Showing papers on "Spectrum analyzer published in 1982"

Experimental Test of Bell's Inequalities Using Time- Varying Analyzers

Abstract: Correlations of linear polarizations of pairs of photons have been measured with time-varying analyzers. The analyzer in each leg of the apparatus is an acousto-optical switch followed by two linear polarizers. The switches operate at incommensurate frequencies near 50 MHz. Each analyzer amounts to a polarizer which jumps between two orientations in a time short compared with the photon transit time. The results are in good agreement with quantum mechanical predictions but violate Bell's inequalities by 5 standard deviations.

Novel directional ion energy analyzer

Abstract: A new ion energy analyzer with high angular resolution (⩽3×10−4 sr) is described. It consists of a microchannel plate followed by a retarding‐grid type analyzer. The microchannel plate is not used for charge multiplication but as a geometric filter with narrow angular passband (ϑ≃0.6°) yet high transparency (T≃60%). The energy analyzer is used to measure the true velocity space distribution of low‐energy ion beams (Eb = 10–100 eV) in a double plasma device. Its superior performance over the conventional gridded energy analyzer is demonstrated. Applications to the study of beam wakes are shown.

Transmission line analyzer for automatically identifying the severities and locations of multiple mismatches

Abstract: A transmission line analyzer for automatically identifying the severities and locations of multiple mismatches generates a ripple waveform which is digitally analyzed by a fast fourier transform method. Foreign and harmonic signals are rejected, and return loss at each mismatch accurately determined.

Voltage and electric field measuring device using light

Abstract: A voltage and electric field measuring device is disclosed. The device uses light, including a polarizer, an electro-optic crystal consisting of a material having an optical rotatory power, and an analyzer arranged in the stated order in the direction of advancement of applied light, with a quarter-wave plate being disposed between the polarizer and crystal or between the crystal and analyzer. The angle of orientation ψ of the analyzer, relative to the optical axis of the crystal, is set to the product of θ and l, where θ represents the optical rotatory power, with respect to the applied light, of the crystal near a point at the center of a range of varying temperatures at the installation environment, and l represents the thickness of the crystal measured in the direction of advancement of light. The specified relation between ψ and θ·l maximizes the temperature stability of the device.

Functional Organization of the Auditory Cortex

Abstract: The properties of an acoustic signal produced by an animal can be studied by examining the output of a microphone displayed on the screen of an oscilloscope. Such an examination, however, gives us only limited information about the signal properties, so that the signal is usually analyzed with a spectrum analyzer. The spectrum analyzer has many filters tuned to different frequencies and it expresses the output of each as a function of time. Therefore, the properties of the acoustic signals are expressed by a pattern that appears in three coordinates: frequency, amplitude and time. To recognize individual acoustic patterns with an instrument, information-bearing elements (elements characterizing the signal) are first extracted and then their combinations are examined. The question next arises: how are acoustic signals analyzed and processed in the auditory system?

Respiratory gas analysis instrument having improved volume calibration method and apparatus

Abstract: An improved gas volume calibration method and apparatus for use in respiratory gas analyzers. A control unit monitors the flow of calibration gas through the analyzer by monitoring the electrical signals produced by a gas turbine and a breath switch. During calibration, a known volume of calibration gas is repeatedly delivered to the analyzer from a calibration syringe at each of a number of different flow rates. On the basis of the information received from the turbine and the breath switch, the control unit generates and stores a piecewise linear approximation of the nonlinear characteristic of the turbine. This stored turbine characteristic is then made available during subsequent measurements to eliminate those volume errors which are associated with variations in the rate at which the sample gas is delivered, thereby affording measurements of improved accuracy.

Automated acousto-optic infrared analyzer system

Abstract: An automated acousto-optic tunable filter infrared analyzer system useable in a variety of industrial and commercial control applications. The system relies upon a narrow band pass tunable acousto-optic filter which is selectively tuned by predetermined rf frequency signals to selectively transmit the narrow band pass of interest which corresponds to a specific molecular species for identification and analysis. The system includes a microcomputer and associated memory function to measure and compare detected signals from an infrared detector which converts the filtered infrared signal to an electrical signal. The memory provides control signals for the computer and for controlling the sequence and frequency of rf energy applied to tune the filter. In this way, the near to mid range infrared can be analyzed for absorption bands corresponding to predetermined molecular species such as combustion product gases, and a feedback signal generated to control the combustion process.

Optical RF downconverter

Abstract: An optical downconverter with very wide bandwidth operable to separately ically downconvert individual spectrum sections of an RF spectrum, comprising the steps of modulating an optical carrier with the RF spectral width to be downconverted, spatially separating via optical gratings the different sections of the spectrum of the optical carrier sidebands into a plurality of optical channels, generating a different phase-coherent optical local oscillator signal for each optical channel at an appropriate frequency such that the difference between the LO frequency and the particular spectrum section on the given optical channel is equal to a predetermined difference frequency; and mixing each optical channel with its appropriate frequency L.O. and detecting the difference frequency resulting therefrom.

Link quality analyzer

Abstract: A link quality analyzer measures the link quality between a calling station and a called station by continuously transmitting a plurality of signal tones. The called station receives the plurality of transmitting tones and sample them. A power spectrum is obtained of the received tones. From the statistics of the power spectrum the parameters of signal-to-noise ratio, multipath delay spread, Doppler frequency spread, frequency offset statistics, frequency-amplitude correlation, average amplitude response versus frequency, signal fading statistics, harmonic and intermodulation distortions, RMS-to-mean signal ratio, noise profile, and various noise statistics are determined. The power spectrum of the plurality of tones is measured through the use of digital sampling techniques and digital fast Fourier transform techniques that are implemented through microprocessor-level technology.

Method and apparatus for locating pipeline damage

Abstract: Apparatus and method are provided for the location of pipeline damage and medium leak therefrom by acoustical monitoring of the soil about a pipe and recording emission noise by microphone and an amplifier which controls a peak noise indicator. Each measurement point detected by the amplifier is applied to a digital memory to display a histogram showing noise distribution along the pipe. The main frequency of the loudest measurement point is determined, and an octave filter is utilized to determine the frequency characterizing medium leakage to precisely locate the pipeline damage. Bar diagrams may be provided on a viewplate by bands of parallel arrays of light emitting diodes to display noise distribution along the pipeline. A frequency analyzer may transmit from the amplifier to the memory the peak frequency value of each observed frequency band to enable frequency analysis of the loudest measurement point. The apparatus may have a case with a lid defining openings sized for viewing the bar diagrams.

Sensor for spectral analyzer for living tissues

Abstract: A sensor for a spectral analyzer includes a relatively movable holder and probe, where the probe is fitted with a reflector, and the holder is provided with a pair of adjacent optical fibers for transmitting/receiving light. When the probe abuts the surface of the object to be measured, the probe and holder move relatively so that the fiber pair approach the reflector. A switch activating the analyzer for data collection is operated in response to the change in reflected light intensity caused by the relative movement.

Radiation measuring device

Abstract: A radiation measuring device comprising a radiation detector for detecting radiation quantum arriving in the Poisson distribution, a phase height analyzer for analyzing a height of an output signal from the detector to extract signal components at a level within a predetermined level, converter for integrating an output signal from the detector to produce pulses of which the number corresponds to the integrated value, a switch for selecting the output signal from the analyzer when the number of arrival photons is smaller than a predetermined value and for selecting the output signal from the converter when the number of photons is larger than the predetermined value and a counter for counting output pulses of the selected analyzer or counter.

Orthopedic diagnostic procedures and apparatus therefor

Abstract: Attempts have been made to facilitate orthopedic diagnostic procedures by microphonic detection of emissions from a moving joint, with analysis of such emissions to establish correlation with pathological conditions, but these attempts have failed. Success in such a procedure is now found to require detection of emissions extending into the subsonic frequency range. Preferably a piezoelectric accelerometer detector (10) is used in direct contact with the skin. A plurality of detectors can be used around a joint with comparative analysis to localize a condition. Analysis suitably involves a frequency analyzer (14) with the possible intermediary of a multi-track tape recorder (12), the analyzer output being displayed by a printer (15) preferably of ink-jet form. One useful correlating emission characteristic is peak frequency for early diagnosis for congenital dislocation of the hip in an infant.

Combination speech synthesis and recognition apparatus

Abstract: A reconfigurable lattice filter is employed to permit the same circuitry to function as a speech synthesizer and as a speech analyzer or recognizer. The lattice filter can be configured both as an all-pole filter (for synthesis) and as an all-zero filter (for analysis), with the choice being determined by the state of an analysis/synthesis signal (i.e., mode control signal) provided thereto. The connections between various elements in the circuitry are controlled by the analysis/synthesis signal, also. In synthesis mode, partial correlation coefficients are supplied to the filter from a microprocessor. The filter is excited by a one of a number of stored patterns simulating a glottal pulse for voiced sounds and by a pseudo-random noise generator for unvoiced sounds. In analysis mode, appropriate feedback control paths are enabled so as to provide to the filter coefficients which change in response to changes in the input speech waveform. Coefficient values thus determined are averaged over fixed intervals and successions of such averaged coefficient sets produce representations of words or phrases which can then be used for speech recognition.

Multiple sound transducer system utilizing an acoustic filter to reduce distortion

Abstract: The present invention relates to acoustic filters for use in combination with a multiple transducer system which includes a low frequency transducer subsystem and a high frequency transducer subsystem each mounted with respect to an axis directed towards the listening environment so as to function acoustically as though having coaxial acoustic centers. Preferably, the acoustic filter is constructed from one or more acoustical elements such as small tubes, narrow slits, perforated baffles, enclosed cavities, and the like combined so as to provide an acoustical impedance which is relatively low for the frequencies produced by the low frequency transducer but which is relatively high for the frequencies associated with the high frequency transducer. The acoustic filter is disposed acoustically between the low frequency transducer and the high frequency transducer so the acoustic filter inhibits the high frequency sounds of the high frequency loudspeaker from being reflected by the low frequency transducer towards the listening environment and thereby results in a noticeable decrease in intermodulation distortion.

Engine analyzer with constant width digital waveform display

Abstract: An engine analyzer for an internal combustion engine includes an analog-to-digital (A/D) converter which digitizes an analog electrical input waveform representing, for example, a secondary or primary voltage waveform of the ignition coil of the internal combustion engine. The digitized input waveform is stored in the form of digital data in a data mamory. Upon request by the operator of the apparatus, a microprocessor selects digital data stored, and supplies that digital data to a display, which displays a visual representation of the waveform based upon the selected digital data. The engine analyzer apparatus produces a constant width waveform regardless of engine RPM, by determining the period of the waveform to be stored, and then varying the sample rate at which the A/D converter samples the analog waveform and converts the sampled waveform to digital data. As a result, the number of data samples, and thus the width of the displayed waveform, is constant.

A folded-type integrated-optic spectrum analyzer using butt-coupled chirped grating lenses

Abstract: A folded-type integrated-optic spectrum analyzer (IOSA) using reflection-type chirped grating lenses butt-coupled to a LiNbO 3 waveguide Bragg cell is presented. The lenses can be easily fabricated by the well-established planar process, and the IOSA has good performance as well as a reduced device length. The spectrum analyzer function of 4.0 MHz resolution in 95-345 MHz RF frequency range is demonstrated.

Optical absorption analyzer

Abstract: An optical absorption analyzer for determining the concentration of low concentration components of a sample gas. Inexpensive voltage to frequency converters, up/down counters, and integrators are used to obtain a high accuracy determination which is independent of fluctuations in the strength of the light source used in the analyzer.

Data Inversion by Simplex Minimization for the Electrical Aerosol Analyzer

Abstract: A data inversion procedure for the electrical aerosol analyzer, based on a simplex minimization algorithm, is described. The method has been tested extensively using data which were generated by a numerical simulation of the instrument's response for a wide range of various unimodal and bimodal log-normal distributions. The sensitivity of the procedure to random errors in the measured data as well as in the response matrix elements has been checked. The application of the program to data from atomizer-generated test aerosols is demonstrated.

Method for measuring material characteristics

Abstract: A fast and reliable method is disclosed for measuring the dynamic mechanical properties of a material, particularly its modulus of elasticity and loss factor. By this method the acoustic characteristics of a material can be determined. An elongate strip of material, whose properties are desired to be known, is provided with miniature accelerometers fixedly secured to its opposite ends. One end of the strip is excited by a random noise source which travels toward the other end where that end and accelerometer is allowed to move freely (unrestrained). The accelerometers measures the ratios of acceleration at two locations over an extended frequency range of 0.2 Hz to 25 KHz, and the information is processed through a fast fourier transform spectrum analyzer for determining amplitude of acceleration ratio and phase difference between the two accelerometers from which Young's modulus and loss factor for that material are determined.

An automatic voltammetric analyzer for the simultaneous determination of toxic trace metals in water

Abstract: A new automatic voltammetric analyzer for the simultaneous determination of toxic trace metals in water is described. It is based on modern microprocessor technology, is compact, robust and reliable and can be produced with moderate costs. The evaluation by the standard addition method ensures the accuracy of the analytical procedure. The device comprises a home made polarograph with the differential pulse mode, the circuitry for an automatic adjustment of the current sensitivity for every peak, a microprocessor based controller with suitable periphery, an automated hanging mercury drop electrode and a printer-plotter. The software is splitted into two independent programs, the “parameter input” program and the “analysis control” program. This enables to readjust the optimal parameters in a large range before every voltammetric analysis. The time consuming repetition of the whole analysis is saved by various test subroutines that control the state of the three electrodes and of the important parts of the device after every measurement. After the analysis the whole voltammetric curve is plotted, every peak in an optimal current sensitivity range, and the heading containing important information about the analysis is printed out. The program routines for digital data processing and print out are under development. The analyzer was tested several months under laboratory conditions and its performance was very satisfactory.

Telephone line analyzer

Abstract: A telephone line analyzer provides automatic attenuation measurement of tie trunk lines and other telephone lines through measurement of the electrical level of a tone responder. The analyzer is primarily directed to testing telephone lines interconnected between trunk line selectable computerized private branch exchanges (PBXs) of the same user. The analyzer automatically dials a remote PBX through a desired tie trunk line; activates a remote tone responder; and measures and records the test results. The analyzer may also perform echo return loss measurements. The analyzer is user programmable and it can be set to initiate line tests at predetermined times so as to minimize interference with the normal telephone line activities of the user.

Sampling spectrum analyzer

Abstract: A sampling spectrum analyzer provides instantaneous continuous wideband spectrum analysis to allow RF signals occurring simultaneously and spaced within the band to be displayed. An input signal is split and each resulting portion is passed down a tapped delay line, with samples at the taps of each line being processed by separate arithmetic units. The output of each arithmetic unit is applied to the taps of output delay lines which are similar to the input delay lines. Each arithmetic unit weights the input samples with a set of coefficients and sums the resulting signal in a prescribed manner, thus transforming the signal into the frequency domain, according to a discrete Fourier transform. The resulting sums are the real and imaginary terms of a signal which are vectorially added, resulting in a signal which is fed to the ordinate of a display having a swept time base representing frequency.

Development of a multichannel electrochemical centrifugal analyzer.

Abstract: A new instrument has been developed that is similar in design and concept to the GeMSAEC centrifugal analyzer (Oak Ridge National Laboratory) except that electrochemical detection is used rather than optical detection. The present version has eight channels, each with its own detector. Problems of speed control and sampling synchronization are greatly minimized from those of a multichannel centrifugal analyzer having a single detector system. All eight sample compartments and polarographic cells are contained in a single Teflon rotor, 7.7 cm in diameter. The working electrodes are planar carbon electrodes. The initial application of the analyzer is in kinetic methods involving the rates of enzyme-catalyzed reactions. The initial system chosen was the glucose oxidase system. When the rotor is spun, the solution moves into the sample cell and up against the planar working electrode. The reaction starts and current is measured as a function of time at a constant applied voltage. The current output from each polarographic circuit is connected to a separate channel of a multiplexed analog-to-digital converter. The analyzer is controlled by a dedicated microcomputer system, which sets the polarographic cell voltages, collects the current-time data, and calculates the results.

Color channel signal-to-noise improvement in digital television

Abstract: Circuitry included in a TV receiver for enhancing the signal-to-noise ratio of the chrominance signal includes an adaptive linear phase, low pass filter which has its bandwidth controlled responsive to the upper frequency components of the current chrominance signal. A frequency analyzer coupled to the chrominance channel counts the number of chrominance signal excursions during predetermined periods to generate a number related to the maximum signal frequency during such periods. The number is applied to a decoder which generates address codes for application to a look up table which provides filter coefficients for altering the filter bandwidth in accordance with the current maximum signal frequency components.

Automatic gain control for an infrared source of an automotive emissions analyzer

Abstract: An automatic gain control circuit for driving a low mass infrared source used in an automotive exhaust gas emissions analyzer. A reference spectrum of radiant energy is monitored, demodulated and converted to an error signal to maintain the source at a constant energy output.