Abstract: A system and method to detect the fundamental frequency of an electric input signal using a feedback control loop including a phase error detector, a loop controller, and a digitally controlled oscillator. The frequency detector may detect the fundamental frequency of an electric input signal and produce an output signal representing the fundamental frequency of the electric input signal. The frequency detector may further include a filter that may be coupled to the frequency detector output signal in order to remove spurious tones or noise from the output signal.

Abstract: A device and method for measuring active and reactive powers of an alternating current includes receiving a first signal representing a current and a second signal representing a voltage, in which the current includes a phase offset with respect to the voltage, calculating an active power and reactive power based on the first and second signals, and calibrating the calculated active and reactive powers with respect to the phase offset using first and second constants, in which the first and second constants respectively correspond to a sine value and a cosine value of the phase offset.

Abstract: A system and method to detect the fundamental frequency of an electric input signal using a feedback control loop including a phase error detector, a loop controller, and a digitally controlled oscillator. The frequency detector may detect the fundamental frequency of an electric input signal and produce an output signal representing the fundamental frequency of the electric input signal. The frequency detector may further include a filter that may be coupled to the frequency detector output signal in order to remove spurious tones or noise from the output signal.

Abstract: In one embodiment, a measuring device may comprise two oscillators. The first oscillator may generate a local reference signal in a frequency detector to detect a fundamental frequency of the AC. The second oscillator may generate two substantially mutually orthogonal sinusoid signals having the selected frequency. The measuring device further may comprise a first group of multipliers that mixes the two sinusoid signals with a current and a voltage data signal of the AC respectively, a group of low-pass filters for removing high frequency components from the multiplication products, a second group of multipliers for mixing the filtered multiplication produces respectively, and a plurality of adders each to sum together a pair of multiplication products of the second group of multipliers.

Abstract: A system and method to detect the fundamental frequency of an electric input signal using a feedback control loop including a phase error detector, a loop controller, and a digitally controlled oscillator. The frequency detector may detect the fundamental frequency of an electric input signal and produce an output signal representing the fundamental frequency of the electric input signal. The frequency detector may further include a filter that may be coupled to the frequency detector output signal in order to remove spurious tones or noise from the output signal.

Abstract: In one embodiment, a measuring device may comprise two oscillators. The first oscillator may generate a local reference signal in a frequency detector to detect a fundamental frequency of the alternating current (AC). The second oscillator may generate two substantially mutually orthogonal sinusoid signals having the selected frequency. The measuring device further may comprise a first group of multipliers that mixes the two sinusoid signals with a current and a voltage data signal of the AC respectively, a group of low-pass filters for removing high frequency components from the multiplication products, a second group of multipliers for mixing the filtered multiplication products respectively, and a plurality of adders each to sum together a pair of multiplication products of the second group of multipliers.

Abstract: A device and method for measuring active and reactive powers of an alternating current includes receiving a first signal representing a current and a second signal representing a voltage, in which the current includes a phase offset with respect to the voltage, calculating an active power and reactive power based on the first and second signals, and calibrating the calculated active and reactive powers with respect to the phase offset using first and second constants, in which the first and second constants respectively correspond to a sine value and a cosine value of the phase offset.

Abstract: In one embodiment, a measuring device may comprise two oscillators. The first oscillator may generate a local reference signal in a frequency detector to detect a fundamental frequency of the AC. The second oscillator may generate two substantially mutually orthogonal sinusoid signals having the selected frequency. The measuring device further may comprise a first group of multipliers that mixes the two sinusoid signals with a current and a voltage data signal of the AC respectively, a group of low-pass filters for removing high frequency components from the multiplication products, a second group of multipliers for mixing the filtered multiplication products respectively, and a plurality of adders each to sum together a pair of multiplication products of the second group of multipliers.

Abstract: A system and method to detect the fundamental frequency of an electric input signal using a feedback control loop including a phase error detector, a loop controller, and a digitally controlled oscillator. The frequency detector may detect the fundamental frequency of an electric input signal and produce an output signal representing the fundamental frequency of the electric input signal. The frequency detector may further include a filter that may be coupled to the frequency detector output signal in order to remove spurious tones or noise from the output signal.

Abstract: A method for measuring active power of alternating current (AC) using a digital phase-locked loop (DPLL) includes the steps of (1) generating via the DPLL a pair of substantially mutually orthogonal sinusoid signals in response to an input voltage data signal, (2) mixing a first sinusoid signal of the pair with a current data signal of the alternating current via a first low-pass filter, (3) mixing the first sinusoid signal of the pair with a voltage signal of the alternating current via a second low-pass filter, and (4) computing an active power of the alternating current based on an output from the first low-pass filter and an output from the second low-pass filter.

Abstract: A method and device for measuring active power of AC with respect to a fundamental frequency or harmonic frequencies using a DPLL include generating via the DPLL a pair of substantially mutually orthogonal sinusoid signals in response to an input voltage data signal, mixing a first sinusoid signal of the pair with a current data signal of the alternating current via a first low-pass filter, mixing the first sinusoid signal of the pair with a voltage signal of the alternating current via a second low-pass filter, and computing an active power of the alternating current based on a further mixing of an output from the first low-pass filter and an output from the second low-pass filter.

Abstract: A sample rate converter reduces the sampling rate of a signal by a fractional number U/D, where U represents an up-sampling rate and D represents a down-sampling rate. The converter comprises an input for receiving an input data stream at a first rate and an FIR filtering stage. The FIR filtering stage comprises a set of D polyphase filter branches, each branch including a set of filter coefficients which operate on a sample of the input signal. The converter also comprises a commutative switch which selectively connects a sample of the input data stream to one of the polyphase filter branches, the switch being arranged to skip every U?1 filter branches during a cycle through the filter branches. An output outputs an output data stream at a second data rate which is lower than the first data rate.

Abstract: A sample rate converter reduces the sampling rate of a signal by a fractional number U/D, where U represents an up-sampling rate and D represents a down-sampling rate. The converter comprises an input for receiving an input data stream at a first rate and an FIR filtering stage. The FIR filtering stage comprises a set of D polyphase filter branches, each branch including a set of filter coefficients which operate on a sample of the input signal. The converter also comprises a commutative switch which selectively connects a sample of the input data stream to one of the polyphase filter branches, the switch being arranged to skip every U-1 filter branches during a cycle through the filter branches. An output outputs an output data stream at a second data rate which is lower than the first data rate.