US5331963A — Apparatus for examining objects by ultrasonic ech…

Claim 1

Independent Claim 338 words

Apparatus for examining objects by ultrasonic echography, comprising an array of m ultrasonic transducer elements, where m is a positive integer, a transmission stage, having n transmission channels, where n is a positive integer less than or equal to m, associated with n transducer elements, among said m elements, defining an ultrasonic aperture, said transmission stage together with said array of transducer elements being means for transmission of ultrasonic signals to the object to be examined, a receiving and processing stage, having n receiving channels associated with said n transducer elements, said receiving and processing stage together with said array of transducer element being means for receiving and processing echographic signals returned to said n transducer elements by the object being examined, said transmission stage comprising transmission-mode means for focusing by the provision of suitable delays in said n transmission channels and said receiving and processing stage comprising receiving-mode means for focusing by the provision of suitable delays in said n receiving channels, the receiving and processing stage further comprising: associated with said n receiving channels, means for determining (n-1) correction values for the focusing delays; and means for correcting said focusing delays as a function of the (n-1) correction values thus determined; wherein said determining means comprises, in parallel, (n-1) correction circuits each correction circuit being coupled for receiving two focused echographic signals from a different pair of outputs, in i th and (i+1) th adjoining channels, where i is a positive integer less than n, of the receiving-mode focusing means and each of said correction circuits being means for determining an i th of said (n-1) correction values, each correction circuit comprising: means for generating a time window signal defining a time window during with the i th correction value is determined; and means for determining, during said time window, a phase shift between the two focused echographic signals received by said correction circuit, said phase shift constituting the i th correction value or being directly related to it, said determining means not including any correlators.

Claim 2

Dependent Claim 338 words

Apparatus for examining objects by ultrasonic echography, comprising an array of m ultrasonic transducer elements, where m is a positive integer, a transmission stage, having n transmission channels, where n is a positive integer less than or equal to m, associated with n transducer elements, among said m elements, defining an ultrasonic aperture, said transmission stage together with said array of transducer elements being means for transmission of ultrasonic signals to the object to be examined, a receiving and processing stage, having n receiving channels associated with said n transducer elements, said receiving and processing stage together with said array of transducer element being means for receiving and processing echographic signals returned to said n transducer elements by the object being examined, said transmission stage comprising transmission-mode means for focusing by the provision of suitable delays in said n transmission channels and said receiving and processing stage comprising receiving-mode means for focusing by the provision of suitable delays in said n receiving channels, the receiving and processing stage further comprising: associated with said n receiving channels, means for determining (n-1) correction values for the focusing delays; and means for correcting said focusing delays as a function of the (n-1) correction values thus determined; wherein said determining means comprises, in parallel, (n-1) correction circuits each correction circuit being coupled for receiving two focused echographic signals from a different pair of outputs, in i th and (i+1) th adjoining channels, where i is a positive integer less than n, of the receiving-mode focusing means and each of said correction circuits being means for determining an i th of said (n-1) correction values, each correction circuit comprising: means for generating a time window signal defining a time window during with the i th correction value is determined; and means for determining, during said time window, a phase shift between the two focused echographic signals received by said correction circuit, said phase shift constituting the i th correction value or being directly related to it, said determining means not including any correlators.

Claim 3

Dependent Claim 136 words

An apparatus as claimed in claim 1, wherein said means for generating a time window signal comprises: means for filtering said focused echographic signal in the i th channel to form a filtered focused echographic signal, which filtering means comprises two flip-flops in series, which two flip-flops also receive a clock signal H 1 ; and a first counter having an output for said time window signal and having an input coupled to an output of said filtering means for receiving said filtered focused echographic signal and a further input for receiving a signal for opening the time window defined by said time window signal, said counter being means for counting a number of pulses of said filtered echographic signal, which pulses are to be accommodated within the time window defined by said time window signal.

Claim 4

Dependent Claim 166 words

An apparatus as claimed in claim 2, wherein said means for determining the phase shift comprises, in series: means for determining the absolute value of said phase shift comprising a first AND gate which receives said time window signal from said generating means and the two focused echographic signals in the i th and (i+1) th channels, a second counter for determining a total duration of time for which said first AND gate is held at its high level during the time window, a divider for dividing by the number of periods during which the output of said gate is held at said high level, and a first memory; and means for determining the sign of said phase shift comprising a second AND gate, a third counter, a divider, and a second memory, which second AND gate also receives said time window signal, the focused echographic signal in the (i+1) th channel, and the focused echographic signal in the i th channel via a delay circuit.

Claim 5

Dependent Claim 166 words

An apparatus as claimed in claim 1, wherein said means for determining the phase shift comprises, in series: means for determining the absolute value of said phase shift comprising a first AND gate which receives said time window signal from said generating means and the two focused echographic signals in the i th and (i+1) th channels, a first counter for determining the total duration of time for which said first AND gate is held at its high level during the time window, a divider for dividing by the number of periods during which the output of said gate is held at said high level, and a first memory; and means for determining the sign of said phase shift comprising a second AND gate, a second counter, a divider, and a second memory, which second AND gate also receives said time window signal, the focused echographic signal in the (i+1) th channel, and the focused echographic signal in the i th channel via a delay circuit.

Claim 6

Independent Claim 48 words

An apparatus as claimed in any one of claims 1 to 4 and 3, wherein said (n-1) correction values are supplied to said correcting means via a readjustment circuit which generates (n-1) readjusted correction values and means for performing a linear regression upon the (n-1) readjusted correction values.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-07-25	1998-01-24	1998-07-26	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-07-25	2002-01-24	2002-07-26	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-07-25	2006-01-24	2006-07-26	$7700.00	Window Closed / Lapsed

Apparatus for examining objects by ultrasonic echography

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