Abstract:
An ultrasound signal processor has a receiving signal digitizing circuit, waveform conversion circuit for mixing a produced digital signal by a reference signal, a cumulation circuit for performing a cumulation processing of a series of converted signals, a delay circuit subject to the cumulation processing, and a circuit for adding delayed signals, whereby the frequency of the receiving signal is shifted to a lower frequency and thereafter subjected to a cumulation processing which perform over-sampling technique so that the accuracy of an analog to digital conversion can be improved drastically. The ultrasound signal processor further has a circuit for converting a receiving signal into a low frequency signal by analog-mixing and a circuit for passing a low frequency component of the analog-converted signal, whereby a higher frequency receiving signal can be digitized even if the digitizing circuit has a insufficient sampling rate.
Abstract:
A rocker arm includes a roller brought into contact with a cam to be rotated and an arm body having a storage portion for the roller. The storage portion has an opening edge including a part receiving lubricant oil flowing along an upper surface of the arm body. The part is formed with a receiving opening edge jutting out so that both widthwise ends are located away from a circumferential surface of the roller and so that a widthwise central portion comes closer to the circumferential surface of the roller. The arm body has a lubricant guide path formed by recessing the upper surface thereof and guiding the lubricant oil into the storage portion. The lubricant guide path has a width that is gradually rendered larger as the lubricant guide path gets close to the widthwise central portion of the receiving opening edge.
Abstract:
A needle-like ultrasonic probe includes an inner needle received in a hollow, tubular outer needle for rotation about an axis thereof. The inner needle has a pointed distal end, and a notch is formed in an outer peripheral surface of that portion of the inner needle which is located adjacent to the distal end thereof. At least one ultrasonic transducer, as well as an acoustic lens for converging an ultrasonic wave, produced by the ultrasonic transducer, onto a point near to the outer peripheral surface of the inner needle, is provided in the notch. A filler, having an outer surface conforming to the outer peripheral surface of the inner needle, is fitted in the notch. With this construction, after the inner needle is smoothly stuck into a living tissue, even if it is rotated and axially moved, the living tissue is less affected or damaged by the inner needle.
Abstract:
A ultrasonic Doppler meter for measuring the speed of a moving body by measuring the phase shift due to the Doppler effect on received signals, comprising a transmitting/receiving unit transmitting ultrasonic bursts with a constant time interval towards the moving body and receiving reflected waves; a unit for measuring a phase difference vector representing a difference between phases of received signals corresponding to two successive transmitted pulses; a unit for calculating a difference between phase differences on the basis of two successive phase difference vectors stated above; and an accumulation unit for adding the difference between phase differences to a preceeding phase difference vector so as to obtain the speed of the moving object.
Abstract:
A rocker arm for an internal combustion engine includes a roller brought into contact with a cam thereby to be rotated, an arm body having a storage portion in which the roller is stored, the arm body being swung by rotation of the cam, thereby opening and closing a valve. The storage portion has an opening edge located on an upper surface of the arm body and opposed to a circumferential surface of the roller, and the opening edge includes a part receiving a lubricant flowing along the upper surface of the arm body, the part being formed with a receiving opening edge jutting out so that both widthwise ends thereof are located away from the circumferential surface of the roller and so that a widthwise central portion thereof comes close to the circumferential surface of the roller.
Abstract:
A rocker arm configured to be supported by a support portion of an internal-combustion engine and to be driven in a swinging manner by a cam. The rocker arm includes a rocker arm body including a cam follower having a first slide-contact surface, wherein the first slide-contact surface is in sliding contact with the cam, a fulcrum portion including a second slide-contact surface, wherein the second slide-contact surface swingably is in sliding contact with respect to the support portion, and a lubricant discharging portion for biasing a lubricant supplied from the fulcrum portion in a direction toward the first slide-contact surface and discharging the lubricant. The fulcrum portion penetrates the rocker arm and is fastened to the rocker arm body. The fulcrum portion has a through hole supplying the lubricant to the lubricant discharging portion through the rocker arm body.
Abstract:
A flow meter, in which pulsed continuous ultrasonic wave is transmitted towards an object at predetermined intervals T to obtain a phase vector from a reception signal of wave reflected by the object and which calculates a Doppler frequency from the average value of phase differences between phase vectors at the sampling interval T to obtain a signal indicating the speed of the object, comprising a phase difference calculator by the auto-correlation method, by which a plurality of phase difference vectors indicating phase differences between phase vectors are added, the argument of the sum vector thus obtained representing the average phase difference, or a phase difference calculator by the 2-axial-component method, by which a phase difference is divided into 2 axial components, a cosine value and a sine value, and the average phase difference is obtained by using the average value for each of the components, and a phase difference calculator by the phase difference averaging calculator, by which a plurality of phase differences are added, as they are, to obtain the average thereof, in order to obtain a phase difference average value having small errors by switching them.
Abstract:
A probe which is inserted into a lumen to obtain an ultrasonic tomogram using mechanical scanning is disclosed. A cylindrical acoustic case is filled with a liquid medium which transmits sound waves, and an elliptical ultrasonic transducer is immersed therein in such a manner that it can be rotated by a motor. The diameter of the transducer parallel to its axis of rotation is greater than that perpendicular to the axis of rotation, so that the lateral resolution parallel to the axis of rotation is improved, as well as the sensitivity.
Abstract:
A rocker arm configured to be supported by a support portion of an internal-combustion engine and to be driven in a swinging manner by a cam. The rocker arm includes a rocker arm body including a cam follower having a first slide-contact surface, wherein the first slide-contact surface is in sliding contact with the cam, a fulcrum portion including a second slide-contact surface, wherein the second slide-contact surface swingably is in sliding contact with respect to the support portion, and a lubricant discharging portion for biasing a lubricant supplied from the fulcrum portion in a direction toward the first slide-contact surface and discharging the lubricant. The fulcrum portion penetrates the rocker arm and is fastened to the rocker arm body. The fulcrum portion has a through hole supplying the lubricant to the lubricant discharging portion through the rocker arm body.
Abstract:
A pulse doppler apparatus transmits a ultrasonic sound wave at transmission intervals T and T+Ts alternately and iteratively, detects the phase difference attributable to the doppler shift in the reflected sound wave signal at the interval T and the phase difference in the reflected signal at the interval T+Ts sequentially, detects the difference between both phase differences, and transforms the difference into a doppler frequency. The apparatus includes an MTI filter which exerts the same filtering characteristics on the reflected sound signals at both intervals T and T+Ts.