Fujitsu Corporation

Hajime Hayashi

Takaki Shimura

Hirohide Miwa

Yutaka Igarashi

Keiichi Murakami

Kenji Kawabe

Akira Shiba

Atsuo Iida

Takehiko Hayashi

Takao Goto

Tadahiko Yanashima

Yoshiyasu Nakashima

Fumihiro Namiki

Tetsuya Matsushima

Shinichi Amemiya

Narutaka Nakao

Norio Fujimaki

Yutaka Fukui

Kohtaro Gotoh

Takai Shimura

Masayuki Matsumoto

Michitoshi Inoue

A plurality of SQUID flux sensors are supplied with their respective bias currents at the same time from a bias source. A superconducting multiplexer multiplexes output signals of the SQUID flux sensors during an interval of time when the bias currents are supplied to the SQUID flux sensors. A multiplexer, placed in a room-temperature environment, distributes each of the multiplexed output signals of the SQUID flux sensors to a respective one of the output terminals which correspond to the SQUID flux sensors. Each signal which has been output to an individual output terminal is counted by a counter, so that an external magnetic flux to a corresponding SQUID flux sensor is measured.

Multichannel SQUID flux meter having multiplexed SQUID flux sensors

An amplitude variable pulse generator is provided with two voltage supply sources. The first voltage source supplies a variable voltage which determines the amplitude of the output pulse. The second voltage source is a fixed or constant voltage source which provides a voltage lower in value than the first voltage. The second voltage source quickly pulls up a voltage between a drain and a source of a switching MOSFET, which generates the output pulse, by providing a charging voltage for an output capacitance of the MOSFET. By doing so, the output capacitance of the MOSFET is quickly reduced, and the trailing edge of the output pulse is not rounded even when the variable voltage is low. As a result, the waveform of the output pulse is not rounded for a very small amplitude pulse. Resolution of a supersonic wave device especially a supersonic diagnostic device is thereby improved.

Amplitude variable pulse generating circuit

An apparatus is provided for measuring a very weak magnetic field generated by a human body, etc. External magnetic noise components coming from other magnetic sources and existing around an object whose magnetic field is to be measured are detected by compensation coils of the apparatus. The compensation coils are oriented in multiple dimensional directions. The detected noise components are weighted and added to each other to correctly find the noise components. Thereafter, the noise components mixed in the objective very weak magnetic field are removed, thereby correctly measuring the very weak magnetic field.

Gradiometer apparatus with compensation coils for measuring magnetic

A digital SQUID control system for measuring a weak magnetic flux irradiated from an object includes: a SQUID having Josephson junctions and a superconductively coil; a pick-up coil detecting the weak magnetic flux from the object and flowing a measuring current in the pick-up coil, and an input coil magnetically coupled to the superconductivity coil through the measuring current; a feedback coil magnetically coupled to the superconductivity coil through a feedback current; a feedback circuit for counting positive and negative pulses input from the SQUID, for converting count values to an analog voltage, and for converting the analog voltage to the feedback current; an alternating has current generating circuit connected to the SQUID through an injection terminal, for supplying the alternating bias current to the SQUID; and a pulse rate measuring circuit for calculating a sum of the positive and negative pulses, for converting the sum to an analog voltage, and for outputting the analog voltage to the alternating current generating circuit. Further, the alternating current generating circuit controls an amplitude of the alternating bias current in such a way that the sum of the positive and negative pulses per unit of time becomes constant, and the feedback circuit controls the feedback current under the controls of the alternating bias current amplitude in such a way that a difference between the positive pulses and the negative pulses becomes zero by flowing the feedback current through the magnetically coupled superconductivity coil.

Digital SQUID control system for measuring a weak magnetic flux

The present invention relates to a signal processing apparatus for quantitatively measuring ultrasonic characteristics of a medium, such as a human body and realizes the high speed quantitative measurement by processing all signals in the time domain. In the processing for eliminating an error, produced by a degree of convergence of the ultrasonic beam, a correcting function that is a function of the depth and frequency is employed. The correcting function is measured in a no-attenuation medium and converted into a form suited to the time domain processing. The function is stored and such frequency characteristics of the function are sequentially read during an actual medium measurement to control the characteristic of a variable characteristic filter to correct the received signal.

Apparatus for characterizing ultrasonic medium

An apparatus for measuring acoustic characteristic values of a medium by sending ultrasound pulses into the medium and analyzing the reflected waves from the medium. Medium characteristic values are extracted from the reflected waves, and spectrum scalloping is eliminated. The present invention executes the nonlinear filtering process, for example, the median filtering process to the spectrums, applies a model spectrum to the filtered result and thereby facilitates measurement of supressing fluctuation even when a small number of space average samples one used, by obtaining .beta. from such model spectrum.

Ultrasound medium characteristics measuring apparatus

A diagnosis apparatus for discriminating a property of the tissue to be observed from the reflected ultrasonic wave uses the nature of the fine structure of the tissue, and more practically uses the interval of small reflecting bodies dispersely distributed in the tissue as the parameters. The intervals flucatuate. Therefore, an average value and/or a degree of fluctuation is calculated and is displayed. For obtaining the average interval, a method of using the cepstrum of the received signal or a method of using the self-correlation of the received signal can be used.

Ultrasonic diagnosis apparatus for tissue characterization

An ultrasonic sector-scan probe comprises at least an array having a plurality of ultrasonic transducer segments, a window for transmitting and receiving ultrasonic waves and an ultrasonic wave propagation medium filled in a front space between the array and the window. A group of the ultrasonic transducer segments are selectively driven as an aperture and ultrasonic waves emitted therefrom are converged into a beam for transmission and reception. By partly or entirely changing the segments in the group with the ones outside the group the scan line is shifted to a new angle, and a member under test contacted with the window on the outside thereof is sector-scanned by the ultrasonic beam. The array is arranged so that scanning lines of the groups intersect at one point in the window or in its vicinity for sector scan. An acoustic lens is provided in the window or in its vicinity so that the ultrasonic beam may be converged over the measuring depth range of the member under test with or without phase control of the segments in the group. Furthermore, the array is arranged multidimensionally or in plural linear arrays so that the scanning lines of the groups intersect substantially at one point in the window or in its vicinity for sector scan, thereby performing sector scan of at least two sections and/or three-dimensional sector scan.

Ultrasonic sector-scan probe

An ultrasonic sector-scan probe comprises at least an array having a plurality of ultrasonic transducer segments, a window for transmitting and receiving ultrasonic waves and an ultrasonic wave propagation medium filled in a front space between the array and the window. A group of the ultrasonic transducer segments are selectively driven as an aperture and ultrasonic waves emitted therefrom are converged into a beam for transmission and reception. By partly or entirely changing the segments in the group with the ones outside the group the scan line is shifted to a new angle, and a member under test contacted with the window on the outside thereof is sector-scanned by the ultrasonic beam. The array is arranged so that scanning lines of the groups intersect at one point in the window or in its vicinity for sector scan. And an acoustic lens is provided in the window or in its vicinity so that the ultrasonic beam may be converged almost over the measuring depth range of the member under test with/without phase control of the segments in the group. Furthermore, the array is arranged multidimensionally or in plural linear arrays so that the scanning lines of the groups intersect substantially at one point in the window or in its vicinity for sector scan, thereby performing sector scan of at least two sections and/or three-dimensional sector scan.

An ultrasonic diagnostic apparatus protected from multi-reflection of sound echoes. Multi-reflection is avoided by eliminating the reflection from the surface of an electro-sound transducer. This invention eliminates the surface reflection of the transducer by following three methods:

Electro-sound transducer eliminating acoustic multi-reflection, and

A probe is provided which comprises a plurality of ultrasonic transducer elements, and is so arranged as to be capable of simultaneously transmitting and receiving ultrasonic beams of plural frequencies. Means is provided for changing the shapes of the effective acoustic field of the ultrasonic beams of each a predetermined number of frequencies by selectively operating the ultrasonic transducer elements or interchanging transducers. The shapes of the effective acoustic fields of the ultrasonic beams of the plural frequencies are made substantially coincident in accordance with the range of distance from the probe. Thereby, the measuring of the tissue or the like with coincident shaped beams of plural frequencies can be realized.

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Yamato, Japan

Hajime Hayashi