Abstract: Methods, systems and other embodiments associated with pre-processing a signal for spectral analysis are presented. A system for pre-processing a digital input signal includes a digital down converter (DDC), an interpolator, and a series of down samplers. The DDC modulates the digital input signal to create a down converted signal. The interpolator re-samples the down converted signal to produce a re-sampled signal. The series of down samplers produces down sampled signals. The multiplexer selects one of the digital input signal, the down converted signal, and the down sampled signals and routes the selected signal to an output line.

Abstract: Embodiments of the invention include methods and instruments for performing combinatorial mask triggering. One or more mask triggers can be configured. Combinatorial mask triggering logic can make various determinations about the relationship between a digitized signal and the one or more mask triggers. The various determinations about the relationship can include considerations of both space and time. When the combinatorial trigger criteria have been satisfied, a trigger signal is generated, and the digital data associated with an incoming signal is stored to memory. The combinatorial mask triggering logic can operate on signals in the frequency domain, the time domain, or both.

Abstract: A frequency spectrum analyzing apparatus for performing a frequency spectrum analysis with respect to a detected value of an operating parameter of an internal combustion engine in synchronism with rotation of the engine, is provided. The operating parameter is sampled at predetermined time intervals, and the sampled value is converted to a digital value. Intensities of first and second elements are calculated with respect to a predetermined number of the sampled values, wherein the first and second elements respectively correspond to a plurality of frequency components contained in the detected value, and a phase of the second element differs from a phase of the first element by 90 degrees. Frequency component intensities corresponding to the plurality of frequencies are calculated in synchronism with rotation of the engine, using the first element intensities and the second element intensities.

Abstract: A frequency measurement device includes: a counter section that counts a supplied pulse stream signal to be measured at a predetermined time interval and outputs a stream of count values corresponding to the frequency of the signal to be measured; and a low-pass filter section that performs a filtering process on the stream of count values, the low-pass filter section including moving average filters in multiple stages, and an output of at least one moving average filter among the moving average filters in multiple stages is downsampled.

Abstract: Provided is a method of selecting a white Gaussian noise sub-band using singular value decomposition (SVD). The method includes selecting a first frequency band, verifying whether a signal is included in the selected first frequency band, determining the first frequency band as a target measurement frequency when the signal is not included in the selected first frequency band, and measuring a background radio noise in the determined target measurement frequency.

Abstract: Disclosed herein are systems and methods for identifying the source of a signal via channel equalization using characteristics of the signal. A system receives a signal, then measures a frequency response of the signal by performing a spectral analysis over the entire signal. The system computes the average amplitude over a subset of time samples from the spectral analysis for each represented frequency and compares the set of averaged amplitudes to a stored set of averaged amplitudes to produce equalization coefficients. Applying the equalization coefficients to the frequency response yields an equalized frequency response, which is compared to a stored frequency response using a classifier to determine a match. Alternately, the system applies the equalization coefficients to the stored frequency response yielding an equalized stored frequency response. The method can recognize speakers, vehicles, electromagnetic signals, sonar signals, optical signals, videos, etc.

Abstract: A method and device are provided for fast impedance measurement of a biological object having dynamically varying in time parameters, wherein a titlet shaped pulse is introduced into the object and a voltage response signal is measured and analyzed by a processing unit for estimating the impedance of the object. The titlet pulse has a start frequency substantially in one end of the frequency range of interest and a stop frequency substantially in the other end of the frequency range of interest and a duration of the titlet pulse is one cycle or less.

Abstract: Embodiments of this invention provide enhanced triggering capabilities such as frequency and phase triggering in a test and measurement instrument, such as a Real-Time Spectrum Analyzer (RTSA) or oscilloscope. A test and measurement instrument can include input terminals to receive RF signals, an ADC to digitize the RF signals, a digital downconverter to produce I and Q baseband component information, and a power detector to determine a power level using the I and Q information. A comparator compares the power level received from the power detector with a user-definable power threshold, and produces a logic signal for enabling one or more phase or frequency demodulators. The one or more demodulators produce IQ-based time-domain traces derived from the I and Q component information when the power level determined by the power detector exceeds the power threshold. Trigger circuitry is configured to trigger on an event responsive to a delayed trigger enable signal.

Abstract: A frequency mask trigger capable of triggering based on a logical combination of two or more areas of a frequency mask transforms a frame of digital data representing an input signal into a frequency spectrum having a plurality of frequency bins, with each frequency bin having a power amplitude value. A frequency mask is defined having a plurality of reference power levels, one reference power level being associated with each frequency bin. Two or more areas of the frequency mask are defined, with each mask area corresponding to one or more of the frequency bins. A violation status is determined for each mask area by comparing all of the power amplitude values within each mask area to the associated reference power level. If any of the power amplitude values within the mask area violates the associated reference power level, then the entire mask area is deemed to be violated. A trigger signal is generated when a logical combination of the violation statuses of the mask areas is satisfied.

Abstract: Disclosed are systems, methods and articles, including an inspection system that includes at least one generator to apply energy to an object at an application point to cause waves to travel, at least partly, through the object. The system further includes at least one detector configured to detect at least a portion of the waves traveling through the object, and a statistical analyzer to perform a statistical analysis based on an output produced by the at least one detector in response to the detected portion of the waves, the statistical analysis being used to determine whether at least one defect is present in the object.

Abstract: A method of isolating a frequency in a rotating machine having at least one sensor includes receiving, from the at least one sensor, a sensor signal that includes at least one frequency, converting the sensor signal to a digital vibration signal, modifying the vibration signal to generate an envelope signal, synchronously oversampling the envelope signal to generate a synchronous envelope signal, and transforming the synchronous envelope signal into a frequency spectrum to isolate the frequency.

Abstract: Various methods and systems are provided for monitoring and analysis of electrical components. In one embodiment, a method includes obtaining raw radio frequency (RF) component data associated with an electrical component, cross-correlating the raw RF component data with a synchronized pseudo-random sequence (PRS) signal injected into the electrical component to determine a correlated impulse response, and determining a condition of the electrical component based at least in part upon the correlated impulse response. In another embodiment, a system includes a signal injection system coupled to an electrical component. The signal injection system injects a synchronized PRS signal into the electrical component. A data capture device obtains raw RF component data synchronized with the PRS signal through a RF antenna. A data analysis device cross-correlates the raw RF component data with the PRS signal to determine characteristics associated with the electrical component.

Abstract: The condition of a structure using remote interrogation of a multi-state passive wireless antenna sensor that has a known resonant frequency when mounted on the structure. The passive wireless antenna sensor is connected to a remotely operated switching circuit that includes a photocell. An interrogation system transmits a series of radio frequency signals with sweeping frequencies around the known resonant frequency to the passive wireless antenna sensor, while simultaneously pulsing a laser to switch the passive wireless antenna sensor between a first state and a second state in which it is exposed to open-circuit or short-circuit conditions. A signal is reflected from the passive wireless antenna sensor in each of the first and second states, and a resonant frequency of the passive wireless antenna sensor is determined by normalizing the received signals to isolate the antenna mode.

Abstract: A color value for an optical fiber of a fiberscope can be generated on the basis of the intensity values of a plurality of sensor elements of a sensor element arrangement that are sensitive to one spectral region each from a set of sensor spectral regions, if calibration values are provided for each of the spectral regions associated with the optical fiber. The intensity values of all sensor elements of the respective spectral region that are illuminated by the light guide can be combined with the provided calibration values, in order to obtain the color value associated with the optical fiber, which reproduces the color of the light transported by the optical fiber.

Abstract: An apparatus and method for splitting a wide band input signal and overlaying multiple frequency bands on each path associated with one or more digitizers. All frequencies from the split signal on each path can be fed to a mixer. The local oscillator of each mixer receives a sum of signals, which can each be set to any arbitrary frequency, as long as an associated matrix determinant of coefficients is non-zero. Each oscillator signal is multiplied by a coefficient, which can represent phase and magnitude, prior to summing the oscillator signals together. Each mixer mixes a combined signal with the input, thereby generating a set of multiple overlaid frequency bands. The digitized signals are processed to substantially reconstruct the original input signal. Thus, the wide band input signal is digitized using multiple individual digitizers. In particular, a system can support two wide band signals using four digitizers of narrower bandwidth.

Abstract: A pre-channelized spectrum analyzer utilizes a channelizer as a preprocessor for parallel-configured low-resolution spectrum analyzers so as to perform as a high resolution spectrum analyzer. The pre-channelized spectrum analyzer has a polyphase filter that channelizes a signal input and an IFFT that generates filter bank outputs derived from the channelized signal. Spectrum analyzers are in communications with the filter bank outputs so as to generate a spectral decomposition of a subset of those outputs. The spectrum analyzers each perform a window and an FFT function on a corresponding one of the filter bank subset.

Abstract: A method for estimating and tracking locally oscillating signals. The method comprises the steps of taking measurements of an input signal that approximately preserve the inner products among signals in a class of signals of interest and computing an estimate of parameters of the input signal from its inner products with other signals. The step of taking measurements may be linear and approximately preserve inner products, or may be non-linear and approximately preserves inner products. Further, the step of taking measurements is nonadaptive and may comprise compressive sensing. In turn, the compressive sensing may comprise projection using one of a random matrix, a pseudorandom matrix, a sparse matrix and a code matrix. The step of tracking said signal of interest with a phase-locked loop may comprise, for example, operating on compressively sampled data or by operating on compressively sampled frequency modulated data, tracking phase and frequency.

Abstract: A signal processing apparatus for receiving a spectral line of an original signal includes a starting point determining module, a searching module and a symbol rate determining module. The starting point determining module finds a maximum energy in the spectral line and determines at least one search starting point according to the maximum energy. From the at least one search starting point, the searching module searches along the spectral line towards a region with a lower energy for at least one minimum energy satisfying a predetermined condition. The symbol rate determining module determines a symbol rate of the original signal according to the at least one minimum energy.

Abstract: A method for distinguishing a signal of interest from one or more interference signals in a received analog signal comprises receiving an analog signal at a radio front end, and transmitting the received analog signal to an analog-to-digital converter to sample data in the received analog signal and output a digital signal. A sub-channel Fast Fourier Transform (FFT) is performed on the digital signal, and sub-channel FFT bin magnitudes are averaged over a set period of time to determine a shape of the received signal. The shape of the received signal is compared to one or more signal reference patterns by computing a metric for the shape of the received signal, and computing a metric for the one more signal reference patterns. The computed metrics are then compared to a predetermined threshold value to determine the presence, or lack thereof, of a signal of interest in the received signal.

Abstract: A waveform acquiring unit acquires a time waveform of an electromagnetic wave. The time waveform is decomposed into wavelet expansion coefficients by wavelet transform. Influence levels of the respective wavelet expansion coefficients to a spectrum are calculated. The wavelet expansion coefficients are weighted based on at least the influence levels of the wavelet expansion coefficients to the spectrum. The weighted wavelet expansion coefficients are converted into time waveforms by inverse wavelet transform. Thus, the time waveforms that holds spectrum information needed for spectroscopic analysis and has a reduced noise is provided.

Abstract: A mechanical seal monitoring system and method that measure the wear of seal faces of a mechanical seal where the mechanical seal seals a rotating machine portion from another portion of the machine. The system preferably uses a wear probe movable relative to a rotating seal component so that the wear probe can contact the rotating component. The wear of the seal is preferably determined by the relative movement that is required for the wear probe to contact the rotating component. Preferably, stress waves induced by the rubbing between the probe and the rotating component are detected by a stress-wave sensor, processed by a signal processor, and either displayed to the user numerically or reported to a monitoring computer. A signal intensity comparison method is preferably used to make the detection process insensitive to background noise generated by sources other than the contact of the wear probe and the rotating component.

Abstract: A test and measurement instrument including an input port configured to receive an input signal; a digitizer configured to digitize the input signal; a decimator coupled to the digitizer and configured to decimate the digitized input signal to generate a decimated input signal; a digital downconverter coupled to the digitizer and configured to frequency shift the digitized input signal to generate a frequency shifted input signal; and a memory configured to store the decimated input signal and the frequency shifted input signal.

Abstract: Systems and other embodiments associated with synthetic instrumentation are presented. A reconfigurable synthetic instrumentation unit comprises an input module, with dual input/output ports and conditioning logic to condition an input signal. An RF down converter selectively down converts the conditioned input signal. A sampled RF down converter selectively samples the conditioned input signal. A pair of narrowband A/D converters are configured to convert one of the conditioned signal, the down converted signal and the sampled signal to produce a narrowband digital signal. A pair of broadband A/D converters convert at least one of the conditioned signal, the down converted signal and the sampled signal to produce a broadband digital signal. Signal processing logic selectively performs digital signal processing on the broadband digital signal or the narrow band digital signal.

Abstract: Some embodiments of the present invention provide a system that controls a device that generates vibrations in a computer system. During operation, a critical vibration frequency is determined for the computer system. Next, a keep-out zone is generated based on the critical vibration frequency, wherein the keep-out zone specifies a range of frequencies to be avoided. Then, the device is controlled based on the keep-out zone to reduce vibrations generated by the device in the keep-out zone.

Abstract: Disclosed is a test and measurement instrument having a multiple variable bandwidth frequency mask. The instrument includes an input processor for receiving an input signal and producing a digital signal, as well as a trigger signal generator for generating a trigger signal on the occurrence of a trigger event. A time to frequency converter converts a frame of digital data from the digital signal into a frequency spectrum having at least two frequency bins of dissimilar frequency widths. Each frequency bin has a power amplitude value. The trigger signal is generated when the power amplitude value of any of the at least two frequency bins violates an associated reference power level. In some cases the output may be shown as a density trace, and the trigger signal generated when any point of the density trace violates an associated density threshold.

Abstract: A method of monitoring a capacitor bank comprising a plurality of capacitor strings connected in parallel, each capacitor string comprising a plurality of capacitors connected in series is provided. The method includes energizing the capacitor bank. The method includes determining dissipation factors of each of the plurality of the capacitor strings. The method further includes comparing each of the determined dissipation factors with an expected dissipation factor and estimating a health state of the plurality of the capacitor strings based, at least in part, on the comparison of the determined and expected dissipation factors.

Abstract: A system for evaluating data points against cadastral regulations to include a plurality of software modules programmed into a computer system with software and hardware configured to store and update a cadastral rule database containing a plurality of rules for determining the validity of the cadastral data (10). The cadastral database obtained from a data source reference data that is indicative of a plurality of established reference data points wherein the received input data corresponds to a plurality of measured data points with steps to co-process the input data and the referenced data according to the plurality of cadastral rules to determine an indication for the plurality of data points (20).

Abstract: An analog waveform signal detection/data acquisition system that is based on negative group delay for reducing inherent delay in analog waveform or signal detection and acquisition and facilitating earlier than otherwise possible responsive actions to analog waveform data. Signal advance amplification and data conditioning reduces distortion and permits greater temporal advance than previously possible.

Abstract: A method for identifying a degraded fan measures acoustic data from an operating datacenter fan. A motor rotation frequency and a vane passing frequency are determined from the acoustic data. Amplitudes of the frequencies are determined from the acoustic data. If the amplitude of the motor rotation frequency is greater than the amplitude of the vane passing frequency, then it is determined that the fan is degraded.

Abstract: A method and a device for determining a frequency mask disposed above or below a frequency spectrum of a detected signal determines every individual ordinate value of a first envelope curve disposed completely above or below the frequency spectrum as the maximum value or minimum value of a given number of respectively adjacent ordinate values of the frequency spectrum linked to a window function. Following this, each individual ordinate value of a second envelope curve disposed completely above or below the frequency spectrum and completely above or below the first envelope curve is determined as the maximum value or minimum value of a given number of respectively adjacent ordinate values of the frequency spectrum linked to a window function.

Abstract: In one embodiment, an apparatus comprises a nano-scale spectrum sensor configured to be electromagnetically excitable at a predetermined frequency based on received ambient electromagnetic radiation. The apparatus is also configured to be able to use this excitation of the nano-scale spectrum sensor to thereby determine ambient electromagnetic radiation spectrum usage.

Abstract: Disclosed is an aerial surveying system for collecting electromagnetic spectrum data. Spectrally tuned antennas are used on an airplane to prefilter the data in accordance with spectral frequency bands. The data is sequentially sampled using an antenna switching device, band pass filtered and downconverted to an intermediate frequency. High speed vector signal analyzers and digitizers create frequency spectral data and I and Q temporal data. The collected data is recorded and compressed using any desirable compression technique, including video compression. Data analyzers analyze the data and display the data on a GIS map.

Abstract: A method of analyzing a spectrum of one-dimensional or multi-dimensional signal X(t) requires a number of steps including deriving coefficients [AN(?), BN(?)] of an Lp-norm harmonic regression of the signal with 0<p?? and p?2, squaring the coefficients, summing the squared coefficients, and scaling the summed, squared coefficients with a constant c to realize a periodogram of X(t) as LN(?)=c{[AN(?)]2+[BN(?)]2}. The method may include receiving the signal X(t), storing the received signal X(t), and outputting the periodogram LN(?). The method may still further include scanning to maximize the periodogram LN(?) by identifying its largest peak(s) and comparing the amplitude of the identified largest peak(s) with a threshold to determine if the largest peak(s) is(are) attributable to a presence of a periodic signal.

Abstract: An antenna testing device includes an analyzer, a transmission probe electrically connected to the analyzer, a receiving probe electrically connected to the analyzer, and a shielded box having a cutoff frequency. The analyzer generates a test signal the frequency of which is lower than the cutoff frequency, the transmission probe receive the test signal and sends the test signal to the shielded box. The antenna is coupled with the transmission probe and generates a coupled signal, the receiving probe receives the coupled signal and sends the coupled signal to the analyzer. The analyzer analyzes the coupled signal and the test signal, the analyzer calculates the return loss of the antenna.

Abstract: A communication device, for connecting one or more electrical appliances to a remote service centre, comprises a control unit (AMC), means (PLG) for connecting the device (HG) to an alternating voltage electric mains network (Vac) and means (SK) for supplying the alternating mains voltage (Vac) to a power supply line of an electric appliance. The device (HG) further comprises first communication means (CSA), prearranged for receiving information possibly generated by the electric appliance and transmitted through the power supply line thereof, second communication means (ZB), prearranged for establishing a connection with a local area network (HN1) and third communication means (GGM), prearranged for establishing a connection with a further communication network, different from the local network (HN1), to which the remote service center is connected.

Abstract: A method for determining the frequency distribution of the signal level of a measured signal measured respectively in overlapping observation intervals via a time or frequency raster. The method includes determining the incrementation of a memory cell in a first memory to be implemented for each measured signal level of the measured signal at a value of the time or frequency raster, and un-delayed summation of the incrementation determined for every memory cell of the first memory in every measurement cycle. The method also includes delayed summation of the incrementation determined for every memory cell of the first memory in every measurement cycle, and subtracting the result of the delayed summation of the incrementation determined for every memory cell of the first memory in every measurement cycle from the result of the un-delayed summation of the incrementation determined for every memory cell of the first memory in every measurement cycle.

Abstract: A front end of a vector network analyzer (VNA) on an integrated circuit includes a clock generator and two ports. The VNA couples to a device under test (DUT) using the two ports. Each port may include a plurality of receivers and a VSWR bridge, and can be configured as either an input or an output. The clock generator can generate a stimulus signal, an in-phase I clock signal, and a quadrature-phase Q clock signal. The output port provides the stimulus signal to the DUT and measures both reference and reflected power from the DUT, such as by utilizing two receivers by using direct conversion and the I and Q clock signals. The input port measures transmitted power through the DUT using a second VSWR bridge and one of its receivers by using direct conversion along with the I and Q clock signals. The VNA IC can provide S-parameter measurements to a processing unit for further processing and/or analysis to compute the DUT S-parameters.

Abstract: A method is provided for determining vibration frequencies of rotating blades mounted on a rotor which rotates relative to and is supported by a rotor support structure. The method includes the steps of: (a) determining possible vibration frequencies of the blade from blade displacements corresponding to the times at which a blade passes a stationary timing probe; (b) converting a vibration signal detectable at the support structure into a vibration frequency spectrum; and (c) identifying the blade vibration frequency by matching a peak in the vibration frequency spectrum with one of the possible blade vibration frequencies.

Abstract: A first frequency analysis range and a second frequency analysis range narrower than the first one are set with an operation panel 34, etc. A first signal path 171 produces first time domain data of a frequency converted signal under test by a first data production rate depending on the first frequency analysis range. A second signal path 172 produces second time domain data of frequency converted signal under test by a second data production rate depending on the second frequency analysis range and slower than the first data production rate. A CPU receives the first and second time domain data in parallel and produces first and second frequency domain data by FFT wherein frequency shift amounts in the frequency conversions in the first and second signal paths are different depending on the difference between the center frequencies of the first and second frequency analysis ranges.

Abstract: A method for monitoring a synchronous machine is described. The method includes injecting a narrowband sinusoidal signal at a first end of a field winding of the synchronous machine. The method further includes monitoring a voltage at a second end of the field winding with respect to ground. The method then identifies a resonant frequency based on the monitored voltage, and generates a winding health indicator based on the identified resonant frequency and an expected resonant frequency.

Abstract: The present invention includes a guided microwave spectroscopy system (1) that eliminates the need for an automatic gain control feature by providing multiple signal processing paths having differing fixed voltage gains. An emitted signal which exits a test chamber (2) containing a material under test is simultaneously amplified by at least a first fixed gain amplifier (4) and a second fixed gain amplifier (7). The output signal of each amplifier is separately digitized and then normalized for further digital signal processing by a computer (13) in order to determine parameters of the material under test which may have variable microwave radiation characteristics that are a function of the frequency of the signal emitted into the test chamber. During the signal processing step a system clock (121) causes the computer to sample only an integral number of complete output signal cycles.

Abstract: A method for measuring frequency includes the steps of obtaining the cycle number of the clock rate of a signal under test based on a reference signal and a clock mask synchronous with the signal under test; obtaining a frequency of the signal under test based on the cycle number; correcting the frequency of the signal under test based on a plurality of phase shift signals generated based on the reference signal; and minimizing an error of the frequency of the signal under test by increasing the quantity of the phase shift signals. The method enhances the accuracy of the obtained frequency of the signal under test, speeds up frequency measurement, and reduces the required circuit areas. A system for measuring frequency is further introduced for use with the method.

Abstract: Spectrum measurement circuit (101) includes: N-(where N is integer equal or greater than 2) phase clock generation circuit (304) for supplying phase-modulated signals in which the phase of a clock signal is shifted by a phase modulation amount each time the settings of the phase modulation amount are switched; mixer circuit (303) for taking the product of a measured signal supplied from a transmitter and the phase-modulated signals supplied from N-phase clock generation circuit (304); average value output circuit (305) for supplying an average voltage value of the output signal of mixer circuit (303); memory (307) for storing the average voltage value supplied from average value output circuit (305) for each phase modulation amount of N-phase clock generation circuit (304); and arithmetic unit (308) for using the average voltage value for each phase modulation amount of N-phase clock generation circuit (304) to calculate the signal strength of the measured signal.

Abstract: A technique detects an abnormal signal in a compound sampled signal recorded in the time domain. The technique involves dividing the sampled signal recorded in the time domain into sample segments; transforming each of the sample segments from the time domain into the frequency domain to determine transformed segments, each transformed segment having frequency points, each frequency point having an amplitude associated with a certain frequency; for a frequency point in a given transformed segment, determining a ratio by dividing the amplitude of the frequency point by a value indicative of an average of the amplitudes of the frequency points at the same frequency across transformed segments; repeating the determination of a ratio for frequency points in each transformed segment to determine ratios for each transformed segment; repeating the determination of ratios for transformed segments; and using the ratios to detect the abnormal signal in the compound sampled signal.

Abstract: The present invention is directed to an apparatus and methodology for performing spurious-free dynamic range (SFDR) measurements on an RF circuit, such as a mixer, using a single analog input port. The present invention is designed for use when access to the intermediate frequency (IF) port in a radio frequency (RF) front-end circuit is not available, when the traditional two-port method for making an SFDR measurement is inadequate. Passing the analog input through a directional coupler between the RF combiner and the mixer facilitates the performance of the traditional third order intermodulation (IMD) test. Key differences between the single-port and traditional two-port setups are considered and examined, and experimental data obtained using the single-port setup is compared to data obtained using the traditional two-port set-up for different mixer models. Comparison of similar results yields confirmation and a calibration to account for the additional losses introduced by the directional coupler.

Abstract: A method for testing output of an electrical device includes the following steps: a device being tested transmits a first signal to a test platform through a channel being tested. A signal received through the channel being tested by the test platform is compared with the first signal to determine if the received signal corresponds to the first signal. The channel being tested is determined to be normal if the received signal corresponds to the first signal. The channel being tested is determined to be abnormal if the received signal does not correspond to the first signal.

Abstract: Computer system and method for determining frequencies of various components of a volume choke volume dampener to be attached to a compressor. The method includes determining a sound spectrum of a cavity of the compressor without attaching the dampener to the compressor; calculating an acoustic wavelength of the cavity; receiving a length of a proximal nozzle of the dampener; and calculating, based on the acoustic wavelength of the cavity and the length of the proximal nozzle of the dampener, multiple order frequencies associated with the proximal nozzle of the dampener and the cavity of the compressor, wherein the proximal nozzle of the dampener is proximal to the cavity of the compressor when the dampener is attached to the compressor.

Abstract: A method of wirelessly interrogating a sensing device comprising a plurality of passive sensors, to determine a measurement parameter, comprises the steps of repeatedly interrogating the sensing device using a predetermined transmission signal and detecting the response; estimating the measurement parameter for each sensor by means of an analysis of the data accumulated as a result of the interrogation step, and determining the average of the parameters derived from the estimating step for each sensor, using a weighted average, in which the weightings depend on the amplitude of the sensor response. The measurement parameter may be a resonant frequency where the passive sensors are resonant devices, and the sensors may be SAW devices.

Abstract: A method is provided that includes receiving and processing a sample signal scan. Processing the sample signal scan includes applying an inner-product operation on the sample signal scan and each of a plurality of eigenvectors to generate a plurality of corresponding coefficients, and subtracting the sample signal scan from a linear combination of the eigenvectors and corresponding coefficients to thereby produce a corrected sample signal scan. In this regard, the eigenvectors have been generated by decomposing a plurality of background reference signal scans according to a singular value decomposition technique. The signal scans include a plurality of electromagnetic signal measurements at a discrete set of frequencies, where each measurement has been taken by a spectrometer system passing an electromagnetic signal through a sample cell including just a base medium (for the background reference signal scans), or both a base medium and a sample medium (for the sample signal scan).

Abstract: A programmable logic device can be configured as a fractional rate resampling filter capable of performing downsampling prior to upsampling without modifying the overall filter response. Input data may be received at a first sample rate and may be downsampled to generate downsampled data. Portions of the downsampled data may be respectively output to different filtering paths. Each filtering path may include a cluster of filter components that corresponds to different subfilters of the overall filter response and may be operable to receive and process the different portions of the downsampled data. Outputs of each cluster may be combined to generate output data at a second sample rate. The resampling filter structure can reduce the number of multiplier circuits used by allowing time-division multiplexing among different filter components.