments, the sum signal is the sum of signals from a plurality of detectors in the optical pick-up unit. The focus sum threshold is set to a fraction of a peak value of the sum signal.

Abstract: A direction sensor in a tracking and focus servo system of an optical disk drive is presented. The direction sensor calculates a direction sum signal and a tracking error signal from side elements of detectors in an optical pick-up unit of the optical disk drive. A first direction can be indicates when the signs of a high-pass filtered sum signal and a high pass filtered tracking error signal are opposite and a second direction opposite the first direction if the signs are the same.

Abstract: A digital servo system for controlling tracking or focus in an optical disk driver is presented. A servo system according to the present invention includes an optical pick-up with detectors providing optical signals, an analog processor receiving the optical signals and providing a digital signal, and digital processors receiving the digital signal and providing a control signal that controls the position of the optical pick-up unit. The digital processor executes an algorithm that calculates an error signal, provides amplification and biasing to the error signal, provides filtering for the error signal, and computes the control signal. The error signal can be the focus error signal or the tracking error signal.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can be operable to detect a first BEMF crossing and setting a first time stamp, to detect a second BEMF crossing and setting a second time stamp, to calculate a measured spin period as the difference between the first time stamp and the second time stamp, to compare the measured spin period to a reference spin period to determine a period error, to operate on the period error with a proportional gain and an integrator gain to provide a command output; and to drive a winding in the spin motor with a current to cause the spin motor to change velocity in response to the command output.

Abstract: A system, method, and apparatus for coordinating tasks in a control system for an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The optical disc drive includes a first processor operable to communicate with a second processor, wherein the first processor includes instructions for performing non-time-critical tasks, and the second processor includes instructions for performing time-critical tasks, such as reading from and writing to optical media in the disc drive. The first processor monitors the status of the time critical tasks in the second processor and transmits commands to perform operations in the second processor. The first processor also controls power mode, manages recovery from errors, controls focus, tracking/seeking, spin, physical sector address (PSA), a laser, adjusts gains, and monitor cartridge load/eject.

Abstract: A method of changing the position of a component controlled by a servo system is disclosed. In accordance with the disclosed invention, the current position and the current control signal corresponding to the current position is determined. A target control signal corresponding to a target position is also determined. A smooth control signal profile is then calculated between the current control signal and the target control signal. The smooth control signal is then applied to move the component form the current position to the target position. In some embodiments, the smooth control signal can be, for example, a half-period sine wave with one extreme at the current control signal and the opposite extreme at the target control signal.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can include a lookup table module providing a reference period corresponding to each of a physical sector address on an optical medium. The system can further include a drive module configured to sense a BEMF zero crossing occurring in a spin motor. A measurement of two of the BEMF zero crossings can be used to calculate a spin period measurement. The reference period can be compared to the spin period measurement to provide a period error value. The system also includes a controller module for providing a control command to drive the spin motor in response to the period error value.

Abstract: A system, method, and apparatus for coordinating tasks in a control system for an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The optical disc drive includes a first processor operable to communicate with a second processor, wherein the first processor includes instructions for performing non-time-critical tasks, and the second processor includes instructions for performing time-critical tasks, such as reading from and writing to optical media in the disc drive. The first processor monitors the status of the time critical tasks in the second processor and transmits commands to perform operations in the second processor. The first processor also controls power mode, manages recovery from errors, controls focus, tracking/seeking, spin, physical sector address (PSA), a laser, adjusts gains, and monitor cartridge load/eject.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can be operable to obtain digital feedback from a spin motor. The present invention includes detecting data representing a position on an optical medium and determining a detection rate; comparing the detection rate to a reference rate to provide an error rate; generating an output command in response to the error rate to provide a drive output which commands a voltage applied to a spin motor to adjust the spin speed of said spin motor.

Abstract: A control system for controlling tracking and seeking in an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The control system determines whether an optical pickup unit is over the premastered or the writeable areas of the optical media by measuring peak to peak amplitude of a tracking error signal. Gains and calibration values are selected based on whether an optical pickup unit is over the premastered or the writeable areas of the optical media. Reading from and writing to the optical media is disabled while jumping tracks. Control of jumping tracks on the optical media includes controlling: jumping a single track on the optical media; jumping a specified number of tracks every specified number of revolutions of the optical media; auto jumpbacks, and jumping in forward or reverse directions.

Abstract: US vi A calibration of input signal offsets for stray light in an optical disk drive is presented. The input signal offsets can be determined by setting a laser power level, receiving digitized input signals, and setting the input signal offsets so that the digitized input signals are zero. The laser power level can be a read power or a write power. In some embodiments, input signal offsets for both read power and write power are determined and stored.

Abstract: A calibration of a loop gain in a digital servo system is presented. The loop gain can be calibrated measuring the response in a control signal generated by the digital servo system when the control signal is replaced by a sum of the control signal and a sinusoidal disturbance. The loop gain can be set to provide a desired gain, for example unity, between the control signal and the sinusoidal disturbance at a cross-over frequency.

Abstract: A notch filter that filters a focus error signal during a multi-track seek operation is presented. The notch filter has a center frequency that relates to the seek reference velocity of a multi-rack seek algorithm. During the multi-track seek operation, a focus control signal is calculated from the filtered focus error signal from the notch filter.