2527results about "Frequency measurement arrangement" patented technology

The subject matter of the present invention is a method for monitoring a photovoltaic generator (1) for generating current with a number of solar cells connected between two external connections by repeated feeding of a current with a frequency spectrum into the generator current circuit, detecting thereby a respective frequency response in the frequency spectrum with the supplied current as the input variable and an electric variable of the generator as the output variable, and detecting a change in the frequency response for monitoring the photovoltaic generator (1) in the event of a change during repeated feeding.

The invention discloses a power signal frequency detection method and a power signal frequency detection system based on phase modulation. The method comprises the steps: sampling a power signal according to preset signal time span and preset sampling frequency, so as to obtain an input signal sequence; measuring the frequency of the input signal sequence, so as to obtain the initial frequency of the power signal, and subtracting the input signal sequence and the plus or minus 1 Pi phase-shift sequence of the input signal sequence by using the initial frequency as reference frequency, so as to obtain two phase modulation sequences of which phases change along with the input signal frequency; respectively mixing, filtering and integrating the two phase modulation sequences, so as to obtain the phases of the two phase modulation phases for frequency measurement. By implementing the power signal frequency detection method and the power signal frequency detection system, frequency measurement results with higher accuracy can be obtained.

The invention discloses a sinusoidal parameter measurement method and system of a power signal. The method comprises the following steps: performing preliminary measurement on fundamental wave frequency of a sampling data sequence to acquire preliminary fundamental wave frequency and multiplying a cosine function and a sine function of the preliminary fundamental wave frequency serving as the reference frequency by the sampling data sequence respectively to generate a real vector sequence and an imaginary vector sequence; performing digital filtering on the real vector sequence and the imaginary vector sequence to generate a real vector filter sequence and an imaginary vector filter sequence, and further integrating to generate a real vector integral value and an imaginary vector integral value; converting the real vector integral value and the imaginary vector integral value into corresponding sinusoidal parameters according to a preset sinusoidal parameter conversion rule. By implementing the method and the system, mixed frequency interference elements in the real vector sequence and the imaginary vector sequence can be inhibited to generate high-precision real vector and imaginary vector sequence integral values so as to finally obtain the sinusoidal parameters with higher precision.

The invention provides a test system and a test method. The testing system comprises a test fixture, a test device and a differential tunable matching network, wherein the test fixture is provided with a bearing structure for loading a chip to be tested and a test port electrically connected to the chip to be tested; the test device comprises a radio frequency signal source, a receiving unit and a processing and display unit; the radio frequency signal source is provided with at least one radio frequency test port; the receiving unit is used for at least receiving a reflected signal and a transmitted signal which are generated after a radio frequency signal passes through the chip to be tested; the processing and display unit is used for processing the received radio frequency signal and displaying the processed signal; and the differential tunable matching network is provided with an input port and a differential output port and is used for tuning the impedance of a load end including the chip to be tested to make the impedance of the load end matched with the internal resistance of the test device and providing the test device to measure the characteristic of the chip to be detected in the test fixture. Compared with the prior art, the invention has the advantages that: the differential tunable matching network is provided for realizing impedance matching, the test system and the test method are easy and convenient to operate, and a more accurate test result can be acquired.

An integrated circuit (IC) is disclosed having circuitry arranged in a plurality of columns. A column in the IC is essentially a series of aligned circuit elements of the same type that extends from a first edge of the IC to a second edge. In addition there may be a center column having circuit elements of different types.

A method for making a light-emitting diode, which including the steps of: providing a substrate having at least one recessed portion on one main surface and growing a first nitride-based III-V group compound semiconductor layer through a state of making a triangle in section having a bottom surface of the recessed portion as a base thereby burying the recessed portion; laterally growing a second nitride-based III-V group compound semiconductor layer from the first nitride-based III-V group compound semiconductor layer over the substrate; and successively growing a third nitride-based III-V group compound semiconductor layer of a first conduction type, an active layer and a fourth nitride-based III-V group compound semiconductor layer of a second conduction type on the second nitride-based III-V group compound semiconductor layer.

A PIM measurement circuit enables making forward and reverse PIM measurements on any 1 port (reflection) or 2 port (transmission) device with the ability to determine in distance where individual PIM impairments are located as well as their magnitude. The PIM measurement circuit includes two frequency sources that are provided through a combiner for a CW characterization of the PIM circuit. To enable distance determination, an FM measurement is created by using a saw tooth offset sweep generator attached to one of the two frequency sources. With downconversion and processing of signals from the PIM impairments, the FM signal provides a frequency variation that is converted using a Fourier transform or spectrum analysis for separation of frequencies, enabling determination of the distance of the PIM sources as well as their magnitudes.

Methods and systems of detecting one or more characteristics of a load are disclosed. One or more characteristics of a first signal may be detected at the output of a Radio Frequency (RF) power generator. The first signal may have a fundamental frequency. The one or more characteristics of the first signal may be sampled at a sampling frequency to produce a digital sampled signal. The sampling frequency may be determined based on a function of the fundamental frequency of the first signal. One or more characteristics of a load in communication with the RF power generator may then be determined from the digital sampled signal.

A power supply circuit for operating high-efficiency lighting devices from a thyristor-controlled dimmer determines the dimming value, i.e., the dimmer duty factor by periodically probing the dimmer output. A minimum conductance is applied across the output of the dimmer during probing intervals that begin at the turn-on time of the dimmer and last until enough information has been gathered to correctly predict a next zero crossing of the AC line voltage that supplies the input of the dimmer. The dimming value is determined from the time interval between the predicted zero-crossing and a next turn-on time of the dimmer. The probing can be performed at intervals of an odd number of half-cycles of the AC line frequency so that a DC offset is not introduced within internal timing circuits of the dimmer. The AC line frequency can also be determined from a time interval between the predicted zero crossings.

The invention discloses a method and a system for orthogonal modulation of power signals. The method comprises the following steps: acquiring an initial sequence length and an initial sequence according to a frequency lower limit, a preset sampling frequency and an initially set integer signal cycle number of a power signal; acquiring a reference frequency according to the initial sequence, and further acquiring a unit cycle sequence length and a preset sequence length; acquiring first forward and reverse sequences according to a preset sequence starting point and the preset sequence length; generating first real-frequency and imaginary-frequency vector sequences and second real-frequency and imaginary-frequency vector sequences according to the first forward and reverse sequences; converting obtained first and second phases into a first forward sequence average initial phase; obtaining a new preset sequence starting point according to the average initial phase; and obtaining a cosine function modulation sequence and a sine function modulation sequence according to second forward and reverse sequences obtained from the initial sequence. By adopting the method and the system of the invention, an orthogonal modulation sequence with consistent amplitude height can be obtained, and the accuracy and anti-jamming performance of sinusoidal parameter calculation are improved.

The high-accuracy synchronous phasor measurement method belongs to the field of automatic measurement technology of power system. On the basis of spaced sampling circulation DFT, when the system frequency is deviated from rated frequency, the influence of frequency deviation can be calculated to make the frequency and phasor measurement have higher accuracy. The field tests show that when the sampling frequency is 4800 Hz and phasor correction calculation frequency is 200 Hz, its static accuracy indexes are: phasor magnitude error is less than 0.5%, phasor phase angle error is less than 1 deg.C and frequency calculation error is less than 0.01 Hz, and its dynamic accuracy indexes are: phosar magnitude error is less than 1%, phasor phase angle error is less than 1 deg. and frequency calculation error is less than 0.01 Hz.

A power distribution monitoring system is provided that can include a number of features. The system can include a plurality of monitoring devices configured to attach to individual conductors on a power grid distribution network. In some embodiments, a monitoring device is disposed on each conductor of a three-phase network. The monitoring devices can be configured to measure and monitor, among other things, current and electric-field on the conductors. Methods of calibrating the monitoring devices to accurately measure electric-field are also provided. In one embodiment, a first monitoring device on a first conductor can transmit a calibration pulse to a second monitoring device on a second conductor. The second monitoring device can determine a degradation of the calibration pulse, and use that degradation to calibrate electric-field measurements around the conductor.

The invention discloses a microwave sensor based on an NV color center diamond. A diamond internally containing a Nitrogen-Vacancy color center is adopted as a sensitive element, electronic energy level stimulation is achieved through lasers, an additionally-arranged static magnetic field is scanned, and the microwave frequency and the microwave intensity are measured through fluorescence intensity detection. Dependency of electronic rabi-flopping of the NV color center in the diamond on the external microwave magnetic field is brought into play, high theoretical accuracy and good stability are achieved, the microwave sensor has the advantages of being small in size, low in cost, high in accuracy, large in temperature range, simple in operation condition and the like and rotates on the basis of solid atoms, and the microwave sensor can serve in all the fields with the requirements for the low-cost high-accuracy microwave frequency and intensity detection in the future.