A method for startup of a crystal oscillator (XO) with aid of external clock injection, associated XO and a monitoring circuit therein are provided. The XO includes an XO core circuit, an external oscillator, and an injection switch, where a quality factor of the external oscillator is lower than a quality factor of the XO core circuit. The method includes: utilizing the external oscillator to generate an injected signal; turning on the injection switch to make energy of the injected signal be injected into the XO core circuit, where an amplitude modulation (AM) signal is generated according to combination of the injected signal and an intrinsic oscillation signal from the XO core circuit; and controlling the external oscillator to selectively change an injection frequency of the injected signal according to the AM signal. More particularly, the injection switch is not turned off until the startup process is completed.

An induction heating device includes a working coil, an inverter including a first switching element and a second switching element that are configured to perform a switching operation and to apply a resonance current to the working coil, a snubber capacitor including a first snubber capacitor connected to the first switching element, and a second snubber capacitor connected to the second switching element, a phase detector configured to detect a phase difference between the resonance current applied to the working coil and a switching voltage applied to the second switching element, and a controller configured to receive, from the phase detector, phase information including the phase difference, provide the inverter with a switching signal to thereby control the switching operation, and adjust an operating frequency of the switching signal based on the phase information to thereby control an output of the working coil.

An improved phasor estimation method for M-class phasor measurement units (PMUs) with a low computational burden is described. The method contains three steps: 1) A phasor measurement filter is designed by selecting parameters of Taylor weighted least square method to prioritize dynamic phasor accuracy and a high level of suppression on high-frequency interferences; 2) A finite impulse response lowpass filter is designed by the equal-ripple method is put forward to suppress low-frequency interferences; and 3) Phasor amplitude is corrected under off-nominal conditions.

The present system relates to a power topology mapping system for identifying which one of one or more equipment components are being powered from a specific phase of a multi-phase AC power source. The system makes use of a plurality of power receiving subsystems which each receive an AC power signal from at least one phase of the multi-phase AC power source. Each power receiving subsystem has a communications card, an identification designation unique to it, and a controller. One of the power receiving subsystems is designated as a reference power domain component. The controllers each carry out phase angle measurements associated with the AC power signal being received by its power receiving subsystem. A topology mapping subsystem is included which analyzes phase angle measurement data reported by the power receiving subsystems and determines which subsystem is being powered by which phase of the multi-phase AC signal.

A system and method for combining a remote audio source with an animatronically controlled puppet includes the steps of entering an audio file on a user client by a person where the audio file is a statement spoken by the person. The audio file is sent to a secondary client that is remote to the user client. The secondary client has a puppet controlled by animatronics. The audio file is received by an audio circuit board that converts the audio file into movement parameters. The movement parameters are sent to at least one servomechanism mounted in the puppet to actuate the animatronics in synchronicity with the audio file. Movement of the puppet is video recorded to define a video file. The audio and video files are combined to define a final video production viewable by the person.

A method for calibrating a single sideband (SSB) receiver, comprising: a) adjusting a mutual phase shift of I- and Q-signals to a first phase shift value; b) feeding a first, a second and a third test signal having a predetermined phase offset to an input to obtain respective SSB signals, and measuring a first and a second phase difference therefrom; c) calculating a first phase error on the basis of the first and second phase differences; d) repeating steps a)-c) with a second phase shift value to obtain a second phase error; and e) calibrating the SSB receiver by using that one of the first and second phase shift values that has yielded the smaller one of the first and second phase errors.

A load identification system includes an AC-power input unit, a load, a zero-crossing detector, a microcontroller, a first and a second current phase detectors. The zero-crossing detector is configured to output a zero-voltage pulse signal when a zero-crossing signal of the AC-power input unit is detected. The first current phase detector detects a current flowing through the load to output a first voltage signal. When the current flows along a first direction, the first voltage signal is at a high level. The second current phase detector is configured to detect the current flowing through the load to output a second voltage signal. When the current flows along a second direction, the second voltage signal is at a high level. The microcontroller is configured to receive and identify the type of the load according to the zero-voltage pulse signal, the first and the second voltage signals.

A system includes a plurality of delay elements configured to receive an input clock signal. The system further includes an edge transition detector coupled to the plurality of delay elements. The plurality of delay elements is configured to detect the input clock signal transitioning from one value to another value. The system also includes a circuitry configured to determine a number of delay elements of the plurality of delay elements that the input clock signal propagates through prior to the input clock signal transitioning. The system also includes a logic or controller configured to determine whether a droop event has occurred based on the number of delay elements.

A power converter circuit included in a computer system may charge and discharge a switch node coupled to a regulated power supply node via an inductor. The power converter circuit may generate a reference clock signal using a system clock signal and a voltage level of the switch node. The reference clock signal may be used to initiate a charge cycle, whose duration may be based on generated ramp signals.

A method for predicting a fault location in a distribution system is provided. In the disclosed method, voltage signals and current signals are obtained from phasor measurement units (PMUs) placed at two terminals of a distribution line (DL) in the distribution system. The two terminals include a sending terminal and a receiving terminal. The voltage signals and current signals of the DL are converted into phasors. A fault type of a faulty line of the DL is subsequently classified in the distribution system based on the converted phasors. The fault type includes a symmetric type and an asymmetric type. A fault location of the faulty line of the DL is predicted based on the fault type through an impedance-based fault location model. Further, inaccuracy mitigation measures on the predicted fault location are applied to improve prediction accuracy.