US4070643A — Acoustic holography apparatus

Claim 1

Independent Claim 178 words

Acoustic holography apparatus comprising: acoustic transmitter means for insonifying an article or object for examination, an acoustic receiver transducer for detecting acoustic signals from the acoustic transmitter means which have passed by or through the said article or object or have been diffracted or reflected therefrom, scanning means for producing a displacement of the acoustic receiver transducer relative to the object, sampling means for taking substantially instantaneous samples of the amplitude of a signal derived from the acoustic receiver transducer at instants selected relative to the phase of the signal transmitted by the acoustic transmitter means, the selected instants being dependent on the current position of the receiver transducer and being determined according to the phase of a chosen notional reference wave at the current position of the receiver transducer relative to the phase of the chosen notional reference wave at a datum point, and plotting means for plotting the samples taken by the sampling means versus the displacement of the acoustic receiver transducer so as to form a graphical diagram representing an acoustical hologram of the object.

Claim 2

Dependent Claim 178 words

Acoustic holography apparatus comprising: acoustic transmitter means for insonifying an article or object for examination, an acoustic receiver transducer for detecting acoustic signals from the acoustic transmitter means which have passed by or through the said article or object or have been diffracted or reflected therefrom, scanning means for producing a displacement of the acoustic receiver transducer relative to the object, sampling means for taking substantially instantaneous samples of the amplitude of a signal derived from the acoustic receiver transducer at instants selected relative to the phase of the signal transmitted by the acoustic transmitter means, the selected instants being dependent on the current position of the receiver transducer and being determined according to the phase of a chosen notional reference wave at the current position of the receiver transducer relative to the phase of the chosen notional reference wave at a datum point, and plotting means for plotting the samples taken by the sampling means versus the displacement of the acoustic receiver transducer so as to form a graphical diagram representing an acoustical hologram of the object.

Claim 3

Dependent Claim 47 words

Acoustic holography apparatus as claimed in claim 1 and wherein a phase-locked frequency-multiplier means is connected to receive the output signal of the acoustic receiver transducer and the sampling means is connected to take the said samples from a harmonic, signal output of the phase-locked frequency-multiplier means.

Claim 4

Dependent Claim 105 words

Acoustic holography apparatus as claimed in claim 1 and wherein the sampling means comprises a sampling gate circuit connected to receive the signal derived from the acoustic receiver transducer and having an output connected to the plotting means, and a scan control means which comprises a comparator amplifier having a first input connected to the acoustic transmitter means and having a second input with switch means for applying a series of predetermined voltages in sequence to the second input of the comparator amplifier and counting means for operating the switch means in synchronism with the motion of the acoustic receiver transducer relative to the object.

Claim 5

Dependent Claim 79 words

Acoustic holography apparatus as claimed in claim 3 and wherein the switch means is constructed to apply voltages to the said second input of the comparator amplifier which are related to each other as the voltages of a sequence of instantaneous samples taken at equal phase increments on a sinusoidal voltage waveform, and the scanning means is constructed for moving the acoustic receiver transducer in steps relative to the object, in synchronism with counting actions of the counting means.

Claim 6

Dependent Claim 49 words

Acoustic holography apparatus as claimed in claim 3 and wherein the scanning means is constructed to move the acoustic receiver transducer in a rectilinear raster scan, and to change the direction of counting of the counting means whenever it changes the direction of motion of the acoustic receiver transducer.

Claim 7

Dependent Claim 35 words

Acoustic holography apparatus as claimed in claim 5 and wherein the scanning means comprises means for causing a selected number of extra counting actions of the counting means after each line of the raster scan.

Claim 8

Independent Claim 116 words

A method for forming an acoustic hologram pattern which comprises: insonifying an object with acoustic waves from a transmitter transducer, detecting the acoustic waves scattered by the object to a receiver transducer, sampling the instantaneous amplitude of a signal derived from the receiver transducer at selected phase times relative to the phase of the acoustic waves at the transmitter transducer, scanning the receiver transducer across a plane, and selecting the said phase times according to a prescribed relationship with the instantaneous position of the receiver transducer, and forming the hologram pattern by plotting the sampled outputs obtained with the receiver transducer in various positions in the plane at corresponding positions in a diagram of the plane.

Claim 9

Independent Claim 116 words

A method for forming an acoustic hologram pattern which comprises: insonifying an object with acoustic waves from a transmitter transducer, detecting the acoustic waves scattered by the object to a receiver transducer, sampling the instantaneous amplitude of a signal derived from the receiver transducer at selected phase times relative to the phase of the acoustic waves at the transmitter transducer, scanning the receiver transducer across a plane, and selecting the said phase times according to a prescribed relationship with the instantaneous position of the receiver transducer, and forming the hologram pattern by plotting the sampled outputs obtained with the receiver transducer in various positions in the plane at corresponding positions in a diagram of the plane.

Claim 10

Dependent Claim 44 words

A method as claimed in claim 7 and wherein the output signal of the receiver transducer is applied to a phase-locked frequency-multiplier circuit and a harmonic signal output of the phase-locked frequency-multiplier circuit forms the said signal to which the sampling action is applied.

Claim 11

Independent Claim 113 words

A method for forming an acoustic hologram pattern which comprises: insonifying an object with acoustic waves from a transmitter transducer; sampling the instantaneous amplitude of a signal representing or derived from the resultant disturbance due to acoustic waves reflected from the object at each of a plurality of positions in a plane at selected phase times relative to the phase of the acoustic waves at the transmitter transducer, the selected phase time in each case being determined according to a prescribed relationship with parameters specifying the position concerned; and forming the hologram pattern by plotting the sampled amplitudes from various positions in the plane at corresponding positions in a diagram of the plane.

Claim 12

Independent Claim 113 words

A method for forming an acoustic hologram pattern which comprises: insonifying an object with acoustic waves from a transmitter transducer; sampling the instantaneous amplitude of a signal representing or derived from the resultant disturbance due to acoustic waves reflected from the object at each of a plurality of positions in a plane at selected phase times relative to the phase of the acoustic waves at the transmitter transducer, the selected phase time in each case being determined according to a prescribed relationship with parameters specifying the position concerned; and forming the hologram pattern by plotting the sampled amplitudes from various positions in the plane at corresponding positions in a diagram of the plane.

Claim 13

Dependent Claim 86 words

A method as claimed in claim 9, wherein the selected phase times are determined by reference to a series of voltages which are related to each other as the voltages of a sequence of instantaneous samples taken at equal phase increments on a sinusoidal voltage waveform and which are selected in sequence by counting actions through comparing the selected voltage with the instantaneous voltage of a signal from the transmitter transducer and determining the appropriate sampling instants from the instants when the compared voltages become equal.

Claim 14

Dependent Claim 63 words

A method as claimed in claim 9, wherein the sampling action is achieved by moving a receiver transducer through a plurality of positions in the said plane and sampling the instantaneous amplitude of the receiver transducer at selected phase times determined according to a prescribed relationship with the parameters specifying displacements of the receiver transducer from a datum point in the said plane.

Claim 15

Dependent Claim 81 words

A method as claimed in claim 9, wherein the sampling action is achieved by moving a receiver transducer through a plurality of positions in the said plane, having a phase-locked frequency-multiplier circuit connected to receive the output of the receiver transducer, and sampling the instantaneous amplitude of a harmonic-signal output of the phase-locked frequency-multiplier circuit at selected phase times determined according to a prescribed relationship with parameters specifying displacements of the receiver transducer from a datum point in the said plane.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1981-01-23	1981-07-25	1982-01-24	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1985-01-23	1985-07-25	1986-01-24	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1989-01-23	1989-07-25	1990-01-24	$7700.00	Window Closed / Lapsed

Acoustic holography apparatus

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