Linear Instruments

Spectra-physics Gmbh

James L Mills

Scot Randy Weinberger

Louis Hlousek

An analog to digital signal converter includes an integrator and a sample and hold circuit. Precisely repeatable timing signals for both the integrator and sample and hold circuit are provided by a microprocessor. The device provides low pass filtering without the phase lag normally associated with linear filters. The device allows one set of data to be acquired while the previous set of data is being digitized. The device is especially applicable to analysis of data generated by a spectrophotometer.

Analog to digital conversion using an integrater and a sample and hold

An electrophoresis instrument includes a capillary tube mounted in an air cooled cartridge. The cartridge also supports a spherical lens which is part of the optical detection apparatus. The cartridge rests in a manifold which includes the sample and buffer reservoirs. The temperature of the capillary tube is controlled by measuring the electrical resistance of the capillary tube during the electrophoresis process and then cooling or heating the cartridge by circulating temperature controlled air over the tube. The optical path associated with the instrument is a fiber optic bundle bifurcated close to dual detectors into a reference arm and a sample arm so as to provide similar reference and sample optical paths. The instrument may be used for temperature control for gradient electrophoresis and also, a neutral marker for determining electro-osmotic flow may be detected.

Thermal control for capillary electrophoresis apparatus

A method and device for smoothly rotating a diffraction grating in a spectrophotometer by means of a galvanometer includes modifications in the software in the microprocessor which controls the galvanometer. The software modifications cause the galvanometer to rotate the grating in a series of discrete steps that stimulate a smooth minimum jerk rotation. The amount of rotation in each discrete step is calculated by the microprocessor.

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Reno, NV, United States of America

James L Mills