Other

Takaki Shimura

Keiichi Murakami

John R Klepper

Hirohide Miwa

John M Reid

The present invention relates to an apparatus which determines the distribution of the attenuation slope coefficient on a real-time basis using the center frequency shift. In one embodiment, the phase difference between a received signal and a reference signal is determined using EXCLUSIVE OR gates or an inverse trigonometric relation stored in a ROM. The phase difference is input to a differentiator which outputs the center frequency shift of the received signal on a real-time basis. The center frequency shift is input to another differentiator which outputs the attenuation slope coefficient. In other embodiments, the received signal is distributed into received signal bands, having different center frequencies, and signal characteristics of the received signal bands are averaged to remove virtually all effects of spectrum scalloping in the time domain. Thus, the attenuation slope coefficient is obtained without the effects of spectrum scalloping using simple hardware and without Fourier transformation.

Apparatus for measuring the characteristics of an ultrasonic wave medium

The present invention relates to an apparatus which determines the distribution of the attenuation slope coefficient on a real time basis using the center frequency shift. The phase difference between a received signal and a reference signal is determined using EXCLUSIVE OR gates or an inverse trigonometric relation stored in a ROM. The phase difference is input to a differentiator which outputs the center frequency shift of the received signal on a real time basis. The center frequency shift is input to another differentiator which outputs the attenuation slope coefficient. Thus, the attenuation slope coefficient is determined using simple hardware and without calculating the power spectrum and the first moment.

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Machida-shi, Tokyo, Japan

Takaki Shimura