Multi channel multiplexed inspection system and method

Field of invention The present invention generally relates to devices and methods for inspecting structures, and more specifically, devices and methods for inspecting structures that provide multiple multiplexed channels for non-destructive inspection of structures. Regarding the method.

background Non-destructive testing (NDI) of structures, also known as non-destructive testing (NDT), is a thorough examination of a structure without damaging it or requiring significant disassembly of the structure. Accompany. Non-destructive inspection is usually preferred to avoid the schedule, work and costs associated with the removal of inspection parts, and to avoid the possibility of damaging the structure. Non-destructive inspection is advantageous for many applications that require a thorough inspection of the exterior and / or interior of the structure. For example, non-destructive inspection is widely used in the aircraft industry to inspect aircraft structures for all types of internal or external damage or defects in aircraft structures. The inspection may be performed during the manufacture of the structure and / or once the structure is in use. For example, inspections may be required during manufacturing and future continued use to verify the integrity and suitability of the structure for continuous use. However, access to the inner surface is often more difficult or impossible without disassembly, such as removing parts for inspection from the aircraft.

Structures that are regularly non-destructively tested include composite structures, such as composite sandwich structures, and other adhesively joined panels and assemblies, including fuselage frames and shear ties, wing stringers, floor beams, and more. Includes, but is not limited to, flanges and radius divisions of horizontal stabilizer ribs, as well as floor columns. In this regard, composite structures are widely used throughout the aviation industry because of the engineering quality, design flexibility and low weight of composite structures, such as the stiffness-to-weight ratio of composite sandwich structures. Therefore, it is often desirable to inspect the composite structure to identify foreign bodies or defects that can adversely affect the performance of the composite structure, such as cracks, cavities or porosity. For example, typical defects in composite sandwich structures commonly made by one or more layers of lightweight honeycomb or foam core material with composite skins or metal skins glued to each side of the core are core and outer. Includes peeling that occurs at the interface with the plate or at the interface between the core and the bulkhead intermediate plate.

Various types of sensors may be used to perform non-destructive inspection. One or more sensors may move over the part of the structure to be examined and receive data about the structure. For example, pulse reflection (PE) sensors, transmission (TT) sensors, or shear wave sensors are used to obtain ultrasonic data such as thickness measurements in structures, layer defect and hole detection, and / or crack detection. May be done. Resonance sensors, pulse echo sensors, or mechanical impedance sensors may be utilized to display cavities or holes in structures such as adhesive bonding lines. High resolution inspection of aircraft structures is commonly performed using semi-automatic ultrasound testing (UT) to provide a planar image of the part or structure being inspected. Homogeneous laminates can be inspected using a single-sided pulse echo ultrasound test (PEU), but composite sandwich structures usually require a transmitted ultrasound (TTU) test for high resolution inspection. In transmissive ultrasonography, ultrasonic sensors, such as transducer pairs or transducers and receiver sensors, are positioned to face the other, but to contact both sides of the structure being inspected, such as both sides of the composite. Ultrasonic signal has few transducer pairs Both are transmitted by one, propagated through the structure and received by the other transducer. The data obtained by a sensor such as a TTU transducer is usually processed by a processing element and the processed data can be presented to the user via a display.

To increase the speed or speed of inspecting structures, the scanning system may be an ultrasonic probe with an array of ultrasonic transmitters and receivers, or a probe with one or more ultrasonic transmitters and receivers. It may include an array. Typically, each "channel" in an array means a pair of transducers and receivers, including a transmit channel to the transducer and a receive channel from the receiver. In general, the more channels available, the wider the physical range of scannable components. Therefore, it is possible to proceed with the inspection of the structure more quickly and efficiently, thereby reducing the cost associated with the inspection.

TTU sensors, or TTU transducers and receivers, may be controlled by a variety of systems, including systems that allow multiple TTU transducers and receivers to be used in a single probe, an array of probes, or a combination thereof. Good. The more pairs of TTU transducers and receivers, the faster the component can be scanned and the control system will be able to keep up with the data transmissions provided by the TTU transducers and receivers. A TTU system that includes a large number of TTU transducers and receivers is said to have a corresponding number of channels, one channel referring to a pair of transducers and receivers. Multi-channel TTU systems are usually expensive to build. Partly because they are TTU<u style="single">Transducer</u> Because it includes a separate RF amplifier and envelope (peak) detector for each receiving channel of ultrasonic data from a pair of receivers. In addition, a typical multi-channel TTU system uses individual pulsar circuits for each channel and requires a great deal of space to accommodate and route a large number of channels together. Often, multi-channel systems are housed in large racks of electronic components. In addition to high cost and large size requirements, maintaining multi-channel systems was usually problematic and costly. Typical multi-channel TTU systems can be difficult to repair due to the number of individual parts and the large number of wires required, in addition to the often obsolete parts. In addition, typical multi-channel TTU systems are limited to communicating processed signals as digital data with a resolution of 8 bits due to slow processing and / or communication paths, and are used to combine individual components together. There is a lot of electronic noise due to the large number of RF cables that are used.

Therefore, there is a need for improved systems and methods for multi-channel nondestructive inspection that provide high data throughput, high dynamic range, and simplification of supporting electronics.

<p> Outline of the invention In view of the aforementioned background, embodiments of the present invention provide improved systems and methods for multi-channel nondestructive inspection that provide high volume data throughput, high dynamic range, and simplification of supporting electronics. To do.</p><p> According to an advantageous embodiment of the present invention, a system including an interface board, at least one pulsar board, a plurality of transmission channels, at least one receiver board, and a plurality of reception channels is provided. The interface board is connected to the pulsar board, and the pulsar board is connected to the transmission channel. The interface board is also connected to the receiver board, and the receiver board is connected to the receiving channel. Receiver board is at least 7 It may include a log amplifier for logarithmic amplification of signals from multiple receive channels over a dynamic range of 0 decibels (dB). The receiver board may also include a tuning filter that is connected to each of the receiving channels and filters the signal received on the receiving channel to a desired frequency, such as 5 MHz. The receiver board and interface board may be capable of processing signals from the receiving channel at a resolution of 12 bits. The interface and pulsar boards may be able to communicate data to the transmit channel at a channel circulation rate of 200 microseconds (μs) per transmit channel, which is 6.4 when 32 transmit channels are used. It is a circulation speed of 5kHz that goes around all transmission channels every millisecond (ms). The receiver board may also be capable of receiving and processing data from the receiving channel at a channel circulation rate of 200 microseconds (μs) per receiving channel.</p><p> The interface board may be connected to a remote device such as a computer with a microprocessor via an Ethernet® connection capable of transmitting scanning data with a resolution of 12 bits in real time. The interface board may also be interface-connectable to the data encoder, such as by using an encoder interface that is coupled to the interface board and capable of receiving data from the encoder and providing the data to the interface board. The encoder interface may include one or more counter chips. The encoder interface may be capable of receiving data such as position data, speed data, velocity data, and distance data.</p><p> According to another advantageous embodiment of the invention, the system for inspecting the structure is an interface board, two pulsar boards each coupled to 16 transmit channels, and 16 receivers each. The receiver board contains data from 32 receiving channels by logarithmically amplifying the signal from the receiving channel over a dynamic range of at least 70 decibels (dB), including two receiver boards coupled to the channel. It can be processed. The pulsar board may be a printed circuit board (PCB) and may contain 16 pulsars, one for each of the 16 transmit channels.</p><p> The receiver substrate of an advantageous embodiment of the present invention comprises a logarithmic amplifier as well as a multiplexer for providing 70 dB isolation between receiving channels, with the 70 dB isolation provided by the multiplexer. Data from multiple receive channels may be able to be processed using log amplification with a dynamic range of 70 dB by a log amplifier. The multiplexer may be a series of multiplexing chips, also referred to as multiple layers of multiplexing switches. 70 dB separation between channels may be provided, for example, by connecting a 60 dB multiplexing chip in series with a 10 dB multiplexing chip. The multiplexing chip may be switchable in receiving channels. The log amplifier may be capable of providing log amplification from -67 dB to + 3 dB.</p><p> In one more advantageous embodiment of the present invention, the receiver board may include a logarithmic amplifier serially coupled to a linear amplifier. The linear amplifier may be capable of providing a linear amplification of 20 dB.</p><p> A more advantageous embodiment of the system for inspecting structures of the present invention is an interface board, at least one pulsar board, multiple transmit channels, at least one receiver board, and multiple receive channels. May include. The interface board is connected to the pulsar board, and the pulsar board is connected to the transmission channel. The interface board is also connected to the receiver board, and the receiver board is connected to the receiving channel. The receiver board uses data from multiple receive channels with a log gain of at least 70 dB. May be processable. The receiver board also has multiple tuning filters, one coupled to each of the receiving channels, a multiplexer serially coupled to multiple tuning filters, a log amplifier serially coupled to the multiplexer, and a log amplifier serially coupled to the log amplifier. It may include a linear amplifier and an analog-to-digital converter serially coupled to the linear amplifier. The receiver board also includes an envelope peak detector for capturing the voltage peaks of the multiplexed, logarithmically amplified, linearly amplified signal connected in series between the linear amplifier and the analog-to-digital converter. You may be. The receiver board also contains a diode for separating the positive voltage from the multiplexed, logarithmically amplified, linearly amplified signal connected in series between the linear amplifier and the envelope peak detector. May be good. The multiplexer may include a series of multiplexing chips, with 70 dB separation between channels being a first layer formed by 60 dB multiplexing chips and a second layer formed by one or more 10 dB multiplexing chips. It may be provided by being serially coupled in a hierarchy, and the multiplexer may be switchable in receiving channels. If a single 60 dB multiplexing chip may be used to switch 16 receive channels, then two 10 dB multiplexing chips may be used to switch 8 receive channels.</p><p> The 32-channel multiplexing system for inspecting the structures of an advantageous embodiment of the present invention includes 32 transmit transducers, 32 receive transducers, 32 receive channels, and a multiplexing system. You may be. The 32 receiving transducers are communicably coupled to receive the ultrasonic signal transmitted by the 32 transmitting transducers through the structure under inspection. To process the ultrasonic signal received by the 32 receive transducers and transmitted through the 32 receive channels, the 32 receive transducers are individually connected to the 32 receive channels coupled to the multiplexing system. Is combined with. The multiplexing system includes a logarithmic amplifier and may be capable of processing data by logarithmically amplifying each channel with a dynamic range of at least 70 dB. Each transmitting transducer may include a pulsed sensor and each receiving transducer may include a receiving sensor communicatively coupled to a corresponding pulsed sensor. Each pulsed sensor may be coupled to a transmit channel and each receive sensor may be coupled to a receive channel. The 32-channel multiplexing system may also include an interface for remote communication to the analytical computer. The multiplexing system may be adapted to switch receive channels. The multiplexing system may further filter the data received from the receiving channel and then switch the data for logarithmic amplification. The multiplexing system may also be capable of linearly amplifying preprocessed data using logarithmic amplification with a dynamic range of at least 70 dB. The linear amplification may have a gain of 20 dB. The multiplexing system may also be capable of converting preprocessed data from analog to digital using logarithmic and linear amplification.</p><p> A method for multiplexing the channels of the inspection system of an advantageous embodiment of the present invention is provided, the step of receiving signals from multiple receiving channels after propagating through the component under inspection. , Including the step of multiplexing the received signal. The steps of multiplexing the received signal include filtering the received signal, switching the received channel to select one received channel, defining the switched received signal, and log-amplifying the switched received signal. It includes a step, a step of linearly amplifying a switched, logarithmetically amplified received signal, and a step of converting a switched, logarithmically amplified, linearly amplified received signal from analog to digital. The step of logarithmically amplifying the switched received signal may include a step of providing logarithmic amplification over a dynamic range of at least 70 dB, for example a step of providing amplification of 67 dB to +3 dB. An embodiment of the method may also include the step of transmitting a signal to a plurality of transmission channels. The method also includes controlling the timing requirements for the step of transmitting the signal to multiple transmission channels and transmitting the multiplexed signal to the remote processor in real time. You may. The step of transmitting the multiplexed signal to the remote processor in real time may include the step of transmitting the multiplexed signal from the receiving channel at a circulation rate of 200 microseconds (μs) per receiving channel. Is a 5kHz cyclic rate that cycle through all receiving channels every 6.4 milliseconds (ms) when 32 transmitting channels are used, and the multiplexed signal is processed at 12-bit resolution and transmitted. Will be done. The step of transmitting a signal to multiple transmit channels may include the step of communicating data to the transmit channels at a cyclic rate of 200 microseconds (μs) per transmit channel, which is used by 32 channels. It is a speed of 5kHz that goes around all transmission channels every 6.4 milliseconds (ms) when it is done. The method may also include the step of processing the multiplexed signal from the receiving channel in 12 bits, which is all every 6.4 milliseconds (ms) when 32 channels are used. It is a speed of 5kHz that goes around the reception channel of. The method may also include a step of capturing the peak voltage. The method may further include the step of separating the positive voltage to capture the peak voltage.</p><p> These and other features of the invention as well as additional details are described further herein with reference to these and other examples.</p><p> Although the present invention has been described in general terms, the accompanying drawings, which are not necessarily drawn to scale, are referred to herein.</p>

Detailed explanation Here, the invention will be described more fully below with reference to the accompanying drawings in which some, but not all, examples of the invention are illustrated. In fact, these inventions may be embodied in many different forms and should not be construed as being limited to the examples described herein. Rather, these examples are provided so that this disclosure meets applicable legal requirements. Throughout, the same numbers and variables refer to the same elements and parameters.

The embodiments of the present invention may be particularly useful for inspection of composite structures in the aircraft industry. Further embodiments of the present invention may also be useful in many areas for a variety of other applications, including, for example, rocket manufacturing and inspection of composite sandwich structures.

Although the examples of the present invention are specifically designed for transmitted ultrasound (TTU) inspection or testing, they can be used for other inspection techniques such as pulse echo non-destructive inspection. Moreover, although the examples of the present invention are specifically designed for 32-channel TTU systems, they may be advantageously used to create TTU systems with fewer than 32 channels, eg 16-channel examples. Or, an embodiment of the invention is an embodiment of a TTU system with more than 32 channels, eg, 64 channels and 128 channels in which a 32 channel system is connected to two or four Ethernet hubs, respectively. It may be combined to be used favorably to make an example. If a multi-channel system has more than 32 channels, traditional Ethernet communication connections require buffering data at the transmit end to take into account the bandwidth of the Ethernet link. In some cases.

The terms "non-destructive testing" (NDI) and "non-destructive testing" (NDT) are used herein as synonyms.

FIG. 1 is a schematic block diagram of a 32-channel multiplexed TTU system according to an embodiment of the present invention. The system includes 32 pairs of corresponding transducers. 64 trance du Of the transducers, 32 are transmission transducers 10 or pulsed transducers on one side of the part or structure to be inspected. The other 32 transducers are the receive transducers 12 on the opposite side of the structure to be inspected. Therefore, 32 channels are provided for the 32 transmit transducers 10 and 32 channels are provided for the 32 receive transducers 12. As used herein, "channel" means a communication link to a transducer. Multiple transducers may be included in one device or probe. Alternatively, the channels are split in such a way that each probe acts as an array of probes, for example a 64 probe array with 32 transmit probes containing one transducer and 32 receive probes. May be done. Although each transmit or receive channel corresponds to an individual piezoelectric crystal transducer, the invention can be used even if one or more transducers correspond to one or more transducers. The individual transducers may be located on a single probe or on multiple probes acting as an array, as described above. For each of the 32 transmit channels 10, for example, the pulsar substrate pulsed channels 1-32, one channel every 200 microseconds (μs), at a repetition rate of 5 kHz. It may be sequentially pulsed to cycle through 32 channels 10 every 4 milliseconds (ms). A pulsar board that pulses a channel means a pulsar board that supplies a transmission signal to a transmission channel for a transducer. An exemplary pulsar board, or interface board, or receiver board may be a printed circuit board (PCB) having an electrical connection or communication path. The interface board 14, and / or the processor or microcontroller of the attached computer (not shown), may also be used to control the sequential pulsing of the 32 transmit channels 10 and the ordering of the received signals. Good. The repetition rate for channel circulation is usually such that the ultrasonic signal reaches the surface of the part through the couplant from the transmitting transducer crystal, passes through the part under inspection, and is received from the surface of the part through the couplant. Selected and limited due in part to the time it travels to the transducer crystal. The repetition rate may also depend on factors such as the communication bandwidth for transmitting the processing signal from the multiplexing receiver board to the computer that controls and / or processes the inspection.

An embodiment of the invention shown in FIG. 1 shows two 16-channel pulsar boards 20, 22, each connected to an interface board 14, each providing 16 of 32 transmit channels 10. doing. A pulsar board is typically a PCB board that can use the corresponding pulsars of the pulsar board to independently supply signals directed to 16 different transducers from the interface board to the 16 corresponding channels. The pulsar supplies an electronic pulse signal for a digital or electronic signal from the interface board. Similarly, it contains two 16-channel receiver boards or RF amplifiers and A / D boards 24, 26, each coupled to interface board 14, 16 of 32 receive channels 12 each. Received pieces. The receiver substrate and its electronic device of the present invention will be fully described below. A 32-channel multiplexed TTU system as shown in FIG. 1 may also include an encoder interface 16 that provides an interface between the position encoder 18 of the scanning system and the interface board 14 of the 32-channel multiplexed TTU system. The encoder interface 16 is provided by LSI Computer Systems, Inc. of Melville, NY. ) Two counter chips, such as the manufactured LS7266R1 counter chip, may be included. The counter chip has an internal register that holds the current value as the encoder on the scanning system moves back and forth with the scanning probe. The counter chip counts up and down from the reference value to provide different values for the counter chip's internal registers. This information is commonly referred to as scanning system location information. Since the encoder mechanically tracks the movement of the transducer, the position information is somewhat physically related to the position of the transducer. For this reason, the location provided by the encoder The information is synchronized with the movement of the scanning probe, but the transducer signal is asynchronous with the movement of the scanner. Therefore, by combining the position information of the encoder via the encoder interface, the microprocessor can combine the two pieces of information to determine the position of the transducer with respect to a specific ultrasonic signal. For example, the microprocessor may incorporate location information from the counting chip of the encoder interface into the same data packet as the corresponding ultrasonic data. Additional software may then be able to analyze that particular data packet as having ultrasonic data values at a particular location that occurred during the scan. Encoders are typically used to provide location information, but in addition to or instead, encoders may be used to provide such data as speed data, velocity data, and distance data. ..

Receiver boards 24, 26 may include a tuning filter 102 for each receive channel 12. For example, the tuning filter 102 may include a bass amplifier and a tank circuit. The tunable capacitor of the tuning filter 102 may be tuned to filter the received signal to a particular frequency, for example the piezoelectric crystal frequency oscillating at 5MHz. After filtering each of the received signals, all 16 signals are fed to the first layer 106 of the multiplexing switch, called the first multiplexing chip. As a non-limiting example, the multiplexing chip allows a signal voltage input range of 15 volts between peak voltage (Vpp), Maxim Integrate in Sunnyvale, California. MAX310CPE multi-manufactured by Maxim Integrated Products, Inc. It may be an overlapping chip. The first layer 106 of the multiplexing switch may provide 60 dB of separation between the 16 signals. Second multiplexing<u style="single">Tip</u>A second layer 108 of the multiplexing switch, also referred to as, may provide an additional 10 dB separation between channels. The second layer 108 of the multiplexing switch may also use the MAX310CPE multiplexing switch. Two layers of multiplexing switches<u style="single">106 and</u>Using 108 can achieve 70 dB separation between channels. 70dB separation between channels affects smaller inputs in one channel than in another, as given by 70dB = 20 × Log (difference) (in the equation, (difference) is equal to 3000 at 70dB). Can be 3000 times larger without giving. For example, one channel can have a 5 MHz signal with a strength of 1 millivolt (mV), and another channel can have a 5 MHz signal with a strength of 3 volts (V) without affecting this 1 mV signal. Can have. In addition, by dividing the multiplexing switch into two layers, the capacitance is reduced so as not to deteriorate the RF signal. Different combinations of channel switching may be used with two layers of multiplexing switches. For example, a single 60 dB multiplexing chip used to switch 16 channels could be used with two 10 dB multiplexing chips to switch 8 channels each. Good. A single receive channel may be selected by selecting the corresponding channels in the first layer 106 of the multiplexing switch and the second layer 108 of the multiplexing switch.

The filtered and multiplexed single receive channel signal is fed to the log amplifier 110, which provides log amplification over a dynamic range of 70 dB, such as a voltage range of -67 dB to + 3 dB, but log amplification has a different dynamic range. Can be the center. For this reason, the layered multiplexing chips 106, 108 provide the full dynamic range of the capabilities of the log amplifier 110. Logarithmic amplification is expressed in the formula Gain_log= 20 × Log (V_{out out}/ V_in). After logarithmic amplification, the signal may be linearly amplified by a linear amplifier 114 to provide, for example, 20 dB linear amplification to adjust the logarithmically amplified signal to the full range of the analog-to-digital converter. Linear amplification is given by the equation Gain_lin= (V_{out out}/ V_in). This signal may then be converted from analog to digital using an analog-to-digital chip 118 (A / D converter), such as an analog-to-digital chip with an input of 0-10 volts. Linear increase so that the peak value is converted to a digital signal by the A / D converter. Envelope (peak) detector 116 and diode 115 may be used between the width and the analog to digital conversion. The diode 115 can separate the positive voltage of the amplified signal so that the envelope (peak) detector 116 can capture the peak amplitude of the signal. For TTU inspection, only the peak amplitude of the signal is needed to identify defects from the changing amplitude. For example, the log amplifier 110 may output a signal with a peak voltage (Vpp) of 1.4 volts centered at 0 volts. The linear amplifier 114 may increase the signal to a signal of 20Vpp (-10V to + 10V). The diode 115 may separate the peak range of + 10V (0V to + 10V). The envelope peak detector 116 may capture the peak amplitude of the signal in the range 0V to + 10V. The analog-digital chip 118 may then convert a 0-10 V signal into a 12-bit resolution digital signal.

The use of logarithmic amplification with a dynamic range as large as 70 dB helps identify small changes or defects in the part being inspected. For example, a 70 dB dynamic range may be needed to find 68 underlayer foreign debris in a 1/2 inch thick piece of graphite under inspection. Here the thickness of one layer is 7/1000 inches. The debris can be approximately at the bottom edge of the graphite piece under inspection when viewed through the component from the transmitting transducer to the receiving transducer. Sound, or specifically the ultrasonic signal, is attenuated as it propagates through the part being inspected. For example, in an inspection of a 1/2 inch thick piece of graphite, the ultrasonic signal reaches the 68th layer, where the debris is located and a 2 dB change may be required to detect the presence of the debris. , May have dropped by as much as 60 dB during transmission. To detect this 2 dB change, the noise must not be large enough to drown out the 2 dB change due to debris. The dynamic range must be large enough to detect defects in the structure under inspection, debris in graphite. By using a large log gain, the scanning system may be able to resolve its details at a high level in the part under inspection. Using logarithmic amplification amplifies small changes rather than large changes in the signal. Large changes in a signal usually include noise. By comparison, when using linear amplification, noise is amplified just as much as the signal. And by using a large dynamic range, the system can scan thick parts. In addition to taking into account the high dynamic range, the system must be able to multiplex the high dynamic range without causing crosstalk or noise between channels. In order to switch or multiplex a signal with a large dynamic range without introducing noise or crosstalk between channels, the multiplexing is a first 60 dB range multiplexing chip and a 10 dB range multiplexing.

FIG. 2 is a schematic block diagram of a 32-channel multiplexed TTU system connected to a remote processor using an Ethernet® connection according to an embodiment of the present invention. As shown in the schematic of FIG. 2, the 32 transmit channels 10 may be coupled to 32 transducers used to inspect component 30. The 32 receive channels 12 may be coupled to 32 receive transducers that receive signals transmitted from the 32 corresponding transducers through component 30 under inspection. A multiplexed TTU system is used to further process, analyze, and display the results of an inspection via a communication connection or link, such as an Ethernet® communication connection 40 or a serial communication connection, as fully described here. It may be connected to a remote processor 42, such as a computer with a microprocessor.

FIG. 3 is a flow chart of an embodiment of a 32-channel multiplexed TTU system according to an embodiment of the present invention. The flow diagram and / or elements of FIG. 3 shown by the dotted lines are performed by the components of the TTU system that may be included in one embodiment of the present invention but are not required to be included. May be good. A pulsar board may be used to transmit the signal to the transmit channel 200. In this process, the processor defines and sends a control signal for the pulsar board to send the pulse signal to the corresponding transducer along the selected channel, and step 202 and the interface board sends the control signal to the pulsar board. Includes 204 and step 206 in which the pulsar board transmits a pulsed signal to the transmit channel as specified and controlled by the processor via the interface board. Once the pulse signal is transmitted to the transmit channel 200, the transmit channel directs the pulse signal to the transmit transducer of the inspection system 210. The inspection signal then passes through the component from the transmitting transducer to the receiving transducer 212. The inspection signal received by the inspection system's receive transducer propagates along the receive channel 214. The receiving channel then directs the received inspection signal to the receiver board 216. The receiver board then processes the received inspection signal 220. The processing of the received signal includes step 222, in which a tuning filter on each receiving channel filters the signal to a tuning frequency, eg 5 MHz, and step 224, where the first layer of the multiplexing switch provides 60 dB of separation between channels. Step 226, where the second layer of the multiplexing switch provides an additional 10 dB separation between channels, a logarithmic amplification 228 with a dynamic range of 70 dB, a linear amplification 230 at 20 dB, and a positive voltage separation 231 and envelope. Includes line peak detection 232 and analog to digital conversion 234. The multiplexed, logarithmically amplified, linearly amplified, analog-to-digitally converted received signal may be transmitted 240 from the receiver board to the interface board. An embodiment of a 32-channel multiplexed TTU system may also include a 250 encoder that sends location information to an encoder interface. The encoder interface may transmit scanning position information to the interface board 252. Inter The face board may combine the received signal data with the scan position information and transmit the signal and position information to the remote processor over an Ethernet® connection 260. The remote processor may match the received signal to the position information from the encoder for further processing and / or analysis of the scan data.

By multiplexing the channels of the receiver board into a single channel, one embodiment of the invention is a limited number of secondary components, such as one logarithmic amplifier and one analog-to-digital (A). / D) Can include a converter. Further, by multiplexing channels, one embodiment of the invention allows for substantial size reduction, eg, one interface board for 32 channels, two pulsar boards, and two receivers. It is possible to realize a unit in which the substrate can be contained in a single box of 17 × 18 × 9 . For example, the unit may be small enough to be mounted beneath the scanner and therefore does not occupy additional floor space at the factory or inspection site.

The embodiments of the present invention can achieve 12-bit analog-digital signal conversion rather than typical 8-bit digital data, thus providing a higher signal-to-noise ratio, i.e., higher sensitivity. Therefore, in a system restricted by a serial communication connection or the like, it is only possible to transmit scanning data in real time at an 8-bit resolution. For example, an analog signal from 0 to 10V is converted to a digital signal with a value from 0 to 255, so the analog resolution is 0.039 volts (10V / 2).⁸). By comparison, systems with improved communications, such as systems with Ethernet connectivity, can transmit scan data in real time at 12-bit resolutions, for example 0-10V analog signals are 0. Converted to a digital signal with a value of ~ 4095, so 0.00244 volts (10V / 2) for analog resolution¹²). By comparison, the noise of an 8-bit system with a dynamic range of 70 dB would be 1 bit or ± 0.276 dB. However, the noise of a 12-bit system with a dynamic range of 70 dB would be only ± 0.02 dB. Serial communication connections such as traditional serial links may not be able to transfer 12-bit data in real time. General In addition, it is preferable to use the highest possible digital signal resolution that can be resolved from an analog signal. This is because it is usually limited by the noise present in the signal.

The use of Ethernet® communication technology has doubled the speed of traditional data acquisition. Increasing the data acquisition rate allows for faster part scanning, which can result in shorter inspection times and lower inspection costs. For example, a current system with 32 channels could scan 5 inches per second. Examples of the present invention may be capable of scanning as much as 10 inches per second using a conventional Ethernet® communication connection using 32 channels.

The embodiments of the present invention are also easily calibrated due in part to the reduced number of components and centralized control via the common interface board.

The embodiments of the present invention are easier to repair than a typical multi-channel TTU system. For example, repairing a failure in a multi-channel TTU system with individual components on each channel requires a technician to determine which of the many channels is not in operation. By comparison, one embodiment of a multi-channel TTU system of the present invention with only five printed circuit boards has fewer components and circuits to repair failures, essentially reducing the number of possible non-operational types. Let me. Similarly, due to the reduced number of components and circuits, the embodiments of the present invention are less expensive to repair than typical multi-channel TTU systems.

An exemplary embodiment of the 32-channel multiplexer of the present invention may use a 17-inch x 18-inch x 9-inch electronic box to hold the electronic components of the 32-channel multiplexer. Due to the high dynamic gain and inspection frequencies such as 5MHz, the RF multiplexer board, also referred to herein as the receiver board, may have a thick shield to provide spacing between components. The interface board, which controls the timing requirements of the multiplexing system, controls the pulsing of the transmitting transducer and is used for communication to processors such as remote computers for analyzing received and processed signals, serial and / or Ethernet®. ) May include connections. The interface board may also include position and / or distance information from the encoder received via the encoder interface in the signal data packet, thus eliminating the need for an external encoder board. An embodiment of the invention provides data digitization with a 32-channel multiplexer, and then reduces noisy RF cables by transmitting data for analysis through a serial or Ethernet® connection. In addition, by providing the entire 32-channel multiplexer in such a small housing, the unit is small enough to be located near the scanning system, for example under a scanner, thereby avoiding additional floor space consumption. To do. These and other features of the invention make the embodiments of the invention a convenient as well as efficient and economical multiplexing system. In particular, the embodiments of the present invention are existing by simplifying the existing system so as to reduce the number of related parts and the complexity of wiring, for example by incorporating the 32-channel TTU multiplexing system of the present invention. Maintenance costs associated with multi-channel TTU equipment can be reduced. For example, the multiplexing technique of the present invention reduces the receiving channels to a single channel on each receiver board, so for each receiver board 1 It requires only one log amplifier, one linear amplifier, and one analog-to-digital converter. In addition, the embodiments of the present invention may be specifically designed for TTU examinations, as compared to existing systems and / or examples that can be designed for pulse echo examinations. For example, the type of electronics and components may be selected to provide a high dynamic range, such as 70 dB, to match the desired TTU inspection characteristics.

As fully described herein, systems and methods for multi-channel nondestructive inspection are provided that provide high volume data throughput, large dynamic range log amplification, and simplification of supporting electronics. More specifically, the structure is inspected using an interface board, two pulsar boards each coupled to 16 transmit channels, and two receiver boards coupled to 16 receive channels each. A system and method according to an embodiment of the present invention for this is provided, the receiver substrate can process data from 32 receiving channels by logarithmically amplifying a dynamic range of at least 70 dB. The receiver board consists of a two-tier series connection of multiplexing switches that provide 70 dB separation between channels, a log amplifier for logarithmic amplification of a 70 dB dynamic range, a linear amplifier, and an analog-to-digital converter. May include.

Many modifications and other embodiments of the invention described herein will come to the mind of those skilled in the art to which the invention belongs, benefiting from the teachings presented in the above description and related drawings. Therefore, it is understood that the invention should not be limited to the specified embodiments disclosed and that modifications and other embodiments are intended to be included in the appended claims. Should be. Although certain terms are used herein, they are used only in a general and descriptive sense and are not used for limited purposes.

<figref num="1">It is a schematic block diagram of the 32 channel multiplexing TTU system of one Example of this invention.</figref><figref num="2">FIG. 6 is a schematic block diagram of a 32-channel multiplexed TTU system connected to a remote processor using an Ethernet® connection of an embodiment of the present invention.</figref><figref num="3">It is a flow chart of one Example of the 32-channel multiplexing TTU system of one Example of this invention.</figref>