Abstract: Methods, circuits, and systems for determining the presence of a chopped input signal are disclosed. A digital signal generator can produce multiple digital signals when an alternating current (AC) signal input reaches multiple threshold voltages. The times at which the threshold voltages are reached can be determined by looking at the times at which the digital signals go high and low. The differences between the times at which the digital signals go high and low are used to determine if the AC signal input is a leading or trailing edge chopped signal. The AC input signal is a leading edge chopped signal when the difference between the times at which the digital signals go high is less than a predetermined time threshold, and is a trailing edge chopped signal when the difference between the times at which the digital signals go low is less than a predetermined time threshold.

Abstract: A signal including at least one group of a group comprised of two slopes having different gradients and a known temporal position relationship is applied to a device under test, the time intervals between the specific transitions of the logic level produced in the output signal of the device under test in response to the slopes included in the applied signal are measured, and the measurements are used to obtain the input threshold level of the device under test.

Abstract: An electrical testing device has non-contact AC voltage sensing, single probe contact AC voltage testing and voltage metering functions. Non-contact voltage sensing is used to detect the vicinity of a live AC conductor and single probe contact sensing is used to determine which conductor of a number of conductors in the vicinity is live. More specific information about the magnitude of the voltage can then be determined using both contact probes. The electrical testing device automatically determines the type (AC or DC) and polarity (if DC) of a voltage applied to test terminals, and provides an indication of the voltage range (AC or DC), without the need to operate any switches or other electrical actuators.

Abstract: A system for measuring signals in a non-linear network is provided which reduces the reliance on hardware and processing support when correcting for A/D offset by performing a pair of dual slope measurement cycles with an integrating analog to digital converter (ADC) circuit. Each of the measurement cycles has at least four phases including a first integrating phase and a first de-integrating phase followed by a second integrating phase and a second de-integrating phase. The system further includes an ADC controller operatively communicative with the integrating ADC circuit for detecting when the first count value is reached during the second de-integrating phase and then resetting the second count value in response to this detection so that the second count value is offset corrected at the end of the second de-integration phase. As a result, a difference calculation is automatically performed during the measurement cycle.

Abstract: A system for measuring signals in a non-linear network is provided which reduces the reliance on hardware and processing support when correcting for A/D offset by performing a pair of dual slope measurement cycles with an integrating analog to digital converter (ADC) circuit. Each of the measurement cycles has at least four phases including a first integrating phase and a first de-integrating phase followed by a second integrating phase and a second de-integrating phase. The system further includes an ADC controller operatively communicative with the integrating ADC circuit for detecting when the first count value is reached during the second de-integrating phase and then resetting the second count value in response to this detection so that the second count value is offset corrected at the end of the second de-integration phase. As a result, a difference calculation is automatically performed during the measurement cycle.