Abstract: The inspection head component of a manipulator employed in the inspection of the interior surface of a nuclear reactor vessel is aligned to an optimum orientation when positioned at a local surface to be inspected. This alignment is carried out by generating ranging information with respect to the local surface using ranging ultrasonic transducers positioned upon the inspection head. The propagation interval of the acoustic signal emitted by these ranging transducers is timed and quantified to develop orientation error signals. Such development is carried out in conjunction with known values for the local surface being inspected and in conjunction with a sequence of data collection at the position. The inspection head is pivotally mounted upon the manipulator so as to be movable about at least two axes by inspection head positioning assemblies which may be provided, for example, as stepper-motors and associated translational movement components.

Abstract: An inboard servo for a controllable pitch propeller of the force rod type comprises a feedback device comprising a feedback ring located externally of the propeller drive shaft, affixed to the force rod for rotation and axial translation therewith and having a planar surface perpendicular to the propeller drive shaft axis, and a distance-measuring device for substantially continuously detecting the position of the ring, and therefore the position of the force rod. The distance-measuring device directs a high frequency pulsed signal onto the ring surface from a fixed position spaced apart therefrom, detects the signal as it is reflected by the ring surface from a fixed position spaced apart therefrom, and processes the directed and reflected signals to produce a signal indicative of the position of the ring surface based on the time difference between the pulses directed onto the ring surface and the pulses reflected from the ring surface.

Abstract: An ultrasonic transducer is provided with an ultrasonic transmitter; an ultrasonic receiver; and a propagation-delay-time calculating device for calculating a propagation delay time from the time when an ultrasonic wave is transmitted by the transmitter until the time when the ultrasonic wave is received by the receiver.

Abstract: A height measurement system uses an inexpensive ultrasonic height measuring evice to provide an apparent height of a descending airborne object. To compensate for movement of the object during the ultrasonic measurement, a Doppler radar velocity measuring device determines the vertical velocity in a short measurement period. The measured vertical velocity is used to determine the vertical distance travelled during the ultrasonic measurement and to compensate therefor by converting the apparent height to a true height of the descending object. Updates of the true height may be obtained by storing the vertical velocity and retrieving the vertical velocity for multiplication by a time value to obtain an updated value of the true height.

Abstract: An acoustic pipe length measuring apparatus for measuring the length of a pipe-like member in accordance with the time between the emission of a pulse-like sound wave from a speaker at one end thereof and the collection of sound waves reflected at the other end thereof, by a microphone, and a sonic velocity, in which data of a sonic velocity at a reference temperature of a gas present in the pipe-like member is stored in memory, and a sonic velocity value at a temperature of gas detected in the pipe-like member is computed with the use of the data of a sonic velocity value which is read from the memory in accordance with a kind of gas in the pipe-like member, thereby it is possible to calculate the length of the pipe-like member from the sonic velocity value obtained through the computation and the above-mentioned time.

Abstract: A device for selectively detecting in real time a moving object progressing on a path in a multidimensional space, the device comprising first means determining an efficiency, corresponding to the ratio of net displacement to total distance travelled, and for selecting moving objects on the basis of this ratio. To account for objects making half turns in an otherwise efficient path, from the data constituted by the measurements of displacements of the moving object, an average of the efficiency of motion is used. The device is useful, for example, for real-time image sequence processing in conjunction with the tracking of moving objects.

Abstract: A passage is periodically scanned by a plurality of ultrasonic transmitters/receivers (sensors) arranged on the ceiling of the passage in two lines to calculate the height of an object to be measured to each sensor and the presence or absence of the measured object(s), moving direction(s) thereof, and the number thereof are reckoned from changes in sensed height and sensing time for each sensor induced by passing an object to be measured through the passage, and the position and a change in position with time of each sensor which senses the measured object concerned to count the number of passers-by in each moving direction. The presence or absence of the object to be measured and the number to be counted are decided in accordance with changes in sensed position and sensed height and the interrelation thereof, so that the number of sensors can be reduced and the number of passers-by can be counted at a high accuracy even when a plurality of persons pass under the sensors in a group.

Abstract: This switch device for detecting an object comprises a transducer for emitting and receiving ultrasonic signals to and from an object, a transmitter for driving the transducer, a receiver for receiving a signal from the transducer, a gate for detecting a short-distant object, a gate for detecting a long-distant object, and a circuit for setting the timings of the gates in accordance with the detecting ranges of the object.

Abstract: One or more passive transducers for converting sounds, including bio-soundwaves from a living aquatic animal source traveling in a body of water, to electrical signals, is combined with an active sonar (echo sounding) to form an integrated marine acoustic system. Moreover, a common display can be used and coupled with a satellite (GPS) or loran position locator so that a fishing vessel carrying the apparatus can have its position displayed on an electronically reproduced chart or map of an area along with the fish location, including an indication of the direction of fish movement, and fish species.

Abstract: An integrated active/passive transducer system includes an active transducer for converting ultrasonic electric energy to pressure waves launched in a body of water and converting reflected ultrasonic pressure waves from a target in the body of water to a first electrical signal. A passive transducer coaxial with the active transducer, converting biosound pressure waves from a living organism in the body of water to second electrical signals. A first processing channel is connected to receive the first electrical signals and determine range to the target. A second processing channel is connected to receive the second eleectrical signals and provide a biosound signal. Logic system connected to receive the first electrical signal and said biosound signal, to validate that the target is a living organism and not an inanimate object only in the presence of biosound signals, and an indication is connected to the logic means for indicating that the target is a living organism.

Abstract: A method and apparatus for sensing the edge of a web which moves along a surface of a body wherein an acoustic pipe is provided in the body with an opening located so that the edge of the web covers a portion of the opening as a function of the position of the web, an air column in the pipe is caused to resonate so that the resultant acoustic signal has a frequency spectrum which is a function of the portion of the opening which is covered by the web, and the resultant acoustic signal is utilized to provide information relating to the location of the edge of the web. The opening can comprise a series of spaced apertures, some of which are covered by the web, or a continuous slot which is partially covered by the web. The resultant acoustic signal can be analyzed by scanning a range of signal frequencies to determine the location of the edge of the web. A web width sensor comprises a pair of adjacent web edge sensors, one for sensing the location of each web edge, for determining web width.

Abstract: Optical radiation is propagated through an attenuating medium to a target om which it is reflected and picked up by an echo receiver system to provide ranging and imaging data during one mode of operation. The optical radiation is transformed into acoustical pulse energy alternatively radiated to and reflected from the target in another mode of operation. The operational mode is selected so as to optimize the data extracted from the echo receiver system under different conditions affecting receiver reception.

Abstract: An ultrasonic detector of the type used to detect the level of a liquid or the magnitude of liquid flow within a conduit by periodically transmitting ultrasonic energy bursts and receiving echoes therefrom is controlled by a controller with a computer program having a number of routines. The routines include a range search routine that searches a defined range of the detector to locate the targets within the range. The range is searched by repeatedly transmitting energy bursts and gradually decreasing the gain of the detector after the transmission of each burst. All targets identified during the range search are then classified as being either bogus targets or the true target. This classification is made with the use of a bogus buffer in which bogus target data is stored.

Abstract: A system for monitoring level of material in a vessel that includes a transducer for transmitting an ultrasonic signal toward and receiving an echo signal from a surface of the material, and a power switch coupled to the transducer for energizing the transducer to transmit the ultrasonic signal. A microprocessor-based controller has an output coupled to the power switch for controlling operation thereof. The output of the microprocessor provides a pulsed periodic signal to the power switch at controllably variable frequency, duty cycle and/or total burst duration to operate the transducer at an ultrasonic frequency that corresponds to the periodic signal frequency, duty cycle and burst duration. The echo signals are compared to successive thresholds between the transmission bursts, and echo signal data is sampled and stored in the microprocessor over a measurement cycle that includes multiple transmission bursts.

Abstract: A process for detecting a phase boundary surface between layers of fluids which are not intermixable with one another includes the steps of penetrating at least one of the fluids with sound waves to strike a reflector, receiving the reflected sound waves, comparing the transmitted sound waves to the reflected and received sound waves, using the comparison to determine the acoustic propagation impedance, and using the results to determine the position of the phase boundary layer.

Abstract: An ultrasonic level detector includes a transducer for generating and receiving bursts of sonic energy at a surface to locate the position of the surface. In response to receiving a burst of energy reflected from the surface, the transducer generates an electrical signal, which is then supplied to a variable gain amplifier. After amplification, the electrical signal is supplied to a comparator and a peak detector. The comparator generates a timing signal upon the electrical signal exceeding a threshold. A window generator circuit generates a receive window that controls whether the electrical signal is supplied to the comparator and the magnitude of the threshold on the comparator. The peak detector determines the maximum amplitude of the electrical signal, which may be used to vary the amplifier gain and the number of pulses included in an excitation signal which drives the transducer. Upon receipt of the timing signal, a microprocessor determines the distance between the transducer and the detected surface.

Abstract: Methods for measuring liquid levels and leak rates in a storage tank, using an acoustic transducer and a quasi-static reference device that positions an acoustic target within a predetermined distance range below the surface of the liquid. A method for measuring the height of the surface of a liquid, i.e., liquid level.

Abstract: This invention relates to a method of, and apparatus for, detecting the position of an object relative to a detector device, in which a pulse signal is transmitted to such object by a transmitter means, and a receiver means receives a signal reflected by the object, the position of the object being determined in dependence upon the time difference between the moment the transmitter means transmits the pulse signal and the moment the receiver means receives the reflected signal. According to the invention, to eliminate the effect of spurious signals, a reference signal stored in a memory means is subtracted from the signal received by the receiver means, which reference signal has previously been received by the receiver means in response to a signal transmitted by the transmitter means in the absence of an object whose position is to be detected.

Abstract: A multi-level probe for sonic range measurements utilizes a plurality of parallel reflectors that each include an opening arranged coaxially about a beam of ultrasonic energy transmitted along a reference axis from an associated transducer. The opening in each reflector permits most of the sonic energy to pass to a subsequent reflective surface, while the periphery about the opening provides echo signals for determining physical conditions in the environment through which the sonic energy has passed. A novel system is used for determining physical conditions that are a function of time differences between signals from different reflectors, calculated with a highly efficient digital signal processing algorithm.

Abstract: A system and method for determining the condition of one or more parameters of a valve, e.g., particularly a check valve in a fluid carrying pipe, by monitoring fluid turbulence downstream of the valve. An ultrasonic transmitter-receiver transducer pair provides a signal modulated by the fluid turbulence, which signal is demodulated and processed to obtain a signature or other signal indicative of the valve condition. The processes signature signal may additionally be compared with a measure of flow rate determined just upstream from the valve. By operating the ultrasonic system at high frequency and using appropriate detecting circuitry, low frequency interference from mechanical shocks and vibrations is avoided, yielding a reliable detection of the flow turbulence caused by the valve.

Abstract: An echo sounding system includes a acoustic gun which is mounted to the wellhead of a borehole. The acoustic gun produces a acoustic pulse which is transmitted down the borehole. A tubing string is installed in the borehole and it has substantially evenly spaced collars. Fluid is pumped from the borehole, or well, by use of a reciprocating pump driven by a pump rod extending to the surface. Fluid is received from a surrounding formation and collects in the borehole. The acoustic pulse produces reflections when it strikes the tubing collars and the surface of the fluid. A microphone detects the reflections to produce a return signal. This signal is digitized and stored. The digitized signal is processed to detect the rate of the collar reflections and the stored signal is narrowband filtered with a passband filter centered at the rate of receipt of the collars. The data signal is further processed to determine the time of occurrence of the acoustic pulse and the liquid surface reflection.

Abstract: Echo locating apparatus for a vision-impaired person which includes: a sound emitter for emitting a stream of sound bursts of ultrahigh frequency; at least one receive channel having a microphone for receiving echoes of the sound bursts and generating echo signals; an echo profile detector for generating an echo profile signal of each echo signal; a delay circuit for adding a variable delay to the echo profile signal, wherein the variable delay increases with the distance to the reflecting at a diminishing rate of increase. The sound burst emitter is preferably arranged to emit a beam of sound bursts having a given beam angle that can be pointed in any direction.

Abstract: The disclosure is directed to a circuit for producing electrical discharges in response to trigger signals, and a form of the disclosure is directed to an apparatus, which includes such a circuit, for determining the transit time of acoustic energy travel between a transmitter location and a receiver location.

Abstract: The present invention relates to methods and apparatus for measuring the linear dimensions and determining the three-dimensional, spatial volume of objects. In the preferred embodiments, ultrasonic sensing is employed, alone or in combination with other measuring methods such as light curtains and the timing of moving objects, to ascertain linear dimensions. The preferred embodiments are particularly adapted to the measurement of large and irregularly configured objects, such as palletized loads, and to the measurement of moving, rectangular objects of random orientation with respect to the direction of travel.

Abstract: The detector for detecting the presence of a liquid comprises: a) a metal veguide having a solid cylindrical top first portion of relatively small section with an outside diameter having a first value d1, which first portion is fixed on a support, a cylindrical rigid bottom second portion whose outside diameter has a second value d2 greater than the first value d1, which second portion extends the first portion downwards and is connected thereto by a short linking portion; b) transducer means disposed in the vicinity of the top portion of the waveguide; and c) electronic processing means. The value of the frequency at which the transducer means are excited is selected in such a manner that acoustic wave trains propagate in the cylindrical first portion at the group velocity of low frequency waves, and propagate in the cylindrical second portion at the minimum group velocity corresponding to the point of inflection in the curve of phase velocity as a function of frequency.

Abstract: A method of extracting target range and Doppler information from a Dopplepread signal is provided. An acoustic waveform is transmitted underwater and impinges upon a submerged Doppler-spread target. Doppler-spread sonar echoes resulting from the transmitted waveform are received and digitized. The received sonar echo is separated into its inphase and quadrature components thereby forming a complex vector function. A fourth-order cumulant spectrum is generated from the complex vector function based upon three time delays. In order to extract the range and Doppler information from the Doppler-spread signal, the first of the time delays is set equal to zero while the second and third time delays are set equal to one another.

Abstract: An acoustic log for vessels includes a transmitter which sends a signal within a lobe region and at least two receivers provided for receiving signals reflected from a reference for determining the velocity component of a vessel relative to the reference in the measuring direction determined by the two receivers. The log further includes a transducer device with five crystals serving as transmitter and receiver elements for transmitting and receiving acoustic signals, and being arranged such that combinations in pairs of the crystals define twelve measuring directions regularly distributed around revolution.

Abstract: In an acoustic pulse-echo ranging system, the transmitter and receiver, which respectively generate pulses of acoustic energy and receive reflections of the same, are electronically tuned to determine their operating frequency, the electronic tuning being controlled responsive to stored data relating to a particular transducer being utilized to transmit and receive a pulse. A single transmitter and receiver can be utilized to service a number of different transducers, being automatically tuned to an appropriate frequency for each transducer as it is used to transmit and receive a pulse. The system can verify the nominal operating frequency of each transducer, and can also adjust the operating frequency used with any particular transducer to optimize its performance.

Abstract: This invention relates to a distance measuring device, in particular for motor vehicles, in which a converter is utilized for transmission of an ultrasonic signal and also for reception of the echo signal. Thereby the echo signal received by the converter is compared at a comparator with a threshold value after having been appropriately amplified. This threshold value is at a particular changeover time changed over from a first high value, which is independent of time, to a smaller, time-dependent value. Thereby the changeover time is computed from a measured time depending on the dying-out behavior of the converter.

Abstract: An ultrasonic obstacle sensor for sensing an obstacle on a road surface is disclosed which projects ultrasonic waves in the form of pulses toward the forwardly distant surface of a road in a downwardly inclined forward direction, and which is able to discriminate an obstacle on the road surface through reflection waves therefrom in a most effective and reliable manner. To this end, a timing instructor intermittently generates an instruction signal, based on which ultrasonic waves are generated. An ultrasonic transmitter projects the ultrasonic waves thus generated toward a road surface, and the reflected waves therefrom are received by an ultrasonic receier which in turn generates a reception signal. A reception signal processor AM detects the reception signal to provide an AM modulation signal. A time calculator calculates a time elapsing from the generation of the instruction signal.

Abstract: A hand held electronic grading level which automatically and accurately calculates the grade of a ground plane and indicates whether said grade is level. The grading level comprises a telescopic site level and a sonar system that is coupled to a microelectronically controlled calculator and a digital read out display. The sight level permits the grading level to be aligned horizontally with a distant sight target. The sonar system then generates an acoustic pulse which is reflected off the ground plane and received at a detector. The elapsed time between the transmission and receipt of the acoustic pulse provides an indication of the vertical elevation from the gorund plane to the sonar system. This elevation is displayed and compared to the known elevation of the distant sight target. The deviation between the shot and known elevations is also displayed to indicate the actual grade of the ground plane and whether said ground plane is level.

Abstract: A distance sensing system includes an ultrasonic transducer, a transceiver and a microcontroller-based signal processing unit. The transducer periodically generates and directs towards the terrain a dual frequency ultrasonic signal. Echo signals from the ground and/or any intervening crop or trash are reflected back to the transducer and are processed. The system generates amplified and filtered echo envelope signals. Leading and trailing edge times are determined as the times the echo signals cross a threshold value which is a certain proportion of a maximum echo amplitude value. A near distance value is derived from the leading edge time of the first echo which exceeds a minimum amplitude. A far distance value is determined as the trailing edge time of the last echo signal which has an amplitude which exceeds a certain value. Multiple echo time and amplitude values are derived from the maximum amplitude echo.

Abstract: The present invention comprises a method and apparatus for measuring the linear dimensions and determining the three-dimensional spatial volume of an object. In the preferred embodiment, all three linear dimensions are ascertained using the travel time of reflected ultrasonic waves. Measurements may be taken while the object is in motion, and the object may also be weighed.

Abstract: A system for determining the cross sectional profile of an object (24) having two opposed surfaces (26,28), includes:an ultrasonic transducer (16) having a reference surface (20) and arranged to emit and receive ultrasonic energy via the reference surface (20);a thickness determining unit (60) connected to the transducer (16) for causing the transducer (16) to emit ultrasonic energy via the reference surface (20) and for detecting reflected ultrasonic energy received by the transducer (16) via the reference surface (20) in order to derive indications of the distance between the reference surface (20) and an ultrasonic energy reflecting surface facing the reference surface (20);a carriage (2) supporting the transducer (16);a guide member (4) defining a linear travel path having a reference point and supporting the carriage (2) for movement along the travel path;a position determining unit (12,44,62) operatively associated with the carriage (2) for deriving an indication of the location of the carriage (2) alon

Abstract: A switch device is disclosed for detecting an object which comprises a transducer for emitting and receiving ultrasonic signals to and from an object, a transmitter for driving the transducer, a receiver for receiving a signal from the transducer, a gate for detecting a short-distant object, a gate for detecting a long-distant object, and a circuit for setting the timings of the gates in accordance with the detecting ranges of the object.

Abstract: In acoustic level sensing apparatus, in which pulses of acoustic energy are transmitted by an electrically energized transducer towards a surface to be sensed, and the electrical output from the transducer following the pulse is digitized and analyzed to detect a return echo from the surface, so as to produce a digitized echo profile. The digitzed echo profile is enhanced by removing narrow peaks likely to correspond with certain types of spurious echo, and narrow valleys which may represent fragmentation of a wanted echo. Echoes are identified by comparing the profile with a time varying threshold generated derived from a linear regression performed on part of the threshold, various different types of comparison being performed and their results combined prior to selecting the most likely true echo on the basis of the combined results.

Abstract: A sonar system is disclosed that includes contiguously angularly disposed d oppositely rotated transmitting and receiving transducers for broadcasting an acoustic signal and for receiving target echoes thereof, respectively, at different angles from within overlapping zones thereof within an aqueous medium. A gated transmitter is employed to timely energize said transmitting transducer, and a gated target seeking receiver is employed to process the output signal of said receiving transducer. A cathode ray tube readout displays target signals from said receiver. A light sensitive probe produces an electrical output signal in response to a target signal displayed on said cathode ray tube which is used for gating the aforesaid transmitter and receiver in such manner as to accentuate the displayed target signal being probed at any given instant.

Abstract: A motor vehicle backup monitor introduces a reflector into the detection range of a sensor in predetermined manner during a test phase. The reflector can comprise, for example, the flap of the housing which encloses the sensor. The reflector is removed from the detection range of the sensor during its operational phase. The monitor unit is particularly applicable to ultrasonic sensors used to monitor a motor vehicle when it is backing up.

Abstract: A doppler compensated sonar system is disclosed as including a transmitter nd a receiver. The receiver of the disclosed preferred embodiment is a single channel receiver which incorporates a mixer and a narrow pass band filter connected in series therein. A phase lock loop of the negative feedback type is connected between the control input and the output of said mixer which effectively determines the occurrence of any doppler effects being processed in said receiver channel and compensates therefor by appropriate adjustment of the frequency of the signal supplied to the control input of said mixer, thereby causing the remainder of said receiver channel, including said narrow band pass filter, to process received target signals without any doppler effects being present therein.

Abstract: An acoustic ranging apparatus directs a burst of acoustic energy toward an acoustically reflective target object. The time it takes for an echo to return to the ranging apparatus is measured to determine the distance between the ranging apparatus and the object. The echo is received, amplified, and compared with a threshold voltage which decays in time in a manner which simulates the attenuation of acoustic energy as a function of distance travelled in the medium. The attenuation function is substantially simulated over the distance range that the ranging apparatus is intended to accurately measure by means of a simple, low cost first order linear circuit. The ranging apparatus responds only to echoes having a magnitude which exceeds the threshold voltage. Suprious or false echoes, such as those due to reflection of acoustic energy in the side lobes produced by an acoustic energy transducer in the ranging apparatus, are ignored.

Abstract: A detector of electrical wires which aer partially submerged in water and rtially extend out thereof having a means for broadcasting electromagnetic energy to the underwater portion thereof and means for receiving electromagnetic energy from the out of the water portion thereof.

Abstract: A sonar system is disclosed having signal analyzing circuitry rendering the ystem responsive to objects of a predetermined size. The signal analysis is accomplished by a spectral analysis of the echo signals returned from the objects. In particular, the relative height of adjacent side lobes of echo signals energy returned to the sonar are compared to indicate the size of the object reflecting the signal.

Abstract: The filling level meter for measuring the filling level in a container includes a transmitting and a receiving arrangement which directs sonic or ultrasonic pulses onto the filling material surface and receives the backscattered pulses reflected by the filling material surface and converts them to electrical reception signals. Connected to the transmitting and receiving arrangement is an evaluating circuit which in a signal processing path generates an envelope signal corresponding to the envelope of the reception signals, digitizes sampled values of the envelope signal, stores in a memory the digitized sampled values for creating a distance-dependent or travel-time-dependent amplitude profile of the measurement distance and evaluates the amplitude profile for determining the travel time of the most probable useful echo signal.

Abstract: The echo ranging system of the invention comprises circuit means to diffetiate between shadows cast by objects and the period of time prior to the receipt of the first bottom return, as well as the lack of bottom reverberation for other reasons. Additional circuit means determines if the length of the shadow signals in comparison to their range exceeds a predetermined value. Circuit means are also included to produce a first electrical signal when such shadow signals are received. Further circuitry analyzes the shadow signals for which the first electrical signals were provided and produces a second electrical signal when said object shadow signals exceed in number or length a predetermined value. Additional circuit means are provided to convert said first and second electrical signals to suitable audible signals which may be readily distinguished, one from the other.

Abstract: A system for measuring the position of a moving object including transceiver means for sending signals to and receiving signals reflected from both a moving object and a reference object maintaining a known, fixed distance from the moving object, wherein by processing the signals sent and received, the position of the moving object can be determined while the effects of temperature on the speed of sound, frequency changes, false echoes and erroneous signals are minimized or eliminated.

Abstract: A vibratory, time variant, pseudorandom sonar system includes a computer controlled pseudorandom digital sweep frequency source, a digital/analog converter for changing the digital output of the source to an analog output and a power amplifier for amplifying the analog output to drive a vibrator or other suitable transducer for injecting corresponding sound waves into a body of water for target detection. A memory is provided for storing the source's digitized output.A target reflects the sound waves for detection by 3 arbitrary non-colinear hydrophones which outputs a plurality of analog signals corresponding to the reflected sound waves to a plurality of channels. Each channel includes a preamplifier and an analog/digital converter for digitizing the analog electrical signals for storage in the memory. A computer controlled timer determines the time lapse between the injection of the source signal and detection of the reflected source signal by each hydrophone of the hydrophone array, for storage in memory.

Abstract: A sonic distance-measuring device (10) for use in air includes three transducers (14, 16, and 18) in an array of transducers, which are driven in a predetermined phase relationship so as to achieve a beam width that is substantially less than that which can be achieved by any of the transducers individually. To enable the user to aim the device (10) effectively, a lamp (20) is provided to shine along the sonic beam and thus help the user direct the beam at a desired target. To conserve energy and increase the ability to distinguish the light beam from ambient light, the lamp (20) is pulsed rather than driven steadily.

Abstract: An ultrasound echo profile sensor for use as a tactile sensor, having an ultrasound measuring head containing a transmitter and a receiver and also having an entrained reference reflector by means of which the current speed of sound of the ambient air can be identified. The respective distance of the tactile sensor from a sensor subject can be correctly measured independently of the variable speed of sound of the ambient air because a reference echo caused by the reference reflector can be discriminated from situation echoes on the basis of its known, proximate position. The reference reflector, whose distance from the ultrasound receiver is constant in the reference case, is arranged such that the distance between the ultrasound receiver and the reference reflector changes in a characteristic way given tactile contact between a sensor head and the sensor subject, particularly a workpiece.

Abstract: In a method of indicating the time of an acoustic pulse at the transmission or reception of the same, the acoustic pulse is a wave package, the amplitude envelope of which having an ascending and a descending flank. The method is characterized in that the beginning of the descending flank of the amplitude is detected for determining of a reference time in the wave package, that a predetermined zero crossing in the wave package is identified from the reference time and that the time of the identified zero crossing is determined.

Abstract: This invention relates to contactless proximity sensing transducers and more particularly concerns a single crystal ultrasonic interferometer comprised of a piezoelectric crystal attached to a Pyrex plate for acoustic impedance matching purposes. When driven at the crystal's resonant frequency, the electrical impedance of the crystal becomes sensitive to the input acoustical impedance of the interferometric path length between the crystal and the target object. By monitoring the crystal impedance at a fixed frequency as target position is varied, the sensor is capable of determining the incremental displacement of the moving target. By monitoring the crystal impedance at a fixed target position as the driving frequency is varied, the sensor is capable of determining the absolute proximity of the target. The geometry of the piezoelectric crystal and the Pyrex plate are used to affect the resolution and frequency response of the sensor.