Keithley Instruments, Inc.

Gregory Roberts, Ii

John G Banaska

William C Weeman

A configurable instrument includes a mainframe having one or more processors, a chassis having slots to accept one or more instrument modules, a communication bus coupled to all of the instrument modules inserted in the slots, and a communication backplane, separate from the communication bus, and configured to allow point-to-point communication between any pair of modules inserted in the slots.

Direct instrument-to-instrument communication without using a system controller

A digital-to-analog converter, including an input to receive a digital signal; a first comparator configured to receive the digital signal and output a first signal based on the digital signal and a first threshold; a second comparator configured to receive the digital signal and output a second signal based on the digital signal and a second threshold, the second threshold different from the first threshold; and an integrator configured to receive the first signal and the second signal and integrate the first signal and the second signal into an analog signal that represents the digital signal.

High-speed high-resolution digital-to-analog converter

A method for compensating for a dielectric absorption effect in a measurement configuration during measurements by an instrument having measurement terminals includes providing a feedback loop in the instrument, the loop having a gain adjustment and a simulation impedance and being adapted to provide a signal counter to the dielectric absorption at the measurement terminals; applying a transient calibration signal to the test terminals for at least two values of the gain adjustment; measuring a response to the calibration signal for each of the at least two values; and determining an operating value of the gain adjustment based on the measured responses. The operating value is used for subsequent measurements by the instrument, the simulation impedance modeling the dielectric absorption characteristics of the measurement configuration.

Dielectric absorption compensation for a measurement instrument

An electronic instrument having in its circuitry a specific solid state switch that exhibits detrimental current leakage at elevated temperatures, a variable voltage device in the instrument connected to the specific switch, the variable voltage device being capable, at an experimentally determined voltage setting, of zeroing out the leakage current in the specific switch, the variable voltage device being set at a voltage setting determined experimentally using said specific switch at an elevated temperature thereby temperature compensating said specific switch.

Output leakage compensation and method for implementing the same

A circuit for controlling a voltage across a device and permitting measurement of a current through the device includes a sense impedance in series combination with, the device, a sensed voltage measured across the sense impedance being representative of the current through the device; a capacitive stability element in parallel combination with the sense resistance, the capacitive stability element being virtually absent by connection to a virtual version of the sensed voltage when the device has a first capacitance and being present when the device has a second capacitance, the second capacitance being larger than the first capacitance.

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Cleveland, OH, United States of America

Gregory Roberts, Ii