Patent EP0150997A2 successfully refreshed from Google Patents.
EP0150997A2
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EP
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Measuring characteristics of an ultrasonic wave medium
Assignee: Fujitsu Ltd
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Filing: 1985-01-25
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Granted: —
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Expires: 2005-01-25
Abstract
Abstract A characteristic, for example attenuation slope coefficient, of an ultrasonic wave medium is determined from a received signal, arising from reflection of a transmitted ultrasonic wave in the medium, on a real-time basis em- pioying only time domain calculations. In some embodiments, the phase difference (ϕ) between a received signal and a reference signal is determined using EXCLUSIVE OR gates (61, 62 - Fig. 6B) or a quadrature detector (14 - Fig. 2 and 9) and a signal conversion circuit (7 - Fig. 2 and 9, Fig. 3A, 3B and 8) using an inverse trigonometric relation stored in a ROM (73, 738 - Fig. 3A, 3B and 8). The phase difference is input to a differentiator (8 - Fig. 2 and 9) which outputs the center frequency shift of the received signal on a real-time basis. The center frequency shift is input to another differentiator (10 - Fig. 2 and 9) which outputs the attenuation slope coefficient (β). In other embodiments, the received signal is distributed into received signal bands, having different center frequencies (by filters 17-1 to 17-m - Fig. 10, 12, 13), and signal characteristics of the received signal bands are averaged, for example phase difference (ϕ) determined as above for each band, or a first derivative (< 0 > ) of phase difference, to remove virtually all effects of spectrum scalloping in the time domain. Thus, the attenuation slope coefficient for example is obtained without the effects of spectrum scalloping using simple hardware and without Fourier transformation.
Inventors
- 👤 John R. Klepper
- 👤 John M. Reid
- 👤 Hirohide C/O Fujitsu Ltd. Pat. Dept. Miwa
- 👤 Takaki C/O Fujitsu Ltd. Pat. Dept. Shimura
- 👤 Keiichi C/O Fujitsu Ltd. Pat. Dept. Murakami
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 14:11
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/52; G01S7/52017; G01S7/52023; G01S7/52036; G01S15/00; G01S15/88; G01S15/89; G01S15/8906; G01S15/895; G01S15/8954; G01S7/52025
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
120 words
An apparatus for detecting characteristics of a medium using an ultrasonic wave pulse transmitted into the medium and received as a received signal after reflection by the medium, comprising: means for supplying a reference signal; means, operatively connected to said reference signal supplying means and operatively connected to receive the received signal, for determining a phase difference between the received signal and the reference signal; first differentiating means, operatively connected to said phase difference determining means, for differentiating the phase difference with respect to time to generate a frequency shift amount signal; and second differentiating means, operatively connected to said first differentiating means, for differentiating the frequency shift amount signal with respect to time to generate an attenuation slope coefficient.
Claim 2
Independent Claim
120 words
An apparatus for detecting characteristics of a medium using an ultrasonic wave pulse transmitted into the medium and received as a received signal after reflection by the medium, comprising: means for supplying a reference signal; means, operatively connected to said reference signal supplying means and operatively connected to receive the received signal, for determining a phase difference between the received signal and the reference signal; first differentiating means, operatively connected to said phase difference determining means, for differentiating the phase difference with respect to time to generate a frequency shift amount signal; and second differentiating means, operatively connected to said first differentiating means, for differentiating the frequency shift amount signal with respect to time to generate an attenuation slope coefficient.
Claim 3
Dependent Claim
87 words
An apparatus as recited in claim 1, wherein said phase difference determining means comprises: a quadrature detector circuit, operatively connected to said reference signal supplying means and operatively connect to receive the received signal, for separating the received signal into an in-phase component and a quadrature component; and a signal conversion circuit, operatively connected to said quadrature detector circuit and said first differentiating means, for determining the. phase difference based on an inverse trigonometric function using the in-phase component and the quadrature component of the received signal.
Claim 4
Dependent Claim
125 words
An apparatus as recited in claim 2, wherein said quadrature detector circuit comprises: a 90 0 phase shifter circuit, operatively connected to said reference signal supplying means, for shifting the reference signal by 90°; a first multiplier circuit operatively connected to said 90° phase shifter circuit and operatively connected to receive the received signal; a second multiplier circuit operatively connected to said reference signal supplying means and operatively connected to receive the received signal; a first low-pass filter, operatively connected to said first multiplier circuit and said signal conversion circuit, for outputting the in-phase component of the received signal; and a second low-pass filter, operatively connected to said second multiplier circuit and said signal conversion circuit, for outputting the quadrature component of the received signal.
Claim 5
Dependent Claim
133 words
An apparatus as recited in claim 2 or 3, wherein said signal conversion circuit comprises: a first analog/digital converter, operatively connected to said quadrature detector circuit, for converting the in-phase component of the received signal into a digital in-phase component; a second analog/digital converter, operatively connected to said quadrature detector circuit, for converting the quadrature component of the received signal into a digital quadrature component; a read only memory, operatively connected to said first and second analog/digital converters, for determining a digital phase difference as the arctangent of a quantity defined by the digital quadrature component divided by the digital in-phase component; and a digital/analog converter, operatively connected to said read only memory and said first differentiating means, for outputting the phase difference by converting the digital phase difference into an analog signal.
Claim 6
Dependent Claim
186 words
An apparatus as recited in claim 2 or 3, wherein said signal conversion circuit comprises: a divider circuit, operatively connected to said quadrature detector circuit, for dividing the quadrature component of the received signal by the in-phase component of the received signal and generating a divided output; a first comparator, operatively connected to said quadrature detector circuit, for outputting the sign of the in-phase component of the received signal; a second comparator, operatively connected to said quadrature detector circuit, for outputting the sign of the quadrature component of the received signal; an analog/digital converter, operatively connected to said divider circuit, for converting the divided output into a digital divided output; a read only memory, operatively connected to said first and second comparators, and said analog/digital converter, for determining the arctangent of the digital divided output in a quadrant identified by the sign of the in-phase and quadrature components of the received signal; and a digital/analog converter, operatively connected to said read only memory and said first differentiating means, for outputting the phase difference by converting the arctangent of the digital divided output into an analog signal.
Claim 7
Dependent Claim
285 words
An apparatus as recited in claim 2 or 3, wherein said signal conversion circuit comprises: a first multiplier, operatively connected to said quadrature detector circuit, for squaring the in-phase component of the received signal; a second multiplier, operatively connected to said quadrature detector circuit, for squaring the quadrature component of the received signal; a first comparator, operatively connected to ground and to said quadrature detector circuit, for outputting the sign of the in-phase component of the received signal; a second comparator, operatively connected to ground and to said quadrature detector circuit, for outputting the sign of the quadrature component of the received signal; an adder, operatively connected to said first and second multipliers, for summing the squares of the in-phase and quadrature components of the received signal; a square root generating circuit, operatively connected to said adder, for generating the square root of the sum of the squares of the in-phase and quadrature components of the received signal; a divider, operatively connected to said square root generating circuit and said quadrature detector circuit, for generating a divided output corresponding to the in-phase component of the received signal divided by the square root of the sum of the squares of the in-phase and quadrature components of the received signal; an analog/digital converter, operatively connected to said divider, for converting the divided output into a digital divided output; a read only memory, operatively connected to said first and second comparators and said analog/digital converter, for determining the arccosine of the digital divided output; and a digital/analog converter, operatively connected to said read only memory and said first differentiating means, for outputting the phase difference by converting the arccosine of the digital divided output into an analog signal.
Claim 8
Dependent Claim
127 words
An apparatus as recited in claim 1, wherein the reference signal has a period and wherein said phase difference determining means comprises: waveform converting means, operatively connected to receive the received signal, for converting the received signal into an input signal representing the sign of the received signal; mean value generating means, operatively connected to said waveform converting means and said reference signal supplying means, for generating a mean value signal representing an amount of time that the input signal and reference signal are opposite in sign divided by the period of the reference signal; and saw-tooth phase means, operatively connected to said mean value means and said first differentiating means, for comparing the mean value signal with a saw-tooth phase characteristic to determine the phase difference.
Claim 9
Dependent Claim
147 words
An apparatus as recited in claim 7, wherein said reference signal supplying means supplies first and second square wave reference signals, the second square wave reference signal being 90 0 out of phase with the first square wave reference signal, and wherein said mean value generating means comprises: a first EXCLUSIVE OR gate, operatively connected to said waveform converting means, and said reference signal supplying means, for EXCLUSIVE ORing the input signal and the first square wave reference signal; a second EXCLUSIVE OR gate, operatively connected to said waveform converting means, and said reference signal supplying means, for EXCLUSIVE ORing the input signal and the second square wave reference signal; a first low pass filter operatively connected to said first EXCLUSIVE OR gate and said saw-tooth phase means; and a second low pass filter operatively connected to said second EXCLUSIVE OR gate and said saw-tooth phase means.
Claim 10
Dependent Claim
82 words
An apparatus as recited in claim 1, wherein said phase difference determining means comprises: means, operatively connected to receive said received signal, for sampling the received signal at a rate considerably higher than the frequency of the received signal; means, operatively connected to said sampling means, for storing the samples of the received signal; and digital processing means, operatively connected to said storing means, said reference signal supplying means and said first differentiating means, for obtaining the phase difference using digital processing.
Claim 11
Dependent Claim
90 words
An apparatus as recited in claim 9, wherein said digital processing means comprises: component means, operatively connected to said storing means and said reference signal supplying means , for distributing the received signal into an in-phase component which is in phase with the reference signal and a quadrature component which is orthogonal to the in-phase component; and trigonometric relation means, operatively connected to said component means and said first differentiating means, for determining the phase difference from a trigonometric relation between the in-phase and quadrature components of the received signal.
Claim 12
Dependent Claim
43 words
An apparatus as recited in claim 10, wherein said trigonometric relation means comprises means, operatively connected to said component generating means and said first differentiating means, for calculating the arctangent of a quantity defined by the quadrature component divided by the in-phase component.
Claim 13
Dependent Claim
54 words
An apparatus as recited in claim 10, wherein said trigonometric relation means comprises means, operatively connected to said component generating means and said first differentiating means, for calculating the arccosine of a quantity defined by the in-phase component spuates of the divided by the square root of the sum of thetin-phase and quadrature components.
Claim 14
Independent Claim
62 words
An apparatus as recited in any one of claims 1 to 12, wherein the reference signal supplied by said reference signal supplying means has a variable frequency, and further comprising a level adjusting circuit, operatively connected to said phase difference determining means and said reference signal supplying means, for varying the frequency of the reference signal in accordance with the phase difference.
Claim 15
Independent Claim
64 words
An apparatus as recited in any one of claims 1 to 13, further comprising means, operatively connected to at least one among said phase difference determining means and said first and second differentiating means, for displaying at least one among the phase difference, frequency shift amount signal, and atttenuation slope coefficient corresponding to the different depths from which the ultrasonic wave pulse was reflected.
Claim 16
Independent Claim
86 words
A method for measuring ultrasonic wave attenuation, comprising the steps of: (a) sending an ultrasonic wave pulse toward an object to be measured; (b) receiving a received signal comprised of ultrasonic waves reflected from different depths; (c) generating a reference signal; (d) determining a phase difference between the received signal and the reference signal; (e) differentiating the phase difference with respect to time to generate a frequency shift amount; and (f) differentiating the frequency shift amount with respect to time to generate an attenuation slope coefficient.
Claim 17
Independent Claim
86 words
A method for measuring ultrasonic wave attenuation, comprising the steps of: (a) sending an ultrasonic wave pulse toward an object to be measured; (b) receiving a received signal comprised of ultrasonic waves reflected from different depths; (c) generating a reference signal; (d) determining a phase difference between the received signal and the reference signal; (e) differentiating the phase difference with respect to time to generate a frequency shift amount; and (f) differentiating the frequency shift amount with respect to time to generate an attenuation slope coefficient.
Claim 18
Dependent Claim
52 words
A method as recited in claim 15, wherein step (d) comprises the substeps of: (di) separating the received signal into an in-phase component and a quadrature component; and (dii) calculating a value for an inverse trigonometric function using the in-phase and quadrature components of the received signal to determine the phase difference.
Claim 19
Dependent Claim
142 words
A method as recited in claim 15, wherein the reference signal generated in step (c) includes first and second square wave reference signals which have a period which is the same for both the first and second square wave reference signals, the second square wave reference signal being 90° out of phase with the first square wave reference signal, wherein step (d) comprises the substeps of: (di) converting the received signal into an input square wave signal; (dii) calculating first and second mean values which are equal to the amount of time the first and second square wave reference signals, respectively, have the same sign as the input square wave signal divided by the period of the first and second square wave signals; and (diii) comparing the first and second mean values with a saw-tooth phase characteristic to determine the phase difference.
Claim 20
Independent Claim
127 words
An apparatus for detecting characteristics of a medium using an ultrasonic wave pulse transmitted into the medium and received as a received signal after reflection by the medium, comprising: signal distributing means, operatively connected to receive the received signal, for distributing the received signal into at least three received signal bands; calculation means, operatively connected to said signal distributing means, for calculating a signal characteristic for each of the received signal bands from which a tissue characteristic can be derived; averaging means, operatively connected to said calculation means, for averaging the signal characteristic of each of the received signal bands to produce an average signal characteristic; and tissue characteristic means, operatively connected to said averaging means, for outputting the tissue characteristic derived from the average signal characteristic.
Claim 21
Independent Claim
127 words
An apparatus for detecting characteristics of a medium using an ultrasonic wave pulse transmitted into the medium and received as a received signal after reflection by the medium, comprising: signal distributing means, operatively connected to receive the received signal, for distributing the received signal into at least three received signal bands; calculation means, operatively connected to said signal distributing means, for calculating a signal characteristic for each of the received signal bands from which a tissue characteristic can be derived; averaging means, operatively connected to said calculation means, for averaging the signal characteristic of each of the received signal bands to produce an average signal characteristic; and tissue characteristic means, operatively connected to said averaging means, for outputting the tissue characteristic derived from the average signal characteristic.
Claim 22
Dependent Claim
26 words
An apparatus as recited in claim 18, wherein said signal distributing means comprises filters operatively connected to said calculation means and to receive the received signal.
Claim 23
Dependent Claim
51 words
An apparatus as recited in claim 19, wherein the received signal has a received bandwidth, wherein each of said filters has a center frequency, wherein the center frequency of each of said filters is different and wherein each of said filters has a bandwidth which is narrower than the received bandwidth.
Claim 24
Dependent Claim
18 words
An apparatus as recited in claim 20, wherein the bandwidth of each of said filters is substantially identical.
Claim 25
Independent Claim
52 words
An apparatus as recited in any one of claims 19 to 21, wherein said calculation means comprises: means for supplying a reference signal; and means, operatively connected to said reference signal supplying means, said filters and said averaging means, for determining a phase difference between the received signal and the reference signal.
Claim 26
Dependent Claim
93 words
An apparatus as recited in claim 22, wherein said phase difference determining means comprises: quadrature detector circuits, respectively operatively connected to said filters, and operatively connected to said reference signal supplying means, for separating the received signal into an in-phase component and a quadrature component in each of the received signal bands; and signal conversion circuits, respectively operatively connected to said quadrature detector circuits, and operatively connected to said averaging means, for determining the phase difference using an inverse trigonometric function of the in-phase component and the quadrature component of the received signal.
Claim 27
Dependent Claim
67 words
An apparatus as recited in claim 23, wherein the received signal has a variance and a standard deviation and wherein said averaging means comprises means, operatively connected to said quadrature detector circuits and said tissue characteristic means, for obtaining at least one of the variance and the standard deviation of the received signal, using the in-phase and quadrature components, to be output by said tissue characteristic means.
Claim 28
Dependent Claim
143 words
An apparatus as recited in claim 22 or 23, wherein said calculation means further comprises first differentiating means, operatively connected to said phase difference determining means and said averaging means, for differentiating the phase difference of each of the received signal bands with respect to time to generate a frequency shift amount signal for each of the received signal bands, wherein said averaging means includes frequency averaging means, operatively connected to said phase difference determining means and said tissue characteristic means, for averaging the frequency shift amount signal for each of the received signal bands to produce an average frequency signal as the average signal characteristic, and wherein said tissue characteristic means comprises second differentiating means, operatively connected to said frequency averaging means, for differentiating the average frequency signal with respect to time to generate an attenuation slope coefficient as the tissue characteristic.
Claim 29
Dependent Claim
167 words
An apparatus as recited in claim 22 or 23, wherein said calculation means further comprises: first differentiating means, operatively connected to said phase difference determining means, for differentiating the phase difference for each of the received signal bands with respect to time to generate a frequency shift amount signal for each of the received signal bands; and second differentiating means, operatively connected to said first differentiating means and said averaging means, for differentiating the frequency shift amount signal for each of the received signal bands with respect to time to generate an attenuation slope coefficient; wherein said averaging means includes frequency averaging means, operatively connected to said phase difference determining means and said tissue characteristic means, for averaging the attenuation slope coefficient for each of the received signal bands to produce an average attenuation slope coefficient as the average signal characteristic, and wherein said tissue characteristic means includes means, operatively connected to said frequency averaging means, for outputting the average attenuation slope coefficient as the tissue characteristic.
Claim 30
Dependent Claim
80 words
An apparatus as recited in claim 19, wherein said calculation means comprises: means for supplying a reference signal; and means, operatively connected to said reference signal supplying means, said filters and said averaging means, for determining a phase difference between the received signal and the reference signal, and wherein said averaging means includes average phase means, operatively connected to said phase difference determining means and said tissue characteristic means, for calculating an average phase difference as the average signal characteristic.
Claim 31
Dependent Claim
70 words
An apparatus as recited in claim 27, wherein said tissue characteristic means comprises: first differentiating means, operatively connected to said average phase means, for differentiating the average phase difference with respect to time to generate a center frequency signal; and second differentiating means, operatively connected to said first differentiating means, for differentiating the center frequency signal with respect to time to generate an attenuation slope coefficient as the tissue characteristic.
Claim 32
Dependent Claim
78 words
An apparatus as recited in claim 19, wherein said calculation means comprises: means for supplying a reference signal; and means, operatively connected to said reference signal supplying means, said filters and said averaging means, for determining a phase difference between the received signal and the reference signal, and wherein said averaging means includes means, operatively connected to said phase difference determining means and said tissue characteristic means, for calculating a weighted phase difference as the average signal characteristic.
Claim 33
Dependent Claim
89 words
An apparatus as recited in claim 19, wherein said calculation means comprises: means for supplying a reference signal; and means, operatively connected to said reference signal supplying means, said filters and said averaging means, for determining a phase difference between the received signal and the reference signal, and wherein said averaging means includes means, operatively connected to said phase difference determining means and said tissue characteristic means, for calculating an average phase difference, weighted by the in-phase component squared and the quadrature component squared, as the average signal characteristic.
Claim 34
Dependent Claim
190 words
An apparatus as recited in claim 19, wherein each of the received signal bands has a power spectrum and said calculation means comprises: means for supplying a reference signal, quadrature detector circuits, operatively connected to said reference signal supplying means and respectively operatively connected to said filters, for separating the received signal into an in-phase component and a quadrature component for each of the received signal bands; and moment calculation means, operatively connected to said quadrature detector circuits and said averaging means, for calculating moments of the power spectrum in the time domain for each of the received signal bands, wherein said averaging means includes means, operatively connected to said moment calculating means and said tissue characteristic means, for producing the average signal characteristic using the moments calculated by said moment calculation means; and wherein said tissue characteristic means comprises: center frequency means, operatively connected to said averaging means, for obtaining a center frequency signal from the average signal characteristic; and differentiating means, operatively connected to said center frequency means, for differentiating the center frequency signal with respect to time to produce an attenuation slope coefficient as the tissue characteristic.
Claim 35
Dependent Claim
38 words
An apparatus as recited in claim 18, wherein said calculation means comprises autocorrelation means, operatively connected to said signal distributing means and said averaging means, for obtaining an autocorrelation function signal for each of the received signal bands.
Claim 36
Dependent Claim
47 words
An apparatus as recited in claim 32, wherein said calculation means further comprises differentiating means, operatively connected to said autocorrelation means and said averaging means, for differentiating the autocorrelation function signal for each of the received signal bands with respect to time to produce the signal characteristic.
Claim 37
Dependent Claim
34 words
An apparatus as recited in claim 32, wherein said averaging means includes means, operatively connected to said autocorrelation means and said tissue characteristic means, for calculating a weighted average as the average signal characteristic.
Claim 38
Dependent Claim
126 words
An apparatus as recited in claim 32, wherein each of the received signal bands has a power spectrum, wherein said calculation means further comprises moment calculation means, operatively connected to said autocorrelation means and said averaging means, for calculating moments of the power spectrum for each of the received signal bands in the time domain; wherein said averaging means includes average frequency means, operatively connected to said moment calculation means and said tissue characteristic means, for obtaining an average frequency signal from the moments calculated by said moment calculation means; and wherein said tissue characteristic means comprises differentiating means, operatively connected to said average frequency means, for differentiating the average frequency signal with respect to time to produce an attenuation slope coefficient as the tissue characteristic.
Claim 39
Dependent Claim
72 words
An apparatus as recited in claim 32, wherein the received signal has a variance and a standard deviation, and wherein said averaging means comprises means, operatively connected to said autocorrelation means and said tissue characteristic means, for obtaining at least one of the variance and the standard deviation of the received signal, using the autocorrelation function signal for each of the received signal bands, to be output by said tissue characteristic means.
Claim 40
Dependent Claim
94 words
An apparatus as recited in claim 18, wherein said signal distributing means comprises; means for supplying reference signals, each of said reference signals having a different frequency; quadrature detector circuits, operatively connected to said reference signal supplying means and to receive the received signal, each of said quadrature detector circuits obtaining in-phase and quadrature components of the received signal for one of the received signal bands in dependence upon a corresponding one of the reference signals; and low-pass filters, respectively operatively connected to said quadrature detector circuits and operatively connected to said calculation means.
Claim 41
Dependent Claim
148 words
An apparatus as recited in claim 37, wherein each of the received signal bands has a power spectrum, wherein said calculation means comprises moment calculation means, operatively connected to said low-pass filters and said averaging means, for calculating moments of the power spectrum of each of the received signal bands in the time domain, wherein said averaging means includes means, operatively connected to said moment calculation means and said tissue characteristic means, for producing the average signal characteristic using the moments calculated by said moment calculation means, and wherein said tissue characteristic means comprises: center frequency means, operatively connected to said averaging means, for obtaining a center frequency signal of the received signal from the average signal characterisic; and differentiating means, operatively connected to said center frequency means, for differentiating the center frequency signal with respect to time to produce an attenuation slope coefficient as the tissue characteristic.
Claim 42
Dependent Claim
76 words
An apparatus as recited in claim 37, wherein the received signal has a center frequency, wherein said tissue characteristic means includes means, operatively connected to said averaging means, for outputting the center frequency of the received signal, and wherein said reference signal supplying means includes means operatively connected to said tissue characteristic means and said quadrature detector circuits, for varying the reference signals in dependence upon the center frequency without changing differences among the reference signals.
Claim 43
Independent Claim
72 words
A method for detecting characteristics of a medium in the time domain using an ultrasonic wave pulse transmitted into the medium and received as a received signal after reflection by the medium, comprising the steps of: (a) distributing the received signal into at least three received signal bands having signal characteristics; and (b) averaging the signal characteristics of the received signal bands to produce a tissue characteristic substantially free of spectrum scalloping.
Claim 44
Independent Claim
72 words
A method for detecting characteristics of a medium in the time domain using an ultrasonic wave pulse transmitted into the medium and received as a received signal after reflection by the medium, comprising the steps of: (a) distributing the received signal into at least three received signal bands having signal characteristics; and (b) averaging the signal characteristics of the received signal bands to produce a tissue characteristic substantially free of spectrum scalloping.
Claim 45
Dependent Claim
36 words
A method as recited in claim 41, wherein said step (a) comprises the substeps of: (ai) filtering the received signal to produce the received signal bands; and (aii) calculating the signal characteristics in the time domain.
References Cited (Backward Citations)
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