Abstract: An ultrasonic beam shaping device includes a plate-like beam shaping element formed of opaque material. The beam shaping element has first and second conical surfaces, with a common axis, formed as opposite surface portions of the beam shaping element. A cylindrical aperture is formed in the beam shaping element along the common axis of the first and second conical surfaces such that the cylindrical aperture is also co-axial with the conical surfaces and passes through the conical surfaces. The beam shaping element thus has a circular open end at each conical surface.

Abstract: An ultrasonic beam shaping device includes a plate-like beam shaping element formed of opaque material. The beam shaping element has first and second conical surfaces, with a common axis, formed as opposite surface portions of the beam shaping element. A cylindrical aperture is formed in the beam shaping element along the common axis of the first and second conical surfaces such that the cylindrical aperture is also co-axial with the conical surfaces and passes through the conical surfaces. The beam shaping element thus has a circular open end at each conical surface.

Abstract: A node having an on-board microprocessor and circuits to perform a particular function in an analytic instrument system having a CANBUS and using distributed logic to control the various analysis functions, including data acquisition, system control, and data transition. The various node circuits and functions include generating a signal to control a motor by pulse width modulation and feedback, control of temperature for sample and reagent reactions (incubations), monitoring the status of instrument control panel switches and visual indicators, voltage sources, test sample location, processing calorimeter measurements, and the like. Each node includes a CAN interface and a reset circuit, which is responsive to the system controller for performing the specific node function and responding to controller commands. The reset circuit allows for reinitializing the node microcontroller on, e.g., system startup, or on demand from the system controller or any other node on the CANBUS.

Abstract: A circuit and method for driving a laser diode with high stability. A steady state current is generated and used to drive the laser diode. A dynamic feedback signal is generated and used to operate the laser diode in a constant power mode. An operational amplifier having a transistor and an RC circuit in the feedback loop is used to couple the drive voltage source to the laser diode. A potentiometer in the inverting amplifier input is used to control the laser diode output current amplitude. A longevity signal is provided to indicate whether or not the laser diode current is excessive.

Abstract: A system and methods for transmitting analog signals, particularly analog signals derived from an optical signal intensity, in a noisy environment over a length of cable. The optical signal is sensed by a photodetector, which is bootstrapped and backbiased to minimize the capacitive effect of the photodetector, and converted to a voltage by a transconductance stage. The voltage signal is then driven over a length of cable by a buffer amplifier having a low impedance output substantially matched to the characteristic impedance of the cable (e.g., twin lead wires having a Z.sub.0 =120), to a second circuit board. The cable length may be, e.g, less than a meter. The second circuit board contains a high gain amplifier stage and circuits for processing the high gain amplifier signal to derive, e.g, a peak pulse amplitude corresponding to the peak intensity of the optical signal sensed at the first circuit board.

Abstract: An analytic instrument utilizing a Control Arena Network (CANBUS) and nodal architecture in the instrument with functions and logic distributed throughout the Nodes. A system controller is connected on the one hand to an operator input device for controlling the instrument, and on the other hand to a plurality of nodes via a CAN scrambler. Each nodes has a CAN microcontroller and related circuitry for performing autonomously a variety of functions of the instrument. The system controller and nodes communicate using CAN interface devices over the CANBUS, passing instructions, commands and data therebetween.

Abstract: The automatic sampling system includes a test apparatus for testing specific characteristics of a fluid withdrawn from a closed test tube. Stoppered test tubes are continuously and automatically delivered to the test apparatus by a conveyor system that includes a continuous linkage of test tube holders. The test tube holders have the capability of pivotal movement about a longitudinal axis of the test tube holders, and tilting movement wherein a longitudinal axis of one test tube holder tilts with respect to the longitudinal axis of another test tube holder in the linkage. The compound pivotal and tilting movement capability of the test tube holders in the linkage enable the linkage to be stacked in a fan-fold or Z-fold arrangement because of the flexible characteristics of the linkage. The linkage also has the capability of having one or more test tube holders tilted together at a group with respect to other test tube holders. Thus, the basis for a mixing operation of specific test tube holders is achieved.