146 results about "THD analyzer" patented technology

TV white space spectrum sensors and methods for detecting and managing the white space are provided. The sensor is provided with a spectrum detector / analyzer, which senses and analizes the wireless signals present in a spectrum of interest, identifies white space, and assigns the white space to secondary services. For reducing the white space detection time, the sensor uses a group detection method whereby multiple channels are sensed simultaneously. For reducing the sensor cost, the dynamic range of the sensor is reduced by operating the sensor in saturation for signals with the energy higher than a threshold. The sensor is also provided with a spectrum manager / planner capable of understanding a plurality of air interface standards, reserving and providing the right amount of white space spectrum to each application, based on the respective standard requirements. The particular architectures used by the sensor result in an affordable addition to any wireless device.

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.

A near IR spectrometer-based analyzer attaches continuously or semi-continuously to a human subject and collects spectral measurements for determining a biological parameter in the sampled tissue, such as glucose concentration. The analyzer includes an optical system optimized to target the cutaneous layer of the sampled tissue so that interference from the adipose layer is minimized. The optical system includes at least one optical probe. Spacing between optical paths and detection fibers of each probe and between probes is optimized to minimize sampling of the adipose subcutaneous layer and to maximize collection of light backscattered from the cutaneous layer. Penetration depth is optimized by limiting range of distances between paths and detection fibers. Minimizing sampling of the adipose layer greatly reduces interference contributed by the fat band in the sample spectrum, increasing signal-to-noise ratio. Providing multiple probes also minimizes interference in the sample spectrum due to placement errors.

Systems and methods are disclosed for using ellipsometer configurations to measure the partial Mueller matrix and the complete Jones matrix of a system that may be isotropic or anisotropic. In one embodiment two or more signals, which do not necessarily satisfy any symmetry assumptions individually, are combined into a composite signal which satisfies a symmetry assumption. The individual signals are collected at two or more analyzer angles. Symmetry properties of the composite signals allow easy extraction of overlay information for any relative orientation of the incident light beam with respect to a ID grating target, as well as for targets comprising general 2D gratings. Signals of a certain symmetry property also allow measurement of profile asymmetry in a very efficient manner. In another embodiment a measurement methodology is defined to measure only signals which satisfy a symmetry assumption. An optional embodiment comprises a single polarization element serving as polarizer and analyzer. Another optional embodiment uses an analyzing prism to simultaneously collect two polarization components of reflected light.

An apparatus for analyzing the condition of a machine having a part rotatable with a speed of rotation, includesan input for receiving an analogue measurement signal indicative of a vibration signal signature having a vibration frequency and a repetition frequency;an A / D converter for generating a digital measurement signal dependent on the analogue measurement signal, the digital measurement signal having a first sample rate, which is at least twice the vibration frequency;an enveloper for generating an enveloped signal indicative of the repetition frequency;a decimator for generating a decimated first digital signal dependent on the enveloped signal such that the decimated first digital signal has a reduced sample rate;an enhancer having an input for receiving the decimated signal, wherein the enhancer operates in the time domain to perform discrete autocorrelation for the decimated first digital signal so as to generate an enhancer output signal sequence; andan analyzer for performing a condition monitoring function so as to analyze the condition of the machine dependent on the output signal sequence.

A method and apparatus is disclosed for measurement and monitoring of in-band optical signal to noise ratio (OSNR). A two channel optical spectrum analyzer (OSA) is advantageously applied in acquiring wavelength division multiplex (WDM) signal data after it has been split according to polarization, then deriving the in-band OSNR from acquired data due to its narrow bandwidth, selective spectral shape, and capability to analyze two components of a polarized signal simultaneously. The in-band OSNR can be measured without interrupting optical transmission traffic in the network.

An optical beam synthesizer formed on a single chip is provided. It allows M-PSK modulation for both beam polarizations. The synthesizer comprises an optical pulse shaper and two M-PSK modulators for each polarization. A single-chip-integrated analyzer is provided to receive a modulated data. Analyzer comprises a pulse shaper operating as an optical sampler and a pair of 90-degrees optical hybrids for each polarization. Each optical hybrids mix incoming portions of the modulated beams with portions of the local oscillator beams. Both the synthesizer and the analyzer include a set of mirrors located on the back and front surfaces of the chips to create compact designs. The output beams from the analyzer are detected by a set of balanced photodiodes, and the data is recovered. It is another object of the invention to provide a communication system for data transmission having the synthesizer and the analyzer.

A network analysis system and methods facilitate a match-corrected signal power measurement using a vector network analyzer (VNA). The network analysis system includes the VNA and a computer program stored in memory and executed by a controller. The computer program has instructions that implement one or both of calibrating a test port of the VNA to determine the match-corrected signal power measurement and correcting a power measured for a signal received at the test port of the VNA using corrected error terms of a port calibration of the test port to yield a corrected measured power. The corrected error terms are determined from error terms of the port calibration using a switch term and an incident power calibration, both of the test port. A method 100 determines the match-corrected signal power measurement and a method 300 calibrates the VNA test port to determine the measurement.

A liquid aspiration method which includes a method for determining the quality of the aspirated sample through mathematical analysis of the standard deviation of the residuals of the linear regression analysis of the aspiration pressure profile generated between the onset of actual aspiration and the end of actual aspiration and comparison of the results with predetermined known values.

A built-in-self test (BIST) scheme for analog circuitry functionality tests such as frequency response, gain, cut-off frequency, signal-to-noise ratio, and linearity measurement. The BIST scheme utilizes a built-in direct digital synthesizer (DDS) as the test pattern generator that can generate various test waveforms such as chirp, ramp, step frequency, two-tone frequencies, sweep frequencies, MSK, phase modulation, amplitude modulation, QAM and other hybrid modulations. The BIST scheme utilizes a multiplier followed by an accumulator as the output response analyzer (ORA). The multiplier extracts the spectrum information at the desired frequency without using Fast Fourier Transform (FFT) and the accumulator picks up the DC component by averaging the multiplier output.

The differences between the center wavelength and half bandwidth of the spectral sensitivity of each pixel of a sensor array in a spectral analyzer to be calibrated and the preprovided respective standard values of the center wavelength and the half bandwidth are expressed as functions of a pixel number (linear functions), and coefficients that define the functions are determined based on the pixel outputs of the sensor array obtained by measuring predetermined wavelength standards. The center wavelength and half bandwidth of each pixel are estimated from the differences obtained from the functions with the determined coefficients and the standard values.

A wideband signal analyzer has a plurality of frequency conversion paths for simultaneously processing different contiguous frequency bands of an input signal. Each frequency conversion path provides time domain data for input to a digital signal processor. The digital signal processor interpolates each group of time domain data to produce interpolated time domain data having a number of data points that satisfies a Nyquist condition for a combined bandwidth of the frequency conversion paths. A calibration signal set to a border frequency between a pair of frequency conversion channels is used to calibrate the gains and phase differences between the frequency conversion paths so that the digital signal processor identifies corresponding time domain data between the interpolated time domain data groups. A suite of frequency domain data is calculated by the digital signal processor from the interpolated time domain data groups and stored for subsequent display.

A wideband four noise parameter measurement system and method uses electro-mechanical wideband tuners and fast noise and small signal receivers (network analyzers) to collect noise data in fast frequency sweeps over a large number of randomly distributed source tuner states; because of the random nature of source impedances, additional monitoring equipment allow evaluating critical device parameters in view of output mismatch and instabilities in order to validate the measured data. Multiple noise parameter extractions for all possible cross-combinations of source impedance states at each measured frequency allows reliable and physically meaningful generation of wideband noise parameters, even for very low noise and potentially unstable DUT's.

A respiratory waveform analyzer, operable to analyze a respiratory waveform, which is generated based on a temporal change of a concentration of a component in respiratory gas of a subject, includes: a respiratory gas concentration generator which generates a concentration signal based on an output signal from a sensor that is placed to measure the concentration of the component; a flatness calculator which calculates a flatness indicative of flat degree of the respiratory waveform based on a temporal change of the concentration signal; and a reliability calculator which calculates a reliability of the respiratory waveform based on the flatness and the concentration signal.

A high-resolution Subspace-Least Mean Square (S-LMS) method for harmonic and interharmonic measurement in power systems is provided. The eigenvector corresponding to the smallest eigenvalue is used to calculate the frequencies of the signal, and the least mean square method is used to estimate the amplitude and phase angle of harmonic and interharmonic components based on the computed frequencies and time domain measurements of the signal. Three schemes, namely sparsity, catch-and-pinpoint, and hybrid are presented. The S-LMS method provides accurate phasor, harmonic and interharmonic measurements for power system monitoring. The speed, accuracy, and resilience of the S-LMS method can be further increased by each of the three schemes. The method has a wide range of applications in power quality analyzers, synchronized phasor measurement, situational awareness, dynamic equivalencing, and smart meters.

A data processing method is provided to enable a calculation based signal analyzer, such as an FFT based spectrum analyzer, to produce results corresponding to a swept spectrum analyzer employing a video bandwidth (VBW) filter. Once a spectrum is produced the frequency axis is replace by a corresponding time axis, so that a time domain filter, such as a video bandwidth (VBW) filter can be applied. In a first example, the filter characteristics are applied by performing an FFT on display spectrum data, which has had its frequency axis replaced by a corresponding time axis, produce frequency domain data, multiplying by the frequency response to produce a filtered version, performing an inverse FFT and replacing the time axis with the original frequency axis to produce a filtered version of the display spectrum data. In another example, a filter impulse response is computed based upon the desired filter characteristics, a convolution integral of the display spectrum data, which has had its frequency axis replaced by a corresponding time axis, and the filter impulse response is conducted, and the time axis is replace by the original frequency axis to produce filtered display spectrum data.

A built-in-self test (BIST) scheme for analog circuitry functionality tests such as frequency response, gain, cut-off frequency, signal-to-noise ratio, and linearity measurement. The BIST scheme utilizes a built-in direct digital synthesizer (DDS) as the test pattern generator that can generate various test waveforms such as chirp, ramp, step frequency, two-tone frequencies, sweep frequencies, MSK, phase modulation, amplitude modulation, QAM and other hybrid modulations. The BIST scheme utilizes a multiplier followed by an accumulator as the output response analyzer (ORA). The multiplier extracts the spectrum information at the desired frequency without using Fast Fourier Transform (FFT) and the accumulator picks up the DC component by averaging the multiplier output.

Characterizing atmospheric conditions is accomplished by measuring at least one varying spectral characteristic of sound at a plurality of intervals from a sound source with the point of measurement and the sound source in relative motion and separated by altitude. The spectral characteristic of the sound at each interval is attributed to a path traveled by the sound and a plurality of simultaneous equations is created for the plurality of paths using a second plurality of altitude segments for each path, each segment having a particular vector as a variable on the spectral characteristic, the initial coefficients in each vector assumed based on predetermined atmospheric models for each altitude segment. The resulting calculated vector and the predetermined atmospheric model are iterated for a minimized cost function in a variational analysis to determine the vector for each altitude segment, the vector providing atmospheric properties for the associated altitude segment.

A touched-position detection device detects a touched position by measuring a propagation time of a SAW (Surface Acoustic Wave) signal generated on a touch panel. The touched-position detection device using the SAW signal includes: a touch panel; a controller for controlling signal generation and a signal generation time; an impulse signal generator for generating an impulse signal; a SAW generator for converting the impulse signal generated from the impulse signal generator into a SAW signal on the touch panel; a SAW sensor for detecting the SAW signal received via the touch panel's surface; a signal analyzer for classifying the SAW signal detected by the SAW sensor into a DW (Direct Surface Wave) signal and an RW (Reflected Surface Wave) signal according to the SAW signal intensity so as to identify the SAW signal, and measuring arrival times of the DW and RW signals upon receiving arrival times of the DW and RW signals and the signal control time of the controller; and a position calculator for calculating the touched positions x and y on the touch panel upon receiving the arrival times from the signal analyzer.

There is provided a system and method for statistical timing analysis and optimization of an electrical circuit having two or more digital elements. The system includes at least one parameter input and a statistical static timing analyzer and electrical circuit optimizer. The at least one parameter input is for receiving parameters of the electrical circuit. At least one of the parameters has at least one of a non-Gaussian probability distribution and a non-linear delay effect. The statistical static timing analyzer and electrical circuit optimizer is for calculating at least one of a signal arrival time and a signal required time for the electrical circuit using the at least one parameter and for modifying a component size of the electrical circuit to alter gate timing characteristics of the electrical circuit based upon the at least one of the signal arrival time and the signal required time.

A measurement device includes a measurement circuit that generates a parametric measurement data signal including parametric characteristics of an input signal. In an exemplary embodiment, the parametric characteristics are measured at predetermined increments of time. A population limit analyzer is coupled to the measurement circuit and generates limit data in response to the parametric measurement data signal. A measurement limit checker is coupled to the population limit analyzer and generates a signal indicating that the characteristics of the parametric measurement data signal is within acceptable limits. With this information, the user is able to quickly grade a selected device under test (DUT). A device performance measurement method includes receiving an input signal. Next, statistical characteristics are determined from the parametric measurements of the input signal. Performance limits are extrapolated from the statistical characteristics of the parametric measurements. Then, a determination is made as to whether the parametric measurements are within the extrapolated performance limits.

The invention relates to a method and platform for testing magnetic performance of a laminated iron core of a transformer in controllable excitation conditions. The method is related with a voltage regulator (1), a programmable frequency converter (2), an LC filter (5), a product-stage transformer laminated iron core model (6) and a power analyzer (9). A computer controls the programmable frequency converter to output needed pulse voltage uniform in amplitude but unequal in width, any needed voltage waveform is obtained after the pulse voltage is filtered, and the filtered waveform serves as excitation voltage of the product-stage transformer laminated iron core model for testing. If a PWM excitation condition needs to be produced, an LC filtering module is removed, and then an inverter directly supplies power to the laminated iron core model. The actual operation work conditions of the iron core of the transformer can be simulated, any voltage excitation condition such as harmonic wave under manual control, bias magnetism and PWM can be generated, and accordingly measurement of a laminated iron core magnetic field and loss performance can be measured in any given excitation condition.

An apparatus for measuring a set of frequency-resolved states of polarization (SOP) of an optical signal includes a local oscillator (LO), a polarization scrambler, a coupler for mixing the polarization-scrambled signal with the optical signal to produce a heterodyned signal with a radio frequency (RF) component, and an analyzer for passing a fixed polarization component and resolving the polarization and frequency from the RF component. The apparatus is used for measuring, monitoring or compensating the polarization mode dispersion (PMD) in a working channel of an optical telecommunication system. A method for measuring frequency-resolved SOP of an optical signal includes tuning and polarization-scrambling a local oscillator (LO), mixing the scrambled LO with the optical signal, and resolving the RF signal in frequency and polarization. The method is applied to measure and monitor PMD in a working optical channel, and to dynamically compensate for the PMD.

An auto voice trigger method and an audio analyzer employing the same are provided. The auto voice trigger method includes: receiving a signal by at least one resonator microphone included in an array of a plurality of resonator microphones with different frequency bandwidths; analyzing the received signal and determining whether the received signal is a voice signal; and when it is determined that the received signal is the voice signal, waking up a whole system to receive and analyze a wideband signal.

The invention provides a noise control method for a cooling tower and relates to a noise control method. The noise control method for the cooling tower comprises the following steps: firstly measuring noise by adopting a B&K high precision noise spectrum analyzer and a TES noise sound level meter, determining the noise according to a noise source, mounting a resistive muffler at a propagation path position, preventing energy of the noise from propagating by adopting a combined type sound barrier, and mounting a damping sound barrier and a wide band combined type sound absorption material, wherein a sound attenuation piece is arranged in the middle of a wide band chip silencer, and the side walls at the left side and the right side are provided with sound absorption materials or have sound absorption structures; and based on field test and analysis and a noise sensitive spot position, isolating the noise by mounting a sound insulation barrier. The noise control method for the cooling tower has the advantages that a noise attenuation effect is obvious, requirements of equipment on ventilation quantity and temperature can be completely met, and a reference is provided for noise control on the cooling tower in engineering practice, so that the noise control method for the cooling tower has guiding significance.

Prior to the measurement of partial discharge, a voltage detected by the antenna is inputted into a spectrum analyzer, a phase difference between an operating voltage and a power supply of the spectrum analyzer is obtained by phase domain analysis using the spectrum analyzer. Based on the phase difference and the voltage phase shift associated with input impedance of the signal converter circuit, the time axis displayed on the screen of the spectrum analyzer is compensated. After the compensation has been carried out, the voltage detected by the antenna is inputted into the spectrum analyzer, the partial discharge pattern which synchronizes with the operating voltage is measured by phase domain analysis using the spectrum analyzer.

An assembly 10 which allows a vehicular damper to be virtually created and evaluated. Particularly, the assembly 10 includes a torque producer 31, a frequency filter generator 50, and analyzers 32, 34, 36 and 38. The torque produce 31 selectively produces a torque signal which is combined with a selected frequency filter provided by the generator 50, thereby producing a dampened signal which is communicated to a transmission assembly 14. The analyzer detects noise and vibration and allows a designer to evaluate the chosen frequency filter. Other filters may be used and a filter is selected based upon the noise and vibration measurements made by the analyzers 32, 34, 36, and 38. An actual damper is then constructed having a frequency characteristic which is substantially similar to the frequency characteristic of the chosen frequency filter.

Method and apparatus for determining a signal-to-noise ratio (SNR) value from a readback signal, such as in a data storage device. A readback signal is obtained by a receiver (such as a data transducing head) coupled to a data recovery channel having a variable gain amplifier (VGA) and a threshold detector (TD). The data channel applies a selectable VGA gain value to the readback signal while errors are accumulated using a selectable error detection threshold from the TD. The SNR value is determined at least from a magnitude of the error detection threshold, and preferably from first and second VGA gain values using a linear regression model. The determined SNR value is highly correlated to classical SNR values obtained using external equipment such as an analyzer or oscilloscope, and is advantageously used in automated fashion during high volume manufacturing certification testing.

There are provided frequency analyzing method and apparatus, and a spectrum analyzer capable of reliably detecting and displaying a radio wave even if the radio wave is a frequency spread or low level one. A signal to be measured existing in a frequency band to be measured is extracted by a plurality of measurement signal extracting devices, and each of the extracted plural signals to be measured is frequency analyzed to compute a correlation value with respect to the plural results of frequency analyses. If the computed correlation value is equal to or greater than a preset value, a decision that the signal to be measured exists in the analyzed frequency is rendered, and if the computed correlation value is smaller than the preset value, a decision that the signal to be measured does not exist in the analyzed frequency is rendered. The decision results are displayed.