Abstract: System and methods are disclosed for fluid measurements which may be utilized to determine mass flow rates such as instantaneous mass flow of a fluid stream. In a preferred embodiment, the present invention may be utilized to compare an input mass flow to an output mass flow of a drilling fluid circulation stream. In one embodiment, a fluid flow rate is determined by utilizing a microwave detector in combination with an acoustic sensor. The acoustic signal is utilized to eliminate 2 &pgr; phase ambiguities in a reflected microwave signal. In another embodiment, a fluid flow rate may be determined by detecting a phase shift of an acoustic signal across two different predetermined transmission paths. A fluid density may be determined by detecting a calibrated phase shift of an acoustic signal through the fluid. In another embodiment, a second acoustic signal may be transmitted through the fluid to define a particular 2&pgr; phase range which defines the phase shift.

Abstract: A fill level measuring arrangement with a fill level meter, and a vessel (1), whereby the fill level meter operates on the radar principle, for measuring the fill level of a medium (2) in the vessel (1) and an electrical conductor arrangement (3) with a signal generator for generating and transmitting an electromagnetic signal, the conductor arrangement (3) extending into the vessel (1) and at least to a region at the bottom (4) of the vessel (1), the signal generator being positioned at the end of the conductor arrangement (3) which is outside the medium (2) so that the signal produced by the signal generator can be coupled into the conductor arrangement (3) at the end located outside the medium (2).

Abstract: A single-antenna short-range radar transceiver emits 24 GHz RF sinewave packets and samples echoes with strobed timing such that the illusion of wave propagation at the speed of sound is observed, thereby forming an ultrasound mimicking radar (UMR). A 12 GHz frequency-doubled transmit oscillator is pulsed a first time to transmit a 24 GHz harmonic burst and pulsed a second time to produce a 12 GHz local oscillator burst for a sub-harmonically pumped, coherently integrating sample-hold receiver (homodyne operation). The time between the first and second oscillator bursts is swept to form an expanded-time replica of echo bursts at the receiver output. A random phase RF marker pulse is interleaved with the coherent phase transmitted RF to aid in spectrum assessment of the radar's nearly undetectable emissions.

Abstract: The invention relates to a method and a device for measuring a level in a receptacle using radar. Via an aerial (1) directed down into the receptacle, an electromagnetic wave is transmitted and a reflected and time-delayed wave is received, the level being calculated from the time delay. Via one and the same aerial (1) at least two waves are transmitted and received, which are mutually distinguishable by a detectable characteristic for each wave. The device according to the invention is characterized in that connected to the aerial (1) is at least one further radar measuring channel (3; 4), the radar waves of which are mutually distinguishable and distinguishable from the radar wave used in a first radar measuring channel.

Abstract: A level transmitter for use in a process application measures the height of a product level in a container, e.g., in a tank. The level transmitter includes an electromagnetic wave antenna directed into the tank. An electromagnetic wave source sends an electromagnetic wave signal through the electromagnetic wave antenna. An electromagnetic wave receiver receives the reflected electromagnetic wave signal. Measurement circuitry coupled to the source and receiver initiates transmitting of the electromagnetic wave signal and determines product level height based upon the received, reflected signal. Output circuitry transmits information related to product height. The device is suitable for use with containers having very small orifices for antenna insertion.

Abstract: Two crystal oscillators are configured as a “plug-and-play” precision transmit-receive clock system that requires no calibration during manufacture. A first crystal oscillator generates a transmit clock and a second crystal oscillator generates a receive clock that operates at a small offset frequency &Dgr; from the transmit clock. A frequency locked loop regulates &Dgr; by regulating the frequency of the detected receive pulses from a radio, radar, laser, ultrasonic, or TDR system. The clock system further includes a wrong sideband reset circuit and a phase lock injection port. Applications include a timing system for automotive backup and collision warning radars, precision radar and laser rangefinders for fluid level sensing and robotics, precision radiolocation systems, and universal object/obstacle detection and ranging.

Abstract: A microwave radar signal system generates separate level indicating signals for transmittal through a sounding tube into a contamination tank having a mixture of fuel and gross free water collected therein. The separate level indicating signals are thereby respectively reflected from the level of a top surface of the collected liquid mixture and a lower level of an interface between the fuel and the gross free water portions of the mixture to respectively provide data for determination of total liquid volume collected and the volumetric content of the fuel therein. The interface level location is established by means of a floatation ball disposed within the sounding tube, from which level indicating signals are reflected.

Abstract: A level transmitter for use in a process application measures the height of a product level in a container, e.g., in a tank. The level transmitter includes an electromagnetic wave antenna directed into the tank. An electromagnetic wave source sends an electromagnetic wave signal through the electromagnetic wave antenna. An electromagnetic wave receiver receives the reflected electromagnetic wave signal. Measurement circuitry coupled to the source and receiver initiates transmitting of the electromagnetic wave signal and determines product level height based upon the received, reflected signal. Output circuitry transmits information related to product height. The device is suitable for use with containers having very small orifices for antenna insertion.

Abstract: A level sensing apparatus for attachment to a sounding tube in order to measure levels of contents in a tank. This level sensing apparatus includes a housing for enclosing the various components of the level sensing apparatus. The level sensing apparatus of the present invention also includes a sounding tube adapter operatively connected to the housing and is further adapted for attachment to a sounding tube. Additionally, the sounding tube adapter includes an orifice disposed through its sidewall. The sounding tube adapter also includes a cover which can seal off the orifice, or may be opened to allow manual liquid level measurement.

Abstract: A time domain reflectometry measuring instrument uses a microprocessor that provides added functionality and capabilities. The circuit electronics and probe are tested and calibrated at the factory. Installation and commissioning by the user is simple. The user installs the probe. The transmitter is attached to the probe. The user connects a standard shielded twisted pair to the electronics. Power is applied and the device immediately displays levels. A few simple parameters may need to be entered such as output characteristics and the process material dielectric constant.

Abstract: A low power radar level transmitter having reduced ground loop errors and a related method are disclosed. A microwave termination is couplable to a reference voltage such as earth ground and is coupled to a microwave transceiver through at least one low frequency isolator. The microwave transceiver generates a microwave signal along the termination which is reflected by a process product interface. A level calculator is coupled to the microwave transceiver to calculate a level of the process product based upon the received, reflected signal. A process loop communicator is coupled to the level calculator and couplable to a process control loop to communicate the calculated level across the process control loop. A power supply is couplable to the process control loop and provides power to all electrical components of the transmitter with energy received from the process control loop.

Abstract: A level transmitter for use in a process application measures the height of a product level in a container, e.g., in a tank. The level transmitter includes an electromagnetic wave antenna directed into the tank. An electromagnetic wave source sends an electromagnetic wave signal through the electromagnetic wave antenna. An electromagnetic wave receiver receives the reflected electromagnetic wave signal. Measurement circuitry coupled to the source and receiver initiates transmitting of the electromagnetic wave signal and determines product level height based upon the received, reflected signal. Output circuitry transmits information related to product height. The device is suitable for use with containers having very small orifices for antenna insertion.

Abstract: A radar gauge adapted to sense fluid level in a tank and including a radar gauge circuit in which radar transmission and level sampling are controlled by a transmit frequency and a sample frequency respectively. A first frequency separation between first and second frequencies is controlled by a control input. The first and second frequencies can be divided to generate the transmit and sample frequencies, separated by a second frequency separation. At least one frequency difference is evaluated and the evaluation used to generate the control input, stabilizing the first frequency difference, and to correct the gauge output.

Abstract: A low power radar level instrument with enhanced diagnostics is disclosed. A microwave transceiver generates a microwave signal that travels along a termination, through a reference impedance discontinuity, and into a process product interface. A first portion of the signal is reflected by the reference impedance discontinuity, and a second portion is reflected by a process product interface. A diagnostic signal is provided based upon a characteristic of the first reflected portion. A level output is provided based upon the first and second reflected portions.

Abstract: A level sensing apparatus for attachment to a sounding tube in order to measure levels of contents in a tank and for determining the purity of contents in a tank. This level sensing apparatus includes a housing for enclosing the various components of the level sensing apparatus. The level sensing apparatus of the present invention also includes a sounding tube adapter operatively connected to the housing and is further adapted for attachment to a sounding tube. Additionally, the level sensing apparatus includes a lock operatively connected to the sounding tube adapter and capable of receiving the housing. Finally, the level sensing apparatus includes a swivel connector operatively connected to the housing, whereby the housing is capable of moving cooperatively with the swivel connector.

Abstract: The invention relates to a device (1) for determining the filling level in a container (4). Moreover, the invention also relates to a method for fastening an input coupling unit (9) on the antenna (7), the antenna (7) being used in the device (1) according to the invention. It is the object of the invention to provide overvoltage protection for an antenna (7), and a method for producing such an antenna (7). The object is achieved by virtue of the fact that the antenna (7) comprises at least two dielectric layers (12, 13). The first dielectric layer (12) has at least one cutout (15) for holding the input coupling unit (9). The second dielectric layer (13) bears an antenna structure (16) on the side facing the first dielectric layer (12) and has a conductive coating (17) with openings (18) on the side averted from the first dielectric layer (12). Contacts (19) are provided in the second dielectric layer (13) and the conductive layer (17) which connect the input coupling unit (9) to the conductive coating (17).

Abstract: Radar is used to measure not only the level of slag on molten steel but also its thickness; the measurement is used to calculate the volume of slag, and, in turn the amount of additives for slag treatment. Time-of-flight data are used to identify peaks representing the distances of the surfaces of the slag and the surface of the underlying steel. The concept is applicable to other materials of differing composition, and particularly where the underlying material is relatively more conductive than the overlying material. Degassing is more efficiently practiced by using the radar slag thickness determinations to assist in vertical placement of snorkels.

Abstract: This invention relates to an apparatus for the determination of the fill state of solid or liquid material in a container with a signal-generating/transmitting unit, a receiving unit, a time-delay circuit which transforms the high-frequency signals into low-frequency signals, and an evaluating unit.

Abstract: A liquid level meter is provided for measuring a level of a liquid (1) in a container (3), which meter measures acceptably in the case of liquids with low dielectric constants, and the installation and maintenance of which are simple and cost effective. This meter comprises an electronic circuit (13), which generates electromagnetic signals in operation, a conductor (7), which projects into the container (3), along which a float (11, 11a, 11b, 11c, 11d, 11e) moves along with the level, which has at least one segment reflecting electromagnetic signals, an injector (9), which transmits the signals from the circuit (13) to the conductor (7), which conductor (7) leads the signals into the container (3) and leads out a signal reflected at the float (11) and a receiving and evaluating circuit (15), which receives the reflected signals, which determines a travel time of the signals and which ascertains the level from the travel time.

Abstract: Disclosed is a low power time domain reflectometry radar (LPTDRR) level transmitter for calculating levels of first and second products in a tank. A termination extends into the first and second products in the tank. A pulse generator transmits a pulse along the termination into the first and second products. A pulse receiver receives first and second reflected wave pulses corresponding to reflection of a first portion of the transmit pulse at a first product interface and reflection of a second portion of the transmit pulse at a second product interface, respectively. A threshold controller generates a first threshold for detection of the first reflected wave pulse and a second threshold for detection of the second reflected wave pulse. A dielectric constant calculator determines a dielectric constant of the first product as a function of the first reflected wave pulse. A level computer calculates levels of the first and second products.

Abstract: Harmonic techniques are employed to leverage low-cost, ordinary surface mount technology (SMT) to high microwave frequencies where tight beamforming with a small antenna makes reliable, high-accuracy pulse-echo radar systems possible. The implementation comprises a 24 GHz short-pulse transceiver comprised of a pulsed harmonic oscillator employed as a transmitter and an integrating, pulsed harmonic sampler employed as a receiver. The transmit oscillator generates a very short (0.5 ns) phase-coherent harmonic-rich oscillation at a sub-multiple of the actual transmitter frequency. A receiver local oscillator operates at a sub-multiple of the transmit frequency and is triggered with controlled timing to provide a very short (0.5 ns), phase-coherent local oscillator burst. The local oscillator burst is coupled to an integrating harmonic sampler to produce an integrated, equivalent-time replica of the received RF.

Abstract: An arrangement for measuring the liquid level in a tank. The arrangement has a microwave transmitting/receiving device and a waveguide that extends into the tank for guiding a coupled-in microwave. The waveguide has clear and constant wave propagation characteristics for a wave with the operating frequency.

Abstract: A method for processing an echo amplitude profile generated by an echo ranging system with reference to a temporal axis to identify return echoes comprised by the profile by identifying amplitude peaks in the profile above with respect to an amplitude axis, a threshold curve on the same temporal axis, wherein the threshold curve is generated by identifying rising edges of echoes in the profile, and generating curve segments extending on the temporal axis from points at or above said leading edges to intersections with descending edges of echoes in the profile, whereby to trace echo base lines delimiting access of the echoes. The invention also extends to a method for processing an echo amplitude profile.

Abstract: Radar is used to measure not only the level of slag on molten steel but also its thickness; the measurement is used to calculate the volume of slag, and, in turn the amount of additives for slag treatment. Time-of-flight data are used to identify peaks representing the distances of the surfaces of the slag and the surface of the underlying steel. The concept is applicable to other materials of differing composition, and particularly where the underlying material is relatively more conductive than the overlying material.

Abstract: An equivalent time pulse-echo radar or other pulse-echo system employs a transmit reference sampler collocated with the transmitter to provide a transmit reference pulse, which initiates a pulse width modulated (PWM) pulse. A receive sampler connected to a receive antenna provides an echo-detection pulse that terminates the PWM pulse, such that the width of the PWM pulse indicates target range. The transmit reference sampler and the receive sampler are driven from a common clock such that transmit-receive timing offset drift precisely cancels on a picosecond scale, thereby enabling sub-mm range accuracy with common, low-cost circuit elements. The radar further includes automatically referenced pulse detectors that are responsive to either the magnitude or the phase of the sampler outputs. The radar can be used for precision tank level measurements, robotics, or automotive ranging applications.

Abstract: Radar is used to measure not only the level of slag on molten steel but also its thickness; the measurement is used to calculate the volume of slag, and, in turn the amount of additives for slag treatment.

Abstract: A FMCW radar tank level gauge (14) that measures a level (13) in a tank (10) by obtaining a set of phase shift data points of mixed transmitted waves and received waves. The set of spectral data phase shift values has a received target marker indicating the level. An adaptive set of masking threshold phase shift values corresponding to at least a portion of the spectral data phase shift values are calculated. The adaptive set of masking threshold values are compared with the corresponding spectral data values to identify at least one spectral data value associated with the level. The level of the tank is calculated from at least one spectral data value and the level of the tank is reported.

Abstract: A level measuring device suitable for highly accurate measurements. A transmission pulse generator generates microwave pulses at a transmission repetition rate and transmits them through an antenna towards a material whose level is to be measured. Echo signal from the surface of the material are received by the antenna. A reference pulse generator generates reference pulses similar to the transmission pulses but at a reference repetition rate which differs from the transmission repetition rate by a small frequency difference. The echo signal and reference pulse are input to a first mixer which generates an intermediate frequency signal that, with respect to the echo signal, is slowed by a time dilation factor equal to the quotient of the transmission repetition rate and the frequency difference. A first subcircuit samples the intermediate frequency signal, the time interval between two successive samplings equaling a time unit.

Abstract: A method and apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining an initial reference signal along a probe, storing the initial reference signal as an active reference signal, periodically detecting a TDR signal along the probe in the vessel, and computing the output result using the TDR signal and the active reference signal. The method also includes the steps of determining an appropriate time for updating the active reference signal, automatically computing an updated reference signal at the appropriate time, and overwriting the active reference signal with the updated reference signal for use in subsequent computations of the output result.

Abstract: For measuring the level of a material in a vessel by a radar-based method an antenna arranged above the highest level anticipated radiates electromagnetic waves to the surface of the material contained in the vessel and receives reflected echo waves. The transit time of the wanted echo waves reflected by the material surface is measured from which the level is computed. Since this transit time corresponds to the group delay, for determining the reduction factor by which the group velocity of the electromagnetic waves differs from the velocity of propagation in the free space due to the geometry of the propagation space the phase difference of the wanted echo waves relative to a reference oscillation and the group delay are measured for various levels and the reduction factor is determined on the basis of the changes in the phase difference as a function of the group delay.

Abstract: The stopping of a load suspended from a crane requires a swing control or, respectively, a swing damping. Upon employment of microwave measuring units, spacings between a carrying cable suspension and a load suspension point are determined on the basis of transit time measurements. The position of the load suspension point can be determined from the transit time measurements quickly and with high precision. Swinging motions are avoided by controlled opposing control of the carrying cable suspension.

Abstract: An improved RADAR sensor for measuring the level of material utilizes conventional medium- or high-power microwave transmitter and microwave receiver devices, while utilizing only the relatively small amount of current supplied by a conventional low current two-wire process control loop. A transmit/receive unit and a control unit are operated intermittently to generate readings, and are set to a current-saving or even currentless standby mode between these periods of active measurement. During the inactive standby period, circuit components such as capacitors collect and store power to be used for the comparably high-power requirement during the active measurement cycles. The inactive standby periods are preferably long compared to the duration of the measurement periods. This permits operation with power entirely supplied from a common two-wire 4-20 mA process control loop.

Abstract: A method for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining a background signal for a probe and detecting a sample TDR signal for the probe in the vessel. At least one transition point is established on the sample TDR signal and the background signal. A portion of the sample TDR signal on one side of the at least one transition point is combined with a portion of the background signal on the other side of the at least one transition point to establish an initial boundary signal, and the initial boundary signal is stored. The method also includes the steps of detecting the TDR signal and calculating the output result using the initial boundary signal.

Abstract: In measuring the level of a material in a container by a radar-based method the echo profile of the received microwaves is registered and a maximum of the echo profile established for determining the microwaves reflected by the material surface. To avoid false readings in the case of a double echo causing in the echo profile a double blip of two overlapping echo blips, consecutive maximum and minimum values of the slope of the echo profile and their distance values are determined starting from the established maximum in the direction towards smaller distances. The amplitude value of the echo profile assigned to the distance value located in the middle between the distance value of the first minimum slope and the distance value of the next maximum slope is used as the peak value of the first echo blip of the double blip decisive for level measuring.

Abstract: A waveguide assembly for a process sealed level gage includes first and second waveguide portions, a process sealing cavity and a mechanical barrier. The first waveguide portion has a first waveguide bore. The second waveguide portion is fastened to the first waveguide portion and has a second waveguide bore which is axially aligned with the first waveguide bore for communicating microwave signals at a waveguide wavelength .lambda..sub.G between the waveguide bores. The process sealing cavity is formed at an interface between the first and second waveguide portions. The mechanical barrier includes a first shaft section positioned within the first waveguide portion, a second shaft section positioned within the second waveguide portion and a raised annular shoulder positioned at the interface, within the process sealing cavity. The raised annular shoulder has a width, which is measured radially outward from an outside diameter of the shaft sections, of approximately 1/2 .lambda..sub.

Abstract: A method of detecting the displacement of a target in a given environment includes storing reference data having data representative of the environment; transmitting a transmit signal towards the target; sensing the return signals from the target and the environment; and detecting the displacement of the target by comparing the return signals and the stored reference data. A method of detecting the level of a sample in a container is also disclosed. Analogous apparatus features are also disclosed.

Abstract: A level measuring device using microwaves comprises an antenna for sending transmitted waves toward the surface of a material whose level is to be measured, and for the reception of echo waves resulting from reflection at the surface, and a receiving and evaluating circuit which derives from the echo waves received by the antenna an echo function representative of the echo amplitudes as a function of the distance and determines from the echo function the transit time of the microwaves from the antenna to the surface of the material and therefrom the distance of the surface of the material from the antenna.

Abstract: A conventional radar module (1) for level measurements is designed for operation within a specific, narrowly restricted frequency range. To enable level measurements to be implemented at a substantially higher frequency without involving any change in the existing radar module (1) whatsoever, a frequency converter circuit (2) is inserted between the duplexer antenna (7) designed for said higher frequency and the antenna port (A) of the radar module (1). This frequency converter circuit (2) which can be realized at small expense converts the lower frequency into the higher frequency in the direction from the radar module (1) to the antenna (7) and the higher frequency into the lower frequency in the opposite direction.

Abstract: A method for measuring the position of at least one surface in a metallurgical process which includes the steps of providing a metallurgical melt, the metallurgical melt including at least a metal portion and a slag layer, providing a signal generator for generating signals at a plurality of frequencies over a frequency band, and providing an antenna for receiving the signals generated by the signal generator and for transmitting circularly polarized radio waves at the plurality of frequencies over the frequency band.

Abstract: In a method of level measurement on a radar basis, microwaves are emitted by means of an antenna to the surface of a material in a container and the echo waves reflected from the surface thereof are received. An actual echo function representing the echo amplitudes as a function of the distance is formed from the echo waves received by the antenna for each measurement, the probable useful echo and the transit time thereof are established from the actual echo function, and the distance of the material surface from the antenna is determined therefrom. To recognize the formation of a deposit and/or other trouble, such as e.g. damage to or loss of the antenna, an undisturbed echo function corresponding to an undisturbed measurement is obtained and stored prior to performing the measurements. In each measurement the actual echo function is compared to the stored undisturbed echo function.

Abstract: The present electronic multi-purpose material level sensor is based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line that is partially immersed in a liquid, powder, or other substance such as grain in a silo. The time difference of the reflections at the start of the transmission line and the air/liquid interface are used to determine levels to better than 0.01 inch. The sensor is essentially independent of circuit element and temperature variations, and can be mass produced at an extremely low price. The transmission line may be a Goubau line, microstrip, coaxial cable, twin lead, CPS or CPW, and may typically be a strip placed along the inside wall of a tank. The reflected pulses also contain information about strata within the liquid such as sludge-build-up at the bottom of an oil tank.

Abstract: The High Accuracy Electronic Material Level Sensor (electronic dipstick) is a sensor based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line or guide wire that is partially immersed in the material being measured; a launcher plate is positioned at the beginning of the guide wire. Reflected pulses are produced at the material interface due to the change in dielectric constant. The time difference of the reflections at the launcher plate and at the material interface are used to determine the material level.

Abstract: To measure the level of contents in metallic tanks by means of short electromagnetic waves, it is proposed to mount the complete level measuring assembly, including the horn antenna, outside the tank. The transmitted waves are projected through an opening in the tank wall toward the surface of the medium whose level is to be measured. The opening is closed with a glass or ceramic plate. To distinguish the useful signal within the unwanted echos caused by multiple reflections of the electromagnetic waves at the glass or ceramic plate, a damping layer of a conventional damping material is interposed between the microwave coupling element and the surface of the glass or ceramic plate. To achieve an optimum signal-to-noise ratio, the damping coefficient is fixable and the distance between the level measuring assembly and the surface of the glass or ceramic plate is adjustable in the axial direction of the opening.

Abstract: The present invention pertains to a radar range finder for high-precision, contactless range measurement, which is based on the FMCW principle and operates with digital signal processing at a limited frequency shift. One exemplary embodiment is described.

Abstract: A device for gauging the level of a fluid in a container is described. It comprises a transmitter for transmitting a polarizable microwave signal through a first waveguide section, a receiver for receiving a reflected microwave signal, an electronic unit for determining the reflex position of the reflected microwave signal and an antenna means with a second waveguide section. The device is primarily characterized in that the transmitter and receiver, respectively, transmits and receives a waveguide mode each, mutually orthogonal, and by an easily replaceable third waveguide section (6, 16, 17) inserted between the first (2) and second (5) waveguide sections, provided with means (12, 14, 15, 22) for polarization and/or damping for optimal adaptation of the device to various containers and antennae.

Abstract: A non-intrusive mounting system and method for coupling microwave instruments to a container flange having an opening into a container. The mounting system includes a microwave transparent window and a mounting flange having a window recess for accommodating the microwave transparent window. The microwave transparent window is compressively fastened over the container opening between the mounting flange and the container flange. Microwave instruments such as radar level sensing apparatus can be mounted on and removed from the mounting flange without breaking the seal to the container.

Abstract: Disclosed is a method for the measurement, by means of a radar, of the distance from a useful obstacle that is surrounded by parasitic obstacles but sends back an echo which is more powerful than their echos. This method of measurement can be applied to the measuring of the level of liquid in a vessel. It consists in transmitting a sequence of non-modulated microwave signals whose discrete angular frequencies are evenly distributed in a certain frequency band, demodulating the signals received in return for the transmitted signals, subjecting the received and demodulated signals to a reverse and discrete Fourier transform with a view to a coarse localization of the delay of the echo from the useful obstacle and a high resolution method for the localization of the radiating sources with a view to a more precise localization of the delay of the echo from the useful obstacle, said delay enabling the assessment of the distance from the useful obstacle to the radar. FIG. 5.

Abstract: A noninvasive ultrasonic liquid level indicator for indicating the level of a liquid in a reservoir is disclosed which comprises an ultrasonic transducer assembly, structures for holding the transducer assembly in a dry coupled attachment with the reservoir at selectable locations against an exterior surface of the reservoir, and a monitor for revealing a change in liquid height. The transducer assembly conveys signals regarding changes in liquid height to a monitor which warns the user in time to add more liquid or replace the reservoir before the liquid supply "runs dry." The manners for holding the assembly in place include, but are not limited to, a strap, a clamp, or adhesive material, such as tape. These allow the user to selectively place the transducer assembly along the reservoir at the desired triggering point.

Abstract: A bandwidth synthesized radar level measurement system includes a transceiver for generating a transmitted signal and a sweep signal. An antenna coupled to the transceiver sends the transmitted signal toward a level corresponding to a product surface and receives a reflected signal therefrom. A sweep generator generates a chirp slope signal in response to the reflected signal. An intermediate frequency (IF) processor receives the chirp slope signal and a difference signal mixed from the transmitted and reflected signals. The IF processor produces an amplified IF signal and a sweep control receives the amplified IF signal to adaptively control the sweep generator and to produce an output signal including a distance from the antenna to the level corresponding to the product surface.

Abstract: A process for measuring the level of a liquid in a tank according to the radar principle, in which microwave energy is transmitted in the direction of the liquid level and the bottom of the tank from an antenna located above the liquid level, a measuring signal reflected from the liquid level is received by an antenna, and the liquid level may be determined from the transit time of the measuring signal, other signals than the measuring signals, i.e.