Abstract: A systems and method generate a progressively corrected scan signal, the progressively corrected scan signal having a magnitude independent of spectral reflectance from a background near a target. One of the methods involves generating a baseline signal by sampling light reflected from the target and background before transmitting a light scan at the target, generating a detected signal by receiving light reflected from the target and background while transmitting the light scan at the target, and subtracting the baseline signal from the detected signal to form the progressively corrected scan signal. One circuit embodiment produces an average level independent output signal from an input signal subject to fluctuations in average level.

Abstract: Disclosed are systems and methods for generating a progressively corrected scan signal, the progressively corrected scan signal having a magnitude independent of spectral reflectance from a background near a target. One of the methods disclosed comprises generating a baseline signal by sampling light reflected from the target and background before transmitting a light scan at the target, generating a detected signal by receiving light reflected from the target and background while transmitting the light scan at the target, and subtracting the baseline signal from the detected signal to form the progressively corrected scan signal. Also disclosed are circuits for producing an average level independent output signal from an input signal subject to fluctuations in average level.

Abstract: An overload protection circuit for an AC-DC transfer standard employing a thermoelement comprising a heater element and a temperature sensor. A first differentiator provides an output that is a function of the voltage across the heater element. A second differentiator produces an output that is a function of the output of the first differentiator. Further including a circuit creating an overload signal provided, which is responsive to the outputs of the first and second differentiators.

Abstract: A compensation circuit for a heater wire and a temperature sensor, the temperature sensor generating a signal whose amplitude is dependent upon the amplitude of the voltage across the heater wire. The circuit comprises a comparator circuit and a priority encoder circuit for generating digital information that is a function of the amplitude of the voltage in the heater wire; a multiplexor/demultiplexor circuit, responsive to the digital information generated, for generating a reversal error compensation signal, the generated reversal error compensation signal having an amplitude that is a function of the Peltier and Thomson effects associated with the heater wire; and amplifier/chopper circuits adapted to generate a compensated sensor signal that is a function of the reversal error compensation signal and the uncompensated sensor signal.