Ultrasonic fault detection system using a high dynamic range analog to digital conversion system
First Claim
1. An object inspection system, comprising:
- a transmit and receive section to generate a test signal and to receive a responsive echo signal;
a transducer that converts the test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least three signal processing channels, each channel scaling the echo signal to a different degree, and each channel having a respective analog to digital converter; and
a selection circuit which selects that output of that analog to digital converter which provides the largest amplification of the echo signal without having overflowed.
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Accused Products
Abstract
A method and apparatus for effecting ultrasonic flaw detection of an object processes an echo signal received from the object being tested in at least three signal channels, wherein the echo signal is scaled to different degrees along each channel to increase and extend the dynamic range of an associated A/D converter system, in a manner which dispenses with the need for using numerous analog high pass and low pass filters and a variable gain amplifier. This reduces complexity and avoids performance limitations. The digital to analog converters sample the differently scaled input signal and a selection circuit selects the output of the digital output obtained from that analog to digital converter which has the highest gain, but which has not overflowed. The digital outputs are seamlessly merged to produce an output that can be displayed as a scan display which shows the location of faults.
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Citations
65 Claims
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1. An object inspection system, comprising:
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a transmit and receive section to generate a test signal and to receive a responsive echo signal;
a transducer that converts the test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least three signal processing channels, each channel scaling the echo signal to a different degree, and each channel having a respective analog to digital converter; and
a selection circuit which selects that output of that analog to digital converter which provides the largest amplification of the echo signal without having overflowed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for ultrasonic object testing comprising the steps of:
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providing a test signal to a transducer to generate an ultrasonic signal capable of being propagated and reflected in a target object to be tested;
receiving an ultrasonic echo signal and producing an echo signal to be processed;
processing the echo signal in at least three signal processing channels with the echo signal being scaled to different degrees in each processing channel and thereafter being converted to a digital output utilizing a respective analog to digital converter in each processing channel; and
selecting an output from that analog to digital converter which provides the largest amplification of the echo signal without having overflowed. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. An object inspection system, comprising:
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a transmit and receive section to generate a test signal and to receive a responsive echo signal, a transducer that converts a test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least one signal processing channels, each channel including a respective preamplifier that scales the echo signal to a different degree;
an analog to digital converter coupled to the preamplifiers via amplification circuits, in a manner that passes to the analog to digital converter only a non-saturated output of at least one of the preamplifiers; and
an automatic gain control circuit which is coupled to the outputs of the preamplifiers and is capable of detecting the magnitudes of the outputs of the preamplifiers and to provide gain settings for the multiplier circuits which are selected to assure that the non-saturated output is provided to the analog to digital converter. - View Dependent Claims (38, 39)
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40. An object inspection system, comprising:
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a transmit and receive section to generate a test signal and to receive a responsive echo signal;
a transducer that converts the test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least two signal processing channels, each channel scaling the echo signal to a different degree, and each channel having a respective analog to digital converter;
a selection circuit which selects that output of that analog to digital converter which provides the largest amplification of the echo signal without having overflowed; and
a channel blender responsive to the selection circuit and operable to blend outputs of said analog to digital converters to produce a blended analog to digital output. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47)
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48. A method for ultrasonic object testing comprising the steps of:
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providing a test signal to a transducer to generate an ultrasonic signal capable of being propagated and reflected in a target object to be tested;
receiving an ultrasonic echo signal and producing an echo signal to be processed;
processing the echo signal in at least two signal processing channels with the echo signal being scaled to different degrees in each processing channel and thereafter being converted to a digital output utilizing a respective analog to digital converter in each processing channel;
selecting an output from that analog to digital converter which provides the largest amplification of the echo signal without having overflowed; and
blending, responsive to said selecting step, outputs of said analog to digital converters to produce a blended analog to digital output. - View Dependent Claims (49, 50, 51, 52, 53, 54, 55, 56)
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57. An object inspection system, comprising:
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a transmit and receive section to generate a test signal and to receive a responsive echo signal;
a transducer that converts the test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least two signal processing channels, each channel scaling the echo signal to a different degree, and each channel having a respective analog to digital converter;
a selection circuit which selects that output of that analog to digital converter which provides the largest amplification of the echo signal without having overflowed; and
a delay circuit for delaying outputs of at least one of the analog to digital converters to allow the analog to digital converters to respond to a leading edge of a fast slewing input signal, prior to processing of said outputs at said selection circuit. - View Dependent Claims (58, 59)
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60. An object inspection system, comprising:
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a transmit and receive section to generate a test signal and to receive a responsive echo signal;
a transducer that converts the test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least two signal processing channels, each channel scaling the echo signal to a different degree, and each channel having a respective analog to digital converter;
a selection circuit which selects that output of that analog to digital converter which provides the largest amplification of the echo signal without having overflowed; and
a delay circuit which is effective to cause the selection circuit to refrain from selecting an analog to digital converter output which has overflowed, until after the overflowed analog to digital converter has recovered from a saturation condition.
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61. An object inspection system, comprising:
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a transmit and receive section to generate a test signal and to receive a responsive echo signal;
a transducer that converts the test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least two signal processing channels, each channel scaling the echo signal to a different degree, and each channel having a respective analog to digital converter;
a selection circuit which selects that output of that analog to digital converter which provides the largest amplification of the echo signal without having overflowed; and
a respective frequency trim circuit for at least one of said signal processing channels, the respective frequency trim circuit causing the frequency responses of the channels to match one another.
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62. An object inspection system, comprising:
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a transmit and receive section to generate a test signal and to receive a responsive echo signal;
a transducer that converts the test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least two signal processing channels, each channel scaling the echo signal to a different degree, and each channel having a respective analog to digital converter;
a selection circuit which selects that output of that analog to digital converter which provides the largest amplification of the echo signal without having overflowed;
a preamplifier associated with each channel; and
a saturating preventing circuit associated with each preamplifier and effective to prevent saturation of a respective input stage of each preamplifier, to prevent signal distortion from affecting inputs to other channels.
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63. An object inspection system, comprising:
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a transmit and receive section to generate a test signal and to receive a responsive echo signal;
a transducer that converts the test signal to an ultrasonic signal, applies the ultrasonic signal to a target object to be tested, receives an ultrasonic echo signal and produces the echo signal for the transmit and receive section;
a signal processing circuit coupled with the transmit and receive section for receiving and processing the echo signal, the signal processing circuit including at least two signal processing channels, each channel scaling the echo signal to a different degree, and each channel having a respective analog to digital converter;
a selection circuit which selects that output of that analog to digital converter which provides the largest amplification of the echo signal without having overflowed; and
a reference voltage circuit respectively applicable to each of said analog to digital converters in each signal channel to adjust a full scale range thereof. - View Dependent Claims (64)
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65. A method for ultrasonic object testing comprising the steps of:
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providing a test signal to a transducer to generate an ultrasonic signal capable of being propagated and reflected in a target object to be tested;
receiving an ultrasonic echo signal and producing an echo signal to be processed;
processing the echo signal in at least two signal processing channels with the echo signal being scaled to different degrees in each processing channel and thereafter being converted to a digital output utilizing a respective analog to digital converter in each processing channel;
selecting an output from that analog to digital converter which provides the largest amplification of the echo signal without having overflowed; and
enabling a full dynamic range of sampled data of the echo signal to be processed on every sample clock cycle, in a manner which allows the sampled data to be rendered on a linear scale or on a logarithmic scale.
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Specification