Abstract: The object of this invention is to produce a monitor which can correctly distinguish normal from abnormal vibration using automatically selected monitoring features and algorithms. The monitor can be used with a variety of devices with different vibration characteristics. The monitor according to this invention has a sensor that detects the vibration of an object. The monitor is operated in learning mode when the object is vibrating normally. The waveform of the vibration detected by this sensor is sampled over an appropriate period and analyzed. The data for each sampling feature are subjected to statistical processing, and the data which evince slight change are extracted as monitoring features. A monitoring algorithm is automatically made for these monitoring features. The algorithm selected in learning mode are used to evaluate the vibration of an object when the monitor is in operating mode.

Abstract: The present invention provides a system for detecting and removing resonance from crankshaft speed measurements comprising signal demodulation and deconvolution processing. According to the invention, a crankshaft speed sensor sends an appropriate signal corresponding to crankshaft speed to an engine controller. The input signal with resonance noise is subjected to a demodulation operation in N demodulation subsystems for resonance detection and identification. Also, the input signal with resonance noise is subjected to a deconvolution operation in N deconvolution subsystems for resonance noise removal. The demodulated signals are compared to a given set of criteria for selecting a desired signal subsystem. The desired demodulated signal subsystem is then used to screen the deconvolved signal so that only a matching deconvolved signal exits the system as the system output.

Abstract: A method of determining the rotational speed of a rotating shaft from machine vibration data. The vibration produced by the shaft is sensed to produce a test vibration signal at an unknown rotational speed of the shaft, which test vibrational signal is converted to a test frequency spectrum. A reference frequency spectrum, corresponding to a known rotational speed of the shaft, is provided, and a stretch factor is determined. The stretch factor provides optimum correlation between the test frequency spectrum and the reference frequency spectrum. The unknown speed of the rotating shaft is calculated using the known speed of the reference frequency spectrum and the stretch factor.

Abstract: A rotational-device test system and method is provided to classify a rotational device according to the type of drive sound thereof. A divider divides the time-series data of an amplitude of the drive sound of an HDD digitized in a converter at intervals of a predetermined time and generates a time-series data group for each frame. An analyzer converts each data item of the time-series data group to a power spectrum. A cycle arithmetic unit selects a maximum point whose self-correlation between a leading frame and each of frames other than the leading frame is maximum, as a candidate point for one cycle of the drive sound, and detects a point whose self-correlation is maximum and which has as a starting point the leading time-series data in the leading frame and the candidate point, and, based on the frame of the candidate point in the detected point whose self-correlation is maximum and on the leading frame, specifies the cycle of the drive sound.

Abstract: A method and apparatus for accurately and quickly enabling a technical representative to diagnose the source (or identify the component(s)) that is the root cause of the motion quality defect being experienced to reduce down time of the printing machine. The output of an encoder on the photoreceptor, electronically measured, translates variations in the photoreceptor velocity into voltage. The voltage is then converted into frequency, using a Fast Fourier Transform, for comparison to a predetermined set of frequencies associated with defective drive components to identify the source of the motion quality defect.

Abstract: A method for analysing regularly recurring mechanical vibrations comprises the steps of plotting an amplitude/time spectrum associated with the vibrations, dividing the amplitude/time spectrum into time intervals shorter than the shortest time lapse between two consecutive excitations, subjecting those parts of the amplitude/time spectrum defined by each time interval to a Fourier transformation in order to obtain an amplitude/vibration-frequency interval spectrum associated with each time interval, and subjecting those amplitudes in each amplitude/vibration frequency interval spectrum associated with certain vibration frequencies to a Fourier transformation in order to obtain an excitation-frequency spectrum associated with the respective vibration frequency.

Abstract: A method and device for processing encoder signals from turbomachines to produce frequency modulation signals representing fully isolated rotor vibrational resonances. Multi-sensor and multi-sideband group processing provides enhanced results. The method provides dramatically improved frequency resolution. Amplitude modulation and random noise effects are removed by a variety of artifact-free techniques. Signals then are completely separated into components for rotational vibration and translational vibration. Fully isolating rotational vibration unmasks previously undetectable signal components of diagnostic value. In cases of high background vibration, Wiener filtering removes the effects of exogenous vibration. By these various techniques, the present invention provides significantly enhanced diagnostic information regarding condition and performance in turbomachines.

Abstract: A vibration detecting and condition monitoring system for the press section, including felts, rollers and presses, employing a feature extracting circuit having a selectable plurality of Bessel type bandpass filters and an enveloping circuit to square the bandpassed signal output prior to FFT analysis of the signal. The system enables the enhancement and detection of highly impulsive signals in the frequency domain, that are indicative of defects in machinery operation.

Abstract: A system and method for homogeneous bioassay uses acoustic energy emissions. A measurement cell is designed for binding reactions of mobile biorecognition molecules. The binding reaction contained in the measurement cell is for example a ligand/receptor binding reaction or a complementary nucleic acid binding reaction. A passive acoustic energy transducer is coupled to the measurement cell for detecting acoustic energy generated by the binding reaction of mobile biorecognition molecules. The passive acoustic energy transducer generates a corresponding analog electrical signal. A signal conditioner coupled to the passive acoustic energy transducer filters and amplifies the electrical signal. A signal analyzer determines spectra of the conditioned electrical signal corresponding to characteristic acoustic energy emissions of the binding reaction of mobile biorecognition molecules.

Abstract: A method is provided for detecting resonant ultra sound (RUS) Spectroscopy peaks which is based upon taking the second derivative of the RUS spectrum. The second derivative provides a more sensitive analysis tool, and makes it possible to separate and distinguish peaks in the spectrum which are not readily discernable by other analyses of the spectrum. Analysis criteria such as cut off heights and Z-widths provide judgment criteria for identification of resonant peaks.

Abstract: A method is provided for determining and for predicting the present and future condition of a machine having at least one rotative element. The method includes an initial step of storing in memory a predetermined logic routine and at least one predetermined key frequency of the at least one rotative element of the machine. The machine is operated in a predetermined operational state and, during operation, the mechanical motion of the at least one rotative element is sensed by at least one sensor. The sensed mechanical motion of the at least one rotative element is converted into a corresponding electrical signal, and the predetermined operational state of the machine is correlated with a corresponding electrical signal. The corresponding electrical signal is inputted into corresponding vibration data by utilizing the predetermined logic routine. Then, the corresponding vibration data is compared with the at least one predetermined key frequency to predict the present and future condition of the machine.

Abstract: A structure of a magnetostrictive shaft applicable to a magnetostriction-type torque sensor and a method for manufacturing the same can achieve a high torque sensitivity. A shaft parent material is made of a non-magnetic austenitic series metallic material (YHD50) and a magnetic thin film is made of a magnetostriction material such as Iron-Aluminum series alloy plasma spray coated on the whole outer peripheral surface of the shaft parent material. In a second embodiment, a mechanical working is carried out for the shaft material on the surface of which the magnetostriction material thin film is coated, the worked shaft material is heated under an inert gas atmosphere, and the heated shaft material is immersed into oil under the inert gas atmosphere to perform oil quenching.

Abstract: Apparatus and a method for detecting glass breaking from an impact. Low frequencies are detected that are characteristics of the glass flexing from the impact, and high frequencies are detected that are characteristic of a) the sound of the impact and b) the glass breaking. An alarm signal is issued when the low and high frequencies occur in a predetermined sequence, and have appropriate durations, that are characteristic of glass breaking events. More specifically, the alarm sounds only when low frequencies are detected not before the high frequencies are first detected but within a predetermined time period after the first detection of the high frequencies.

Abstract: Method and apparatus for deriving four independent elastic constants (longitudinal and transverse Young's moduli, in-plane shear modulus and major Poisson's ratio) of composite materials from the modal resonance data of a freely-supported rectangular thin plate made from the material.

Abstract: In chatter monitoring of twin drives of roll stands, vibrations of an upper drive and a lower drive are detected and monitored to determine whether a predetermined amplitude has been exceeded. If the amplitude has been exceeded, a chatter detection signal is generated. In order to prevent the chatter detection signal from being generated erroneously due to an operational pass vibrations, the frequencies of the vibrations of the upper drive and the lower drive are monitored for identity; when the frequencies are identical, the chatter detection signal is suppressed.

Abstract: The present invention provides a method and system for analyzing signals from rotating machines containing rotating components that slip and, thereby, to detect faults in those components. The signals are processed by a series of steps to generate coherently averaged spectra and derived features that indicate defects in, or certain other features of, machine components that slip or rotate asynchronously.

Abstract: To improve the coupling adjustment workability and precision of a rotor, irrespective of change in bearing characteristics due to an increase of rotational speed, the apparatus detects angular frequencies (.omega.) and reference mark positions (.theta.) of the rotor; detects vibration displacements (r) of the rotor; analyzes vibration vector components (.omega.), (r) and (.theta.) of rotation synchronizing vibrations; extracts a specific angular frequency (.omega..sub.1) at which a higher harmonic vibration frequency (.omega..sub.R) matches a natural frequency of the rotor, and various rotation synchronizing vibration vector components at (.omega..sub.1), at (.omega..sub.R) and (.omega..sub.2 to .omega..sub.i), respectively; estimates static vibration vector components (r.sub.0, .theta..sub.0) at zero angular frequency (.omega..sub.0) on the basis of rotation synchronizing vibration vector components (r.sub.T, .theta..sub.T) at (.omega..sub.1 to .omega..sub.

Abstract: A method of detecting a counterflow in a pump comprises providing with detecting means for detecting variations in the discharge pressure of the pump and signal analyzing means for analyzing oscillation components contained in an output signal from the pressure detecting means, and detecting the pump's operating point to have entered a counterflow characteristic operation region when a waveform of the detection signal generated in association with the variations in the discharge pressure of the pump exhibits a predetermined spectrum distribution. Further, when it is detected that the operating point enters a counterflow characteristic operation region, the escape from that region is performed by temporally throttling the guide vane and temporally increasing the rotating speed.

Abstract: A friend-or-foe (IFF) identification system (10) comprises a laser generator (12) for generating and transmitting a laser beam (B). A beam splitter (16) divides the laser beam into two beams. One of the beams (B1) is directed along a reference path (P). This beam is reflected back along the path by a mirror (24) positioned at the end of the path. The other laser beam (B2) is directed at an object (T) to be identified as a friend or foe. This second beam reflects off the object and the return, reflected beam is detected. The reflected beam includes a vibration signature of the object under investigation. The return beam and reference beam are processed together to correct the vibration signature of the object for arty distortions. This allows an accurate target signature to be obtained. Next, the target signature is compared against other signatures. The results of the comparison provide the IFF identification.

Abstract: A monitoring diagnostic apparatus for detecting an abnormality occurring in an object being monitored such as electrical equipment and determining the cause of the abnormality is disclosed. First of all, vibration or partial discharge occurring in the monitored object is detected by using a sensor installed in close proximity to the monitored object. A detection signal output by the sensor then undergoes predetermined signal processing such as the Fourier transform and normalization. After the predetermined signal processing is completed, a neural network identifies the abnormality occurring in the monitored object and determining the cause of the abnormality. The neural network carries out a learning process based on causes of abnormalities occurring in the monitored object, outputting signals corresponding to the causes of the abnormalities.

Abstract: Method and apparatus are provided for detecting crack-like flaws in components. A plurality of exciting frequencies are generated and applied to a component in a dry condition to obtain a first ultrasonic spectrum of the component. The component is then wet with a selected liquid to penetrate any crack-like flaws in the component. The plurality of exciting frequencies are again applied to the component and a second ultrasonic spectrum of the component is obtained. The wet and dry ultrasonic spectra are then analyzed to determine the second harmonic components in each of the ultrasonic resonance spectra and the second harmonic components are compared to ascertain the presence of crack-like flaws in the component.

Abstract: The present invention provides for an inspection system and method for detecting defects in test objects which includes means for generating expansion inducing energy focused upon the test object at a first location, such expansion being allowed to contract, thereby causing pressure wave within and on the surface of the test object. Such expansion inducing energy may be provided by, for example, a laser beam or ultrasonic energy. At a second location, the amplitudes and phases of the acoustic waves are detected and the resonant frequencies' quality factors are calculated and compared to predetermined quality factor data, such comparison providing information of whether the test object contains a defect. The inspection system and method also includes means for mounting the bearing ball for inspection.

Abstract: An apparatus for monitoring a vibrating structure, such as a bridge, uses multiple motion sensors spaced along the structure, each of which produces an analog raw data signal which is then filtered in anti-aliasing filters to remove substantially all frequency components of the signal above a selected cutoff frequency, f.sub.co. The filter outputs are connected to addressed inputs of an analog multiplexer which then multiplexes the signals in response to a channel address clock which repeatedly generates a sequence of channel addresses to scan the data input channels at the multiplexer corresponding to the addresses in the sequence. The complete sequence of addresses is repeated at a frequency of at least twice the cutoff frequency to obtain substantially simultaneous samples from the sensors so that data from different sensors may be correlated. The multiplexed signal is then converted to digital form and stored.

Abstract: A system is disclosed for monitoring a structure and detecting disturbances and faults associated with such structure. The system includes an actuation device for mechanically exciting the structure, a sensing device for transducing vibrations experienced by the structure, and digital signal processing means for processing signals output by the sensing device. The response of the structure due to the mechanical excitation is analyzed and a baseline or normal response is determined. Vibrations of the structure are then analyzed and compared to the normal response of the structure and the nature of disturbances identified. Another aspect of the invention relates to a system for monitoring cracks, strains and the like and includes a continuity/strain sensor having a piezoelectric layer, and first and second low resistance layers. By suitably monitoring sensors in accordance with the invention, the magnitude as well as the location of a force can be determined.

Abstract: A defect detecting method for detecting whether or not an object to be measured has a defect includes the steps of vibrating the object to be measured, picking up the vibration, and detecting that a spectrum of the characteristic vibration of the object to be measured is separated into two portions. Also, a defect detecting apparatus includes a vibrator for vibrating an object to be measured, a vibration detector for picking up a vibration of the object to be measured and for converting the vibration into an electric signal, and computation process and determination equipment for receiving the electric signal from the detector, for analyzing a spectrum of a characteristic vibration of the object to be measured, and for determining whether a defect is present or absent depending on whether a spectrum of a defect of the object to be measured is present or absent.

Abstract: A method and apparatus for detecting completion of the dissolution of a soluble solid material in a liquid in a container. The container and its contents are excitated by a wide frequency band excitation signal, causing the container and its contents to respond at a predominant frequency. The frequency response of the container and its contents is successively sampled and measured, and the respective predominant frequency response values are compared with preceding values. As the solid dissolves in the liquid, the predominant response frequency will change. Once the predominant frequency response stabilizes from sample to sample at a particular value, the dissolving process is complete. The detection method and apparatus can be used to control a motorized agitator to prevent overmixing and save energy.

Abstract: The invention relates to a method of monitoring the drilling of a borehole through an earth formation with a rotating drill bit fixed at the lower end of a drillstring. At least one physical quantity associated with the vibrations resulting from the interaction of the rotating drill bit with the earth formation is detected and an oscillatory signal is generated in response thereto. Filter coefficients a.sub.k of an auto-regressive filter model are determined by fitting the filter output signal with the oscillatory signal. The reflection coefficients of the vibrations propagating along the drill string and being reflected by a mis-match of impedance of two successive elements of the system earth formation/drillstring are derived from the filter coefficients. Finally, the hardness of the formation being drilled, the contact of the drillstring with the borehole and the vibration level of the vibration along the drillstring are determined from the reflection coefficients.

Abstract: A calibrator and the derivation of an associated calibration data base for computationally compensating for gain and phase mismatch in sound intensity probes comprised of two unmatched pressure transducing microphones is described herein. The calibrator utilizes a unique `phase plug` to maintain temporal uniformity (in addition to standard spatial uniformity) in the sound field of the calibration chamber. Gain and phase calibration factors are independently obtained for each probe of interest using the calibrator and these data are compiled into an independent data base for storage and subsequent application. Such linear correction factors as applied to associated signal processing of probe measurements serves to computationally compensate for phase mismatch between the unmatched microphone pair.

Abstract: A vibration monitoring system employing a capacitive accelerometer determines the energy associated with one or more frequency components within the frequency spectrum of the vibration signal. The capacitive accelerometer operates as a mixer due to its time varying capacitance which provides a measure of the vibration. When the accelerometer is excited by an AC signal the output from the accelerometer comprises beat frequencies due to the mixing of the time varying capacitance and the AC signal. By changing the frequency of the AC signal the location of the beat frequencies in the frequency domain of the accelerometer output can be shifted. Subsequent bandpass filtering to attenuate frequencies except those associated with the frequency component and demodulation to bandshift the energy of the filtered signal energy to DC, creates a DC value which provides a measure of the energy present at the frequency component.

Abstract: A resonant ultrasound spectroscopy method provides a unique characterization of an object for use in distinguishing similar objects having physical differences greater than a predetermined tolerance. A resonant response spectrum is obtained for a reference object by placing excitation and detection transducers at any accessible location on the object. The spectrum is analyzed to determine the number of resonant response peaks in a predetermined frequency interval. The distribution of the resonance frequencies is then characterized in a manner effective to form a unique signature of the object. In one characterization, a small frequency interval is defined and stepped though the spectrum frequency range. Subsequent objects are similarly characterized where the characterizations serve as signatures effective to distinguish objects that differ from the reference object by more than the predetermined tolerance.

Abstract: In a process for early detection of damage top machine parts, particularly rolling element bearings, vibrations are detected by means of a vibration pickup in order to make it possible to describe the present condition of the machine part as well as to estimate the remaining service life of the machine part. The picked-up signals are broken down into periodically determined stochastic and generally stochastic signal components. The signal components for determining the parameters for the stress of the machine part are examined as a function of time and the ascertained stress parameters are compared with characteristics values for the permissible stress of the machine part for purposes of determining the type of damage and/or for determining the extent of the damage.

Abstract: A grain loss monitor for a harvesting machine is provided with detector mechanism including a sensor plate and a transducer associated with the sensor plate. The detector mechanism is disposed for detecting grain loss through the impact of grain kernals on the sensor plate and the transducer has a resonant frequency in the range of 8 to 25 KHz. The grain loss monitor also includes a circuit operable to process the output signals from the transducer.

Abstract: A process for the detection and measurement of wall coke at a specific location in a fluid bed coker through the measurement of the vibrations of the external shell of the coker at the location.

Abstract: A motor current noise signature analysis method and apparatus for remotely monitoring the operating characteristics of an electric motor-operated device such as a motor-operated valve. Frequency domain signal analysis techniques are applied to a conditioned motor current signal to distinctly identify various operating parameters of the motor driven device from the motor current signature. The signature may be recorded and compared with subsequent signatures to detect operating abnormalities and degradation of the device. This diagnostic method does not require special equipment to be installed on the motor-operated device, and the current sensing may be performed at remote control locations, e.g., where the motor-operated devices are used in accessible or hostile environments.

Abstract: Paper pulp mill chemical recovery boiler steam piping is monitored for leaks by an acoustic leak detection system responsive to atmospherically carried sound transmissions. Energy level amplitudes of respective analog electrical signals generated by a multiplicity of microphones are digitized in a rapid time sequence. Such digital values are temporarily stored in a data memory bank to be subsequently processed by a Fast-Fourier Transform analysis into amplitude vs. frequency domain data. Such amplitude vs. frequency data respective to each microphone is further refined for comparison to historical threshold data for a probability determination of a leak status.

Abstract: A process is disclosed for the detection and measurement of wall coke at a specific location in a fluid bed coker through the measurement of the vibrations of the external shell of the coker at that location.

Abstract: In the test of a casing enclosed shaft and impeller for structural integrity against defects such as loose bolts or cracks, an apparatus and process is disclosed which enables in-situ testing to occur within a casing. A model of the shaft and impeller, such as a spare part, is suspended so as to simulate the in casing boundary conditions and is then vibrated. Vibration or "ringing" occurs through a normally exposed end of the shaft far removed from suspected defects. A cap can be used to suspend the shaft and impeller or rotor. Vibration is imparted to the remote end of the shaft, sometimes on the cap, with an instrumented hammer blow of specific duration and known energy. Measurement and resolution of the resultant vibrations and energy dissipating damping occurs by mounting accelerometers to the remote normally exposed shaft end and recording and playing back the vibrations from the mounted accelerometers through a spectrum analyzer.

Abstract: Information on tooth wear is obtained from the frequency distribution spectrum of a vibrational quantity influenced by the impact of cutter teeth on the bottom of a bore. For example, spectra may be obtained from the product of signals indicative of torque and torsional acceleration. Tooth wear is then indicated by the shift upwardly in frequency of peaks in the spectra. Other quantities which may be used, singly or together to enhance spectral information, are weight on bit, vertical acceleration, transverse acceleration, standpipe pressure. Abrupt changes in frequency distribution curves indicate abrupt occurrences such as broken teeth or stuck cones. A stuck cone is also indicated by unidirectional peaks in a plot of torsional acceleration against time.

Abstract: An automatic spectrum analyzer is provided with enhanced features for measured data handling and analysis. One feature allows the user to establish a sequence of operations to be performed at the end of each sweep of the instrument. Another feature enables the user to specify a particular signal amplitude and to have a marker placed on a displayed signal trace at that amplitude. Still another feature provides a marker that can be positioned on the next signal peak to the right or the left of the current marker position, enabling the display of the amplitude and frequency of the signal on which the marker is placed.

Abstract: An automatic spectrum analyzer is provided with enhanced features for measured data handling and analysis. One feature allows the user to establish a sequence of operations to be performed at the end of each sweep of the instrument. Another feature enables the user to specify a particular signal amplitude and to have a marker placed on a displayed signal trace at that amplitude. Still another feature provides a marker that can be positioned on the next signal peak to the right or the left of the current marker position, enabling the display of the amplitude and frequency of the signal on which the marker is placed.

Abstract: An apparatus monitoring the vibrations of a rotary machine precisely at all times. In a control processor, a rotational frequency is calculated with a data signal from a register which operates on the basis of period pulses from a key phaser, while a vibration level corresponding to the rotational frequency is read out of a memory, and an alarm level obtained by giving the vibration level a constant from an alarm level setting unit is sent to a signal processor. The vibration waveform of a vibration sensor selected by a scanner is converted by an A/D converter into a digital signal, which is applied to the signal processor through a shift register. In the signal processor, the alarm level from the control processor is compared with vibration data from the shift register, and the calculated result is sent to the control processor. The control processor operates output appliances on the basis of the information from the signal processor.

Abstract: An abnormal noise detector for detecting abnormal noises produced by a gear unit with an eccentrically mounted gear is disclosed. A first embodiment comprises a microphone placed in the vicinity of a gear unit to be tested, a bandpass filter connected to the microphone which passes only a band of frequencies centered around an integral multiple of the normal fundamental frequency of the noise produced by the meshing of the gears of the gear unit, an amplitude detector which detects the amplitude of the signal from the bandpass filter, a frequency deviation detector which detects the frequency deviation of the signal from the bandpass filter, and recorders for recording the values of the signals from the amplitude detector and the frequency deviation detector as a function of time. A second embodiment comprises a microphone, a digital frequency analyzer and a central processing unit for determining whether abnormalities exist in the data produced by the digital frequency analyzer.

Abstract: An abnormal noise detector for detecting abnormal noises resulting from a marred tooth surface in a gear of a gear unit is disclosed. A first embodiment of a detector comprises a microphone placed in the vicinity of a gear unit to be tested, a bandpass filter for filtering the output of the microphone so as to pass only an integral multiple of the fundamental frequency of noise due to meshing of the gears of the gear unit, a rectifier for rectifying the filtered output from the bandpass filter, a differentiator for differentiating with respect to time the DC output from the rectifier, a waveform shaper for shaping the output from the differentiator into pulses suitable for counting, and a pulse counter for quantifying the pulses in the output from the waveform shaper. A second embodiment comprises a microphone, a digital frequency analyzer, and a data monitoring computer responsive to the digital frequency analyzer for monitoring the output thereof.

Abstract: The vibration of a moving device which has repetitive movements, for instance a rotary compressor, are sensed at the outer case and analyzed in real time in both the time and frequency plane. For the time analysis the envelope of the signal is generated; for the frequency analysis a fast Fourier transform is performed and separate power spectra for fractions of a revolution are produced. The signatures are compared with those of an acceptable device to identify rejects and abnormalities at a particular position of a moving part.

Abstract: A portalbe apparatus is disclosed for the diagnosis of a rotating machinery utilizing a fast Fourier transform frequency spectrum analysis system. The presence or absence of an abnormality or trouble in the rotating machinery is determined by selecting high amplitudes out from the frequency spectrum computed by the FFT frequency spectrum analysis system, arithmetically processing distribution data of spectrum amplitudes adjacent each frequency giving the corresponding high amplitude, and detecting the amplitude, at which the frequency of vibrations of the rotating machinery has attained a maximum value, together with such frequency. The diagnosis of the rotating machinery with this apparatus can be performed in situ, i.e., at the site of installation of such machinery.

Abstract: A system employing structural moment detectors for collecting and interpreting data reflecting the effect of at least a selected one of a plurality of forces acting on a structure such as a machine tool. The output signals from the moment detectors are processed to modify the information content (including rejecting components of the signals which reflect extraneous forces other than the selected one). The processed signals are then manipulated to provide secondary signals which are responsive to the condition of the structure as a result of the application of the selected force.

Abstract: Turbine blade vibration detection apparatus having two or more extremely narrow beam radar sensors positioned to direct their radar signals towards predetermined blade row or rows. A blade identification circuit is provided for each blade row having an associated radar sensor for providing an output count indicative of which blade is being examined by a particular radar sensor. The gating of the blade count and radar sensor signals is governed by a computer which performs a frequency analysis of the radar signals and compares the result with predetermined threshold values.

Abstract: In a method and apparatus for monitoring tool wear, noise emission signals associated with a cutting operation of the tool are monitored and evaluated to determine when the tool has become blunt. With the system disclosed, friction noises associated with the cutting tool are excluded from analysis.

Abstract: A method and apparatus for quantitatively measuring sound from a phonographic-type record disc and using such measurements to analyze the sound characteristics and to thereby improve the sound recording. Selection of one or more sound samples to be taken from a phonographic-type record disc are made and electrical signals representative of these samples on the record disc are generated. These signals may be filtered in order to obtain individual frequency bands and decibel levels for each of the frequency bands is determined. Decibel levels for certain of or all frequencies or bands of frequencies for each sample may be averaged. In this way, it is possible to obtain signals representing decibel levels as a function of frequency for each discrete sample. The signals are used to present a profile of the decibel levels with respect to the frequency and for the selected time interval of each sample in order to thereby enable evaluation of the sound characteristics of that record disc.

Abstract: A data acquisition system utilizing a microcomputer and incorporating a plurality of monitors each adapted to produce an electrical signal indicative of a physical condition of apparatus to be monitored. The electrical signals are fed via multiplexing equipment and analog-to-digital converters into the microcomputer which is equipped with print-out means. The system is such that the level of any one or all of the signals from the respective monitors can be printed out as well as a change in the condition of any signal. Means are incorporated into the computer for calculating and printing the trend (i.e., the slope of a plot of signal amplitude versus time) of a succession of stored signals from any monitor which would indicate a probable malfunction of a device being monitored and the probable time to failure. In the case where the signals from the monitors comprise, vibration signals, the system performs an automatic frequency spectrum analysis whenever a probable or actual malfunction is detected.