Showing papers on "Spectrum analyzer published in 2011"

System and method of mechanical fault detection based on signature detection

Abstract: A mechanical fault detection method and system computes a similarity index to quantify the relationship of a measured spectral signature to a theoretical fault signature. A vibration sensor detects vibrations on machinery with rotating components. The vibration sensor generates a representation of the vibration and provides it to a vibration analyzer. The vibration analyzer is configured to identify peak amplitudes in the generated representation, determine a corresponding frequency for each of the peak amplitudes, and match the determined corresponding frequencies to a theoretical set of frequencies. The analyzer determines a number of matching frequencies and identifies a detection condition when the number of matching frequencies meets a predetermined criterion. The system and method combines vibration amplitude threshold detection with similarity index threshold detection to significantly reduce false fault alarms and false pass errors. The system and method is also used to identify incorrect vibration amplitude thresholds.

Terahertz Frequency Metrology Based on Frequency Comb

Abstract: Two techniques for terahertz (THz) frequency metrology based on frequency comb, namely, a THz-comb-referenced spectrum analyzer and a continuously tunable, single-frequency continuous-wave (CW)-THz generator, are reviewed. Since the frequency comb enables to coherently link the frequency among microwave, optical, and THz regions, it is possible to establish the THz frequency metrology traceable to time of the SI base units. Using a THz-comb-referenced spectrum analyzer based on a stable THz comb generated in a photoconductive antenna for THz detection, the absolute frequency of CW test sources in the sub-THz and THz regions was determined at a precision of 10-11. Furthermore, a continuously tunable, single-frequency CW-THz generator was demonstrated around 120 GHz by photomixing of an accurately tunable CW laser and a tightly fixed CW laser in the optical frequency region, phase locked to two independent optical combs. The combination of the CW-THz generator with the THz-comb-referenced spectrum analyzer will open the door for establishment of frequency metrology in the THz region.

Optimal multisine excitation design for broadband electrical impedance spectroscopy

Abstract: Electrical impedance spectroscopy (EIS) can be used to characterize biological materials in applications ranging from cell culture to body composition, including tissue and organ state. The emergence of cell therapy and tissue engineering opens up a new and promising field of application. While in most cases classical measurement techniques based on a frequency sweep can be used, EIS based on broadband excitations enables dynamic biological systems to be characterized when the measuring time and injected energy are a constraint. Myocardial regeneration, cell characterization in micro-fluidic systems and dynamic electrical impedance tomography are all examples of such applications. The weakness of such types of fast EIS measuring techniques resides in their intrinsic loss of accuracy. However, since most of the practical applications have no restriction over the excitation used, the input power spectrum can be appropriately designed to maximize the accuracy obtained from the measurements. This paper deals with the problem of designing the optimal multisine excitation for electrical bioimpedance measurements. The optimal multisine is obtained by the minimization of the Cramer–Rao lower bound, or what is the same, by maximizing the accuracy obtained from the measurements. Furthermore, because no analytical solution exists for global optimization involving time and frequency domains jointly, this paper presents the multisine optimization approach partially in both domains and then combines the results. As regards the frequency domain approach, a novel contribution is made for the multisine amplitude power spectrum. In the time domain, multisine is optimized by reducing its crest factor. Moreover, the impact on the information and accuracy of the impedance spectrum obtained from using different multisine amplitude power spectra is discussed, as well as the number of frequencies and frequency distributions. The theory is supported by a set of validation measurements when exciting with the optimal and flat multisine signals and compared to a single frequency ac impedance analyzer when characterizing an RC circuit. In vivo healthy myocardium tissue electrical impedance measurements show that broadband EIS based on multisine excitations enable the characterization of dynamic biological systems.

A new time-of-flight SIMS instrument for 3D imaging and analysis

Abstract: We have built a mass spectrometer which utilizes a new method of time-of-flight analysis to provide rapid data acquisition with simultaneous high spatial resolution and high mass resolution. The mass analysis is performed by sampling the secondary beam into a two-stage time-of-flight system. This removes the requirement for a pulsed primary beam as a ToF reference. No tradeoff exists between spatial and mass resolution, and acquisition speed is not limited by the primary beam duty cycle. The analyzer comprises the combination of a shaped field buncher and a nonlinear reflectron. This configuration allows the inclusion of a collision cell and an intermediate time-of-flight selection gate. So, the analyzer can operate in ms-ms mode as well as in normal time-of-flight mode. The instrument is equipped with 40 kV C60 and liquid metal cluster primary beams, which can run in d.c. mode, or, when charge neutralization is required, in slow pulsed mode. Data acquisition is continuous, eliminating loss of data during depth profiling etch cycles. The instrument has an automated sample entry system with heating to 670 K and cooling to 105 K, and includes a novel method of freeze-fracture for tissue samples or other organic samples in aqueous suspension.

Method and apparatus for enhanced ion mobility based sample analysis using various analyzer configurations

Abstract: A ion mobility-based analyzer system including a first ion mobility-based filter for passing selected ions through a time-varying field where the time-varying field being compensated by an adjustable compensation setting. The analyzer also includes a second ion mobility-based filter for receiving a first portion of ions from the first ion mobility-based filter. The second ion mobility-based filter includes a voltage gradient for separating ions of the first portion of ions where the ions have associated retention times based on their times of flight through the voltage gradient. The second ion mobility-based filter includes a detector for detecting the ions at their retention times. The analyzer system further includes a display that displays the detected ions in a plot relating the retention times of the ions in the second ion mobility-based filter with compensation settings of the first ion mobility-based filter.

Wide bandwidth system identification of AC system impedances by applying pertubations to an existing converter

Abstract: A new approach is developed using an existing single-phase power electronics inverter to make a wideband impedance measurement at its interface using a pseudo-random binary sequence (PRBS) voltage perturbation and digital network analyzer techniques. Since the PRBS is an approximation to white noise, all frequencies of interest can be excited simultaneously. The perturbation at the interface is measured and cross-correlation techniques are applied to construct the wideband impedance of the system under test. Online monitoring of interface impedances is a key enabler for a number of smart-grid related capabilities, such as grid health monitoring, active filter re-tuning, identifying system interaction, and adaptive control of grid-connected switching converters. Knowledge of the converter's surroundings enables smarter control actions, which lead to improved stability, performance and reliability of the smart grid.1

A portable, integrated analyzer for microfluidic - based molecular analysis

Abstract: A portable, fully automated analyzer that provides actuation and flow control to a disposable, self-contained, microfluidic cassette (“chip”) for point-of-care, molecular testing is described. The analyzer provides mechanical actuation to compress pouches that pump liquids in the cassette, to open and close diaphragm valves for flow control, and to induce vibrations that enhance stirring. The analyzer also provides thermal actuation for the temperature cycling needed for polymerase chain reaction (PCR) amplification of nucleic acids and for various drying processes. To improve the temperature uniformity of the PCR chamber, the system utilizes a double-sided heating/cooling scheme with a custom feedforward, variable, structural proportional-integral-derivative (FVSPID) controller. The analyzer includes a programmable central processing unit that directs the sequence and timing of the various operations and that is interfaced with a computer. The disposable cassette receives a sample, and it carries out cell lysis, nucleic acid isolation, concentration, and purification, thermal cycling, and either real time or lateral flow (LF) based detection. The system’s operation was demonstrated by processing saliva samples spiked with B. cereus cells. The amplicons were detected with a lateral flow assay using upconverting phosphor reporter particles. This system is particularly suited for use in regions lacking centralized laboratory facilities and skilled personnel.

Charged test method for current transformer and application thereof

Abstract: The invention discloses a charged test method for a current transformer and application thereof. The method comprises the following steps of: serially connecting a charged analyzer with a secondary low-voltage loop to serve as a test loop through two switches of a secondary terminal box on a secondary side loop of the current transformer under the condition of operating the charged current transformer; injecting a different-frequency test signal generated by the analyzer into the test loop through the analyzer, and realizing a charged error test and a charged frequency response test by measuring and calculating loop key parameters under an injected frequency signal; and changing a method for secondary load impedance to change excitation conditions through the analyzer, and measuring load change influence to test a charged exciting characteristic curve. Compared with the prior art, the method has the advantages that: the charged test of the current transformer can be performed without contact of primary voltage, an upward current source, a standard transformer or a load box, the safety and reliability of an uninterrupted power test are guaranteed, the equipment is high in integration, portable and light, and the method is favorable for on-site and laboratory tests and long-term online monitoring.

Frequency division beamforming for sonar arrays

Abstract: A sonar array for forming multiple transmit and/or receive acoustic beams by a frequency beamforming technique. In frequency division beamforming, beam steering direction is made a function of frequency by driving (receiving) each element of a uniformly spaced line array by a signal which leads or lags its nearest neighbor by a fixed phase shift, Δφ. This permits scanning a transmit and/or receive beam through a range of angles by changing its frequency. The same principle can be used to form multiple simultaneous transmit and/or receive beams. This is accomplished by transmitting a wide bandwidth signal and receiving the echoes through a spectrum analyzer. Each frequency bin of the spectrum analyzer then corresponds to a beam pointing in its own unique direction. Advantages of such a sonar system include improved cost, weight, and size versus performance for a variety of systems including ahead looking sonars and bottom mapping sonars.

Experimental Comparison of Low-Cost Sub-Nanosecond Pulse Generators

Abstract: In this paper, six low-cost pulse generator devices having sub-nanosecond transition time are analyzed and compared. Some of the possible applications for these devices are also described, along with an overview of the different approaches for sub-nanosecond pulse generation. Furthermore, the architecture and principle of operation of the realized prototypes are explained. The considered pulse generation techniques are based on logic gates, Step-Recovery Diodes, and transistors driven in the avalanche region. Some experimental results obtained by using an equivalent-time sampling oscilloscope and a spectrum analyzer are shown and discussed, providing both a time-domain and a frequency-domain characterization of the prototypes. Finally, an approach for the generation of modulated pulses in the 6-GHz band (for ultra-wideband applications) is investigated, and experimental results are provided.

Electrostatic Mass Spectrometer With Encoded Frequent Pulses

Abstract: A method, apparatus and algorithms are disclosed for operating an open electrostatic trap (E-trap) or a multi-pass TOF mass spectrometer with an extended flight path. A string of start pulses with non equal time intervals is employed for triggering ion packet injection into the analyzer, a long spectrum is acquired to accept ions from the entire string and a true spectrum is reconstructed by eliminating or accounting overlapping signals at the data analysis stage while using logical analysis of peak groups. The method is particularly useful for tandem mass spectrometry wherein spectra are sparse. The method improves the duty cycle, the dynamic range and the space charge throughput of the analyzer and of the detector, so as the response time of the E-trap analyzer. It allows flight extension without degrading E-trap sensitivity.

Apparatus and method for decomposing an input signal using a downmixer

Abstract: An apparatus for decomposing an input signal having a number of at least three input channels comprises a downmixer (12) for downmixing the input signal to obtain a downmixed signal having a smaller number of channels. Furthermore, an analyzer (16) for analyzing the downmixed signal to derive an analysis result is provided, and the analysis result 18 is forwarded to a signal processor (20) for processing the input signal or a signal derived from the input signal to obtain the decomposed signal (26).

Note: The intermodulation lockin analyzer.

Abstract: Nonlinear systems can be probed by driving them with two or more pure tones while measuring the intermodulation products of the drive tones in the response. We describe a digital lockin analyzer which is designed explicitly for this purpose. The analyzer is implemented on a field-programmable gate array, providing speed in analysis, real-time feedback, and stability in operation. The use of the analyzer is demonstrated for intermodulation atomic force microscopy. A generalization of the intermodulation spectral technique to arbitrary drive waveforms is discussed.

Automatic Detection, Estimation, and Validation of Harmonic Components in Measured Power Spectra: All-in-One Approach

Abstract: The detection of periodic components buried in noise is a general problem in various engineering fields. The amplitudes in the frequency domain of a disturbed signal follow Rice distribution, which is fully described by two parameters. Most methods are restricted to automatically detecting the harmonic components. In this paper, we extend the methodology to detect significant harmonics in measured spectra such that, aside from detection, the magnitude of the harmonic component is also estimated, together with the probability that the harmonic component was incorrectly detected.

Fully automatic chemical luminescent immune analyzer

Abstract: The invention discloses a fully automatic chemical luminescent immune analyzer which comprises a working main body (1) and a control computer (20) connected with the working main body (1), wherein a control box (40) and a storage bin (30) are arranged below the working main body, and the working main body (1) comprises a sample bin (11), a reagent bin (3) and an automatic sampling/reacting tube loading device (2) and a sample feeding head unloading device (223), wherein the automatic sampling/reacting tube loading device (2) and the sample feeding head unloading device (223) are arranged between the sample bin and the reacting bin. The fully automatic chemical luminescent immune analyzer realizes fully automatic operations of the immune reaction process, such as reacting tube loading, automatic sample feeding, automatic reagent filling, reaction solution incubation reaction, automatic cleaning of a reaction solution to detection and analysis of reaction results, reduces the influence of personal factors on the experiment due to the automatic operations, and improves the sensitivity.

A portable analyzer for pouch-actuated, immunoassay cassettes

Abstract: A portable, small footprint, light, general purpose analyzer (processor) to control the flow in immunoassay cassettes and to facilitate the detection of test results is described. The durable analyzer accepts disposable cassettes that contain pouches and reaction chambers for various unit operations such as hydration of dry reagents, stirring, and incubation. The analyzer includes individually controlled, linear actuators to compress the pouches in the cassette, which facilitates the pumping and mixing of sample and reagents, and to close diaphragm-based valves for flow control. The same types of actuators are used to compress pouches and actuate valves. The analyzer also houses a compact OEM scanner/reader to excite fluorescence and detect emission from labels. The analyzer is hydraulically isolated from the cassette, reducing the possibility of cross-contamination. The analyzer facilitates programmable, automated execution of a sequence of operations such as pumping and valving in a timely fashion, reducing the level of expertise required from the operator and the possibility for errors. The analyzer's design is modular and expandable to accommodate cassettes of various complexities and additional functionalities. In this paper, the utility of the analyzer has been demonstrated with the execution of a simple, consecutive, lateral flow assay of a model biological system and the test results were detected with up converting phosphor labels that are excited at infrared frequencies and emit in the visible spectrum.

Apparatus for generating an enhanced downmix signal, method for generating an enhanced downmix signal and computer program

Abstract: An apparatus for generating an enhanced downmix signal on the basis of a multi-channel microphone signal comprises a spatial analyzer configured to compute a set of spatial cue parameters comprising a direction information describing a direction-of-arrival of a direct sound, a direct sound power information and a diffuse sound power information on the basis of the multi-channel microphone signal. The apparatus also comprises a filter calculator for calculating enhancement filter parameters in dependence on the direction information describing the direction-of-arrival of the direct sound, in dependence on the direct sound power information and in dependence on the diffuse sound power information. The apparatus also comprises a filter for filtering the microphone signal, or a signal derived therefrom, using the enhancement filter parameters, to obtain the enhanced downmix signal.

A dual analyzer for real-time impedance and noise spectroscopy of nanoscale devices.

Abstract: This paper introduces a simple portable dual analyzer which allows real-time ac-impedance measurements and noise spectroscopic analysis simultaneously, employing one or two data acquisition systems together with a low noise current-to-voltage preamplifier. The input signal composed of numerous selected frequencies of sinusoidal voltages with a dc bias was applied to a device under the test (DUT): single walled carbon nanotube field effect transistors (SWCNT-FETs). Each frequency component, ranging from 1 to 46.4 kHz, was successfully mapped to a Nyquist plot using the background of the electrical noise power spectrum. It is, thus, clearly demonstrated that this dual analyzer enables the real-time ac-impedance analysis and the frequency response of the carrier transport in the SWCNT-FETs as a DUT.

Pore structure analyzer based on non-contact impedance measurement for cement-based materials

Abstract: Measurement of the impedance and complex resistivity of a sample is used for measuring parameters resulting from a change in physical or chemical state A variable frequency signal is provided by a transformer primary coil A secondary coil of the transformer with a closed loop and electrically coupled said sample is monitored along with a leakage current sensor Sampling at multiple signal frequencies is performed at the multiple signal frequencies

Real Time Statistical Triggers on Data Streams

Abstract: Logic analyzers and real-time spectrum analyzers use real-time statistical processes as a basis for creating a trigger. The statistical displays within a test and measurement system such as a Logic Analyzer (LA) or Spectrum Analyzer (SA) or other instrument are used in a user interface to define a trigger based on the statistical event itself. In brief, the invention is a Real Time Statistical trigger established by the user through a direct interaction with the Real Time Statistics displays. This interaction can be via a graphical user interface, or the user interface can employ a non-visible display (e.g., a speaker) or input device (e.g., a microphone).

Non-disperse infrared multi-component flue gas analyzer

Abstract: The invention discloses a non-disperse infrared multi-component flue gas analyzer. In the non-disperse infrared multi-component flue gas analyzer, a light source with similar black body radiation characteristic is adopted and can cover infrared absorption bands of all component gases to be tested and interfered component gases; high-stability light source emission is realized by designing a voltage-stabilizing and current-stabilizing circuit; an optically filtering wheel is provided, so double effects of optically filtering and modulating light waves are achieved, and stability and measuring accuracy of a system are improved; concentration of various gases in the flue gas can be measured at the same time by reasonably selecting parameters of optical filters; a water vapor measuring channel is introduced on the optically filtering wheel, so an analyzer can work in the damp environment normally; a sample pool adopts a multi-time reflection pool structure, so gas absorption optical distance is increased and detection sensitivity of the system is improved; and the sample pool adopts a heating and temperature control system, so water vapor condensation and combination of the water vapor and acidic gases to be tested such as sulfur dioxide (SO2) and nitrogen dioxide (NO2) are avoided, and measuring accuracy and corrosion resistance of the system are improved.

Temperature-adjusted spectrometer

Abstract: A temperature- adjusted spectrometer includes a light source, a temperature sensor and a spectral analyzer. The light source is configured to direct light along a light path through a first lens toward a substrate position in the process chamber; the spectral analyzer is configured to receive light scattered from a material sample in sample area on a substrate located at the substrate position in the process chamber; and the temperature measurement device is configured to measure the temperature of a material sample on a substrate located at the substrate position in the process chamber. Further, the spectrum is corrected by means the measured temperature by a calibration module to provide a temperature - adjusted spectrum.

Multiparameter water quality comprehensive analyzer

Abstract: The invention provides a multiparameter water quality comprehensive analyzer, which is connected with an operation management center. The multiparameter water quality comprehensive analyzer comprises a power module connected with an external power supply, an energy storage module, of which the circuit is connected with the power module, a central control module connected with the power module, a sensor module connected with the central control module and a sensor cleaning module connected with the power module, the central control module and the sensor module. The multiparameter water qualitycomprehensive analyzer has the advantages that water quality parameters are measured by utilizing the measuring technology of a spectral analysis method, an ionic analysis method and the like withoutusing of chemical agents, so secondary pollution is prevented; in addition, the transmission mode and communication technology of a digitalized sensor fulfill the aims of multiparameter measurement, flexible configuration and intelligentized automatic management, and an energy storage device of the multiparameter water quality comprehensive analyzer can normally operate under the condition of no external power supply, so that the multiparameter water quality comprehensive analyzer is applied to the field monitoring environment conveniently.

Adaptive control of power converters using Digital Network Analyzer Techniques

Abstract: We describe a new method for design of adaptive controls for switching power converters that leverages the information-rich frequency response data obtained using the correlation-based analysis dubbed Digital Network Analyzer Technique. Compared to existing single-frequency based adaptive control methods such as limit-cycle and relay-feedback based autotuning, this method provides a unified approach to target many distinct problems plaguing converter control designers. The major strength of this method is that a single adaptive controller structure is able to fix multiple converter problems with a generalized and online identification and adaptation procedure. Also, unlike the conservative nature of robust control, adaptive control attempts to maintain relatively high performance at each time instant whenever possible. A step-by-step procedure is given which explains how the control platform can use the converter to perturb the system, identify the non-parametric frequency response of the plant, fit the data to a parametric model, and synthesize a control which meets user specifications. Simulation results are provided for a comprehensive set of realistic scenarios, where each test case uniquely degrades the converter frequency response. In each case, the performance and stability degradation is mitigated through targeted control adaptation.

On-board ultrasonic frequency spectrum and image generation

Abstract: A portable apparatus for determining testing the condition of a machine or device using ultrasonic signals with an array of ultrasonic sensors for receiving an ultrasonic signal transmitted from the machine or device. The apparatus possesses a heterodyne circuit coupled to receive the output signals from the ultrasonic sensors and convert the output signals to a heterodyned audio signal to be analyzed via a digital spectrum analyzer integral to the portable apparatus. The digital spectrum analyzer performs real-time fast fourier transformations on the heterodyned audio signal. After analyzing the signals, the hand held device uses a variety of audiovisual cues to direct a user to portions of the machine in need of repair or monitoring.

Development of the gamma-ray analysis digital filter multi-channel analyzer (GMCA)

Abstract: Gamma-ray spectroscopic systems with high efficiency and energy resolution have become important in many fields. Conventional systems with analog shaping are being replaced by digital systems that can provide higher throughput, better energy resolution and better stability. Therefore, we present the development of our new versatile real time Multi-Channel Analyzer with digital signal processing, the GMCA. The device has two independent channels and is compatible to various detectors like Coplanar Grid (Cd,Zn)Te, HPGe, LaBr 3 , NaI and CsI. Different sensors for temperature, pressure and humidity provide additional information. In this work we will show energy resolution measurements and compare spectra measured with different detectors connected to our system and to commercial systems, both analog and digital.

Water Vapor Interference Correction in a Non Dispersive Infrared Multi-Gas Analyzer

Abstract: We demonstrate an effective method to eliminate the interfering effect of water vapor in a non-dispersive infrared multi-gas analyzer. The response coefficients of water vapor at each filter channel are measured from the humidity of the ambient air. Based on the proposed method, the water vapor interference is corrected with the measured response coefficients. By deducting the absorbance of each filter channel related to water vapor, the measuring precision of the analyzer is improved significantly and the concentration retrieval correlation accuracy of each target gas is more than 99%.

Spatial Spectral Photonic Receiver for Direction Finding via Wideband Phase Sensitive Spectral Mapping

Abstract: An apparatus includes a single or dual output port, dual-drive Mach-Zehnder Interferometer configured to generate a first optical signal in one path, and to generate a second optical signal in a different path. The apparatus also includes an optical spectrum analyzer configured to receive output from at least one port of the dual-drive Mach-Zehnder Interferometer. A method includes causing radio frequency signals from two different antennae to modulate an optical carrier at a corresponding drive of a dual-drive Mach-Zehnder Interferometer, and causing output from at least one port of the Mach-Zehnder Interferometer to be directed to an optical spectrum analyzer. The method further comprises determining arrival angle at each of a plurality of frequencies in the radio frequency signals based on output from the optical spectrum analyzer.