Abstract: A modulated pulse wave requires a pulse width of 1 nsec or less, but it is difficult that a PIN diode, which is conventionally used treats such a modulated pulse wave with narrow pulse width. In order to solve such a problem, it is an object to provide a pulse modulator, which outputs a modulated pulse wave with narrow pulse width and a pulse wave radar device, which can output a modulated pulse wave with narrow pulse width. In order to achieve this operation, the pulse modulator and the pulse wave radar device of the present invention differentiate a pulse from a pulse generating circuit so as to generate a differentiated wave with narrow width, and switch an oscillated wave from an oscillating circuit according to the differentiated wave so as to output a modulated pulse wave with narrow pulse width.

Abstract: A range detection apparatus comprising a transmitter adapted to transmit a microwave signal and a receiver adapted to receive an echo signal reflected from a target which corresponds to a portion of the transmitted signal; a signal generating means adapted to generate a drive signal to be applied to the transmitter to produce the transmitted signal, the signal generator producing a drive signal which includes a first signal frame comprising at least two frequencies and a second signal frame comprising at least two frequencies, the second signal frame differing from the first, and a processor adapted to process the echo signal together with the transmitted signal so as to determine the distance to the target that produced the echo signal. The apparatus may reduce ambiguity in range measurements and is particularly suited for Frequency Shift Key (FSK) radar in automotive, typically adaptive cruise control functions.

Abstract: A system and method for measurement are disclosed which may include providing an input command signal; convolving the input command signal with a plurality of impulse signals to produce a transducer drive signal; and activating a first pressure transducer with the drive signal to transmit a pressure wave output from the transducer.

Abstract: A micro-machined ultrasonic transducer substrate for immersion operation is formed by a particular arrangement of a plurality of micro-machined membranes that are supported on a silicon substrate. The membranes, together with the substrate, form surface microcavities that are vacuum sealed to provide electrostatic cells. The cells can operate at high frequency and can cover a broader bandwidth in comparison with conventional piezoelectric bulk transducers.

Abstract: A method of automatically performing a patch test for a sonar system is disclosed, where data from a plurality of overlapping 3D sonar scans of a surface as the platform is moved are used to compensate for biases in mounting the sonar system on the platform.

Abstract: Low probability of marine mammal impact (LPMMI) sound signals have a modulation component selected to reduce a behavioral response from a marine mammal from that which would occur when transmitting another sound signal having approximately the same time duration component, approximately the same bandwidth component, and approximately the same center frequency component as the LPMMI waveform but having a modulation component comprising a frequency modulation.

Abstract: The invention relates to an ultrasonic sensor with an adjustable detection range for use in gaseous media, preferably air. A threshold value generator generates threshold value curves that are fed to a comparator. The change in the detection range of the ultrasonic sensor, namely, the change in its switching point curve, is carried out by influencing the threshold value curves, whereby, in a selectable manner, the detection range can be adjusted either exclusively in the lateral extension of the sonic cone or else in the axial and lateral extensions of the sonic cone.

Abstract: A navigation system extends satellite navigation to divers, underwater vehicles, and surface vessels. The navigation system comprises a location reference unit and a plurality of sub-surface beacon units. The location reference unit includes a receiver to receive navigation signals from earth-orbiting satellites and/or an inertial navigation system. The location reference unit further includes processing circuits to communicate with to sub-surface beacon units and to transmit location information to said sub-surface beacon units, and a sonar transmitter to transmit location information to the sub-surface beacon units. The beacon units include processing circuits to determine the location of the beacon unit based on location information received from the location reference unit, and a sonar transceiver to receive location information from the location reference unit and to transmit location information to a diver unit to provide navigation assistance to the diver unit.

Abstract: The invention relates to an electro-acoustic transducer, particularly an ultrasonic transducer, comprising a plurality of electrostatic micro-cells of the cMUT type. The electrostatic micro-cells are arranged in homogeneous groups of micro-cells having the same geometrical characteristics. The micro-cells of each group have geometries different from the geometry of the micro-cells of the other group or groups.

Abstract: An oscillation generator for seismic applications includes a housing in which two coils are housed, both coils being acted upon with alternating current or electrical impulse and permanent magnets, and which is coupled via a coupling element to the object to be examined. The coils of the oscillation generator are each borne on a center leg of a packet of sheets cut in an E-shape, the free legs of the sheets associated with respective ones of the coils pointing away from one another. The coils are coupled to a block that can be linearly displaced in the housing. Securely attached to the side walls of the housing on a non-magnetic plate are permanent magnets that are disposed in the extension of the free end of the legs of the sheets, and the polarity of the exterior permanent magnets is reversed relative to the center permanent magnet.

Abstract: The factory-calibrated target discrimination threshold of a radar-based motor vehicle back-up aid is adaptively lowered under specified vehicle operating conditions to provide enhanced target detection sensitivity without causing false target detection. The threshold is initialized to the calibrated value on transition to the reverse range, and is thereafter subject to adaptive adjustment so long as a target is not detected and a high-clutter condition is not in effect. The adaptive adjustment is carried out by low-pass filtering the resultant data of the radar sensor, starting with a factory-calibrated noise baseline, to determine the current noise level, and then calculating the threshold from the noise level. The adaptive adjustment is suspended for an interval after target detection, and the threshold is increased when a high clutter condition is detected based on rate of change in vehicle speed.

Abstract: Systems and methods relate to an aircraft with a CAS that may be employed to enhance pilot awareness. The CAS may be employed on a formation member aircraft to provide a TA that is distinctive for an intruding formation member aircraft, as opposed to a TA provided as a result of an intruding nonmember aircraft. The CAS may also provide a plurality of status indications for aircraft engaged in airborne refueling, as well as aural indications of the present mode of operation for the CAS.

Abstract: A gunshot location system computes candidate gunshot locations [314] from angle-of-arrival information [304, 308] and time-of-arrival information [312] provided by acoustic sensors [300, 302]. In addition to an angle, each sensor calculates an angular uncertainty [306, 310] from impulses received at four or more microphones having rotational symmetry. An intersection of one or more time-of-arrival hyperbolas with one or more angle-of-arrival beams [322] is used to determine a candidate gunshot location. In simple environments, a location can be confirmed with just two sensors allowing sensor density to be significantly reduced, while in complex environments including reflections, blocking, and interfering acoustic events, the additional angle-of-arrival information improves location accuracy and confidence, allowing elimination of candidate locations inconsistent with the combined time-of-arrival and angle-of-arrival information.

Abstract: A seismic data acquisition system includes a plurality of sensors which are arranged so they can be used to measure translation movements of a medium with three independent spatial components and of the rotation movements around each of the three independent spatial components, thus forming a six-component system.

Abstract: Data recorded by directing a single sonar beam pulse towards a surface, and recording the reflected sonar signals with a large plurality of detectors, is used to generate a mathematical representation of the surface. The mathematical representation of the surface is chosen to fit the recorded data according to a criterion such as a least squares fit of a plane to the recorded data points. A mathematical representation of on object is built up from a number of non-overlapping mathematical objects such as triangles, each triangle joined to adjoining triangles to form a continuous surface in three dimensions. Images of such mathematical representations are then presented to the observer.

Abstract: A method for characterizing function of an air gun includes measuring, with respect to time, a parameter related to pressure in a charge chamber portion of the air gun. The measurements with respect to time are used to characterize the function of the air gun.

Abstract: In a radar apparatus, IF beat signals are detected in a first section and a second section serving as two adjacent frequency up-modulation sections of a transmitted wave. Frequency conversions such as FFTs are performed on the IF beat signals so that the frequency spectra are obtained. Subsequently, peak frequencies are detected from the frequency spectra in the corresponding sections, and the phase difference between the peak frequencies is determined. Since the phase difference calculated in this manner depends on the relative moving distance ?r during the interval between the first section and the second section, the relative moving distance ?r, the relative distance, and the relative velocity at this moment can be calculated from the phase difference.

Abstract: In an under water detection for detecting the phase difference of an echo by two reception beams according to a split beam method, the difference ?? between the phase difference of an echo detected by first and second reception beams formed in some direction and the phase difference of the echo detected by first and second reception beams which is formed in a direction rotated from the former direction concerned by a predetermined angle is detected by a phase detector. A reliability judging unit judges whether the difference ?? detected by the phase detector is within a predetermined range or not. If the difference ?? is within the predetermined range, an echo is displayed on a display unit. If the difference ?? is not within the predetermined range, the echo is displayed with a specific color tone or the echo is not displayed.

Abstract: A radio wave transmission/reception device capable of detecting an obstacle in front of a vehicle using radio waves is disclosed. The device includes a radio wave transmission/reception unit; a radio wave reflection unit installed around the radio wave transmission/reception unit and changing the direction of the radio waves such that the radio waves can be propagated forwards from the vehicle; a radio wave rectilinear propagation guide unit installed in front of the radio wave reflection unit and guiding rectilinear propagation of the radio waves; and a viewing window installed in front of the radio wave rectilinear propagation guide unit and oriented toward the radiator grille. The radio wave rectilinear propagation guide unit has an inductive film parallel to the viewing window, with at least a reflection protrusion formed on the inductive film. The device improves the rectilinearity of radio wave propagation and improves the appearance of the radiator grille.

Abstract: An apparatus for mitigating the effects of shock loading on occupants, cargo and gear the apparatus located in a watercraft the apparatus having a deck positioned and arranged in said watercraft for supporting thereon said occupants, cargo and gear, a hinge communicating with said deck and said watercraft and supporting the forwardly portion of said deck and permitting said deck to move and rotate about said hinge and prevent said deck from substantial side to side movement, a dampener communicating with said deck and said hull of said watercraft the dampener positioned and arranged to move in response to said moving and rotating deck and said dampener absorbing at least a portion of the energy of said moving deck as said deck moves and rotates, and a spring communicating with said deck and said hull of said watercraft the spring positioned and arranged to support the rearwardly portion on said deck and to move in response to said moving and rotating deck the spring absorbing at lease a portion of the energy