Abstract: An improved method for calibrating threshold voltage levels on comparators corresponds to providing a dithered DC signal to one input and adjusting the threshold voltage on the other input in response to the comparator output. Such calibration may be necessary for comparator circuitry associated with measurement devices. A circuit to generate a dithered DC signal sums a precise DC value with a time-varying signal that has been modified, such as a rectified AC signal. During the calibration procedure, the internal threshold voltage is varied until no timing measurements are present. The difference between the determined optimum threshold voltage and the ideal voltage is stored in a system computer associated with the measurement device and used later in the measurement process to produce a precise threshold voltage input.

Abstract: Improved input circuitry for use in conjunction with measurement devices is disclosed. The subject input circuitry enables a single measurement device to take measurements on both single-ended and differential signal inputs. Software-implemented control signals can be programmed by a user or set to default values to select which type of input signal is to be measured. The input circuitry minimizes the use of electromechanical relays and other components or phenomena that may degrade the quality of the input signals, and also includes resistor networks to additionally help maintain signal integrity. A plurality of common programmable voltage sources is provided for use in accordance with select embodiments of the disclosed technology to serve as either termination voltages, threshold voltages, or both.

Abstract: An improved method for calibrating threshold voltage levels on comparators corresponds to providing a dithered DC signal to one input and adjusting the threshold voltage on the other input in response to the comparator output. Such calibration may be necessary for comparator circuitry associated with measurement devices. A circuit to generate a dithered DC signal sums a precise DC value with a time-varying signal that has been modified, such as a rectified AC signal. During the calibration procedure, the internal threshold voltage is varied until no timing measurements are present. The difference between the determined optimum threshold voltage and the ideal voltage is stored in a system computer associated with the measurement device and used later in the measurement process to produce a precise threshold voltage input.

Abstract: Improved input circuitry for use in conjunction with measurement devices is disclosed. The subject input circuitry enables a single measurement device to take measurements on both single-ended and differential signal inputs. Software-implemented control signals can be programmed by a user or set to default values to select which type of input signal is to be measured. The input circuitry minimizes the use of electromechanical relays and other components or phenomena that may degrade the quality of the input signals, and also includes resistor networks to additionally help maintain signal integrity. A plurality of common programmable voltage sources is provided for use in accordance with select embodiments of the disclosed technology to serve as either termination voltages, threshold voltages, or both.