Showing papers on "Spectrum analyzer published in 2000"

Methods and apparatus for high-speed longitudinal scanning in imaging systems

Abstract: An imaging system (2) wherein an optical signal (185, 195) is transmitted to both a sample (25) to be measured and a rotating element (175) which is calibrated to the system. A return signal (186, 196) is detected by the system, and a scan analyzer and correction unit (160) uses the system calibration information along with synchronization information (177, 171) to correct for return signal degradation or errors due to imperfections in the rotating element (175) in real time. This allows for an accurate measurement of the sample (25). The system (2) can also include a coarse path-length adjustment unit (45) to allow the system to track a region of interest within a sample (25) to further allow for accurate sample measurement.

Radiation filter, spectrometer and imager using a micro-mirror array

Abstract: A spectrometer (10) includes a two-dimensional array of modulatable microm-irrors (18), a detector (20), and an analyzer (22). The micro-mirrors are positioned for receiving individual radiation components forming a part of a radiation source. The micro-mirrors are modulated at different modulation rates in order to reflect individual radiation components at known and different modulation rates. The micro-mirrors combine a number of the reflected individual radiation components and reflect them to the detector. The detector receives the combined radiation components and creates an output signal. The analyzer is coupled to the detector to receive the output signal and to analyze at least some of the individual radiation components making up the combined reflection. By using a micro-mirror array that modulates the radiation components at different rates, all of the radiations components can be focused onto a single detector to maximize the signal-to-noise ratio of the detector.

Acoustic-based remotely interrogated diagnostic implant device and system

Abstract: A system (30) for remotely interrogating a diagnostic implant device (32) utilizes acoustic energy to power, and interrogate the device (32). Acoustic energy is utilized by an acoustic source/detector unit (38) to excite the device (32) from outside the body of a patient. By analyzing the response of the device (32) to such excitation with an acoustic analyzer (36), it is possible to ascertain the condition of the device (32). Additionally, acoustic energy may be used to provide operating power to the device (32).

Physical description of nuclear materials identification system (NMIS) signatures

Abstract: This paper describes all time and frequency analysis parameters measured with a new correlation processor (capability up to 1 GHz sampling rates and up to five input data channels) for three input channels: (1) the 252 Cf source ionization chamber; (2) a detection channel; and (3) a second detection channel. An intuitive and physical description of the various measured quantities is given as well as a brief mathematical description and a brief description of how the data are acquired. If the full five-channel capability is used, the number of measured quantities increases in number but not in type. The parameters provided by this new processor can be divided into two general classes: time analysis signatures and their related frequency analysis signatures. The time analysis signatures include the number of time m pulses occurs in a time interval, that is triggered randomly, upon a detection event, or upon a source fission event triggered. From the number of pulses in a time interval, the moments, factorial moments, and Feynmann variance can be obtained. Recent implementations of third- and fourth-order time and frequency analysis signatures in this processor are also briefly described. Thus, this processor used with a timed source of input neutrons contains all of the information from a pulsed neutron measurement, one and two detector Rossi- α measurements, multiplicity measurements, and third- and fourth-order correlation functions. This processor, although originally designed for active measurements with a 252 Cf interrogating source, has been successfully used passively (without 252 Cf source) for systems with inherent neutron sources such as fissile systems of plutonium. Data from active measurements with an 18.75 kg highly enriched uranium (93.2 wt%, 235 U ) metal casting for storage are presented to illustrate some of the various time and frequency analysis parameters. This processor, which is a five-channel time correlation analyzer with time channel widths as small as 1 ns, was developed at the Oak Ridge National Laboratory and the Oak Ridge Y-12 Plant where it is in use for verification and confirmation of weapons components and other fissile materials in storage and for receipts from other Department of Energy and Department of Defense Facilities.

A frequency domain method for the measurement of nonlinearity in heterodyne interferometry

Abstract: This paper presents a method for the measurement of nonlinearity in heterodyne interferometry which utilizes the frequency spectrum of the output of the photodetector for the direct measurement of the magnitudes of the first and second harmonic nonlinearities. The underlying theory and the experimental technique are discussed. Results showing the application of this technique for the determination of the influence of the azimuthal alignments of the polarization beamsplitter, the analyzer and measurement retroreflector are presented. The applicability of the technique to the in situ optimization of an interferometer system is demonstrated. It is shown that using this technique an interferometer system can be optimized to reduce the first-harmonic nonlinearity to below 0.5 nm p-p and the second harmonic nonlinearity to 2 nm p-p. This method is contrasted with other methods and the advantages conferred by the elimination of an external reference and the phase measuring electronics are highlighted.

Fiber-edge electrooptic/magnetooptic probe for spectral-domain analysis of electromagnetic field

Abstract: We propose a new class of an electromagnetic-held probing scheme for microwave planar circuit diagnosis. The measurement principle is based on the electrooptic/magnetooptic effects of crystals glued at optical fiber facets. We have combined the concept of those fiber-edge probes with a fiber-optic RF spectrum analyzing system containing a continuous-wave semiconductor laser source, a fast photodetector, and an RF spectrum analyzer to realize a highly sensitive measurement equipment of local impedance. Electromagnetic-field intensity on a microstrip transmission line has been measured in the frequency domain, where voltage and current amplitudes have been independently investigated with sensitivities of 16 mV/Hz-1/2 and 0.33 mA/Hz-1/2, respectively. In addition, it has been shown that the former value can be improved to be 0.7 mV/Hz-1/2 or smaller by the resonant cavity enhancement effect.

Absolute measurements and modeling of radio frequency electric fields using a retarding field energy analyzer

Abstract: Measurements of the rf electric field have been made along the z axis of a helicon reactor using a retarding field energy analyzer. A fluid code and a simple analytical model have been developed to analyze the ion energy distribution functions, especially in the case of bimodal distributions where the ion transit time through the sheath in front of the analyzer is comparable to the rf period. A generalized curve (and an analytical approximation to that curve) has been developed from the analytical model and confirmed by the self-consistent fluid model for high, low, and intermediate ion transit time, which can be used by experimenters to quickly convert the experimental results (energy peak separation, plasma potential and density, electron temperature), which are related to rf sheath oscillations, to absolute values of the rf electric field. An analysis of the errors involved in the derivation of the field is given. The results agree qualitatively with rf pickup measured with a floating Langmuir probe.

Portable data collector and analyzer: apparatus and method

Abstract: A portable data collector and analyzer apparatus and method provides predictive and preventative maintenance of a multiplicity of assets through the use of a unique architecture that allows a variety of different application programs to be downloaded to the apparatus for providing a single multi-purpose portable data collector and analyzer apparatus that can employ the variety of different application programs for configuring, inter alia, different measurements types, different transducers types and different signal processing types for collecting and analyzing sensed physical data from a variety of different assets found in industrial plants. A unique frequency shifting and decimation method is employed for spectrum calculation that, inter alia, retains DSP addressing efficiency and increases signal processing speed. Additionally, a unique synchronous sampling method is employed that generates synchronous sample waveforms from asynchronous sample waveforms. Furthermore, a unique clear touch screen overlying a quarter VGA display, an ergonomically designed keypad, and an intuitive user interface allow quick and easy setup and operation for in-field data acquisition, analysis and display.

Systems and methods for characterizing and correcting cyclic errors in distance measuring and dispersion interferometry

Abstract: The invention features interferometry systems that characterize cyclic errors. In many embodiments, the systems include a phase-shifting component (81), such as a phase shifter or frequency shifter, for introducing a variable and controlled phase between the reference and measurement beams of an interferometer (69). By analyzing the distance measurements of the interferometer (69) as a function of the introduced phase, an analyzer (27, 29) in the interferometry system can characterize the cyclic errors in the interferometer. Once the cyclic errors are characterized, the analyzer (27, 29) can directly correct the distance measurements to remove contributions from cyclic errors.

Mini-lidar sensor for the remote stand-off sensing of chemical/biological substances and method for sensing same

Abstract: A method and apparatus for remote, stand-off, and high efficiency spectroscopic detection of biological and chemical substances The apparatus including an optical beam transmitter which transmits a beam having an axis of transmission to a target, the beam comprising at least a laser emission An optical detector having an optical detection path to the target is provided for gathering optical information The optical detection path has an axis of optical detection A beam alignment device fixes the transmitter proximal to the detector and directs the beam to the target along the optical detection path such that the axis of transmission is within the optical detection path Optical information gathered by the optical detector is analyzed by an analyzer which is operatively connected to the detector

Fluorescent x-ray analyzer

Abstract: A fluorescent x-ray analyzer has a light-dispersing crystal and a detector which are rotatable while maintaining a specified angular relationship between them such that fluorescent x-rays from a sample are scanned. A first-order profile and a higher-order profile showing x-ray intensities against scan angle are produced from detection signals from the detector respectively within a different specified range of wavelengths. Data related to ratios between preliminarily measured peak intensities of diffracted beams of first-order and higher-order obtained from a plurality of elements are stored and used to identify peaks in these profiles, if there is a possibility of a peak formed by a first-order spectrum of one element and a higher-order spectrum of another element overlapping each other and the nature and extent of contributions to the peaks in the profiles from the first-order and higher-order spectra are determined.

The new high resolution ultra small angle neutron scattering instrument at the high flux reactor in Grenoble

Abstract: In 1998, the combined Interferometer and Ultra Small Angle Neutron Scattering (USANS) instrument S18 at the 58 MW High Flux Reactor at the Institute Laue-Langevin in Grenoble (France) started operation. The instrument has been upgraded to allow more advanced neutron optics experiments for fundamental, nuclear and condensed matter physics. The new supermirror guide along with the two channel cut silicon perfect crystals, configured as an advanced high resolution Bonse-Hart camera, provides optimal intensity conditions. A large range of wavelengths is accessible by variations of the Bragg angle and by using different reflecting planes of a properly cut silicon monochromator block in combination with different channel-cut analyzer crystals. The fine adjustment analyzer system is achieved by an advanced piezo drive, which has an accuracy of 0.036 seconds of arc. The basic features of the USANS camera, which takes advantage of a new tail suppression method, and the results of various test measurements concerning intensities, long term stability and the accessible wavelength range will be presented. A high resolution position sensitive detector can either be used to analyze beam profiles or to perform neutron radiography experiments.

Time-lens-based spectral analysis of optical pulses by electrooptic phase modulation

Abstract: The authors present a first experimental demonstration of time-lens-based operation by electrooptic phase modulation to perform real-time spectral analysis of optical pulse trains The obtained resolution was 004 nm Under certain conditions the resolution of the real-time spectrum analyser can exceed that of conventional optical spectrum analysers

Selectable band-pass filtering apparatus and method

Abstract: A selectable band-pass filtering apparatus for use at the input of analysis instrumentation, such as a spectrum analyzer for testing a multi-channel communication system, comprises a high-pass filter section including a plurality of separate high-pass filters, each characterized by a respective high-pass cut-off frequency within a predetermined input frequency spectrum characterizing the communication system and a low-pass filter section including a plurality of separate low-pass filters each characterized by a corresponding low-pass cut-off frequency within the input frequency spectrum. The apparatus further comprises switching devices capable of connecting a selected high-pass filter In series with a selected low-pass filter in order to select passband having center frequency and bandwidth characteristics defined by corresponding high-pass cut-off frequency and low-pass cut-off frequency.

Method and apparatus for expanding band of audio signal

Abstract: A low-pass filter (1) of over-sampling type over-samples an input digital audio signal T1 and filters and removes the low frequency components of the produced aliasing noise. A spectrum analysis circuit (3) calculates the spectrum strength of a predetermined band of the output signal from the low-pass filter (1). An expansion signal generating circuit (5) generates an expansion signal having higher frequency components from the output signal from the low-pass filter (1). A level control circuit (4) controls the level of the expansion signal according to the output signal from the spectrum analysis circuit (3). An adder (2) adds the level-controlled expansion signal to the output signal from the low-pass filter (1) thereby to generate a digital audio signal T2.

Unified analog/digital waveform software analysis tool with video and audio signal analysis methods

Abstract: A unified software apparatus and method for evaluating a generic electrical signal, complex multiple-format video signals and audio signals. The methods may be operated manually via a user interface (20) or programmatically via an automated programmable interface (16) and are especially intended for evaluating analog signals within an automated testing environment. The test signal data is supplied by an external source (12) such as an external hardware digitizer or other means. This signal data may be analog or digital in nature and may comprise up to three separate channels. The virtual spectrum analyzer (10) generates visual aids and supporting numerical computations, resulting in concrete and tangible results, allowing analysis based upon user selected criteria such as voltage measurements, histograms, frequency domain computations, or total harmonic distortion. In addition to these methods, video waveforms may be analyzed for content based upon numerical measurements applied to a region-within-a-region concept. Within a definable 'region of interest', a section of the test video signal's content may be isolated and compared to a surrounding 'region of interest' to determine the accuracy of image placement and intensity.

Device for verifying the accuracy of a spectral analyzer

Abstract: The present invention provides an artificial member (80, 210), which mimics the absorbance spectrum of a body part and includes the spectral components of blood analytes. The artificial member comprises a light scattering and reflecting material, and has a chamber portion comprising one or more chambers (90, 100, 220). The artificial member is configured to be reproducibly received in a measuring receptor which receptor is operatively connected to a non-invasive monitoring device.

Method and apparatus for amplifying electrical test signals from a micromechanical device

Abstract: An apparatus and method is provided for testing performance characteristics of a MEMs device. The apparatus includes a test probe that is electrically connected to a mechanical member of the MEMs device for receiving electrical data signals from the MEMs device that are indicative of the movement of the mechanical member due to external excitation. The apparatus also includes communications means for transmitting the signals from the test probed and an analyzer for receiving the signals and for analyzing the signals to determine the performance characteristics of the MEMs device. The apparatus also includes an amplifier connected between the test probe and the communication means. The amplifier is placed in close proximity to the test probe such that it amplifies the signals prior to transmission of the signals by the communication means. As such, the electrical data signals are amplified before sufficient noise is introduced into the signals to reduce their signal to noise ratio to less than a predetermine level. By amplifying the signals prior to the introduction of significant noise, the signals, which may have relatively small amplitude, are not obscured by the noise.

A rudimentary electron energy analyzer for accelerator diagnostics

Abstract: We have constructed a compact, planar retarding field analyzer for the diagnostics of low-energy, background electrons in a high-energy particle accelerator. Bench measurements of the analyzer have been made to characterize it, and the results are reasonable in light of models of this type of analyzer. Comparisons to results obtained using a beam-position monitor (BPM) show the advantages of this analyzer for electron diagnostics. Sample results from analyzers installed at the Advanced Photon Source storage ring at Argonne National Laboratory and the Proton Storage Ring at Los Alamos National Laboratory show how the analyzers can be used for studying the intensity, energy, and time structure of electrons in an accelerator environment.

System and method for enabling an operator to analyze a database of acquired signal pulse characteristics

Abstract: A pulse management system configured to perform a plurality of pulse measurements on each of a plurality of pulses of an acquired signal and to store results of the pulse measurements in an accessible data structure. The pulse management system includes a pulse analyzer that searches the data structure for pulses of the acquired signal that satisfy operator-provided search criteria. Similarly, the pulse analyzer can sort the selected subset of pulses based on sort criteria provided, for example, by an operator. The pulse analyzer can provide the operator with a user interface environment in which the operator specifies the search and sort criteria and in which the pulse analyzer displays the selected pulses with their associated pulse measurement results. The operator can advance through the selected pulses in any manner desired to display different pulses together or separately. The pulse analyzer thereby provides an operator with the capability to gain insights into a large number of acquired pulses through the selection of individual pulses meeting desired characteristics or relative time of occurrence, through the filtering or selection of pulses meeting specified criteria, and through the arrangement of those pulses according to the same or different criteria.

High sensitivity noise measurement with a correlation spectrum analyzer

Abstract: A spectrum analyzer with enhanced sensitivity has been built and used in noise measurements. It is based on the processing of the input signal by two independent channels in parallel and takes advantage of the incoherent property of the noise in each of the two input stages. The instrument has demonstrated an improvement in sensitivity of at least 50 dB with respect to a traditional system, and therefore can measure low input signals down to the hundred pV//spl radic/Hz range.

A LabVIEW based virtual instrument for power analyzers

Abstract: In this paper, a PC-based virtual instrument (VI) for a power analyzer is developed. Instead of theoretical research, a practical VI that can be integrated into an existing VI system is developed. The functions of power analyzer developed in this paper include the harmonic analyzer and instantaneous power measurement. The proposed VI is based on the LabVIEW (Laboratory Virtual Instrument Engineering Workbench) language under the workbench of the MS Windows 95/98 operating system. The capability of the proposed method can be expanded according to the requirements of users. Some sub-VIs for the power analyzer are developed in this paper and the idea of software integrated circuit (IC) can be achieved by using these sub-VIs. All sub-VIs developed in the paper are free for noncommercial use.

Method and apparatus for measuring and characterizing the frequency dependent electrical properties of dielectric materials

Abstract: A method and apparatus for measuring complex permittivity of dielectric materials in solid, liquid, or gas form. The apparatus is includes a TEM or quasi-TEM transmission line test fixture, which contains the dielectric material under test, a set of unique reflective load assemblies for inducing reflections in the fixture, an analyzer that measures magnitude and phase, a custom calibration kit, and a computer with computational software. The method begins by sequentially placing the set of load assemblies at the input of the analyzer. One port s-parameters are then obtained. Next, the set of load assemblies is sequentially placed at one end of the test fixture while the other end of the fixture is placed at the input of the analyzer and one port s-parameters are then obtained. Connectors are coupled to both ends of the fixture. A computer then executes a program to solve a set of equations constructed from the s-parameter data for computing input reflection coefficients. The program also de-embeds and mathematically curve-fits a specified electrical model of the transmission line to best replicate the reflection coefficients. Complex permittivity is calculated from the computed impedance values of the model.

Phase locked 270-440 GHz local oscillator based on flux flow in long Josephson tunnel junctions

Abstract: The combination of narrow linewidth and wide band tunability makes the Josephson flux flow oscillator (FFO) a perfect on-chip local oscillator for integrated sub-mm wave receivers for, e.g., spectral radio astronomy. The feasibility of phase locking the FFO to an external reference oscillator is demonstrated experimentally. A FFO linewidth as low as 1 Hz (determined by the resolution bandwidth of the spectrum analyzer) has been measured in the frequency range 270–440 GHz relative to a reference oscillator. This linewidth is far below the fundamental level given by shot and thermal noise of the free-running tunnel junction. The results of residual FFO phase noise measurements are also presented. Finally, we propose a single-chip fully superconductive receiver with two superconductor–insulator–superconductor mixers and an integrated phase-locked loop.

Intermodulation product cancellation circuit

Abstract: A cancellation circuit (800) is provided for canceling undesirable intermodulation (IM) products in electrical circuitry. The IM cancellation circuit (800) includes a stepping spectrum analyzer (9) which recognizes and measure the frequencies and amplitudes of different signal components of an RF signal across a desired frequency band. This information is forwarded to a processor (11) which contains look-up tables or the like which provides information relating to the frequencies and/or amplitudes of signal components which are intended to reside in the RF signal. By comparison of the look-up tables to the frequencies and amplitudes measured and recognized by the sweeping spectrum analyzer (9), the processor (11) of the cancellation circuit is able to determine whether the signal components in the RF signal are intended “information” carrying signals or unintended IM products. Where the processor (11) has determined that a signal component is an unintended IM product, the processor (11) controls a variable voltage controlled oscillator and variable amplifier to create a cancellation signal having an identical frequency and amplitude as the frequency and amplitude of the IM product. A phase shifter (17) is provided to shift the phase of the cancellation signal 180 degrees with respect to the IM product and the cancellation signal is combined with the RF signal to produce an output signal (29) having the IM product cancelled.

Influence of aliasing in time and frequency electrochemical noise measurements

Abstract: This paper points out the importance of anti-aliasing filtering in the analog-to-digital conversion performed in electrochemical noise (EN) measurements. This operation is currently implemented in spectrum analyzers, but it is generally ignored in data acquisition systems based on acquisition cards in personal computers or on digital voltmeters. It is shown that without filtering, aliasing occurs and leads to fallacious amplitudes of the EN, that is, too-high standard deviations in the time domain and too-high power spectral density levels in the frequency domain. In particular the white noises, which are commonly encountered in localized corrosion at low sampling rates, always have a wrong amplitude when measured without filtering. Anti-aliasing filtering may be carried out with analog filters or a combination of analog and digital filters. A comparison of two different digital filters, which are easily implementable in personal computers, shows that the slope of the filter roll-off has to be high enough to avoid aliasing for all types of EN and to obtain a good overlapping of the power spectral densities measured at various sampling rates.

Experimental determination of the transmission factor for the Omicron EA125 electron analyzer

Abstract: In this article a study of the transmission factor of the Omicron EA125 analyzer equipped with the universal lens is presented. The procedure is based on a model by Cross and Castle [J. Electron Spectrosc. Relat. Phenom. 22, 53 (1981)] and is applicable to every spectrometer which can be operated in the constant analyzer energy (CAE) and in the constant retarding ratio measuring mode. The advantage of the method is its independence on the sample and on the inelastic mean free path of the electrons. We find that the transmission factor for the CAE mode is proportional to Ekin−1 for most measuring setups. This dependence is predicted by theory for an ideal analyzer. Deviations from this behavior are observed if the retarding ratio for a given kinetic energy is too small. The limit value of the retarding ratio for ideal behavior, i.e., an Ekin−1 transmission factor, depends on the analyzer entrance slit aperture which has been selected.

Method of monitoring placement of voltage/current probes on motors

Abstract: A motor performance analyzer senses currents and voltages applied to the motor, converts the sensed signals to digital data signals, and stores the digital data signals. The analyzer includes a processor for evaluating and comparing the digital data signals to predetermined values for voltage and current of the motor to determine and check for the correct placement of the current and voltage probes along corresponding phases of the motor. The analyzer also includes [and] a display for alerting a user or technician to potential motor problems, or to developing problems, including winding faults and broken rotor bars. [Advanced signal processing techniques are used to further evaluate stored data and to provide trending information.]

Improved distortion analayzer for compensation apparatus of first-orderpolarization mode dispersion (PMD)

Abstract: The effect of polarization mode dispersion that an optical signal experiences as it propagates through an optical transmission fiber is compensated for at a receiver using a birefringent compensator, in which a distortion analyzer repeatedly examines the signal outputted by the compensator and causes the compensator to reduce the effect of such polarization mode dispersion based on the results of such examination.

Self-sufficient electronic system for instant monitoring of steam traps, valves and installations

Abstract: Self sufficient electronic system for monitoring and continuous surveillance of steam traps, valves and installations using fluids. The system comprises three essential elements: a multi sensor, an electronic analyzer and an optional receiver. The sensor measures fluid conductivity, pressure and temperature. The electronic analyzer continuously controls the status (pressure, temperature) and conductivity of fluid, supplying optical, acoustic and digital information, in situ or from a remote point, in accordance with the results of analysis carried out. The receiver centralizes and processes the signals emitted by the analyzer. The analyzer electronic circuits are fed by batteries recharged through photovoltaic cells incorporated in the equipment. The multiple probe also incorporates an ultrasonic sensor which detects ultrasounds generated in the steam trap or valve. The analyzer and the remote receiver also add the corresponding electronic circuits for a continuous surveillance of ultrasounds level. This system may be applied to the continuous surveillance and control of steam leaks and, generally, to control fluid flow in any installation. The system can solve the problem of automatic inspection and continuous monitoring of energy losses in steam traps, without human attention. It substantially reduces power consumption by detecting steam losses simultaneously and instantly at all points of installation.