Abstract: The present invention is an optical detection system to detect various areas of an optical storage medium. The optical detection system comprises a pickup head, a signal adder and an adding comparator. The pickup head have a light source for providing an incident light beam to the data area and the header, and generating the corresponding reflective light beam. The pickup head detects the reflective light beam to generate left-side detection signals and right-side detection signals. The signal adder adds the amplitudes of the left-side detection signal and the right-side detection signal to generate an adding signal. The adding comparator compares the adding signal with a predetermined adding reference signal to generate a compared adding signal. According to the compared adding signal, the optical detection system can determine that the reflective light beam detected by the pickup head comes from the data area or the header.

Abstract: An offset calibration system of a control loop at least comprises a pre-amplifier circuit and a post-amplifier circuit. The pre-amplifier circuit generates a pre-output signal and then transmits the pre-output signal to the post-amplifier circuit to amplify. The offset calibration system comprises a comparator, an offset calibration module, and a determination circuit. The comparator compares the pre-output signal with a predetermined pre-reference signal to generate a pre-compared signal. The offset calibration module stores a predetermined and adjustable offset calibration value for adding to the pre-output signal. The determination circuit adjusts the offset calibration value based on the pre-compared signal, so the offset calibration value can be added to the pre-output signal dynamically to compensate and calibrate the offset of the pre-output signal caused by the pre-amplifier circuit to avoid the post-amplifier circuit amplifying the offset of the pre-output signal again.

Abstract: A hand held grinder includes a hollow cowl and a vibration absorber mounted in the cowl. The vibration absorber includes a longitudinal through hole defined through center parallel to the axis of the cowl, and a radial through hole defined in the vibration absorber. The radial through hole communicates with the longitudinal through hole. A socket is defined in the vibration absorber and communicates with the longitudinal through hole and the radial through hole. A transmission device penetrates the vibration absorber and forms a pivot pivotally received in the socket of the vibration absorber. The transmission device has a hollow threaded shaft formed on the exterior end and a neck formed on the other end. A main shaft eccentrically connects and drives the transmission device. The main shaft includes an enlarged external end and a shank extending from the enlarged external end along the axis of the main shaft.

Abstract: An analog to digital converter for the conversion of an analog input signal to a digital output code of n bits has a plurality of voltage references created in a voltage reference generator that divides the total range of voltage of the conversion input into increments of voltage equal to the smallest increment of resolution. The n bits of digital output are divided into most significant bits and least significant bits. The most significant bits are encoded from a set of digital signals that are formed in a set of coarse comparators, that compare the analog input signal with a subset of the voltage references representing the coarse range. The digital code that is the output of the coarse comparators is used to determine the selection of the subset of the plurality of the voltage references that are the fine voltage references. The least significant bits are encoded from a set of digital signals that are formed in a set of fine comparators that compare the analog input signal to the fine voltage references.

Abstract: An analog to digital converter for the conversion of an analog input signal to a digital output code is disclosed. The analog to digital converter has a voltage reference generator to create a plurality of voltage references that divides the total conversion range of the input into increments equal to the smallest resolution increment. The digital output code is divided into most significant bits, intermediate significant bits and least significant bits. The most significant bits are encoded from a set of coarse digital signals that are formed in a set of coarse comparators. The coarse digital code is used to determine the selection of the sub-coarse voltage references. The intermediate significant bits are encoded from a set of subcoarse digital signals. The subcoarse digital code that and the coarse digital code are used to determine the selection of the fine voltage references.