Showing papers on "Spectrum analyzer published in 1995"

Delayed extraction matrix‐assisted laser desorption time‐of‐flight mass spectrometry

Abstract: A new delayed extraction matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometer system is described which provides dramatically improved performance over that obtained with identical TOF analyzers operated with constant electrical fields In this system the ions formed by MALDI are produced in a weak electrical field, and subsequently extracted by application of a high voltage pulse after a predetermined time delay Three parameters can be independently adjusted to optimize the performance These include the field magnitude and direction during and immediately following ion production, the magnitude of the extraction field, and the time delay between the laser pulse and application of the extraction field Theoretical equations are presented which guide the selection of these parameters to optimize the performance Results are presented from three TOF analyzers of similar design, but ranging in size from a 13 m linear analyzer to a 64 m reflector In all cases delayed extraction provides substantially improved resolution over that obtained from static operation In the smallest linear analyzer resolution of M/ΔM (full width at half maximum) of 4000 is demonstrated for angiotensin I, and with the largest reflecting analyzer, the isotope peaks of bovine insulin are resolved nearly to baseline With larger proteins, the isotopic peaks are not resolved, but resolution approaching the width of the isotopic envelope is obtained Resolution improvement is demonstrated for proteins up to 30 kDa In addition to improved resolution, delayed extraction is shown to improve the quality of MALDI mass spectra by suppressing matrix background, reducing chemical noise, and minimizing the effect of laser intensity on performance

Vehicle system analyzer and tutorial unit

Abstract: A vehicle analyzer and tutorial system is provided. The unit includes an engine analyzer and display unit. The unit further includes a remote controller and display unit, operably interconnected with the engine analyzer and display unit through a radio frequency interface, for remotely monitoring the engine analyzer display and for controlling the engine analyzer.

Segregated spectrum RF downconverter for digitization systems

Abstract: Disclosed is an apparatus for digitizing an electromagnetic input signal having frequency components within at least first and second segregated frequency bands, particularly useful in a wireless communications system. The apparatus includes a filtering circuit arrangement for passing only frequency components of the input signal substantially within the first and second frequency bands, to provide a filtered signal having a spectrum with spectral components below a predetermined power level within a frequency gap between the first and second frequency bands. An analog to digital (A/D) converter samples the filtered signal at a sampling rate sufficient to provide a digitized output signal with a frequency spectrum corresponding to that of the filtered signal and also with a replica of spectral components of one of the frequency bands appearing within the frequency gap. Preferably, the sampling rate used is less than the Nyquist sampling rate for the composite frequency band extending from the lowest to highest frequencies of the two bands. This allows a single A/D converter to be employed to sample the filtered signal, even when a large frequency gap exists between the segregated bands. A single mixer stage can then be used in conjunction with the single A/D converter in a wireless communications receiver application.

Fully automated analysis method with optical system for blood cell analyzer

Abstract: A method of performing a first analysis and a second analysis on a single blood sample obtained with a single blood draw from a patient with an automated analyzer includes the steps of supplying the single blood sample obtained with the single blood draw from the patient to the automated analyzer. A memory on the automated analyzer containing a software routine is automatically accessed. The software routine is useful to adapt an optical system on the automated analyzer to correspond to the first analysis and the second analysis. The optical system on the automated analyzer is automatically adapted with the software routine in real time to correspond to the first analysis. The first analysis is automatically performed with the automated analyzer. The optical system on the automated analyzer is automatically adapted with the software routine in real time to correspond to the second analysis. The second analysis is automatically performed with the automated analyzer.

Asymmetric Instrument Response Resulting from Mixing Effects in Accelerated DMA-CPC Measurements

Abstract: Several method have been proposed to accelerate the measurements made with differential mobility analyzers (DMA), including the Scanning Electrical Mobility Spectrometer (SEMS) and the Scanning Mobility Particle Sizer (SMPS). Wang and Flagan (1990) developed a data analysis procedure that accounts for the migration of the particles through a time-varying electric field and the delay associated with transport from the analyzer column outlet to the detection point. Experience using a variety of detectors and scan rates has indicated that the instrument response depends on the plumbing configuration if a condensation particle counter (CPC) is used as a detector. When a sharply peaked distribution is analyzed, the apparent breadth of the measured distribution depends on the detector used and on the scan rate. Size distributions measured with an increasing voltage scan exhibit a tail toward large particle sizes, while decreasing voltage scans produce a more pronounced tail on the small particle end of the distribution. The reduction in peak height with increasing scan rate can be attributed to particle retention in the plumbing between the outlet of the DMA analyzer column and the point in the CPC where the particles are detected optically. This paper examines the smearing of the transfer function of the SEMS as a result of flow non-idealities in the system. A model has been developed to predict the distortion of the transfer function in terms of the particle residence time distribution within the instrument. Results of this model are compared with calibration data as a function of the detector employed and the scan rate. We include laboratory observations of the phenomenon and examine the use of data inversion techniques to retrieve the true size distribution.

Method and system for calibrating an ellipsometer

Abstract: A method for calibrating an ellipsometer, and an ellipsometer including a processor programmed to control the analyzer, polarizer, and other ellipsometer components, and to process the data measured by the ellipsometer to perform the calibration method automatically. Where the ellipsometer's polarizer rotates and the analyzer remains fixed during measurement, the method determines coarse approximations of values A0 and P0, and then processes reflectivity data obtained at two or more analyzer angles to determine refined approximations of the values A0 and P0, where P0 is the angle of the polarizer's optical axis at an initial time, and A0 is the offset of the actual orientation angle of the analyzer from a nominal analyzer angle. Preferably the ellipsometer is a spectroscopic ellipsometer, the reflectivity data determine a tanψ spectrum and a cosΔ spectrum for each of the analyzer angles, and the coarse approximations of A0 and P0 are refined by processing the reflectivity data by performing regression on A0 and P0 until the differences among the tanψ and cosΔ spectra for several analyzer angles are minimized. Where the ellipsometer's analyzer rotates and the polarizer remains fixed during measurement, the method coarsely determines values A'0 and P'0, and then processes reflectivity data obtained at two or more polarizer angles to determine refined approximations of the values A'0 and P'0, where P'0 is the angle of the analyzer's optical axis at an initial time, and A'0 is the offset of the actual orientation angle of the polarizer from a nominal polarizer angle.

Respiratory gas analyzer

Abstract: An apparatus and method for measuring the concentration of carbon dioxide in respiratory gases. The apparatus is a non-dispersive gas analyzer (100) attached in series with the respiratory airway which is universally compatible with any host system. The analyzer (100) includes a housing (102) which supports a sample cell containing the respiratory gases, and which contains an infrared radiation source (130) encased in shock absorbing material, means for directing the radiation into a collimated beam through the sample cell, means (145) for splitting the beam and directing it towards two infrared detectors (142, 146) for measuring the amount of absorption of carbon dioxide in the sample cell. The analyzer has two heating servos (118, 152), one regulating the temperature of the sample cell windows to inhibit condensation build-up and one regulating the ambient temperature surrounding the detectors (142, 146) to ensure more accurate measurements. Calibration means within the analyzer housing (102) stores and provides information characterizing performance parameters of the analyzer (100).

Data collection and processing for digital AC power system monitor/analyzer

Abstract: A digital monitor/analyzer (1) for an ac electrical power system (3) samples the current and voltage waveforms at a slow rate for performing metering functions, and at a high rate for analyzing harmonic content. Sampling is performed in sampling frames (35) comprising a plurality of repetitions (37₁-37₄) of sampling for a selected number of cycles followed by a delay (δ) of a fraction of a cycle. This effects equivalent sampling at a higher rate for slow speed sampling over a frame (35). High speed sampling is performed over only one repetition (37₃) of the selected number of cycles in a frame (35) so that it can be carried out sychronously as required for the harmonic analysis. The high speed sampling rate is an integer multiple of the slow speed rate so that slow speed data can be extracted from the high speed samples for continuous metering. Fourier analysis of the harmonic content of the waveforms is performed (61) on the odd interrupts while all of the other tasks are apportioned out (59) over the even interrupts of a sampling frame. Both the odd and even interrupts initiate sampling.

Spectrum sharing communications system for monitoring available spectrum

Abstract: A mobile radio communications network is provided with a system for allocating one or more ranges of transmission frequency to the communications network, in order to prevent the network from interfering with received signals of an incumbent radio system. The allocating system may be provided with a device for receiving and monitoring information indicative of the presence and location of incumbent radio stations. A signal level monitoring system monitors signals transmitted from incumbent radio stations to determine the frequency and degree of RF isolation, with respect to a monitoring antenna of the monitoring system, of the stations. The monitoring system includes monitoring antennas, a spectrum analyzer, a device for controlling the spectrum analyzer, and a device for processing and correcting the data produced by the spectrum analyzer.

Spectrally selective gas cell for electrooptical infrared compact multigas sensor

Abstract: Progress in a new electrooptical compact gas sensor system is reported. The sensor measures pollutant concentrations in the atmosphere by comparing the absorption of infrared light in a gas cell at specific wavelengths. This task is performed by a non-dispersive spectral analyzer that operates at discrete wavelengths and has no moving parts (spectral retina). Several gases can be detected with the same detection principle, by simply selecting different signal channels. The spectral analyzer is made by coupling an array of integrated narrow band-pass optical filters to an array of PbSe detectors. Simultaneous detection of CO and SO 2 with no cross-talk is demonstrated. A specific spectrally selective gas cell has been designed and fabricated. The new design greatly simplifies the fabrication process of the spectral analyzer and expands the range of operation towards longer wavelengths, useful for more sensitive detection of SO 2 and NO 2 .

AFC frequency synchronization network

Abstract: A frequency synchronization network is disclosed that is particularly suited for a Eureka-147 system transmitting synchronization symbols and multiple data carriers, wherein the multiple carriers are transmitted simultaneously and separated from each other by a bin quantity. The network comprises a Fast Fourier transform (FFT) network, a complex rotation device, and a power analyzer. The power analyzer determines the peak condition of the FFT bin quantities and routes this information to an interpolation sequence that determines the zero-crossover condition of the peak bin quantity, and which ultimately determines an output as the frequency offset of the AFC frequency symbol. The frequency offset quantity is provided to an automatic frequency control (AFC) network to provide for frequency locking of the transmitting and receiving elements of the Eureka-147 system.

Multiport analyzing, time stamp synchronizing and parallel communicating

Abstract: A plurality of digital transmission network analyzers are arranged to analyze and compare the appearance of a data packet on the plurality of ports of a network. Each analyzer has its own internal clock for time stamping of data packets in addition to other internal timing purposes. In order to synchronize the time stamping of the packet as it appears to each analyzer at a each different port, the clock outputs of the several analyzers are connected together; and a controlling CPU commands one of the analyzers to supply the master clock to the others. That master analyzer then commands the other analyzers to disable or disconnect their own clocks, thereby all of the analyzers involved in a given test are under timing control of the clock of the master analyzer. Packet headers and time stamps are transmitted between analyzers for comparison, analysis, and reporting to the controlling CPU. This analyzer intercommunication is done over a separate bus that interconnects all of the analyzers and the controlling CPU.

Digital pulse-shape analyzer based on fast sampling of an integrated charge pulse

Abstract: A novel configuration for pulse-shape analysis and discrimination has been developed. The current pulse from the detector is sent to a gated integrator and then sampled by a flash analog-to-digital converter(ADC). The sampled data are processed digitally, thus allowing implementation of a near-optimum weighting function and elimination some of the instabilities associated with the gated integrator. The analyzer incorporates pileup rejection circuit that reduces the pileup effects at high counting rates. The system was tested using a liquid scintillator. Figures of merit for neutron-gamma pulse-shape discrimination were found to be: 0.78 for 25 keV (electron equivalent energy) and 3.5 for 500 keV. >

Analyzer having sensor with memory device

Abstract: An analyzer includes an exchangeable and consumable element such as a sensor, column or reagent the characteristic of which specifies an analyzing condition. The element is provided with a non-volatile semiconductor memory which holds an analyzing condition adapted for the element as data. When the element is mounted on an analyzer body, a controller of the analyzer reads the analyzing condition from the memory to update an analyzing condition inherently provided in the analyzer body. The result of analysis and/or operational history information of use of the element may be written into the memory with which the element is provided.

Multiport analyzing with time stamp synchronizing

Abstract: A plurality of digital transmission network analyzers are arranged to analyze and compare the appearance of a data packet on the plurality of ports of a network. Each analyzer has its own internal clock for time stamping of data packets in addition to other internal timing purposes. In order to synchronize the time stamping of the packet as it appears to each analyzer at a each different port, the clock outputs of the several analyzers are connected together; and a controlling CPU commands one of the analyzers to supply the master clock to the others. That master analyzer then commands the other analyzers to disable or disconnect their own clocks, thereby all of the analyzers involved in a given test are under timing control of the clock of the master analyzer. Packet headers and time stamps are transmitted between analyzers for comparison, analysis, and reporting to the controlling CPU. This analyzer intercommunication is done over a separate bus that interconnects all of the analyzers and the controlling CPU.

A New Sensitive and Portable Mercury Vapor Analyzer Gardis-1A

Abstract: A possibility to build a mercury (Hg) analyzer based on the cold vapor atomic absorption spectrometry (CVAAS) with a sub-picogram detection limit was investigated. Construction of the gold traps and the optical cell, carrier gas flow rate and gold traps heating power were chosen in order to effectively concentrate sampled Hg vapor and to obtain highest possible response in the optical and electronic system. The newly created analyzer is able to detect 0.5 pg of elemental Hg vapor. Optimization of construction resulted in stable performance and good selectivity for gaseous Hg of the analyzer. The instrument is commercially available.

Random pulse burst range-resolved doppler laser radar

Abstract: An laser radar system employing transmitted random and pseudo random optical pulse trains and signal processing that provides unambiguous range and Doppler velocity data. The system comprises a diode-pumped fiber laser local oscillator and an optical random pulse signal generator comprising a mode-locked fiber laser source for generating and transmitted randomly spaced optical pulses. A heterodyne output pulse monitor processes the local oscillator signals and samples the transmitted optical pulses. A heterodyne receiver detector processes the local oscillator signals and received optical pulses reflected from a target. An acoustic charge transport delay line provides a selectable signal delay for the signal provided by the heterodyne optical pulse monitor, and a mixer mixes signals provided by the heterodyne receiver detector and delay line and provides correlation output signals. A Doppler analyzer processes the correlation output signals from the mixer to provide frequency spectrum for each range bin, and an executive processor processes the frequency spectra from the Doppler analyzer to provide a range-resolved Doppler image on the display. The range-resolved Doppler output signals provided by the executive processor allow identification of a wideband weather signature and a narrow band target signature that are displayed on the display. The system employs a single waveform to provide the needed measurements, and eliminates trade-offs between range and velocity ambiguities. The present invention may be employed in vehicular collision avoidance radars and laser sensors, and in adaptive cruise control, robotic vision, and metrology-gauging applications.

Frequency response analyzer and shaping apparatus and digital hearing enhancement apparatus and method utilizing the same

Abstract: A signal frequency analyzer and frequency response shaping apparatus using digital techniques and apparatus and methods using the same which is applicable, in one embodiment thereof, to the enhancement of hearing in hearing impaired persons. Analog techniques are used in another embodiment of the invention. The invention includes hearing enhancement apparatus and methods which employ digital transformation, processing and memory functions for performing a wide range of hearing enhancement functions including the control of instantaneous signal gain levels as a function of instantaneous frequency and amplitude values of an audio signal. In another embodiment, the invention is applicable as a simple and inexpensive frequency analyzer which provides many of the characteristics of a complete Fast Fourier Transform (FFT) suitable for audio signals and other signals where a lower resolution FFT equivalent is acceptable.

Method for detecting defects in semiconductor insulators

Abstract: The reliability of thin film insulators is determined with noise measurements which find the barrier height mean and standard deviation A constant voltage source is applied across the thin film insulator A low noise amplifier is connected across a resistor which is in series with the insulator A spectrum analyzer is connected to the low noise amplifier The power density is obtained by observing the output of a spectrum analyzer The current spectral density is compared to a predetermined reference to detect the presence of defects in the insulator

A calibration system for evaluating the performance of harmonic power analyzers

Abstract: The paper describes a calibration system which is being used to evaluate the performance of harmonic power analyzers and related equipment. A method for verifying the software based calculations of the harmonic quantities obtained with the digital recorder of the calibration system is discussed. Test results of a harmonic power analyzer are also included. >

A differential-spectrum ion-energy analyzer with electrostatic slanted grids

Abstract: A novel end‐loss ion‐energy spectrometer is designed for plasma‐ion diagnostics in open‐ended plasma‐confinement devices. This analyzer significantly upgrades a previous slanted grid end‐loss analyzer (SELA) to essentially eliminate secondary‐electron current, and to provide a differential‐spectrum mode of operation, in addition to the usual integral‐spectrum operation of gridded ion‐energy analyzers. The upgraded SELA does not perturb the ambient magnetic field due to its electrostatic operation. Either the differential or integral spectra are obtained by a time sweep of grid voltages, collecting the ion current on a single‐channel plate. Because the angular alignment of the SELA is not critical, it can be used as a spatially scannable diagnostic of ion‐energy distributions and plasma potentials. It is characterized using computer simulations of ion trajectories, monoenergetic ion beams, and end‐loss plasma from the world’s largest tandem mirror—GAMMA 10.

HIBP diagnostics on T‐10

Abstract: A heavy ion beam probe diagnostic was installed on T‐10 tokamak. Cs+ and Tl+ beams with the energy 100–280 keV and intensity about a few dozen μA were used. The diagnostic is able to make two‐dimensional measurements of plasma parameters along the detector line. The detector grid covered the first quadrant of the plasma cross section. The measurements are possible with r/a=0.3–1, and ω=0°–90° for B=1.5 T and Cs+ ions. High‐voltage stabilizers keep the analyzer and accelerator voltage drift on the level ΔU/U∼10−5. An absolute in situ calibration of the energy analyzer, using He target will allow to make a more accurate absolute referencing of the potential. The time dependence of the local plasma parameters was obtained. A scan along the detector line by variation of injection angle and obtaining the whole profile during one pulse is possible. The diagnostic is also sensitive to poloidal magnetic field.

High efficiency compact illumination system

Abstract: An improved illumination system employing two concave reflecting mirrors (24, 26) and a non-imaging reflector (14) to concentrate energy (light) more efficiently is disclosed. The use of this system in a novel spectral analyzer is also disclosed.

Vehicle classification system using a passive audio input to a neural network

Abstract: A system and method for classifying vehicles based on the sound waves produced by the vehicles are disclosed. Analog sound pressure levels are input into the system and converted to digital sound pressure levels by an analog to digital converter (22). A spectral analyzer (24) converts the digital sound pressure levels into a power spectrum. Fuzzification functions are applied to the power spectrum by a dimension reducer (26) to produce a characterizing vector that characterizes the power spectrum. A neural network (28) then classifies the vehicle based on the characterizing vector.

Method and device for expanding voice band

Abstract: PROBLEM TO BE SOLVED: To synthesize a voice of high tone quality by converting a band-limited input voice into a broadband voice having a wide frequency band including the frequency band in the input voice. SOLUTION: This device is equipped with a voice analyzer 101 which separates the band-limited input voice into a narrow-band residue signal and a narrow-band spectrum envelope by taking a voice analysis, a residue band widening unit 102 which generates a broadband residue signal from the narrow- band residue signal, an envelope band widening unit 103 which estimates a broadband spectrum envelope from the narrow-band spectrum envelope, a voice synthesizer 104 which synthesizes a broadband synthesized voice from the broadband residue signal and broadband spectrum envelope, a filter 105 which extracts out-band components other than the frequency band that the input voice has from the broadband synthesized voice, and a voice superposing unit 106 which superposes the waveforms of the out-band components and input voice on the time base to synthesize a broadband voice having a frequency band including the frequency band that the input voice has.

Waveform display apparatus of frequency sweep type for facilitating display of a high definition waveform

Abstract: A measurement unit U100 measures an input signal to be measured by sweeping frequencies in a measurement range having a predetermined frequency band so as to obtain waveform data to be developed on the frequency axis such as spectrum data in, e.g., a spectrum analyzer. The waveform data obtained by the measurement of the measurement unit U100 is displayed by a display device 500 via a display data processor U20 included in a control unit U200 to be developed on the frequency axis of the display device, i.e., in correspondence with the measurement frequencies. The control unit U200 includes a measurement controller U30 for controlling the measurement unit U100 so as to display waveform data obtained by enlarging or reducing waveform data, before a measurement frequency condition is changed, at a predetermined magnification to have a predetermined point on the frequency axis as the center on the basis of a change in measurement frequency condition set by a condition setting unit U900, and an enlargement display/stable display processor U40 for controlling the display data processor U20. The enlargement display/stable display processor U40 realizes high-definition waveform observation, and has a function of controlling the display device U500 as the control unit U200.

Method and apparatus for nondisruptively measuring line impedance at frequencies which are relatively close to the line frequency

Abstract: Impedance of an energized electrical line which carries electrical current at a predetermined line frequency is nondistruptively measured at frequencies which are above and below the predetermined line frequency. A measurement current is generated at a measurement frequency between, for example, 10 Hz and 30 kHz for a 60 Hz line. The current generator is coupled to the energized electrical line by an isolating circuit which blocks only the predetermined line frequency and frequencies which differ from the predetermined line frequency by substantially less than the predetermined line frequency. For example, a notch filter may be used. A current sensor measures the line current in the energized line at the measurement frequency. A voltage sensor measures the line voltage in the energized electrical line at the measurement frequency. An analyzer determines impedance of the energized line at the measurement frequency. The measurement is repeated over a wide range of frequencies above and below the line frequency. Preferably, the current sensor and voltage sensor use the same current sensor to cancel errors. Improved nondisruptive line impedance measuring is thereby provided.

High precision rf vector analysis system based on synchronous sampling

Abstract: The signals to be measured are transformed in the system to discrete time digital signals by synchronous sampling. These digital signals are then processed by a digital signal processor for vector detection and for computing digital feedback sent to the sampling gates. The analyzer has improved characteristics in the area of linearity, drift and test port signal injection because of its highly optimized architecture based on synchronous sampling with digital feedback. It possesses unique characteristics such as the ability to tune to a harmonic or a subharmonic of the excitation frequency and a good sensitivity in a high impedance environment.

Routing YIG-tuned mixer

Abstract: A routing YIG-tuned resonator filter integrated with an image-enhanced, double-balanced mixer. The YIG-tuned resonator filter is preferably a four-sphere YIG-tuned preselector which is integrated with a low-loss, fundamentally or harmonically mixed, image-enhanced, double-balanced mixer to provide a high level of dynamic range in a harmonically mixed front end. An input resonator of the preselector in combination with a dual PIN diode switch switches low-frequency input signals (e.g., 0 to 2.9 GHz) to a low-band mixer. For RF input signals (e.g., 2.7 to 26.5 GHz), the four-sphere YIG-tuned preselector is combined with the image-enhanced, double-balanced mixer which incorporates a GaAs monolithic diode bridge integrated circuit. This provides a cost effective front end for a microwave spectrum analyzer.

On the advantages of the LMS spectrum analyzer over nonadaptive implementations of the sliding-DFT

Abstract: Based on the least mean squares (LMS) algorithm, the LMS spectrum analyzer can be used to recursively calculate the discrete Fourier transform (DFT) of a sliding window of data. In this paper, we compare the LMS spectrum analyzer with the straightforward nonadaptive implementation of the recursive DFT. In particular, we demonstrate the robustness of the LMS spectrum analyzer to the propagation of roundoff errors, a property that is not shared by other recursive DFT algorithms. >