Abstract: The present disclosure provides an underwater detector including a power source for applying a predetermined voltage, a voltage control circuit for controlling the voltage based on a control signal, a gate signal generating module for outputting a gate signal, a switching circuit for outputting a reference signal based on the voltage controlled by the voltage control circuit and the gate signal outputted from the gate signal generating module, and a transducer for transmitting an ultrasonic signal underwater, an envelope of which being controlled based on a waveform of the control signal by being applied with the reference signal.

Abstract: The present disclosure provides an underwater detector including a power source for applying a predetermined voltage, a voltage control circuit for controlling the voltage based on a control signal, a gate signal generating module for outputting a gate signal, a switching circuit for outputting a reference signal based on the voltage controlled by the voltage control circuit and the gate signal outputted from the gate signal generating module, and a transducer for transmitting an ultrasonic signal underwater, an envelope of which being controlled based on a waveform of the control signal by being applied with the reference signal.

Abstract: A transducer is constructed of a plurality of transducer elements which are arranged in multiple layers and columns forming as a whole a generally cylindrical shape. A scanning sonar employing the transducer thus constructed can be switched between horizontal scan mode in which a vertically focused beam having a narrow horizontal beam angle (high horizontal directivity) is steered around the transducer using all the transducer elements and vertical scan mode in which a horizontally focused beam having a narrow vertical beam angle (high vertical directivity) is steered in a vertical plane directed in a specified scan azimuth to find out the angle of incidence of a received signal. The horizontally focused beam is formed by using the transducer elements of specific columns centered on the specified scan azimuth. A vertical scan signal obtained in the vertical scan mode is multiplied by a chirp signal.

Abstract: The present invention is directed to provide an underwater detection system which can determine frequency components contained in echoes arriving from all azimuthal directions at high speed and enhance target discriminating capabilities by presenting such frequency components.The underwater detection system rotates a pair of ultrasonic receiving beams having a fixed phase angle difference, measures phase differences between two signals picked up by both ultrasonic receiving beams, determines carrier frequencies contained in target echoes from the phase differences, derives magnitudes and directions of moving velocities of targets from the carrier frequencies, and displays such target data in different colors. Furthermore, it provides such information as over-the-ground velocities of targets themselves upon compensating target velocity data with ship velocity data.

Abstract: A detection system forms a plurality of reception beams successively in angular directions by receiving incoming signals from various directions in a manner that the Doppler effect is produced to vary the carrier frequency of the incoming signals. The detection system displays underwater conditions on an indicator. To determine the underwater conditions, the detection system uses a plurality of ultrasonic transducers for receiving incoming signals, a plurality of preamplifiers for amplifying the reception signals produced by the ultrasonic transducers. A first coupling device which connects at least two of the ultrasonic transducers to a single preamplifier, and a matched filter for pulse-compressing reception signals produced by the ultrasonic transducers. A second coupling device successively couples the output terminals of the preamplifiers to an input terminal of the matched filter. The indicator displays output signals from the matched filter.

Abstract: A scanning sonar system for detecting objects and displaying them on a circular screen and producing audible signals coordinated with the visual signals indicating the detection of an object.

Abstract: An ultrasonic detection system which includes means for the transmission of signals in all directions, a circular array of transducers arranged at uniform intervals, means for producing output signals from spaced transducers and then sequentially combining outputs from sets of adjoining transducers to produce a plurality of received signals for display on indicating means.

Abstract: A plan position indicating system which includes a display screen and means for indicating on the screen the tilt angle of the transmitted beam and received signals to enable measurement not only of direction and distance but also the horizontal and vertical components thereof.

Abstract: Apparatus for controlling the angular direction of wave transmission of an ultrasonic transmitting system having a plurality of uniformly spaced transducers which includes means for successively shifting the phase of the signals emitted by each transducer and providing means for controlling the magnitude of the phase shift to alter the angle of transmission.