Abstract: A reproduction apparatus includes a reproduction unit reading a reproduced signal of the data recorded on an optical disk, a reproduced signal processing unit performing ECC decoding for the reproduced signal using a predetermined parameter value, a storage unit storing the parameter number associated with the currently set parameter value and a parameter table listing parameter values and associated parameter numbers, and a control unit controlling the reproduction unit and the reproduced signal processing unit. The control unit, when ECC decoding fails, changes the parameter values in the order of the parameter numbers and controls the reproduced signal processing unit until ECC decoding succeeds in retried reproduction processing and, when ECC decoding succeeds, stores the parameter number associated with the currently set parameter value and sets in the next retried reproduction processing the parameter value associated with the stored parameter number in the reproduced signal processing unit.

Abstract: A receiving beam is formed using 60 elements arranged in a 90° sector area of a cylindrical receiving array. Receiving beam 0 is formed with elements 0-59 divided into two (front and rear) groups. Specifically, the elements 0-59 are divided into rear group 1 (elements 0-8, 51-59) and front group 2 (elements 9-50) in the beam direction, and the receiving beam is formed by using sample data obtained from the transducer elements 0-8, 51-59 of group 1 in a current scanning cycle as well as sample data obtained from the transducer elements 9-50 of group 2 in a preceding scanning cycle. This approach makes it possible to form the receiving beam such that incoming waves of a short-pulse signal would simultaneously hit the relevant transducer elements of the receiving array and thereby improve directivity and sensitivity of the receiving beam for the reception of short-pulse waves.

Abstract: A received beam-forming apparatus is disclosed is which echo signals received by multiple ultrasonic transducer elements arranged in a linear form are sampled at a specific scanning frequency to obtain sample data. A receiving beam-forming apparatus includes a memory which stores the sample data derived from multiple scanning cycles; and a beamformer which divides the multiple ultrasonic transducer elements into multiple blocks, reads out the sample data derived from different scanning cycles for the individual blocks from said memory, and forms a receiving beam in a specific direction using the individual sample data which have been read out. A sonar system using the receiving-beam forming apparatus is also disclosed as is a matched filter which selects an arc-shaped part of an ultrasonic transducer element array.

Abstract: A receiving beam is formed using 60 elements arranged in a 90° sector area of a cylindrical receiving array. Receiving beam 0 is formed with elements 0-59 divided into two (front and rear) groups. Specifically, the elements 0-59 are divided into rear group 1 (elements 0-8, 51-59) and front group 2 (elements 9-50) in the beam direction, and the receiving beam is formed by using sample data obtained from the transducer elements 0-8, 51-59 of group 1 in a current scanning cycle as well as sample data obtained from the transducer elements 9-50 of group 2 in a preceding scanning cycle. This approach makes it possible to form the receiving beam such that incoming waves of a short-pulse signal would simultaneously hit the relevant transducer elements of the receiving array and thereby improve directivity and sensitivity of the receiving beam for the reception of short-pulse waves.

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: An ultrasonic diagnostic apparatus for diagnosing a characteristic of a body to be examined by passing ultrasound through the body to be examined which is placed between a pair of ultrasound transducers.The apparatus comprises a pair of ultrasound transducers which are fixedly disposed facing to one another, with one of the ultrasound transducers (5) having a first standoff on the transmitting/receiving surface thereof, with the other ultrasound transducer (4) being housed in a movable tank having a second standoff at its front end, and moves the movable tank so that the body between the front end surface of the first standoff and the front end surface of the second standoff are brought into contact thereto and diagnoses a characteristic of the body based on signals emitted and received by the ultrasound transducers.

Abstract: The object of the present invention is to rotate a head with high precision along a predetermined rotation locus in a rotary drum apparatus for recording and/or reproducing predetermined signals on a tape recording medium. A locus of the head on the rotary drum connected to the first rotary shaft can be adjusted to coincide with the predetermined locus by dividing the rotary shaft into two shafts, and adjusting the two shafts with an adjustment mechanism. The adjustment mechanism can be in the form of threaded screws or electrical actuators. Sensors can be provided for measuring the horizontal degree and vertical degree of the rotary shaft holding material supporting the first rotary shaft for adjusting the two shafts using electrical actuators based on the measured results.

Abstract: A system measures the velocity of a moving body such as a ship and a water body. The system uses a first apparatus which measures the speed of a moving body by detecting a phase difference between a reference signal and echo signals resulting from a transmitted ultrasonic signal, implementing a Fourier transformation on the phase difference data obtained, computing the speed of the ship with respect to the water based on the Fourier spectrum data, and, computing the velocity of a water current based on the speed of the ship with respect to the ground and the speed of the ship with respect to the water obtained.

Abstract: A pneumatic bias tire including a two-ply carcass layer comprising an inner carcass ply and an outer carcass ply, which respectively comprise cords of an aromatic polyamide fiber and cords of nylon, the cords of the inner carcass ply crossing the cords of the outer carcass ply, the outer carcass ply having a cord angle .beta. to the circumferential direction of the tire which is smaller than a cord angle .alpha. of the inner carcass ply to the tire circumferential direction.

Abstract: A phase control device for producing a reference pulse train and a plurality of pulse trains and controlling the latter pulse trains so that each of the latter pulse trains is independently displaced by a desired phase amount from said reference pulse train. The device can be preferably embodied in underwater detection systems.

Abstract: The present invention is directed to a detection system which forms reception beams successively in a series of angular directions. The detection system comprises receiving means for receiving incoming signals in such a manner that the frequency of the incoming signals is varied in accordance with the Doppler effect, and a matched filter for pulse-compressing output signals from said receiving means, with output signals from said matched filter being displayed in an indicator.