Abstract: An electronic unit having three connectors connected to three other connectors which constitute the terminal parts of respective bundles of electric cables. A first bundle relates to cables connected to the actuators, sensors and devices installed in the bodywork of the vehicle, a second bundle relates to cables connected to the actuators, sensors, and devices installed in the engine of the vehicle, and a third bundle relates to cables connected to the actuators, sensors, and devices installed in the air intake assembly. The unit is carried by a body of the air intake assembly.

Abstract: Frequency-modulated wave trains are used in target locating by means of transmitted pulses and evaluation of portions reflected by the target in relation to bearing, distance and speed, wherein the pulse length and bandwidth of the transmitted pulse are pre-selected. The received signals are evaluated in Doppler channels by calculation of the ambiguity function. To make possible an increase in accuracy of the speed determination with the same number of Doppler channels, the frequency of the wave train within the bandwidth is calculated in accordance with an irrational function, the exponent of which has a value between 0 and 1. The smaller the value, while keeping the same pulse length, the greater the Doppler sensitivity. This method for modulating the wave train in the transmitted pulse can be advantageously employed for target identification by means of sound waves and electromagnetic waves.

Abstract: Apparatus and a method using ultrasonic signals to determine the distance between the displacement of two points in space. An ultrasonic distance measurement unit (1) generates frequency modulated ultrasonic waves using binary shift keying. The signals are transmitted by the transmitting transducer (2) towards a reflector assembly (30), preferably comprised of two reflectors (31, 32). One of the reflectors (31) is smaller than the other reflector (32), and the smaller reflector (31) is positioned in front of the larger reflector (32). The reflected signals are received by the receiving transducer (3). The unit (1) phase digitizes and processes the received signal by recording time stamps of zero-crossings of the received signal. The speed of sound may be determined by a temperature measurement system (5) and/or by measuring the transit time difference between the two reflectors (31, 32) of the assembly (30).

Abstract: A warning device is provided for use in an electric vehicle which includes a frame member and ground engaging wheels operative mounted relative to the frame member. An electric motor is operatively connected to the frame member and the ground engaging wheels for supplying rotational motion to the ground engaging wheels. A switch member is provided for selectively energizing the electric motor. An indicator member is provided for indicating to an operator that the electric vehicle has completed a preparing to start operation. The switch member may be a switch for operatively connecting the electric motor to a source of power. The indicator member may provide a visual display or an audible sound for warning the operator.

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: This invention provides a vehicular proximity sensing system having a plurality of preferably utrasonic distance-detector devices disposed around the vehicle's periphery and connected with a simulated vehicle display on the dashboard which display includes visual means to alert the driver to the close approach of an external object to the vehicle, in which the distance-detector devices use a coded signal characteristic of the vehicle and recognizable by the system, so as to distinguish reflections from interfering signals from other vehicles. In a preferred embodiment, the simulated vehicle display is provided with tricolor LED warning devices, wired to a computer or a box holding the LED's, and these can be illuminated by optical fibres and a vehicle representation is illuminated by a luminescent panel. A valuable option is a remote and an externally audible warning device enabling a parked vehicle to be provided with defensive means against being hit by another vehicle.

Abstract: The invention relates to a simple, cheap sonar system with high image rate, for the detection of objects and the imaging of sea bottoms. It consists in transmitting n uncorrelated successive codes in a sector of angular width exactly equal to n times the angular width of the reception sector .theta..sub.R, the reception antenna continuing to turn during this time whilst the first signal transmitted has not yet reached the maximum range dmax, and in receiving, in the sector of angular width .theta..sub.R, the echoes of these n codes, coming from n propagation regions which are adjacent in relation to the reception axis, and lying between 0 and dmax in space, each of them having a depth equal to dmax/n.

Abstract: In a time continuous transmit active sonar system the frequency of the transmitted waveform is interrupted at predetermined intervals so that a frequency discontinuity in the transmitted waveform occurs at each interruption. The starting and ending frequencies at the beginning and end of the interruptions provide indications for properly resolving the range/Doppler ambiguity that is inherent in prior continuous transmit sonar systems. The transmitted signal may be frequency modulated. Further, the frequency of the transmitted waveform may be rapidly changed and/or multiple frequency waveforms may be transmitted within the same time interval. An existing passive sonar detection system may be modified to include an active continuous transmit sonar system whose echo returns may be processed by the passive system, thereby achieving benefits over conventional active pulsed sonar systems.

Abstract: A method of acoustic processing for acoustic image classification of an underwater target from a set of known target hypotheses is provided. An acoustic waveform is transmitted into a test volume of water containing the target to be classified. The test volume is divided into test cells such that each test cell contains a portion of the target or scatterer that will scatter the transmitted waveform. Scattering of the transmitted waveform at each test cell is described by a scattering coefficient that is unique for each of the targets in the set of known hypotheses. Accordingly, the scattering coefficient serves as an identifier of the target to be classified. The relationship of the set of scattering coefficients for each of the known target hypotheses is provided by a known covariance matrix. An acoustic receive array receives a portion of the scattered waveform from each of the test cells in the test volume.

Abstract: Doppler insensitive waveforms, such as portions of hyperbolas having the same asymptotes, may be used to modulate pulses or sub-pulses of energy for probing a determined environment so that when the modulated energy is transmitted and received, the received energy may be processed, such as by correlation with the transmitted energy without regard to any Doppler frequency shift between the transmitted energy and the received energy. The Doppler frequency shift may have been imparted by reflection of the transmitted energy from an object having a relative radial velocity with respect to a sensor of the received energy. Also included are apparatus for processing received energy by correlation with transmitted energy, a method for modulating energy that may be transmitted and a method for detecting an object without regard to Doppler frequency shift or relative radial velocity.

Abstract: Apparatus and method for providing increased gains in detection and classcation of active sonar targets while concurrently preventing target cognizance of detection. Operation starts with transmission of a sequence of FM slides as subpulses alternately up slide, down slide, up slide, etc., while varying randomly the start frequency of each. Subpulse lengths short enough to avoid overlap of echoes from multiple major reflectors are used. Each slide is started at a randomized frequency. Just enough bandwidth is used on each slide to achieve the range resolution desired for searching. Considering only the individual subpulse bandwidth, subpulses are transmitted throughout the systems total bandwidth. Enough subpulses are transmitted to achieve the bandwidth/time product desired for searching.

Abstract: The difficulty of making Doppler shift velocity measurements in a chirp pulse echo ranging system is overcome by employing a pulse frequency compression filter, suitably a SAW compressor 45, having individual outputs 64, 65, 66, 67 respectively relating to adjacent contiguous frequency bands A, B, C, D, (FIG. 3) each having a bandwidth approximately equal to the chirp frequency swing. Signal detection and processing means 70 senses the occurrence of a compressed pulse on any of the outputs and measures the amplitudes of signals on all the outputs. A computer then computes the Doppler shift from the amplitude ratio of the sensed signals to adjacent frequency bands, determines the target velocity therefrom and uses the result also to correct the range measured by the counter 5.

Abstract: An electric rearview mirror system for a motor vehicle, in which drive mechanism, which have a function of turning the mirrors of the mirror units of said system and a function of moving the case of said units back and forth between a use position and a put-away position, are provided in said cases housing said mirrors, so that said mechanisms are operated in prescribed manners by a plurality of kinds of command signals supplied from manipulation means provided in the body of said vehicle, characterized by comprising a transmission means provided in the body of said vehicle to convert said command signals into serial signals and transmit said serial signals to said mirror units through electric wires; and control means provided in said cases to operate said drive mechanisms in said prescribed manners on the basis of said serial signals received by said control means from said wires.

Abstract: A sonar system having a sonar transmitter which is programmed to broadcast wo sets of several increasing frequency signals, with the frequency gap between each set thereof sufficient to cause them to distinguish between deep and shallow water targets, respectively. A heterodyne receiver receives target echoes of said sets of several frequency signals and converts them to two sets of identical frequency signals which are then readout as a single continuous target display signal.

Abstract: A sonar system having a transmitter for successively broadcasting a pair of coustical signals having different frequencies, a programmer for determining the times said pair of signals are broadcast, a receiver for receiving said pair of signals after they have been reflected from a target, a programmer for effecting the conversion of said received pair of signals into a continuous unitary electrical signal having variable consecutive time periods which alternately contain the respective frequencies thereof, and a readout for displaying said continuous unitary electrical signal.

Abstract: A distance detecting apparatus has a transmitter for transmitting a cyclic output signal. The transmitter is digitally controlled to adjust the frequency of the output signal in relatively small increments through a band of frequencies. A receiver receives a cyclic reflected signal and has an adjustable center frequency of response. There is a device for adjusting the center frequency of response to correspond to the frequency of the output signal. The apparatus may have digital control for controlling the power level of the output signal. There may be a digital control for the gain of the receiver. The apparatus may also include a transducer for converting electrical signals to ultrasonic signals and include controls for adjusting the frequency of the output signal according to requirements of the transducer.

Abstract: An improved method and apparatus for precision ranging is described using a frequency-modulated signal source to stimulate creation of interference fringes at a rate proportional to absolute distance to a target. According to the invention, a low frequency modulating signal modulates a relatively high frequency signal source having a predetermined long coherent length compared to the distance to be measured. The resulting frequency-modulated signal is transmitted to the target to generate a reflected version thereof. Because of the long coherent length of the signal source, the transmitted frequency-modulated signal maintains spatial coherence as it travels to and from the target. Moreover, the low frequency modulating signal stimulates production of 360.degree. instantaneous phase differences between the transmitted and received frequency-modulated signals when these signals are superimposed. The number of these 360.degree.

Abstract: A volume is scanned with a raster scan about a center of rotation using a transmitter/receiver at a selected range while gating a range window on the receiver with a selected range differential. The received signals are then demodulated to obtain signals representative of a property within the volume being scanned such as the density of a tumor. The range is varied until the entire volume has been scanned at all ranges to be displayed. An imaging display is synchronously scanned together with the raster scan to display variations of the property on the display. A second transmitter/receiver with associated equipment may be offset from the first and variations displayed from each of the transmitter/receivers on its separate display. The displays may then be combined stereoscopically to provide a three-dimensional image representative of variations of the property.

Abstract: A continuous-transmission frequency-modulated (CTFM) scan converted sonar with improved capability for detecting swimmers, miniature submarines and other small intruders in harbors and inlets, and adjacent offshore structures. The system is microprocessor based and menu driven from an operator interactive touch screen. The system utilizes a fast fourier transform (FFT) based frequency analyzer for range discrimination. An area moving target indicator (AMTI) portion of the system cancels echo returns from stationary objects that otherwise mask the echo return of the moving targets. The AMTI causes the system to survey the search area for a number of consecutive scans and store the data. On successive scans, only target information that differs from the stored target map is displayed, thereby reducing clutter caused by surrounding terrain.

Abstract: Imaging apparatus including an array of transmitters for simultaneously transmitting more than two coded signal beams in different directions to cover different regions of a field of view, said beams being modified by objects within said field of view, signal means for providing individual coded signals to respective transmitters, at least one receiver for simultaneously receiving plural coded modified signals derived from the coded signal beams, and a processor for separating the plural coded modified signals of different codes and processing them into an image signal.

Abstract: Sonar ice thickness measurement comprises transmitting an AM and subsequent CW sonic radiant energy signals from the water toward the sonic signal reflecting ice cap. Reflection of the CW signal from the water-ice interface and reflection from the water-air interface of the modulating frequency, generated by non-linear or parametric effects in the water by the modulated transmit signal, causes the CW signal to be modulated to generate side bands at the modulating frequency on each side of the carrier frequency to provide an FM high frequency signal. Detection of the FM signal determines the time of arrival of the echo of said detected FM signal relative to the detection of the reflected modulated signal from the water-ice interface.

Abstract: In a color sonar system especially suitable for displaying fish echo signals, high and low frequency echo image signals are displayed utilizing colors corresponding to the echo signal strength, when the signal strength differences between the simultaneously received high and low frequency echo image signals are within a preset level range, when the differences between the high and low frequency echo image signals are outside the preset level range, the selected high frequency or low frequency echo image signals are displayed utilizing colors indicative of the differences in signal strength between the corresponding high frequency and low frequency echo signals.

Abstract: A low cost, effective electronic audio aid for the blind who have good hearing. The aid employs a hand held housing about the size of a flashlight which contains a battery power supply and electronic-audio circuit together with a somewhat directional audio speaker for emitting a low power, directional beam of acoustic energy having specially-shaped audio waveforms which when impinging on an object in the vicinity of the user return an altered, reflected characteristic sound signal which can be audibly discerned by the user to detect the presence of the object and its approximate location.

Abstract: A display system for fish sonar displays two ultrasonic echo signals of different frequencies from the left side to the central portion and from the central portion to the right side on the screen of a cathode ray tube. After the two ultrasonic echo signals are displayed on the entire screen of the cathode ray tube, the old echo signals are eliminated and the display is refreshed with new echo signals so that a picture of a school of small fish which is displayed by ultrasonic echo signals of high frequency can be compared with a horizontally adjacent picture of a large fish simultaneously displayed by ultrasonic echo signals of low frequency on a single cathode ray tube screen.

Abstract: A radar apparatus which includes a transmitter that generates a train of pulses arranged in groups of two, each group including a long pulse and a short pulse of different frequencies. These long and short pulses are separated in a receiver by a range gate which passes the pulses through the upper receiving channel when reflected from long ranges and the lower receiving channel when received from short ranges. The upper channel includes a filter which passes only the long pulses, which are frequency swept, and then compressed. The lower channel includes a filter which passes only the short pulses which are not frequency swept. The transmitter reverses the order of the pulses in adjacent groups. Alternatively, both the long and short pulses may be frequency swept. In either event there are adjacent pairs of swept pulses in contrast to known systems in which each swept pulse has immediately been preceded or followed by an unswept pulse.

Abstract: The receiver (3') of a laser range finder operating on the pulse propagation and including a transmitter unit (1) and a first receiver unit (2) is sampled by a spike pulse (5) derived from the transmitter pulse in such a way as to produce a low-frequency representation (10). The non-linearity of the phase modulation of this spike pulse, which is detrimental in very accurate measurements taken over long distances, is eliminated in that the oscillations of high-frequency oscillator (8) are supplied to a second receiver unit (2') in which they are scanned by the same spike pulse (5) and are then also suitably transformed into a low-frequency representation (10'). A counter (12) then counts the low-frequency zero-passages of the oscillator, beginning with the onset of the low-frequency cycle, thereby eliminating all errors (FIG. 1).

Abstract: An intruder detector system employing Doppler radar consists of an encoder for modulating RF pulses with a cyclic pulse code, the code being cycled at a frequency equal to the RF pulse frequency and the pulses being modulated on a VHF carrier for transmission along one of a pair of parallel radiating cables. The signal received from the other cable is demodulated and digitized by a zero crossing detector functioning as a 1-bit analog-to-digital converter. A bank of exclusive-OR gates functioning as 1-bit correlators then simultaneously correlates each successive bit of the digitized signal with the values of the respective bits in each fixed position of the transmitted code sequence.

Abstract: A sonic ranging and/or object detection system, particularly useful for the blind, periodically employs widely different pulse frequencies in order to distinguish between objects located directly in front of the energy transmitting portion of this system and those located to either side. The higher frequency pulses produce a relatively narrow sonic energy beam width for detecting centrally located objects and the lower frequency pulses produce a relatively broad sonic energy beam width for detecting lateral or off-center objects. One or more time-related audible tones are superimposed on each of the pulse frequencies for range determining and/or object distinguishing purposes.

Abstract: A system measures the (x, y) coordinates of a target, for example, a pointed finger on a flat surface such as a rectangular plate. A pair of ultrasonic transducers are placed on the plate so that one transducer is located at each of the two left corners of the plate or at each of the two top corners of the plate. The transducers transmit short ultrasonic pulses which are reflected as echos off the target and then received by the transducers. The time elapsed between the transmitting of each pulse and receiving its echo is converted into distances between the transducers and the target, which distances are then converted into the target's (x, y) coordinates.The system is designed to clamp onto a number of flat surfaces, thereby allowing the system to be used with printed representations of keyboards, graphs, CRT monitors and standard television screens. The system is interfaced with any of a variety of computers and provides a signal representative of the location of the target to the computer.

Abstract: A sonar system comprises a vehicle (1) capable of moving over the bottom of an extent of water, with an emitter of acoustic pulses and a receiver of acoustic energy mounted on said vehicle. Signal processing and display circuitry (e.g. on board a surface vessel 2) are connected to receive signals representative of the acoustic waves emitted by the emitter, of the acoustic waves received by the receiver, and of parameters describing the motion of the vehicle. The signal processing and display circuitry generates an image of objects hidden in the water bottom on the basis of the signals. The emitter of acoustic pulses is provided with at least one parametric transducer having a spot radiation pattern capable of forming a plurality of channels that bathe spots of the water bottom in sound waves, and an electronic pointing system for scanning the channels.

Abstract: A detection system for imaging by sonar or radar signals. The system associates diversified transmissions with an interferometric base. This base provides an angular channel formation means and each signal formed in this way is processed by matched filtering in a circuit containing copy signals characterizing the space coloring obtained by the diversified transmission means. The invention is particularly applicable to side or front looking detection sonars.

Abstract: A bidimensional imaging system by echoes including a transmitting array and a receiving array. The transmitting array includes a row of transmitters (E.sub.1, E.sub.2, . . . , E.sub.i, E.sub.N) parallel to a direction Oz and the receiving array includes a row of receivers in a direction Ox. All the transmitters simultaneously transmit signals with different codes. The signals received are demodulated and the real and imaginary components of these signals are applied to two multiplexing circuits (61.1, 61.2). After modulation the multiplexed signals are applied to a Fourier transformation circuit (63), which sequentially supplies reception channels V.sub.k (.theta..sub.k) for the direction referenced by angle .theta..sub.k and which are stored in memories (66.1, 66.2). Other memories (70.1, 70.2) contain signals S.sub.i (.phi..sub.i) transmitted in an angular direction referenced by .phi..sub.i. The two pairs of memories (66.1, 66.2 and 70.1, 70.

Abstract: A sonar transceiver system and method includes an oscillator and programmable divider which are arranged to cause a transmitting transducer to transmit a plurality of four consecutive closely spaced tones in the manner of a pseudo-chirp. The receiver includes hard limiting means for converting received echo signals to binary signals and tone correlation and detection means including a shift register which compares samples of the binary received signal with a sample of a sine wave as hard limited which is carried on a storage register. A series of exclusive-OR comparator circuits effect the comparison and produce output signals of a desired magnitude when correlations are found. Switching means responsive to detection of the first of the transmitted tones causes the programming means to vary the divisors of the programmable divider to produce clock pulses of varying frequency to the shift register for the time and in the order of the transmitted tones.

Abstract: A sonar system for positive identification of certain resonant body targets such as mines. Two acoustic signals of different frequencies are transmitted toward the target and the acoustic returns are separated into the component frequencies, detected, and thereafter subtracted from one another. A signal, above a threshold value, resulting from the subtraction is indicative of a resonant body target and the indication is displayed and/or recorded.

Abstract: A system for detection by an echo containing transmission and reception sources for detection by acoustic waves in particular. A circular base with N columns T.sub.1, T.sub.2, -T.sub.i,-T.sub.N of electroacoustic transducers. To each column such as T.sub.i corresponds a transmission at the frequency f.sub.i. A switch makes it possible to change from transmission to reception. The signals received are applied to a channel forming device. For each channel such as V.sub.k the signals are filtered at frequencies f.sub.1, f.sub.2, -f.sub.N, which are applied to time offset circuits taking into account the base geometry and the channel direction. The signals obtained such as d.sub.i.k are applied to a display device which supplies the range, direction and speed of the targets detected. This is particularly applicable to underwater surveillance by sonar or radar.

Abstract: A device for the transit time measurement of electric, electromagnetic or oustic signals, particularly supersonic signals, of at least one predetermined frequency range, having a signal transmitter for the sending of measurement signals to an object and a signal receiver for the receiving of the measurement signals reflected by the object which have a substantially predetermined frequency corresponding to the frequency of the other signals sent and having a time measuring device for determining the transit time of the measurement signals between the signal transmitter and/or receiver and an object, from which the distance of the object from the signal transmitter and/or the signal receiver can be derived. A signal generator is provided both at least to trigger the signal transmitter and to control the signal receiver, and a filter stage for the tuning of the signal receiver in accordance with the reception frequency and for filtering out external frequencies is connected with the signal generator.

Abstract: Apparatus to detect and/or locate an inhomogeneity in a medium comprises a transducer to transmit frequency-modulated ultrasonic energy through the medium and a transducer to receive reflected energy. The transducers are connected to a phase-locked loop which maintains a required relationship between the phase of the transmitted modulation and the phase of the received modulation by adjustment of the modulation frequency. The modulation frequency adjustment is kept within predetermined upper and lower frequency limits so that the loop can lock only on to received ultrasonic energy which has travelled a distance within a predetermined region in the medium. The energy may be scanned across the region to produce a profile of the inhomogeneity, such as tissue at a certain depth within a limb.

Abstract: A digital pulse compression processor for reducing the processing loss in rget-echo signals caused by sampling time errors comprising a first processing channel for sampling the echo signal in accordance with pulses from a first clock signal and a second processing channel for sampling the echo signal in accordance with pulses from a second clock signal at the same sampling frequency as the first clock signal but with its pulses interlaced, in time, approximately midway between the pulses of the first clock signal to ensure that the largest sampling error will be one-quarter of a sampling period or less. The sampled signals in each channel are then digitized and compressed, and then processed to form the compressed signal envelope. The resultant signal envelopes from each channel are multiplied together to form a low-sidelobe narrow output pulse.

Abstract: A digital sonar system including a redundant receiver channel is arranged to operate substantially simultaneously in both F.M. and C.W. modes. Upon failure of one receiver channel the system reverts to a single mode or alternate modes on alternate cycles.

Abstract: In a method and apparatus for surveying for nodular targets of a grain size of 1 to 15 cm present on the sea floor, pulse waves in each of three frequency ranges of 3 to 4, 10 to 14 and 25 to 50 KHz are radiated onto the sea floor from a ship navigating on the sea. The reflected sound waves of the three frequency pulse waves are received and the reflexibilities of the respective sound waves are measured from the reflected sound pressures and the reflexibilities are composed. The population of the nodular targets is determined from the composed reflexibility and, as required, the grain size of the nodular targets can be determined from at least one of the ratio of the reflexibility of the sound waves of the frequency range of 3 to 4 KHz to the composed reflexibility and the ratio of the reflexibility of the sound waves of the frequency range of 3 to 4 KHz to the reflexibility of the sound waves of range of 25 to 50 KHz.

Abstract: An acoustic distance measuring device using a predetermined frequency shift keyed bit pattern as the acoustic signal transmitted and received. A phase lock loop detector is provided. Variations in lag from the time required for the loop to lock are eliminated and the remainder of the FSK bit sequence is detected and accumulated in response to changes in the phase detector output. Preferably the FSK bit sequence is generated via radio frequency transmitter from a first location and reproduced and transmitted acoustically from a second station back to the first station.

Abstract: An echo sounder including a unit for transmitting, into a medium, acoustic signals at two slightly differing high frequencies and in the form of pulses, resulting in the creation of an acoustic signal in the medium at a low frequency equal to the difference between the two high frequencies, and a receiving unit including a receiving transducer for receiving echoes of acoustic signals at the difference frequency and a display device for recording the echo signals in accordance with their travel times, the display device having a signal input which is connected with the low frequency receiving transducer, is further provided with a second receiving transducer responsive to high signal frequencies for receiving echoes of acoustic signals at at least one of the two transmitting frequencies, and a member connecting the second receiving transducer to the signal input of the display device.

Abstract: A fish detector capable of detecting species of fish. Two ultrasonic sounds at different frequencies and echoes are detected by receivers tuned to said different frequencies, respectively. The output signals from the receivers are converted into binary-coded signals and one of the binary-coded signal is divided by the other binary-coded signal. The ratio or quotient thus obtained is compared with a plurality of reference signals at different levels or strengths so as to detect whether or not the ratio or quotient is higher than the highest level or strength reference signal, lower than the lowest level or strength reference signal or between two reference signals at adjacent levels or strengths and subsequently to display in color depending upon a level of the ratio or quotient thus detected.

Abstract: 1.

Abstract: A system for measuring the depth of the ocean, or other body of water, from a moving vessel uses acoustical sounding from the vessel and enables improved bottom definition during high-speed vessel travel. A succession of pulses of different tone frequencies is transmitted from the vessel. The echoes produced when these tone pulses reflect from the water bottom are received at the vessel and are sorted according to frequency. This arrangement assures that the determination of the transit time of a pulse at one frequency is not confused by receipt of an echo at another frequency. The transit times of the several pulses and their echoes are measured for use in determining water depth.

Abstract: An ultrasonic ranging system for a camera includes an ultrasonic transducer responsive to a keying pulse for transmitting a frequency modulated burst of ultrasonic energy toward a subject. The leading half of the burst is a chirp whose frequency varies from a higher to a lower value; during the trailing half of the burst, the frequency remains substantially constant. The system also includes a receiver for processing an echo signal produced by the transducer on receipt of an echo within a predetermined time interval following the burst, and producing a range signal with a characteristic linearly related to the distance of a subject being photographed from the camera. A variable Q filter in the receiver filters echo signals produced by the transducer eliminates the need for a matched filter.