Abstract: Methods, systems and apparatus are provided that implement duty cycle modulation of periodic time-synchronous (PTS) receivers for noise reduction. For instance, when a composite signal is received at a PTS receiver, the composite signal includes an input signal and a noise signal. The composite signal is input to a transmission gate of the PTS receiver. The PTS receiver also receives a gating control input signal that turns the transmission gate on and off. A duty cycle controller adjusts a variable duty cycle of the gating control input signal applied to the transmission gate to output an output signal from the transmission gate such that one or more components of the noise signal present in the composite signal is/are reduced in the output signal that is output by the transmission gate.

Abstract: Methods, systems and apparatus are provided that implement duty cycle modulation of periodic time-synchronous (PTS) receivers for noise reduction. For instance, when a composite signal is received at a PTS receiver, the composite signal includes an input signal and a noise signal. The composite signal is input to a transmission gate of the PTS receiver. The PTS receiver also receives a gating control input signal that turns the transmission gate on and off. A duty cycle controller adjusts a variable duty cycle of the gating control input signal applied to the transmission gate to output an output signal from the transmission gate such that one or more components of the noise signal present in the composite signal is/are reduced in the output signal that is output by the transmission gate.

Abstract: An on-line monitor for electrical faults in the stator of an ac motor has a single di/dt current transformer or three separate di/dt current transformers coupled to the three phase conductors of the ac supply. The windings of the transformer, or transformers, are selected to generate a single sensed signal containing a linear combination of components of current in the three phase conductors weighted relatively so that algebraic differences between components from any two phase conductors is non-zero, such as preferably 2A+B-C or 3A+2B+C. The single sensed current signal is bandpass filtered to generate a pulse signal which is applied to an analyzer. The analyzer, preferably implemented by a microcontroller, generates an output based upon a combination of the amplitude and frequency of occurrence of the current pulse signal including a time attenuated accumulation of the pulses.