摘要:
An optical disc system including a focusing mechanism and a tracking mechanism, wherein the mechanisms are controlled by feedback loops having electronic circuits for generating a servo error signals. The error signals are communicated in the feedback loop for effecting corrections of the focusing mechanism and the tracking mechanism. The optical disc system is provided with digital lead/lag compensation circuit assembly including a servo loop having servo loop transfer function and an error signal. The circuit assembly includes a motor or actuator having a mechanical resonance frequency being less than a predetermined sampling frequency and a compensation circuit for stabilizing the servo loop. The error signal of the servo loop is sampled at the pre-determined sampling frequency. Normalization of the error signals to the information signal occurs during sampling. The compensation circuit has a compensation transfer function including a single lead and a complex lag for producing a notch filter with a notch. The compensation transfer function is formulated so that the notch occurs at approximately one half the predetermined sampling frequency thereby reducing amplitude of the mechanical resonance frequency in the servo loop transfer function. The optical disc system also includes a mechanical isolator for vibration isolation and accommodation of thermal expansion, an oscillator with a tank circuit having an increased resistance, an improved focus capture system, and means for identifying blank sectors in a storage medium.
摘要:
The optical drive system described comprises an optical assembly, a light source, an objective lens disposed in an objective lens subassembly, an actuator assembly which suspends the objective lens subassembly for relative motion thereof with respect to the actuator assembly, first and second servomotors for moving the objective lens subassembly in tracking and focusing directions, respectively, relative to the actuator assembly, a third servomotor for moving the actuator assembly in the tracking direction relative to a medium, first electronic means for controlling the first, second and third servomotors, a motor with a hub assembly for moving the medium relative to the objective lens subassembly, a photo detector, second electronic means responsive to an output signal of the photo detector for decoding information carried in the light returning from the medium, third electronic means for enabling the light source to emit light at a first intensity level to encode information on the medium and at a second intensity level to read information encoded thereon, data receiving means for accepting data that is storable on the medium, data encoding means being responsive to the data receiving means for representing the data to be stored in a predetermined format, the data encoding means also for directing data to the third electronic means, a magnetic field generator for producing a magnetic field on a portion of the medium and for coacting with the third electronic means and the light source to write and erase information on the medium, a cartridge leading assembly, servo error detecting means coupled to the first electronic means, and a housing structure for positioning components of the optical drive system with respect to one another. Most of the systems claimed include means to monitor and use a Quad Sum signal associated with the return light for focus capture.
摘要:
An optical disc system includes a laser driver for controlling an electrical current directed to a laser. The driver includes means for switching the drive voltage between a first voltage level and a second voltage level, so that electric power is only consumed when the laser is energized, thereby achieving enhanced rise and fall switching characteristics. The means for applying the drive voltage may include a CMOS buffer output.
摘要:
An optical disc system including a focusing mechanism and a tracking mechanism, wherein the mechanisms are controlled by servo error and control assembly having at least one servomoto and an analog to digital convertor (U11). The analog to digital convertor has a reference voltage input (REF+,REF-). The reference voltage input is supplied by a quad sum signal from a photodetector, and is used to normalize the focus and tracking error signals (FE,TE) for input into the servo loop. The optical disc system mayalso include an improved focus capture system.
摘要:
An optical disc system includes a laser driver for controlling an electrical current directed to a laser. The driver includes means for switching the drive voltage between a first voltage level and a second voltage level, so that electric power is only consumed when the laser is energized, thereby achieving enhanced rise and fall switching characteristics. The means for applying the drive voltage may include a CMOS buffer output.
摘要:
The optical drive system described comprises an optical assembly, a light source, an objective lens disposed in an objective lens subassembly, an actuator assembly which suspends the objective lens subassembly for relative motion thereof with respect to the actuator assembly, first and second servomotors for moving the objective lens subassembly in tracking and focusing directions, respectively, relative to the actuator assembly, a third servomotor for moving the actuator assembly in the tracking direction relative to a medium, first electronic means for controlling the first, second and third servomotors, a motor with a hub assembly for moving the medium relative to the objective lens subassembly, a photo detector, second electronic means responsive to an output signal of the photo detector for decoding information carried in the light returning from the medium, third electronic means for enabling the light source to emit light at a first intensity level to encode information on the medium and at a second intensity level to read information encoded thereon, data receiving means for accepting data that is storable on the medium, data encoding means being responsive to the data receiving means for representing the data to be stored in a predetermined format, the data encoding means also for directing data to the third electronic means, a magnetic field generator for producing a magnetic field on a portion of the medium and for coacting with the third electronic means and the light source to write and erase information on the medium, a cartridge loading assembly, servo error detecting means coupled to the first electronic means, and a housing structure for positioning components of the optical drive system with respect to another. Most of the systems claimed include means to monitor and use a Quad Sum signal associated with the return light for focus capture.
摘要:
The optical drive system described comprises an optical assembly, a light source, an objective lens disposed in an objective lens subassembly, an actuator assembly which suspends the objective lens subassembly for relative motion thereof with respect to the actuator assembly, first and second servomotors for moving the objective lens subassembly in tracking and focusing directions, respectively, relative to the actuator assembly, a third servomotor for moving the actuator assembly in the tracking direction relative to a medium, first electronic means for controlling the first, second and third servomotors, a motor with a hub assembly for moving the medium relative to the objective lens subassembly, a photo detector for decoding information carried in the light returning from the medium, third electronic means for enabling the light source to emit light at a first intensity level to encode information on the medium and at a second intensity level to read information encoded thereon, data receiving means for accepting data that is storable on the medium, data encoding means being responsive to the data receiving means for representing the data to be stored in a predetermined format, the data encoding means also for directing data to the third electronic means, a magnetic field generator for producing a magnetic field on a portion of the medium and for coacting with the third electronic means and the light source to write and erase information on the medium, a cartridge loading assembly, servo error detecting means coupled to the first electronic means, and a housing structure for positioning components of the optical drive system with respect to one another. Most of the systems claimed include means to monitor and use a Quad Sum signal associated with the return light for focus capture.
摘要:
The optical drive system described comprises an optical assembly, a light source, an objective lens disposed in an objective lens subassembly, an actuator assembly which suspends the objective lens subassembly for relative motion thereof with respect to the actuator assembly, first and second servomotors for moving the objective lens subassembly in tracking and focusing directions, respectively, relative to the actuator assembly, a third servomotor for moving the actuator assembly in the tracking direction relative to a medium, first electronic means for controlling the first, second and third servomotors, a motor with a hub assembly for moving the medium relative to the objective lens subassembly, a photo detector, second electronic means responsive to an output signal of the photo detector for decoding information carried in the light returning from the medium, third electronic means for enabling the light source to emit light at a first intensity level to encode information on the medium and at a second intensity level to read information encoded thereon, data receiving means for accepting data that is storable on the medium, data encoding means being responsive to the data receiving means for representing the data to be stored in a predetermined format, the data encoding means also for directing data to the third electronic means, a magnetic field generator for producing a magnetic field on a portion of the medium and for coacting with the third electronic means and the light source to write and erase information on the medium, a cartridge loading assembly, servo error detecting means coupled to the first electronic means, and a housing structure for positioning components of the optical drive system with respect to another. Most of the systems claimed include means to monitor and use a Quad Sum signal associated with the return light for focus capture.