Abstract: A pulse modulation system of a radio frequency (RF) power supply includes a modulation output circuit and a frequency adjustment circuit. The modulation output circuit is configured to modulate an output signal of the RF power supply and output a pulse modulation RF signal. Each pulse cycle of the pulse modulation RF signal includes a pulse-on phase and a pulse-off phase. An overshoot sub-phase is set in an initial preset time of the pulse-on phase. The frequency adjustment circuit is electrically connected to the modulation output circuit. The frequency adjustment circuit is configured to adjust an RF frequency of the pulse modulation RF signal of the overshoot sub-phase to cause a reflected power of the overshoot sub-phase to satisfy a preset reflected power or a reflected coefficient to satisfy a preset reflected coefficient.

Abstract: An integrated circuit includes a first amplifier and a second amplifier. A first impedance matching circuit is coupled to the first amplifier, a first charge pump, and a single MEMS transducer. A second impedance matching circuit is coupled to the second amplifier, a second charge pump, and to the single MEMS transducer. A first capacitive load as measured at an input of first amplifier, and a second capacitive load as measured at an input of the second amplifier exist. The first capacitive load and the second capacitive load are balanced with respect to each other. A single pressure change causes the single MEMS transducer to create a first electrical signal and a second electrical signal. Both the first electrical signal and the second electrical signal are matched or approximately matched in magnitude, and 180 degrees or approximately 180 degrees out of phase with respect to each other.

Abstract: Turbine generator faults can be detected by receiving a current signal from the turbine generator, and synchronously sampling the current signal to obtain a set of current signal samples that are evenly spaced in the phase domain, in which phase differences between adjacent current signal samples in the set of current signal samples are substantially the same. The process includes generating a frequency spectrum of the current signal samples, identifying one or more excitations in the frequency spectrum, and detecting a fault in the turbine generator based on the one or more excitations in the frequency spectrum.

Abstract: A test apparatus with physical separation feature is disclosed. The test apparatus includes probes (210), a peripheral circuit (220), a circuit of special function (230), wherein the peripheral circuit and the circuit of special function are separately arranged on different circuit boards (240, 250). The peripheral circuit and the circuit of special function are both electrically connected to the probes. In the test apparatus with physical separation feature, the peripheral circuit and the circuit of special function are separated in physical spaces, so that interference between the components is prevented and the testing cost is reduced.

Abstract: Systems and techniques for return loss estimation are described. A forward power sample is taken from a power amplifier of a transmitter by sampling a feedback signal used for power control of the amplifier, and a reflected power sample at an output of the power amplifier is taken by observing the power at a circulator termination of the power amplifier. A difference determination is made for the forward power sample and the fleeted power sample in the analog domain to determine a return loss and may be digitized for further processing such as return loss measurement and comparison against thresholds. A further comparator circuit may be used to insure that measurements are made when the signal strength is adequate.

Abstract: An apparatus for AC physical signals measurement and data acquisition and the method for the same are provided. The apparatus for AC physical signals measurement and data acquisition comprises an analog sampling channel for inputting an AC signal and outputting an analog sampling value; a sampling switch for performing re-sampling to obtain data frequency as required by the receiving side; a register for storing a re-sampling value from the sampling switch; a bus for outputting the re-sampling value in the register to the receiving side; a timing controller for controlling the analog sampling channel and the re-sampling frequency of the sampling switch; and a digital low-pass filter, which has an input connected with the analog sampling value outputted by the analog sampling channel and an output connected with the sampling switch, filters out high frequency components from the sampling value, and has a cut-off frequency that should be lower than 0.5 times the re-sampling frequency of the sampling switch.

Abstract: A system and a method is provided for the detection and capture, and in particular for an ultra high speed detection and capture, of transients in input voltages by an intelligent electronic device. The system and method detects transients for input voltages in either phase to phase or phase to neutral measurements and permits a user to set threshold levels for detecting transients in input voltages. In an embodiment, the system and method further provides a field programmable gate array as a controller for managing transient detection. The field programmable gate array includes a state machine for determining the state of the sampled signal with respect to a threshold level at a specified waveform sample period.

Abstract: In one general aspect, an apparatus can include a block defining a temperature control channel therethrough and a defining a sample chamber. The apparatus can also include an electrode disposed inside of the block such that the sample chamber is fluidically isolated from the temperature control channel by the electrode. The electrode can be configured to receive a signal from an impedance analyzer during a dielectric spectroscopy experiment related to a sample included in the sample chamber.

Abstract: A method for improving bandwidth of an oscilloscope involves, in preferred embodiments, the use of frequency up-conversion and down-conversion techniques. In an illustrative embodiment the technique involves separating an input signal into a high frequency content and a low frequency content, down-converting the high frequency content in the analog domain so that it may be processed by the oscilloscope's analog front end, digitizing the low frequency content and the down-converted high frequency content, and forming a digital representation of the received analog signal from the digitized low frequency content and high frequency content.

Abstract: There is described a pulse analyzer (1) for sampling a pulse or a repetitive stream of pulses. The pulse analyzer multiplies a pulse by a set of basis functions (c1, c2) to generate a plurality of multiplied pulse functions, and a synthesizer (9a, 9b, 13) combines the multiplied pulse functions to generate a pulse sample. In particular, the synthesizer performs at least one integrating operation over an integration interval substantially corresponding to the duration of the pulse and at least one adding operation. The basis functions are such that the output of the synthesizer corresponds to a pulse sample for a sample time interval shorter than the integration interval.

Abstract: A capacitive measurement system for generating a measurement signal representative of a measured position or distance to a target.

Abstract: Detection of fault occurrences within a power distribution system. A transient detector and fault classification system (10) implements an algorithm that detects transients which may result from the occurrence of a fault in the power distribution system. The system includes a detection module (18) which processes a set samples obtained from electrical waveforms propagated of through the power distribution system and appear to be statistically anomalous compared to other sample data. This is done using an adaptive detection algorithm that is applied when large changes occur in a waveform over a relatively short period of time. The identified samples are then provided to a signal classifier module (20) which processes sets of samples to classify a transient they represent as a likely fault occurrence or some other type of anomaly which is likely not a fault occurrence.

Abstract: A method and apparatus for determining AC voltage waveform anomalies. The apparatus comprises a threshold generator for generating at least one time-variant threshold based on information regarding an AC voltage waveform. The apparatus further comprises a threshold detector for comparing a sample of the AC voltage waveform to the at least one time-variant threshold to identify an AC voltage waveform anomaly.

Abstract: The invention relates to the sampling of temporally changing amounts of charge (102) by receiving varying amounts of charge (102) varying as a function of time, transforming the varying amounts of charge received into a linear distribution pattern, sampling the linear distribution pattern at a plurality of discretely spaced sampling locations (104), and collecting the amounts of charge (102) located between two adjacent scanning locations, and further detecting the collected amounts of charges (102).

Abstract: A system and method for identifying turn faults in a stator of a motor are provided. The method includes determining a normalized cross-coupled impedance from the symmetrical components of measured voltages and currents of the motor. Additionally, the normalized cross-coupled impedance may be normalized to a negative sequence impedance. The negative sequence impedance may be determined through a regression analysis using parameters of the motor, such as line-to-line voltage, horsepower, and number of poles. A system is provided that includes a device having a memory and processor configured to determine a normalized cross-coupled impedance, compare the normalized cross-coupled impedance to one or more thresholds, and trigger and alarm and/or trip the motor.

Abstract: Systems and methods are provided for use in an IED that perform high resolution waveform capture to generate multi-rate waveform data in real-time. In one embodiment, high-resolution sampled data is dynamically pre-ordered into separate high resolution and low resolution data streams for presentation and storage. This pre-ordering of data is optimized so as to minimize the amount of data manipulation required to prepare the sampled data for eventual presentation and storage in the IED. Pre-ordering of data facilitates minimum performance impact so that continuous real-time data capture can be achieved.

Abstract: An instrument (1) and a method for measuring pulses of partial electrical discharges in an electrical system comprise data processing means (5) operatively associated both with an input stage (2), able to receive an analogue signal (3) representing said pulses and to provide a digital representation of the entire wave form of the pulses, to receive said digital representation, extract the value of predetermined parameters relating to the wave form of the pulses and transfer to and output stage (4) a processed digital signal comprising said values, the processing means (5) being able to operate substantially in real time, i.e. with no need for a memory for the intermediate storage of the data.

Abstract: Pre-trigger and post-trigger acquisition for a no dead time acquisition system, where the data being displayed does not include a related trigger event, has a variable record length buffer having a maximum record length equal to a maximum desired pre-trigger interval, and has a trigger FIFO and timer for delaying the related trigger event. The record length of the buffer is determined by the desired pre-trigger interval, and fast rasterizers access the oldest data that encompasses the desired pre-trigger data. A first trigger event in the trigger signal may be delayed by a desired post-trigger interval before the fast rasterizers begin drawing the waveform data that encompasses the desired post-trigger data.

Abstract: A method includes monitoring a fill in an adaptive slip buffer of a digital to analog convertor; adjusting a number of samples that are read from the adaptive slip buffer per page as a function of the fill; and reading the number of samples from the adaptive slip buffer. An apparatus includes a digital to analog convertor including an adaptive slip buffer and a read address generator coupled to the adaptive slip buffer, wherein the read address generator includes an increment control that adjusts a number of samples that are read from the adaptive slip buffer per page as a function of fill of the adaptive slip buffer.

Abstract: Various embodiments provide methods, apparatuses, and systems for sampling a waveform using relatively prime sampling methods. A waveform with a first plurality of cycles and a first frequency may be sampled with a waveform sampling device. Sampling the waveform may include sampling the waveform at a sampling rate of the waveform sampling device. Sampling the waveform may include taking a sample number of samples of the waveform where the sample number may be relatively prime with respect to the number of cycles of the waveform. The sample number of samples of the waveform may be interleaved with a controller.

Abstract: This disclosure describes a capacitive interface circuit for a low power system. The capacitive interface circuit is configured to achieve very low noise sensing of capacitance-based transducers, such as a micro-electro-mechanical system (MEMS)-based sensor, with high resolution and low power. The capacitive interface circuit uses a differential amplifier and correlated triple sampling (CTS) to substantially eliminate, or at least reduce, kT/C noise, as well as amplifier offset and flicker (1/f) noise, from the output of the amplifier. The capacitive interface circuit may further include an output stage that reduces glitching, i.e., clock transients, in the output signal by allowing transients in the amplifier output to settle. In this manner, the circuit can be used in a low power system to produce a stable, low-noise output.

Abstract: A method is disclosed for analyzing an AC voltage signal with a transformation which transforms the signal from a representation in the time-domain to a representation in the frequency-domain. This transformation can be a fast Fourier transform, a discrete Fourier transform or a Laplace transform. By selecting a second higher sampling frequency which is an integer multiple of a first sampling frequency, the zero crossings of the AC voltage signal can be accurately determined.

Abstract: A structure is provided, the structure includes a metallic coupler circuit formed within a disk located within a coaxial cable connector. The metallic coupler circuit is located in a position that is external to a signal path of a radio frequency (RF) signal flowing through the connector. The metallic coupler circuit is configured to extract samples of the RF signal flowing through the connector.

Abstract: A method and apparatus is disclosed for adaptively sampling an analogue signal to increase the sampling rate in the presence of high frequency content within the signal, for example, QRS complex of an ECG signal. In one aspect, a change in a derivative of the analogue signal is used to control a voltage-controlled oscillator to provide a clock signal for an analogue-to-digital converter. The change in the derivative is compared to an automatically controlled threshold value. The clock signal controls the sampling rate of the analogue-to-digital converter so that the sampling rate is increased from one level, where only P and T waves are present to another higher level when the QRS complex has been detected.

Abstract: There is described a pulse analyser (1) for sampling a pulse or a repetitive stream of pulses. The pulse analyser multiplies a pulse by a set of basis functions (c1, c2) to generate a plurality of multiplied pulse functions, and a synthesiser (9a, 9b, 13) combines the multiplied pulse functions to generate a pulse sample. In particular, the synthesiser performs at least one integrating operation over an integration interval substantially corresponding to the duration of the pulse and at least one adding operation. The basis functions are such that the output of the synthesiser corresponds to a pulse sample for a sample time interval shorter than the integration interval.

Abstract: A three-port TDR front end comprises numerous components. An exemplary three-port TDR front end is a DSL modem. Information-bearing TDR signals are distorted as they pass through these components. With a perfect model of the response of its front-end, a TDR system usually can compensate for the effects of its front-end. In reality, however, the electrical characteristics of each component vary from design-to-design, board-to-board, and slowly over time. The result is imperfect knowledge about the true response of the front-end, errors in the model of the front-end, and degraded TDR performance. At least for this reason it is important to precisely calibrate the response of the TDR front-end through the use of a TDR modeling system.

Abstract: A signal analysis control system is provided with a signal analyzing section for analyzing signals inputted to a transmission section and generating analysis information, and a signal control section for controlling signals inputted to a receiving section by using the analysis information.

Abstract: Various embodiments provide methods, apparatuses, and systems for sampling a waveform using relatively prime sampling methods. A waveform with a first plurality of cycles and a first frequency may be sampled with a waveform sampling device. Sampling the waveform may include sampling the waveform at a sampling rate of the waveform sampling device. Sampling the waveform may include taking a sample number of samples of the waveform where the sample number may be relatively prime with respect to the number of cycles of the waveform. The sample number of samples of the waveform may be interleaved with a controller.

Abstract: A self-adjusting hold-off trigger circuit and method detects a threshold crossing between consecutive samples of a digitized input signal as edge events, identifies the crossing as a qualified trigger event if the crossing is in a desired direction based upon trigger criteria, and provides a trigger output when the qualified trigger event occurs greater than an approximate average or peak time after a preceding edge event.

Abstract: A method for determining a time interval between leading edges of two adjacent cyclic input pulses of a series of cyclic input pulses. A sample of the cyclic input pulses is taken at each of a series of sampling times to produce sampling hits, each sampling hit being an indication of a presence of a cyclic input pulse, recording a count number at each of the sampling hits, determining initial sampling hits from the detected sampling hits, determining a minimum sampling interval between initial sampling hits, and determining a count number located at a back end of the minimum sampling interval, count numbers of the minimum sampling interval being used to determine a time interval between lead edges of two adjacent cyclic input pulses.

Abstract: The invention relates to the sampling of temporally changing amounts of charge (102) by receiving varying amounts of charge (102) varying as a function of time, transforming the varying amounts of charge received into a linear distribution pattern, sampling the linear distribution pattern at a plurality of discretely spaced sampling locations (104), and collecting the amounts of charge (102) located between two adjacent scanning locations, and further detecting the collected amounts of charges (102).

Abstract: A method for digital triggering of a digital recording of a digitized measurement signal having a superimposed noise signal. The method includes generating from the digitized measurement signal a digital triggering signal for the digital triggering of the digital recording of the measurement signal, and performing band-limitation of the noise signal superimposed on the digitized measurement signal via a low-pass filtering before the digital triggering signal is generated. The bandwidth of the low-pass filtering is adjusted dependent upon edge steepness of the measurement signal, in order to reduce variance ?t2 in jitter of the digital triggering signal.

Abstract: A “no dead time” data acquisition system for a measurement instrument receives a digitized signal representing an electrical signal being monitored and generates from the digitized signal a trigger signal using a fast digital trigger circuit, the trigger signal including all trigger events within the digitized signal. The digitized signal is compressed as desired and delayed by a first-in, first-out (FIFO) buffer for a period of time to assure a predetermined amount of data prior to a first trigger event in the trigger signal. The delayed digitized signal is delivered to a fast rasterizer or drawing engine upon the occurrence of the first trigger event to generate a waveform image. The waveform image is then provided to a display buffer for combination with prior waveforms and/or other graphic inputs from other drawing engines. The contents of the display buffer are provided to a display at a display update rate to show a composite of all waveform images representing the electrical signal.

Abstract: The invention relates to electronic circuits for measuring, by synchronous detection, weak signals whose reference level is not well known and is subject to large fluctuations. A first correlated double sampling is performed between a time T1 situated just before the start of the measurement pulse and a time T2 situated just before the end of the measurement pulse; subsequently, a second correlated double sampling is performed between time T2 and a time T3 situated after the end of the measurement pulse. Finally, the difference between signal levels coming from the two measurements is taken, this difference being a representation of the signal value Vm considered with respect to a reference level that is intermediate between the reference levels at times T1 and T3.

Abstract: A system and method for monitoring RF power is described. In one embodiment the system samples RF power that is generated by an RF generator to obtain RF signals that include information indicative of electrical characteristics at a plurality of particular frequencies that fall within a frequency range. The RF signals are digitized to obtain a stream of digital RF signals that include information indicative of electrical characteristics at the plurality of particular frequencies, and the information indicative of electrical characteristics is successively transformed, for each of the plurality of particular frequencies, from a time domain into a frequency domain.

Abstract: A direct sampling circuit and a receiver which carry out discrete time analog processing with a high degree of design freedom and are provided with a filter property which is achievable to comply with the receipt of a broad band signal. A plurality of discrete time analog processing circuits (101) are connected in parallel with each other, a gm value and a capacitance of a capacitor in each circuit system are set independently based on a prescribed condition, and an output signal obtained from each circuit system is synthesized by means of a buffer capacitor (102), so that an equivalently high-dimensional IIR filter can be put into practice.

Abstract: A method for rapidly extracting data file samples with an a signal monitor and an automatically adjusted decimation ratio is provided to solve the long-standing problems caused by large data files and small buffers by reducing a large data segment to a smaller, more manageable size automatically so that a lower resolution version of the data segment will be loaded into a fixed-size small buffer in the computer's working space buffer for further data editing. In accordance with the methods of this invention, the segment size will vary during the operation of a means for zooming-in and the decimation ratio is updated and adjusted automatically based on the variation of segment size. The present invention insures that the best resolution of the data segment will be achieved when fitting the varying large size data segment into the fixed small size buffer.

Abstract: A logic analyzer that performs analog-type measurements on digital data includes circuitry in its acquisition system that is programmable to search through acquired data to detect analog-type signal characteristics. In a first embodiment, the logic analyzer includes a graphical user interface employing a drag-and-drop operation to apply one or more selected analog-type measurements to selected portions of the digital data record. In a second embodiment, a user may designate a particular waveform or data listing by means of a mouse-click. Each of the choices of analog-type measurements can be represented by an icon, or text, or both icon and text.

Abstract: This invention relates to generation of a sample error coefficient suitable for use in an audio signal quality assessment system. The invention provides a method of determining a sample error coefficient between a first signal and a similar second signal comprising the steps of: determining a first periodicity measure from the first signal; determining a second periodicity measure from the second signal; generating a ratio in dependence upon said first periodicity measure and said second periodicity measure; and determining a sampling rate error coefficient in dependence upon said ratio.

Abstract: The invention relates to electronic circuits for measuring, by synchronous detection, weak signals whose reference level is not well known and is subject to large fluctuations. A first correlated double sampling is performed between a time T1 situated just before the start of the measurement pulse and a time T2 situated just before the end of the measurement pulse; subsequently, a second correlated double sampling is performed between time T2 and a time T3 situated after the end of the measurement pulse. Finally, the difference between signal levels coming from the two measurements is taken, this difference being a representation of the signal value Vm considered with respect to a reference level that is intermediate between the reference levels at times T1 and T3.

Abstract: A compressor for waveforms having at least two waveform states separates the waveform samples into waveform state sample vectors for each waveform state. Waveform state encoders encode the waveform state sample vectors separately to provide compressed waveform data. The waveform state encoder selects waveform state pattern vector and associated codes to represent the waveform state sample vectors. The differences between samples of the waveform state sample vector and waveform state pattern vector are calculated and encoded. Encoding can be lossless or lossy. The waveform state pattern vectors and other parameters for compression are determined during a training period. The waveform state encoders detect features in the waveform state sample vectors and waveform state pattern vectors that are useful for common oscilloscope measurements. Typical waveform states include level states and edge states.

Abstract: An apparatus, computer program product and method of analyzing complex signals. Independent versions are generated for the complex signal, e.g., by adding multiple instances of white noise. Intrinsic mode functions (IMFs) are extracted from each of the independent versions, e.g., using Empirical Mode Decomposition (EMD). Corresponding IMFs from each independent version are combined into Ensemble IMFs (EIMFs), e.g., taking the mean of the corresponding IMFs.

Abstract: A method and apparatus for acquiring a signal employing a coherent timebase are provided. The method comprises the steps of defining a pattern length count of a repetitive pattern in a signal to be acquired, defining a number of samples per unit interval, and providing data strobes synchronous to a coherent timebase. An arbitrary one of the data strobes is designated as a timing for a potential trigger. A number of subsequent data strobes is counted in accordance with the pattern length count times the samples per unit interval and a portion of the signal corresponding to the pattern length count times the samples per unit interval is acquired beginning at a point in the signal defined by the designated arbitrary data strobe.

Abstract: The invention relates to a method and an apparatus for measuring a rotational speed, in particular a rotational speed of a wheel of a motor vehicle, by means of a speed sensor, wherein the speed sensor produces an output signal characterizing the actual rotational speed and wherein the output signal of the speed sensor is sampled and further processed in accordance with sampled values thus obtained. For an—in hardware terms—simple realization, according to the invention it is provided that the output signal is sampled at a predetermined sampling rate over at least one measuring cycle, that in each case the amplitude of sampled values obtained in the measuring cycle is determined and that from the rate of occurrence of sampled values of an amplitude lying within a predetermined amplitude range at least one signal level occurring during the measuring cycle in the output signal is determined.

Abstract: One embodiment of the present invention provides a system that reconstructs a high-resolution signal from a set of low-resolution quantized samples. During operation, the system receives a time series containing low-resolution quantized signal values which are sampled from the high-resolution signal. Next, the system performs a spectral analysis on the time series to obtain a frequency series for the low-resolution quantized signal values. The system next selects a subset of frequency terms from the frequency series which have the largest amplitudes. The system then reconstructs the high-resolution signal by performing an inverse spectral analysis on the subset of the frequency terms.

Abstract: In order to detect high-speed transients in the alternating current of a power distribution system, the rate at which the power on the distribution system is sampled is increased so that even high-speed transients are detected. The sampling rate can be increased in at least two ways. First, where a single analog-to-digital converter samples multiple lines through a multiplexer, the multiplexer is controlled to allow the converter to sample only one line at a much-increased rate. Alternatively, the sampling speed of the analog-to-digital converter (or A/D array) can be controlled and increased as needed.

Abstract: A system comprising a plurality of digital storage oscilloscopes (DSOs) in which each DSO acquires a common signal under test (SUT) according to respective clock signals having common frequency parameters and respective phase parameters such that a plurality of acquisition records may be interleaved to produce a higher effective resolution acquisition record.

Abstract: A sampling circuit for use in testing an analog waveform includes a sampling switch for sampling an analog waveform, a sample storage capacitance including a single capacitance and a plurality of capacitances selectably connected in parallel; and a sampling pulse generating circuit.

Abstract: A timebase establishes the timing of samples acquired by a signal sampler relative to a trigger signal that is synchronous with an input signal applied to the signal sampler. The synchronous trigger activates a first pair of samplers included in the timebase to acquire samples of a reference signal and of a shifted version of the reference signal provided within the timebase. A divider receives the reference signal and divides the frequency of the reference signal by a predesignated divisor, and a third sampler included in the timebase acquires samples of this divided reference signal, also according to the synchronous trigger. The samples of the input signal are acquired by the signal sampler according to the divided reference signal. A timing analyzer determines the timing of these acquired samples of the input signal relative to the synchronous trigger, based on the acquired samples of the reference signal, the shifted reference signal and the divided reference signal.

Abstract: A method and an apparatus for measuring the instantaneous frequency of FM modulated signals, includes sampling, instantaneous frequency computing, and lowpass filtering. FM modulated signal are sampled at prescribed intervals to provide digitized FM signal. The instantaneous frequency is computed by manipulating the digitized FM signal mathematically using a new mathematical equation proposed in this invention to provide the instantaneous frequency based on digitized FM signal samples. More accurate instantaneous frequency values can be obtained by filtering the computed instantaneous frequency values using a lowpass filter.