Showing papers on "Spectrum analyzer published in 2001"

Apparatus and system for multivariate spectral analysis

Abstract: An apparatus and system for determining the properties of a sample from measured spectral data collected from the sample by performing a method of multivariate spectral analysis. The method can include: generating a two-dimensional matrix A containing measured spectral data; providing a weighted spectral data matrix D by performing a weighting operation on matrix A; factoring D into the product of two matrices, C and ST, by performing a constrained alternating least-squares analysis of D=CST, where C is a concentration intensity matrix and S is a spectral shapes matrix; unweighting C and S by applying the inverse of the weighting used previously; and determining the properties of the sample by inspecting C and S. This method can be used by a spectrum analyzer to process X-ray spectral data generated by a spectral analysis system that can include a Scanning Electron Microscope (SEM) with an Energy Dispersive Detector and Pulse Height Analyzer.

The Electron and ion Plasma Experiment for Fast

Abstract: The ion and electron plasma experiment on the Fast Auroral Snapshot satellite (FAST) is designed to measure pitch-angle distributions of suprathermal auroral electrons and ions with high sensitivity, wide dynamic range, good energy and angular resolution, and exceptional time resolution. These measurements support the primary scientific goal of the FAST mission to understand the physical processes responsible for auroral particle acceleration and heating, and associated wave-particle interactions. The instrument includes a complement of 8 pairs of ‘Top Hat’ electrostatic analyzer heads with microchannel plate (MCP) electron multipliers and discrete anodes to provide angle resolved measurements. The analyzers are packaged in four instrument stacks, each containing four analyzers. These four stacks are equally spaced around the spacecraft spin plane. Analyzers mounted on opposite sides of the spacecraft operate in pairs such that their individual 180° fields of view combine to give an unobstructed 360° field of view in the spin plane. The earth’s magnetic field is within a few degrees of the spin plane during most auroral crossings, so the time resolution for pitch-angle distribution measurements is independent of the spacecraft spin period. Two analyzer pairs serve as electron and ion spectrometers that obtain distributions of 48 energies at 32 angles every 78 ms. Their standard energy ranges are 4 eV to 32 keV for electrons and 3 eV to 24 keV for ions. These sensors also have deflection plates that can track the magnetic field direction within 10° of the spin plane to resolve narrow, magnetic field-aligned beams of electrons and ions. The remaining six analyzer pairs collectively function as an electron spectrograph, resolving distributions with 16 contiguous pitch-angle bins and a selectable trade-off of energy and time resolution. Two examples of possible operating modes are a maximum time resolution mode with 16 angles and 6 energies every 1.63 ms, or a maximum energy resolution mode with 16 angles and 48 energies every 13 ms. The instrument electronics include mcp pulse amplifiers and counters, high voltage supplies, command/data interface circuits, and diagnostic test circuits. All data formatting, commanding, timing and operational control of the plasma analyzer instrument are managed by a central instrument data processing unit (IDPU), which controls all of the FAST science instruments. The IDPU creates slower data modes by averaging the high rate measurements collected on the spacecraft. A flexible combination of burst mode data and slower’ survey’ data are defined by IDPU software tables that can be revised by command uploads. Initial flight results demonstrate successful achievement of all measurement objectives.

Tandem high field asymmetric waveform ion mobility spectrometry (faims)/ion mobility spectrometry

Abstract: A method for separating ions is disclosed. A first analyzer region is provided defined by a space between first and second spaced apart electrodes. A second analyser region is defined in operational communication with the first analyzer region and having two electrodes. Ions are provided to one of the first analyzer region and the second analyzer region and then coupled from there to the other analyzer region. A first asymmetric waveform and a first direct-current compensation voltage are applied to electrodes for providing an electric field within the first analyzer region. The first asymmetric waveform is typically selected for effecting a difference in net displacement between two different ions in the time of one cycle of the applied first asymmetric waveform and the first compensation voltage is selected to support selective transmission of a first subset of the ions within the first analyzer region. Conditions are provided within the second analyzer region for effecting a second separation of ions therein to support selective transmission of a second subset of the ions within the second analyzer region.

Demonstration of a radio-frequency spectrum analyzer based on spectral hole burning

Abstract: Spectral hole-burning (SHB) technology is considered for >10‐GHz instantaneous bandwidth signal-processing applications. In this context we report on what is believed to be the first demonstration of a SHB microwave spectrometer. A set of gratings engraved in a SHB crystal is used to filter one sideband of the optically carried microwave signal. The setup is confined to narrow-bandwidth operation, over a 35-MHz-wide interval. The first findings confirm the validity of the architecture in terms of spectral resolution, angular channel separation, and simultaneous detection of multiple spectral lines.

Self test circuit for evaluating a high-speed serial interface

Abstract: A data transceiver including a self-test data generator for generating test data, which includes a first pseudo-random number generator programmable so as to allow the operator to input the test data values. The data transceiver further includes a transmitter section coupled to the self-test data generator, a receiver section coupled to the transmitter section, and a test data analyzer coupled to the receiver section, wherein the test data analyzer includes a second pseudo-random number generator, which allows the operator to input the data value via a data bus coupled to the test data analyzer. Both the self-test data generator and the test data analyzer are independently controllable.

Mach-zehnder interferometer as a spectral analyzer for molecular Doppler wind lidar.

Abstract: The theoretical performance of a Mach–Zehnder interferometer used as a spectral analyzer for wind-speed measurement by direct-detection Doppler lidar is presented. The interferometer is optimized for measurement of wind velocity from the signal backscattered by the molecules. Two arrangements are proposed, involving two detection channels (DMZ) or four detection channels (QMZ). Using the assumption of a pure molecular signal with a Gaussian spectral profile, we derive an analytic expression for the standard deviation of the measurement error for each arrangement. They are then compared with the ideal spectral analyzer (ISA) and with the double-edge Fabry–Perot (DFP) in the case of a shot-noise-limited signal. The DMZ measurement error is shown to be only 1.65 times that of the ISA and is 1.4 times lower than that given by the DFP. The QMZ arrangement provides a measurement that is insensitive to the aerosol scattering contribution but gives a measurement error that is 1.4 times higher than that of the DMZ.

High-speed, high-sensitivity aerosol fluorescence spectrum detection using a 32-anode photomultiplier tube detector

Abstract: We employ a 32-anode photomultiplier tube (PMT) in a fluorescence detection system and demonstrate its ability to record broad fluorescence spectra at frame rates in excess of 1.4×103 Hz, which is 56× faster than the frame rate of an intensified charge coupled device detector. The multi-anode PMT has single-photon detectable sensitivity. A new data acquisition and processing system for the multi-anode PMT, together with the system-controlling software, has been developed. The performance characteristics of the fluorescence detection system, including the data rate capability, dynamic range, signal-to-noise ratio, and crosstalk among the different anodes, are reported. The 32-anode PMT and acquisition system are suitable for a real-time, field-portable, multichannel optical analyzer.

Facility to measure solar cell ac parameters using an impedance spectroscopy technique

Abstract: An experimental setup has been developed to measure the solar cell ac parameters using an impedance spectroscopy technique. It consists of an electrochemical interface to set the dc bias voltage and to apply the signal voltage across the solar cell and a frequency response analyzer to generate the excitation signal with varying frequency and analyze the result. The setup is calibrated with a standard RC network and measured an error of ±4% (maximum). Solar cell capacitance, parallel resistance and series resistance are calculated from the measured data.

An implantable analyzer of bio-impedance dynamics: mixed signal approach

Abstract: An on-chip implantable lock-in analyzer of variations of the electrical bio-impedance has been designed and pilot versions of the ASIC based analyzer have been fabricated and tested. A mixed signal approach, as the most suitable way for accomplishing a low voltage and low power ASIC for applications in portable and implantable devices for various biomedical applications, is discussed.

Ingress monitoring system and method

Abstract: A system for monitoring reverse paths of a bi-directional cable communication network such as a CATV network, to detect and analyze ingress signals entering a reverse path and ending to a network sub-headend or headend through a corresponding one of communication lines, comprises a plurality of radio frequency signal detectors connected thereto. The radio frequency signal detectors are provided with bandpass filter for receiving any radio frequency signal within the frequency band used, to generate corresponding output signals indicative of the strength of the received radio frequency signal. Th output signal generated by the frequency signal detector which is coupled to the communication line corresponding to the ingress signal carrying path is indicative of the strength of the received ingress signal with any received reverse signals. The system further comprises a signal processor for analyzing the detector output signals through comparison with one or more predetermined ingress thresholds to generate an alarm signal whenever the ingress signal is detected. The system further comprises a control computer receiving the alarm signal to generate monitoring sequence control data indicative of the communication line corresponding to the ingress signal carrying path to be monitored. The system also comprises a selector switch having a plurality of inputs being connected to the communication lines and being responsive to the monitoring sequence control data to select the input connected to the communication line to be monitored, and signal monitoring instrumentation such as a spectrum analyzer and a broadband analyzer coupled to an output of the switching device and being responsive to the monitoring sequence control data for analyzing the ingress signal and generating alarm message data accordingly. The control computer receives the alarm message data to further generate diagnostic sequence control data for the monitoring instrumentation also used to determine source characteristics of the ingress signal.

A wideband lag correlator for heterodyne spectroscopy of broad astronomical and atmospheric spectral lines

Abstract: WASP2 is a lag correlation spectrometer that is optimized for astronomical heterodyne observations of spectral lines from mid-infrared through centimeter wavelengths. Since the instrument is a wideband microwave spectrum analyzer, its basic technology is well suited to radio astronomy, atmospheric remote sensing, and any other application which requires observations of broad spectral lines. In this specific instrument, eight 16 lag correlator boards form a 128 lag spectrometer with 33 MHz spectral resolution. The spectrometer's present microwave components dominate its gain shape, yielding a spectrometer which covers a useful (6 dB bandwidth) single band of 3600 MHz, from 280 to 3880 MHz. The correlator boards have a 3 dB bandwidth of 4000 MHz, from below 100 MHz to near their aliasing limit of 4200 MHz. WASP2 obtains its wide bandwidth with fully analog high frequency components: the voltage multipliers are transistor circuits and the delays are lengths of microstrip transmission line. WASP2 is simple, compact, requires little power, and integrates stably for many hours.

Dynamic photometric imaging polarizer-sample-analyzer polarimeter: instrument for mapping birefringence and optical rotation

Abstract: An imaging dynamic photopolarimeter in an optical configuration P(α)SA(n) (polarizer-sample-analyzer) having harmonically rotating polarizer (P) and analyzer (A), is presented for studies of inhomogeneous birefringent media. The method is capable of simple and precise measuring of birefringence and optical rotation across a two-dimensional field. Although the basic principle upon which the method operates has been proposed earlier, the focus here is on its extension, applicable to a whole field, and immediate measurement of three optical parameters, which have direct physical meaning. Earlier versions of the instrument either operate with a single beam or measure components of Jones or Mueller matrices. The operation of the given method is consistent with a general idea of dynamic photopolarimetry by discrete Fourier analysis and entails digital procession of intensity images, obtained at nine equispaced positions of the polarizer and the analyzer during synchronous rotation of them. A technique of data acquisition is described, and a detailed error analysis is provided. Theoretical considerations are supplemented with testing measurements of a quartz phase plate.

Scanning fluorescent systems for various diagnostic

Abstract: An angularly multiplexed store contains filters derived from prior examination of input image reference samples, a spectrum analyzer produces spectral data representing the frequency spectrum of the input image under examination, a computer produces an encoded map of the spectral data representing the input image frequency spectrum. The encoded map is transformed, inputted into the store while close match spectral correlation light beams emerge from the multiplexed store, each having an emerging angle associated with that filter within the multiplexed store producing a close match with the first transform. An array of light beam detectors and a display present images having colors that indicate the nature of the input image such as a type of cancer. An associated memory-retro-reflector arrangement displays characters naming the materials making up the input image such as types of abnormal tissue. The disclosed apparatus can have significant application in medicine, food industry, spectroscopy, material science and other various areas.

Electromagnetic wave analyzer

Abstract: An electromagnetic wave analyzer determines intensity and phase characteristics of an electromagnetic wave such as an ultrashort laser pulse. The analyzer passes the electromagnetic wave through a Fresnel biprism that produces a probe pulse and a gated pulse. The probe pulse and the gated pulse intersect and interact in a nonlinear optical medium, such as a second harmonic generating (SHG) crystal. The nonlinear optical medium then time gates and frequency filters the electromagnetic wave producing an input pulse gated signal. A lens maps delay in a horizontal direction and crystal output angle in a vertical direction. A camera detects the output of the lens and creates a spectrogram of the electromagnetic wave.

The Time-of-Flight Energy, Angle, Mass Spectrograph (Teams) Experiment for Fast

Abstract: The Time-of-flight Energy Angle Mass Spectrograph (TEAMS) is being flown on the FAST Small Explorer mission to measure the 3-dimensional distribution function of the major ion species present in the lower magnetosphere. The instrument is similar to time-of-flight plasma analyzer systems that have been designed and planned for flight as CODIF (Composition and Distribution Function analyzer) on the four European Space Agency Cluster-II spacecraft and, as ESIC (Equator-S Ion Composition instrument) on Equator-S. This instrument allows the 3-dimensional distribution functions of individual ion species to be determined within 1/2 spin period (2.5 s). Two-dimensional distributions are measured in 80 ms. These capabilities are crucial for the study of selective energization processes in the auroral regions of the magnetosphere. The design, operational characteristics, and test and calibration results for this instrument are presented. The sensor consists of a toroidal top-hat electrostatic analyzer with instantaneous acceptance of ions over 360° in polar angle. After post-acceleration of the incoming ions by up to 25 kV, a time-of-flight mass spectrograph discriminates the individual species. It has been demonstrated through calibration that the instrument can easily separate H+, He2+, He+, O+ and, for energies after post-acceleration of > 20 keV, even O 2 + molecules. On-board mass discrimination and the internal accumulation of several distinct data quantities combined with the spacecraft’s flexible telemetry formatting allow for instrument data rates from 7.8 kb s−1 to 315 kb s−1 to be telemetered to ground through the FAST centralized Instrument Data Processor.

A multi-application FFT analyzer based on a DSP architecture

Abstract: A digital signal processor (DSP)-based FFT analyzer capable of adapting its behavior according to specific application requirements was set up. A suitably designed user-interface allows both the specific application to be chosen and its main parameters to be defined. An automatic optimization procedure then reorganizes the instrument configuration in order to meet user requirements. Multi-DSP architecture implementation ensures real-time behavior. The experimental test results indicate that the instrument is capable of optimally operating in a large number of typical applications.

Methods and apparatus for time-domain measurement with a high frequency circuit analyzer

Abstract: A method of measuring the response of an electronic device to a high frequency input signal is performed with an analyzer (1) The method includes providing an electronic device (for example a transistor or amplifier) to be tested, providing a measurement system (10, 11 a , 11 b , 12, SA, SB) including a microwave transition analyzer (MTA) (10) connected to the device, applying a signal to the device and measuring with the MTA (10) the resulting incident and reflected waves at a port (3, 4) of the device, ascertaining first calibration data regarding the measurement system (10, 11 a , 11 b , 12, SA, SB), processing signals representative of the waves as measured by the MTA (10), with the use of the first calibration data, to compensate for the influence of the measurement system and the connection between the MTA (10) and the device on the waves between the port (3, 4) of the device and the MTA to produce vector corrected s-parameters, ascertaining, by measuring signals at a port of the device with a real network with known properties, second calibration data concerning voltage waveforms at the port, and processing said vectors corrected s-parameters with the use of the second calibration data to produce output signals from with the absolute values of the magnitude and phase of waves at the port of the device may be directly ascertained The method is of use in improving the efficiency and power capabilities of amplifiers for use in mobile communication base stations

Spectrum analyzer and vector network analyzer combined into a single handheld unit

Abstract: A spectrum analyzer is combined with the VNA in a housing measuring approximately 4 pounds with the spectrum analyzer portion operating from slightly above DC to above 3.0 GHz. The components for the spectrum analyzer are provided on a separate printed circuit board from the two printed circuit boards for the display and VNA components in the housing. The design of components for the printed circuit board enable a significant reduction of size from a typical spectrum analyzer which weighs 40 pounds or more and measures on the order of 2 feet by 3 feet by 0.5 feet.

Frequency conversion sweep measuring method

Abstract: A preselector is omitted in a spectrum analyzer, for example, which is used to prevent an image signal from being inputted. In addition, an image signal of a signal which is located outside a range of set-up measured frequencies is suppressed as much as possible. For a range of set-up measured frequencies F 1 ˜F 2 , and for each of a plurality of intermediate frequencies F i , the frequency of the sweep signal is swept over a range F 1 +F i ˜F 2 +F i to determine first measured data, and is also swept over a range F 1 −F i ˜F 2 −F i to determine second measured data. The first and the second measured data are compared against each other for each measured frequency point, and if they are equal, the data value obtained or a data value having a minimum value unless they are not of an equal value is delivered to obtain measured data in which image data based on image signals has been suppressed.

Optical switch with connection verification

Abstract: An optical switch is equipped with a set of optical intensity controllers at its input, each intensity controller being driven to vary a corresponding WDM input traffic signal with a low power test signal. The switch is also equipped with optical splitters at its output and a path integrity analyzer connected to the splitters and to the intensity controllers. The path integrity analyzer generates or controls generation of the test signals applied by the intensity controllers. The path integrity analyzer also receives the tapped portions of the WDM output signals and separates them into their single-carrier components in order to recover a set of switched single-carrier optical signals. The path integrity analyzer is further provided with test signal detectors used to detect the presence of a test signal in each recovered switched single-carrier optical signal. The path integrity analyzer thus ascertains the integrity of the connection involving each switched single-carrier optical signal by comparing detected test signals to expected test signals that are derived from a connection map.

A method and apparatus employing optical emission spectroscopy to detect a fault in process conditions of a semiconductor processing system

Abstract: A method and an apparatus system feature detecting faults in process conditions of a plasma-based semiconductor processing system by sensing the spectral emissions of the plasma. As a result, the method includes sensing optical energy produced by the plasma and identifying the fault in the process conditions as a function of one or more of the plurality of spectral bands. To that end, the apparatus includes a detector in optical communication with the processing chamber to sense optical energy generated by the plasma, and a spectrum analyzer, in electrical communication with the optical detector. The spectrum analyzer resolves the spectral bands and produces information corresponding thereto. A processor is in electrical communication with the spectrum analyzer, and a memory is in electrical communication with the processor. The memory includes a computer-readable medium having a computer-readable program embodied therein that controls the system to carry-out the method.

Phase noise measurement module and method for a spectrum analyzer

Abstract: A phase noise measurement module (PNMM), system and method for measuring phase noise improve accuracy of phase noise measurements of a signal under test (SUT) using a spectrum analyzer. The PNMM includes an RF to hF frequency converter and a selectable frequency divider. The system includes the PNMM connected to the spectrum analyzer and employs an LO signal from a tunable LO in the spectrum analyzer. The method includes directly converting an input SUT to an IF signal having either a second or a third IF frequency that is applied to a corresponding frequency conversion stage of the spectrum analyzer before the phase noise is measured. The present invention bypasses a first conversion stage, and typically a second conversion stage as well, of the spectrum analyzer and directly converts the SUT to either the second or third IF frequency, thereby reducing phase noise added to the SUT.

Phase-noise measurement with compensation for phase noise contributed by spectrum analyzer

Abstract: A method and apparatus compensates for phase noise added by a spectrum analyzer from phase noise measurements of a signal under test (SUT) taken by the spectrum analyzer. The method comprises the steps of measuring the phase noise of the SUT, determining the added phase noise of the spectrum analyzer, and applying a mathematical correction to the measured phase noise. A spectrum analyzer apparatus that compensates for added phase noise comprises a controller portion, a memory portion, a signal conversion and detection portion, and a compensation algorithm stored in the memory portion. A system that compensates for added phase noise comprises a controller having a control algorithm and a spectrum analyzer. The compensation and control algorithms are computer programs that implement the method of the present invention.

Dorsal aortic flow velocity in chick embryos of stage 16 to 28.

Abstract: The objective of this study was to evaluate two Doppler frequency-detection methods to measure blood flow velocity in the developing chick embryo. We compared the commonly used directional zero-crossing counter and a customized digital bidirectional spectrum analyzer. At development stages 16 up to 28 (2.5 to 6 days incubation), a reversed flow component in the dorsal aorta was demonstrated using the bidirectional spectrum analyzer. Dorsal aortic velocities obtained with the directional zero-crossing counter were significantly lower than with the bidirectional spectrum analyzer in stages 16, 20 and 28. In addition to the differences in the absolute velocity values, there was also a remarkable discrepancy in the velocity waveform shape using the two Doppler frequency processors. The calculated heart rate using the two Doppler frequency processors was identical. It is concluded that a Doppler velocity detector based on spectral analysis is superior to the hitherto used zero-crossing counter in the chick embryo. With the customized digital bidirectional spectrum analyzer, we can accurately measure the hemodynamics of the developing chick embryo.

PD Signal Propagation Characteristics in GIS and Its Location System by Frequency Components Comparison

Abstract: Propagation characteristics of partial discharge (PD) signal in gas-insulated switchgear (GIS) were investigated in a laboratory and at a 300 kV underground substation. The laboratory test indicates that signal damping can be attributed to two major mechanisms: reflection due to irregularity of characteristic impedance such as spacers and the mode shift from TEM to TE or TM. Tests at the substation show that the signal damping phenomena are independent of propagation direction and the mode shift gives rise to a large signal damping. The major higher mode seems to be TE11. Amplitudes of observed waveforms using narrow-band filters that agree well with the corresponding frequency components observed with a spectrum analyzer show irregular or random behavior depending upon their observation point. This indicates that narrow-band filters do not seem to be suitable for a PD location system by a frequency component comparison, and the reliability of the system using broadband filters instead is discussed.

Computer-aided design of power line filters with a low cost common- and differential-mode noise diagnostic circuit

Abstract: It is important to be able to separate common-mode and differential-mode noises in the conducted emission. We propose new discriminators, which are low-cost, easily manufactured and are able to give exact noise readings without further adjustment. This diagnostic circuit is used in CAD of power line filters. To this end, we also propose a relatively cheap approach using an oscilloscope. The time-domain measurement is performed and transformed into frequency domain using FFT. A realistic design example is shown to give satisfactory results.