Abstract: In a sonar-based transducer system, single or multiple transducers may collect and transmit data to a management module for analysis to optimize and/or control a process. Secondary sensors may provide additional product data for analysis. Historical data may be stored in a data library for future reference. Real time data may be transmitted to a control center via a virtual dashboard.

Abstract: A method of detecting objects includes transmitting toward an object a first acoustic signal including a first set of pulses including a first number of pulses, and checking if a first echo signal resulting from reflection of the first acoustic signal is received with an intensity reaching an echo detection threshold. If the intensity of the first echo signal reaches the echo detection threshold, the distance to the object is calculated as a function of the time delay of the first echo signal. If the intensity of the first echo signal fails to reach the echo detection threshold, one or more further acoustic signals are transmitted including a set of pulses wherein the number of pulses is increased with respect to the number of pulses in said first acoustic signal.

Abstract: Various implementations described herein are directed to a marine device including a waterproof housing including a mounting element. The housing is configured to be at least partially submerged in the underwater environment and the mounting element is configured to attach to at least one of a vessel or a trolling motor. The marine device also includes at least one transducer and an acoustic speaker positioned within the housing. The at least one transducer is positioned and oriented within the housing such that the at least one transducer is configured to transmit one or more sonar beams into a portion of the underwater environment when the housing is at least partially submerged. The acoustic speaker is positioned and oriented within the housing such that the acoustic speaker is configured to emit the fish attraction sound into the underwater environment when the housing is at least partially submerged.

Abstract: An electronic apparatus is disclosed. A display is configured to be able to change brightness of the display. A water detector is configured to detect water. A communication unit is configured to be able to communicate with another electronic apparatus. At least one processor is configured to, when the at least one processor detects, using the water detector, that at least part of the electronic apparatus is located in the water and detects, using the communication unit, that the another electronic apparatus is not located in the water, brighten the display compared with that when the at least one processor detects, using the water detector, that the at least the part of the electronic apparatus is located in the water and at least part of the another electronic apparatus is located in the water.

Abstract: An apparatus, system and method for measuring quantity of a material are disclosed. One or more sensors are used to measure the quantity of the material are measured and error causing parameters are also measured. Error causing parameters are processed by executing one or more correction methodologies to determine a correction output. The quantity of the material is measured by using the correction output. One or values associated with the quantity of the material are measured and displayed. The one or more values are transmitted to a server and informative messages are received from the server.

Abstract: Methods are provided for determining an exhaust fluid level in an exhaust fluid storage tank based on a signal, and a quality of the signal from an exhaust fluid level sensor located in the exhaust fluid tank of a vehicle.

Abstract: A material level indicator includes a probe, first and second signal compensating units, arranged at first and second ends of the probe respectively, and a controlling module arranged at the first end and includes a signal processor, a signal emitter, and a signal receiver. The second end is opposite to the first end. The signal processor is connected to the signal emitter and the signal receiver. The signal emitter emits an electromagnetic signal from the first end to the second end of the probe. The first and second signal compensating units reflect the electromagnetic signal, and the signal processor generates first and second time interval differences according to the reflected electromagnetic signal received by the signal receiver. The signal processor calibrates an environmental coefficient and indicates a dielectric coefficient of the material according to the first and second time interval differences respectively.

Abstract: The invention relates to a length measuring device having a measuring slide, a linear guide in the form of a hollow profile, on which the measuring slide is mounted so it is externally displaceable, an inner slide, which is mounted so it is displaceable in the interior of the hollow profile, a magnet assembly, which magnetically couples measuring slide and inner slide, so that the inner slide follows every movement of the measuring slide along the hollow profile, a measuring unit for measuring the position of the inner slide, and a display, which is visible in the exterior of the hollow profile, of the length ascertained by the measuring unit in accordance with the measured position of the inner slide. The measuring unit has a sound source, a sound receiver, and a control and analysis unit connected thereto.

Abstract: A touch panel device includes a detector, a display unit, and a controller. The detector detects one or more touches on a display screen. The display unit displays, on the display screen, one or more touch-detected marks at least around a position of the touch, each touch-detected mark indicating that the touch is detected. The controller controls a color of the touch-detected mark to be different between a case where the detector detects only a touch at a single position and a case where the detector detects touches at two positions.

Abstract: A sensor probe for monitoring levels of chemical solutions used in automatic car washes, the sensor probes comprising an elongated sensor probe tube able to be installed by being inserted into a hole in the top of storage drums. A sealed enclosure mounted to the top of the tube is thereby positioned above the associated tank, which enclosure contains a liquid level sensor and a wireless receiver/transmitter able to send data to a computer/display/and web server.

Abstract: Embodiments of the present invention provide an ultrasonic probe having an increased number (e.g., twelve) of ultrasonic sensors for measuring the level of liquid within a sealed container. The ultrasonic probe includes a neck tube that enables the ultrasonic probe to be used with existing, standardized container fittings despite having an enlarged barrel to accommodate the increased number of ultrasonic sensors. Embodiments of the present invention also provide a system and method in which ultrasonic sensors within an ultrasonic probe are activated one at a time to reduce crosstalk between the ultrasonic sensors and their wiring.

Abstract: A fishfinder data display device is provided. The display device includes a memory for storing fishfinder data obtained by a fishfinder detecting underwater and a location where the fishfinder data is acquired so as to associate the fishfinder data with the location, a display unit for displaying an image created based on the fishfinder data, and a controller, when an operator performs a specifying operation to a predetermined part of the image displayed by the display unit, for reading the location corresponding to the fishfinder data based on the specified predetermined part of the image from the memory, and causing an autopilot device to execute an autopilot operation with the location as a destination.

Abstract: An apparatus for measuring a filling level of a urea container by determining distance using sound waves (ultrasound) emitted by a sensor and echoes thereof, includes a urea container bottom and a sump with an overall height. The sump is adjacent the urea container bottom and located below the level of the urea container bottom. The sump is connected in an open manner to the urea container and bounded at the bottom by a sump bottom. The sensor is accommodated in the vicinity of the sump and, with a sound-emitting surface for emitting sound waves and receiving echoes of the sound waves, is fitted in the urea container with the sound-emitting surface of the sensor at most adjacent the level of the urea container bottom. A motor vehicle having the urea container is also provided.

Abstract: In a method for logging the location of a fluid depth in a wellbore, an acoustic event is allowed to take place in a specific manner at the ground surface. This acoustic event generates pressure waves. The pressure waves travel in the wellbore downward. The pressure waves traveling in the wellbore are reflected at least also at the fluid depth. At the ground surface, the pressure waves traveling there out of the wellbore are picked up and the time of travel since the acoustic event is measured. The picked-up and measured pressure waves are analyzed and, together with the associated time of travel, the location of the fluid depth is deduced. The acoustic event generates a signal pattern having a predetermined, time-variable frequency spectrum. The signal pattern is emitted as vibration event into the wellbore, travels downward, and is reflected. At the ground surface, the picked-up signals originating from the wellbore are analyzed.

Abstract: A measurement instrument comprises a sensor circuit comprising a drive circuit for transmitting a pulse signal at a target of interest and a receive circuit receiving reflected echoes of the pulse signal and developing an analog signal representative of the reflected echoes. An analog processing circuit is operatively coupled to the sensor circuit for receiving the analog signal and comprising a gate for selectively transferring the analog signal to a comparator that compares the gated analog signal to a select threshold level to develop a data signal representative of location of the target of interest. A programmed digital processing circuit is operatively coupled to the sensor circuit and the analog processing circuit and comprises a measurement module to control the drive circuit and evaluate the data signal to determine material location.

Abstract: A fuel measurement system and method that can determine the fuel level in a vehicle fuel tank, even when the fuel is sloshing, splashing, or experiencing other dynamic conditions. Generally speaking, the system and method use different fuel measuring techniques to address different fuel tank conditions. For example, during normal conditions a traditional fuel level sensor may be used. During dynamic conditions, such as when the vehicle is experiencing significant acceleration, maneuvering, inclination, yaw rate, etc., the system may employ other measuring techniques that are better suited to address such an environment. One measuring technique that may be used is a consumption-based technique that uses fuel usage signals from one or more fuel injector sensor(s) to determine the amount of fuel consumed, and then subtracts that amount from a previous fuel level reading.

Abstract: The present invention discloses an acoustic borehole source and method of using the source for generating elastic waves through an earth formation that may be used for logging or permanent installations. The acoustic source is comprised of a first motorized reaction mass and at least two pads, each pad connected to the sonde and the motorized reaction mass using pushing rods. In an alternate embodiment, the source has a first and second motorized reaction mass and at least two pads. The motorized reaction masses may be activated to allow the pads to move at an angle ? relative to the axis of the sonde. In a third embodiment, the acoustic borehole source includes additional pairs of motorized reaction masses so that pads may be independently activated.

Abstract: Methods and apparatus for generating a signal with a signal generator comprising a tool body disposed in a tubular member. A first and second electromagnets are disposed within the tool body such that the second electromagnet is opposite the first electromagnet. A power supply selectively provides electrical current to the first and second electromagnets so as to displace the tubular member and generate a signal in the surrounding formation.

Abstract: A device for measuring the level of a fluid in a container by means of a sound guide tube and an ultrasonic transducer disposed inside the container mounted in a fluid feeding device within the container.

Abstract: The present invention provides for a system and method for measuring the height of a guest at a theme park, including employing an ultrasonic emitter and sensor to determine height. The park may have a plurality of different predetermined minimum height ranges or categories for certain rides and attractions, which must be met by a guest before the guest is allowed to participate. The results of the height measurement are provided on indicia and given to the guest to use at rides throughout the park. The device may be a wristband affixed to the guest, and displaying a color or symbol based on the height of the guest. The guest would be allowed to participate in an attraction provided the color code matches the minimum requirements of the attraction. This present invention may eliminate the need to check the height of the guest at each ride.

Abstract: Systems, devices and methods are provided for monitoring water temperature. One method includes receiving water temperature data and graphically presenting the data. The data is presented having the water temperature data graphically differentiated to indicate when the water temperature data crosses a threshold temperature.

Abstract: A screen on which water depth information obtained from an echo signal is historically displayed and a screen on which fish school detection information obtained from an echo signal is displayed, are displayed side by side on a display screen of a display instrument or either one is displayed by switching. Thus, a large amount of information is displayed on a limited space of a small display instrument efficiently and effectively and to be easy to see. Further, when a water depth value becomes a set value of an alarm water depth mark or less, an alarm is displayed on the display screen of the display instrument, and an alarm is given by sound. At the same time as this, the brilliance of the display screen is raised to the maximum brilliance to make the screen brighter, so that the contents of the alarm are made easy to see. Thus, quick measures can be taken in an emergency.

Abstract: A screen on which water depth information obtained from an echo signal is historically displayed and a screen on which fish school detection information obtained from an echo signal is displayed, are displayed side by side on a display screen of a display instrument or either one is displayed by switching. Thus, a large amount of information is displayed on a limited space of a small display instrument efficiently and effectively and to be easy to see. Further, when a water depth value becomes a set value of an alarm water depth mark or less, an alarm is displayed on the display screen of the display instrument, and an alarm is given by sound. At the same time as this, the brilliance of the display screen is raised to the maximum brilliance to make the screen brighter, so that the contents of the alarm are made easy to see. Thus, quick measures can be taken in an emergency.

Abstract: The invention concerns a device for measuring liquid level, comprising a detection set (Si) including two piezoelectric cells (10, 12) associated with control means for transmitting ultrasonic waves respectively opposite a reference reflector (16), located at a known distance (D) from the associated cell, and from the top surface (14) of the liquid, and processing means for determining the level of liquid by operating on the respective propagation times of the ultrasounds emitted by each of the two cells (10, 12). The invention is characterised in that it comprises means for defining, after the device has been charged, an initialising phase (1100, 1100 bis) during which the control means control the piezoelectric cells (10, 12) such that the ratio between the excitation rate of the reference cell (12) and that of the level-measuring cell (10) is higher than the ratio between those same rates during the subsequent stabilised measuring phase (1300).

Abstract: Disclosed herein are processes for detecting the location of an interface between phases. In one embodiment, the process comprises: introducing a reaction mixture into a vessel wherein the reaction mixture is the product of an at least two phase interfacial reaction, and a difference in densities between at least two of the phases is less than or equal to about 1 g/cc, separating the reaction mixture into the phases with an interface located therebetween, measuring electrical inductance of the reaction mixture at different latitudinal locations; and determining the location of the interface.

Abstract: An apparatus for detecting a fluid level is disclosed, which includes a coaxial sensor having a pair of conducting tubes positioned with respect to each other in spaced coaxial arrangement, a coaxial transmission line connected to the sensor, a means for injecting a standing wave into the coaxial sensor, a summer for summing the injected wave and a reflected wave connected to the sensor, a means for adjusting the frequency of the injected wave in response to the voltage and phase of the summed signal, and a processor for processing and displaying the frequency as a representation of the level of the fluid. A method for detecting the fluid level is also disclosed.

Abstract: A device for measuring a fill level of a liquid includes an ultrasonic sensor with two sensor elements. One of the sensor elements determines the echo time of an ultrasonic wave to a float which follows the liquid level. The other of the sensor elements determines the echo time of the ultrasonic wave up to a measuring reflector arranged at a known distance from the other of the sensor elements. An evaluation unit compares the echo times and determines the fill level of the liquid from the ratio of echo times and from the known distance to the measuring reflector.

Abstract: A device and process for measuring tide levels comprising a guide tube having its lower open end immersed below the lowest tide level, a transducer positioned substantially at the upper end of the guide tube for generation and reception of electrical and acoustical signals, a switching circuit for isolating the transmitting and receiving signals, and at least one branch tube provided near the upper portion of the guide tube. The length of the branch tube is determined by a formula that takes into account the wavelength and velocity of the sound signals, and the diameter of the guide tube is determined by a formula that takes into account the wavelength of the sound signals.

Abstract: A method and apparatus for determining the surface level of a given body using acoustic ranging that incorporates processes natural to human beings to improve identification of the echo from the water surface when spurious echoes might otherwise overshadow it. An acoustic beam is transmitted toward the surface where it is reflected. The beam also reflects off various interferences creating spurious reflections or echoes. The echoes from the surface as well as the spurious echoes are then received. Each echo is then evaluated according to several criteria, in order to determine which echo is associated with the surface.

Abstract: For monitoring a predetermined level of a liquid in a container an ultrasonic sensor is fitted on the outer surface of the container wall at a measurement point situated at the height of the level to be monitored, said sensor containing an ultrasonic transducer having a diaphragm in contact with the container wall. The components of the ultrasonic sensor including those of the ultrasonic transducer are grouped together in a sensor block which is releasably connected to an adapter secured to the container wall, this adapter being configured so that it can be secured in any way required to containers of differing shape and/or material.

Abstract: A sensor for determining both the presence of a liquid in a container or conduit, and identifying its type has a sensor housing body containing both a pair of piezoelectric elements used as the transmitter and receiver of ultrasonic waves directed across a gap therebetween in an ultrasonic liquid presence detecting circuit and a pair of electrodes exposed to any of such liquid in the gap used in a circuit for identifying the liquid type. The liquid identification circuit is either of the capacitance type, which produces a variable amplitude output signal depending on the type of liquid in the gap between the two electrodes, or operates to measure the difference in response time between pulses applied to each of the electrodes with one serving as a reference.

Abstract: The invention discloses a level measuring device which can be made up from components. It comprises a sonic or ultrasonic transducer which is arranged in a first housing and forms a self-contained functional unit; the electrical circuit arranged in a further separate housing forms a second functional unit. The functional units are so constructed that they can be assembled from the various components to a complete level measuring device in accordance with the required use conditions by arrangement of a steel plate above the sonic or ultrasonic transducer, or by potting with a commercially usual potting composition, or the selection of two different similar housings for receiving the sonic or ultrasonic transducer or the arrangement of selectively different but dimensionally identical sonic or ultrasonic transducers, and the selective mounting by means of a loose flange on a container, or by means of a suspension bracket in the interior thereof or above a drain.

Abstract: An ultrasonic liquid level gauging sensor has a transducer at the lower end of a tube that is filled with liquid to the same height as liquid outside the tube. The sensor has an axial rod extending along the tube and supporting several calibration reflectors. The rod enables the sensor to be used at high tilt angles.

Abstract: In one aspect of the present invention, an apparatus for measuring the height of liquid contained in a storage tank is disclosed. A tube is disposed inside the tank. A float is disposed inside the tube and is buoyed on the surface of the liquid. An ultrasonic transducer is disposed inside the tube. The ultrasonic transducer emits ultrasonic pulses toward the float, receives the reflected ultrasonic pulses, and responsively produces an echo signal. The float has a top portion and a bottom portion separated by a cylindrical portion. The bottom portion including an spherical surface which receives the ultrasonic pulses. The spherical surface has a predetermined radius which is a function of the inside diameter of the tube, the height of the cylindrical portion of the float and the outside diameter of the cylindrical portion of the float. A temperature sensor monitors the temperature of the liquid and produces a thermometric signal in response to the liquid temperature.

Abstract: To determine the depth of a body of water, ultrasonic pulses are transmitted from a point above the water at a known distance. Reflections from the water are received and the time of each of the leading edge of the reflections and the trailing edge are recorded as well as the amplitude. This information is used to sort the reflections and the most significant reflections are used to calculate the level of the water.

Abstract: An ultrasonic liquid-level sensing system has a sensor with a number of reflectors mounted one above the other along the length of a tube that extends upwardly from a transducer and is filled with liquid to the same height as outside the tube. Liquid height is calculated from the difference between the arrival times of the pulses reflected from the two uppermost submerged reflectors and the difference between the arrival times of pulses reflected from the surface of the liquid and the uppermost submerged reflector.

Abstract: A method for measuring the temperature-compensated change in the height of a surface of a liquid. The method positions an acoustic signal transducer for emitting and receiving acoustic signals below the surface of the liquid, positions a quasi-static reference device with a fiducial such that the fiducial lies within a predetermined range below the surface of the liquid, and positions one or more fiducials below the surface of the liquid to establish points separated by known distances. The transducer emits acoustic signals, and receives their reflections. The travel times of the reflections from the liquid surface and the fiducials are used to calculate changes in travel times during the measurement period, to estimate the speed of sound in the liquid, to correct for temperature-induced changes in the travel times, and to obtain a temperature-compensated change in travel time to the liquid surface.

Abstract: In a level measuring device for containers filled with fluid, preferably tanks in tank installations, the fill level height h is determined from the transit time of ultrasound pulses which are emitted by first sound pulse transmitters along a main measuring path extending from the bottom region of the tank to the fluid surface and are reflected from the fluid surface to first sound pulse receivers. Temperature sensors are provided for finding the temperature distribution throughout the fill level height h. Processing the measurements provides a mean temperature TM in the fluid volume. In addition to the main measuring path there is a reference path in the fluid volume, with second sound pulse transmitters and receivers and a reference temperature sensor for measuring a reference temperature T.sub.Ref. The reference path makes it possible to find the sound velocity v*(T.sub.Ref) in the fluid volume at the reference temperature T.sub.

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: An ultrasonic method and apparatus for measuring liquid level in a vessel employing an acoustic waveguide (16) connected to an ultrasonic transducer (14) and the vessel (18). Guiding means (24) situated inside a vessel (18) directs the acoustic energy pulse to a surface (22) of the liquid. The acoustic energy pulse is reflected from the surface (22) and returned along the guiding means (24) to the acoustic waveguide (16). A pulser/receiver (10) connected thereto measures the reflected acoustic energy pulse for determining liquid level from the transit time.

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 hand-held underwater distance measurement device has a first end having a waterproof housing which houses a digital display and a suitable electronics package, a second end housing a transceiver, a middle section having a pair of rectangular telescoping rigid tubes with a spring lock clip for fixing the relative locations of the tubes at two or more locations via the provision of holes in each of the tubes, and a flexible conductor for coupling the transceiver and the electronics package. The upper of the pair of telescoping rigid tubes is mechanically coupled to the waterproof housing, while the lower of the pair is coupled to the transceiver, which in one embodiment is rotatable relative to the lower tube to permit horizontal scanning. In using the device, the transceiver is immersed at least six inches below the water surface while grasping the device by a hand grip located just below the electronics package housing.

Abstract: A system for sensing the level of contents in a container is disclosed. A tubular member is vertically disposed in the container and sealed from the contents of the container. A marker located in the tubular member and generating a peripheral polarized magnetic field, is levitated at the height of float means located around the tubular member buoyed on the contents of the container and generating a polarized magnetic field within the tubular member of like polarity beneath the polarized magnetic field of the marker. A depth transducer located at one end of the tubular member forms part of a pulse-echo ranging system which calculates ranges on the basis of a time lag between emission of an ultrasonic signal by the depth transducer and receipt of at least one return echo signal from the marker in order to determine the depth of the marker in the tubular member, and indirectly, the level of contents in the container.

Abstract: The invention relates to a method and an apparatus for investigating a filling of liquid in a container, e.g. a fuel tank in respect of actual volume, density, temperature, opacity or other condition. From an emitter (19) at the bottom of the container there are emitted pulses of ultrasonic waves which are reflected by one or more horizontal border faces (17, 21) of the liquid and returned to the bottom of the container and detected by a receiver (20) there. The passage times of the reflected signals are compared with the passage times of direct and not-reflected signals that are detected by a plurality of receivers (1, 2, 3, 4, 5) placed above each other in fixed known positions. The result of said comparison is made the basis of a calculation of the sought quality. Measurement of the passage times, comparison, calculation and exposition of the result takes place by the use of electronic or data equipment (23).

Abstract: A device for determining the depth below the ground surface of a working member of an earth moving equipment, comprises a sensor for transmitting ultrasonic signal from underneath and toward the ground surface and for receiving a portion of the signal reflected from the ground surface. The sensor is positioned underneath the ground surface in fixed spatial relationship to the working member such that the sensor means is under the ground surface when at least a portion of the working member is under the ground surface. A circuit is provided for processing the received reflected signal to thereby indicate the depth under the ground surface of the working member, whereby the depth is proportional to the time of travel of the signal to the ground surface and the reflected signal to the sensor means.

Abstract: A system is provided for the detection of an unsuitable water condition in which either large globules of solid material or bait fish suspended in the water beneath a vessel adjacent the hull of the vessel are detected and the associated depth sounding device is inhibited from providing a depth output. This eliminates the display or annunciation of erratic depth data, or the use of erratic data for closed or open loop control systems. In one embodiment, the unsuitable water condition is sensed through the detection of returns in a short water column adjacent the hull. In a further embodiment, returns from the water column coupled with receiver gain being open above a predetermined threshold provide the indication of the presence of the unsuitable water condition.

Abstract: Acoustic delay means are interposed between the face of a transducer and the bottom of a vessel, with the delay being equal to or greater than the shallowest depth the associated depth sounder capable of, whereby subtracting out the depth associated with the acoustic delay, the water under the vessel can be measured down to zero feet. In a preferred embodiment, a water column is utilized as the delay media, with the transducer being mounted at the top of the water column and with the water column being terminated at the bottom of the boat. The transducer pulses are projected through the water/hull/water interface to the water beneath the vessel. For digital depth sounders, the depth associated with the water column may be subtracted out to give the zero reading.

Abstract: An improved microprocessor-controlled sonar depth sounder, which is automatically operative to detect and lock to the bottom of a body of water, fill in the display below the detected bottom, change display scales in response to the detected bottom going off-scale, and reformat the entire display in response to a scale change. A memory is provided for storing target data up to the operable depth limits of the device, thereby allowing display reversing and display expansion or "zoom" of a predetermined portion of the display selected by a zoom cursor. The zoom or cursor is variably positionable at different depths. The device employs an improved variable sensitivity amplifier. Also disclosed is an improved water-resistant switch construction for marine electronic equipment.

Abstract: Apparatus and a method for displaying depth sounding data with nautical range are disclosed for use on vessels or the like, the device including a transceiver for transmitting an acoustic signal downwardly through surrounding water and for receiving echo signals, a motion sensor for determining nautical distance, a microprocessor for storing and conditioning the echo signals and distance signals and a display device for providing an XY display of underwater conditions represented by the echo signals. Range display means associated with or included in the display device and operated by the microprocessor display nautical range of a selected and preferably adjustable point on the X axis. The microprocessor includes a range memory stack, a stack manager and an internal register for storing bytes or distance data for successive vertical scans. The device also preferably includes a differential temperature sensor.