CN115901966A - Ultrasonic signal acquisition system based on time sequence control - Google Patents
Ultrasonic signal acquisition system based on time sequence control Download PDFInfo
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- CN115901966A CN115901966A CN202211675123.6A CN202211675123A CN115901966A CN 115901966 A CN115901966 A CN 115901966A CN 202211675123 A CN202211675123 A CN 202211675123A CN 115901966 A CN115901966 A CN 115901966A
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Abstract
The invention discloses an ultrasonic signal acquisition system based on time sequence control, which comprises a time sequence control module and a data acquisition module, wherein the time sequence control module is used for generating a plurality of paths of time sequence signals under the control of an external trigger signal, a time sequence signal A is used for controlling the moment and the pulse width of an excitation pulse section generated by an external ultrasonic signal generating device, and a time sequence signal B is used for controlling the data acquisition module to acquire a sampling interval of an ultrasonic echo sequence under the excitation pulse section; the data acquisition module is used for starting sampling at the rising moment of the time sequence signal B, the time sequence signal B is delayed for the time sequence signal A by tau, the data acquisition module is used for controlling the sampling starting moment of the data acquisition module to be aligned with the appearance moment of the ultrasonic echo sequence, the sampling is stopped at the falling moment of the time sequence signal B, and the falling moment of the time sequence signal B is set according to the storage space of the data acquisition module. The invention can collect the effective signals in the ultrasonic echo sequence under the condition of certain storage space.
Description
Technical Field
The invention belongs to the technical field of digital signal acquisition and time sequence control, and particularly relates to an ultrasonic signal acquisition system based on time sequence control.
Background
In various scientific researches, researchers need to completely collect and store various signals output by the experimental device, and then carry out scientific analysis by using software. After various signals are converted into electric signals through a conversion device, the electric signals are collected through a sampling card, the method is a common method in scientific experiments, and useful signal parts are collected and stored intact, so that the method is a premise for all scientific analyses.
Taking an ultrasonic measurement as an example, an ultrasonic signal belongs to one of acoustic signals, and under the most common echo measurement, the ultrasonic signal is often presented as an ultrasonic echo sequence composed of a plurality of ultrasonic pulse segments. Under a single excitation, the ultrasonic wave will be reflected back and forth in the sample to form a pulse sequence, wherein each pulse has a certain duration, adjacent pulses have different time intervals due to the size of the sample, and two adjacent excitations also have larger time intervals, so that the signal actually needed to be analyzed is only a small section where the echo sequence is located. In order to meet more advanced measurement requirements, the resonant frequency of the acquisition card is higher and higher nowadays, the required sampling rate is also higher and higher, and the storage space required for acquiring signals with the same duration is larger and larger. If the sound velocity is monitored in real time for a long time, and if the sampling interval is not designed but is continuously acquired, the space occupation is larger.
Under the requirement of the situation, if a common oscilloscope is adopted for signal acquisition, the storage depth of the oscilloscope is insufficient in a high sampling rate mode, and complete signal acquisition in the whole measurement process cannot be realized; the sampling rate of the wave recorder often cannot meet the requirement. In contrast, chinese patent CN201610577470.3 adopts a single-pole double-throw sampling timing control scheme, which is similar to a duplexer, and only can select a sampling object, but cannot adjust an effective sampling interval, cannot improve a storage space utilization rate, and also faces a problem that a large amount of storage is difficult during high-speed sampling; chinese patent CN201710134813.3 adopts a single chip microcomputer with an AD module to perform signal acquisition, only uses an excitation signal of the single chip microcomputer to control the start of sampling, and has no function of stopping sampling, so that the sampling interval design cannot be performed, and continuous acquisition can only be performed after the sampling is started until the sampling is full or stopped, during which a large number of useless signal segments are generated, which wastes storage space and is inconvenient for users to perform subsequent analysis.
Disclosure of Invention
In view of the defects of the prior art, an object of the present invention is to provide an ultrasound signal acquisition system based on time sequence control, which can acquire effective signals in an ultrasound echo sequence under a certain storage space.
In order to achieve the above object, the present invention provides an ultrasonic signal acquisition system based on time sequence control, which is used for acquiring ultrasonic echo signals, and comprises a time sequence control module and a data acquisition module, wherein,
the time sequence control module is used for generating a plurality of paths of time sequence signals under the control of an external trigger signal, wherein one path of time sequence signal A is sent to an external ultrasonic signal generating device, the time sequence signal A is synchronous with the trigger signal and controls the time and the pulse width of an excitation pulse section generated by the ultrasonic signal generating device through the rising time and the pulse width of the time sequence signal A, and the other path of time sequence signal B is sent to the data acquisition module and is used for controlling the data acquisition module to acquire a sampling interval of an ultrasonic echo sequence under the excitation pulse section and convert the sampling interval into a digital signal to be output to an external signal processing system for signal processing;
the data acquisition module is used for starting to sample the ultrasonic echo sequence at each rising moment of the time sequence signal B and stopping sampling the ultrasonic echo sequence at each falling moment of the time sequence signal B; the time sequence signal B is delayed for a time tau moment relative to the time sequence signal A, and is used for controlling the initial time of sampling of the data acquisition module to be aligned with the occurrence time of the ultrasonic echo sequence, the falling time of the time sequence signal B is set according to the storage space of the data acquisition module, and when the storage space is limited, the falling time of the time sequence signal B is set at the ending time of the ultrasonic echo signal under each excitation pulse segment.
The ultrasonic signal acquisition system based on time sequence control provided by the invention controls the sampling start and stop of the data acquisition module by utilizing the multi-channel time sequence signals of the time sequence control module, can flexibly determine the pulse echo sequence signal section to be acquired according to the actual position of the effective ultrasonic signal section and by controlling the position and the width of the time sequence signals, abandons useless signals, saves space and effectively improves the acquisition depth.
In one embodiment, the timing signal B is delayed with respect to the timing signal a by the time τ by the calculation formula:
τ=2L/v 0
in the formula (I), the compound is shown in the specification,Lrepresenting the size of the sample to be tested;v 0 and the sound velocity of the sample to be measured in the normal-temperature field-free environment is shown.
In one embodiment, the timing control module adopts a timing controller composed of an FPGA chip and a peripheral circuit thereof, the FPGA chip internally adopts a counter, a Carry4 Carry chain and two idelay2 delay chains under the control of a 200MHz master clock, and one of the idelay2 delay chains and the Carry4 Carry chain constitute the external trigger jitter compensation module.
In one embodiment, the data acquisition module employs an ADS54J42EVM acquisition card.
In one embodiment, the ultrasound signal acquisition system further comprises a storage controller and a data storage device, wherein the storage controller is respectively connected with the data storage device and the data acquisition module, and the storage controller is used for sending the digital signals output by the data acquisition module to the data storage device for temporary storage of data.
In one embodiment, the memory controller is connected to the timing control module, and the memory controller is further configured to provide temporary storage and reading of timing control data for the timing control module.
In one embodiment, the memory controller is implemented by a MIG IP core inside the FPGA chip.
In one embodiment, the data storage device adopts MT41K256M16HA-125 DDR3 memory chips.
In one embodiment, the signal processing system is configured to perform sinc interpolation and resampling on the digital signal according to shannon sampling theorem according to user selection, and then perform signal processing on the resampled signal.
In one embodiment, the ultrasonic signal generating device includes a pulse generator and two ultrasonic transducers, the pulse generator is configured to generate a corresponding excitation pulse segment according to the timing signal a, one of the ultrasonic transducers is configured to emit an ultrasonic signal to one end face of the sample according to the excitation pulse segment, and the other ultrasonic transducer is configured to measure an ultrasonic echo sequence emitted from the other end face opposite to the one end face of the sample.
Drawings
Fig. 1 is a schematic structural diagram of an ultrasound signal acquisition system based on time sequence control according to an embodiment of the present invention;
FIG. 2 is a timing diagram of the operation of the data acquisition module under the control of the timing control module according to the present invention;
FIG. 3 is a timing diagram illustrating a two-stage interpolation delay of the timing control module according to the present invention;
fig. 4 is a schematic structural diagram of an ultrasound signal acquisition system based on timing control according to another embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
In order to solve the problem that the conventional continuous acquisition ultrasonic echo sequence occupies a large storage space, the invention provides an ultrasonic signal acquisition system based on time sequence control, and as shown in fig. 1, the system comprises a time sequence control module 10 and a data acquisition module 20.
The timing control module 10 is configured to generate a plurality of timing signals with adjustable pulse widths under the control of an external trigger signal. As shown in fig. 2, one of the paths of timing signals a (excitation timing signals) is sent to an external ultrasonic signal generating device, the timing signal a is synchronized with the trigger signal, and the time and the pulse width of the ultrasonic signal generating device for generating the excitation pulse segment are controlled by the rising time and the pulse width of the timing signal a. The other path of time sequence signal B (sampling time sequence signal) is sent to the data acquisition module 20, and is used for controlling the data acquisition module 20 to acquire a sampling interval of the ultrasonic echo sequence under the excitation pulse section, and converting the sampling interval into a digital signal, and outputting the digital signal to an external signal processing system for waveform display, sound velocity calculation and analysis.
In this embodiment, the ultrasonic signal generating device may adopt an ultrasonic signal generating device commonly used in the field of ultrasonic echo measurement, for example, an ultrasonic signal generating device composed of a pulse generator and two ultrasonic transducers, where the pulse generator is configured to generate a corresponding excitation pulse segment according to the timing signal a, one of the ultrasonic transducers is configured to emit an ultrasonic signal to one end surface of the sample to be measured according to the excitation pulse segment, and the other ultrasonic transducer is configured to measure an ultrasonic echo sequence emitted from the other end surface facing the one end surface of the sample to be measured. Considering the time interval between the generation of the excitation pulse by the ultrasonic signal generating device and the measurement of the actual ultrasonic echo, the time sequence signal B sent to the data acquisition module 20 is delayed to the occurrence time of the actual effective signal segment, i.e. the starting time of the data acquisition module 20 for acquiring the ultrasonic echo sequence is aligned with the occurrence time of the actual ultrasonic echo signal.
Specifically, in order to align the starting time of the data acquisition module 20 with the time of the actual ultrasonic echo signal, the time sequence signal B may be set to be delayed by a time τ with respect to the time sequence signal a, and the delay time τ may be estimated according to the type and size of the sample actually used, i.e., τ =2L/v 0 ，LRepresenting the size of the sample to be tested;v 0 and representing the sound velocity of the sample to be measured in the normal-temperature field-free environment.
In order to accurately control the data acquisition module 20 to acquire an effective signal segment in the ultrasonic echo sequence, except that the delay time sequence signal B aligns the start time acquired by the data acquisition module 20 with the appearance time of an actual ultrasonic echo signal, the data acquisition module 20 needs to be controlled to stop signal acquisition in the interval time period of two adjacent excitation pulses, and the specific control mode is as follows:
the data acquisition module 20 samples the occurrence time of the ultrasonic echo signal under a segment of the excitation pulse at each rising time of the timing signal B, and stops sampling at each falling time of the timing signal B. The descending time of the time sequence signal B is set according to the storage space of the data acquisition module, when the requirement on the storage depth is high, namely the storage space is limited, the descending time of the time sequence signal B is set at the finishing time of the ultrasonic echo sequence under one section of excitation pulse, so that the whole echo sequence signal section under one section of excitation pulse is acquired, useless empty signals between the finishing time of the echo sequence and the beginning time of the next section of excitation pulse are abandoned, and the utilization rate of the storage space is improved; when the requirement on the storage space is not high, the falling time of the time sequence signal B can be set at the time when all sampling is finished or the storage space is full, and a whole segment of signal is continuously collected.
Further, after the effective signal is transmitted to the signal processing system from the high-speed return interface, the signal processing system can perform sinc interpolation and resampling on the signal according to shannon sampling theorem according to the selection of a user, so that higher equivalent sampling rate and higher signal restoration degree can be obtained as far as possible under the condition that the sampling rate of the data sampling card is limited.
At the original sampling rateF x = 1/T x New sampling rateF y = 1/T y For example, first, the entire signal with N sampling points is sampledx(nT x )And (3) carrying out sinc interpolation reconstruction:
wherein:
the signal is then resampled at the new sampling rate:
considering that the original signal x has a finite length, the operation process in the program is:
in the new signaly(mT y ) In the method, each point needs to be calculated once, and a new signal after resampling can be obtained after M times of operation.
The ultrasonic signal acquisition system based on time sequence control provided by the embodiment utilizes the multi-channel time sequence signals of the time sequence control module to control the sampling start and stop of the data acquisition module, can flexibly determine the pulse echo sequence signal segment to be acquired according to the actual position of the effective ultrasonic signal segment and through controlling the position and the width of the time sequence signals, abandons useless signals, saves space and effectively improves the acquisition depth.
In one embodiment, the timing control module 10 may adopt a timing controller composed of an FPGA chip and its peripheral circuits, where the FPGA chip internally adopts a counter under control of a 200MHz master clock and an IDELAYE2 (two-stage interpolation delay structure) delay chain, and can realize a multi-path high-precision timing generation function with two stages of precision of 5ns and 78ps, respectively, and a delay range of 21.5 s. Preferably, the external trigger jitter compensation module built based on the Carry4 Carry chain and the additional IDELAYE2 delay chain can be used for reducing the external trigger jitter, and the time sequence trigger stability is improved.
The working principle of the timing controller provided by the embodiment is as follows: when the trigger signal comes, the time schedule controller carries out beat time delay on the edge of the trigger signal according to a main clock and a clock period length equal to the number of the count value and fine time delay series data, and then sends the edge of the trigger signal into a fine time delay chain formed by combinational logic to carry out fine time delay within one clock period length so as to form a delayed pulse edge and output the pulse edge; meanwhile, the trigger signal is sent to the Carry4 Carry chain, each stage output of the Carry chain is respectively connected to a register, the result of the register is stored at the rising edge of the captured trigger signal, the jitter size of the external trigger is judged, the jitter size is supplemented to an additional IDELAY2 compensation stage number which needs to be used and has the length of 5ns (the synchronization of the trigger and the clock edge is ensured), and the delayed pulse edge is supplemented with the delay. The delay effect of a single channel is shown in fig. 3, and the combination of the pulse edges processed by a plurality of different delays forms a time sequence pulse sequence.
In one embodiment, the data sampling module 20 may employ a data acquisition card of the type ADS54J42EVM, which can implement high-precision and fast sampling of 14 bits and 625Msps of dual channels, and an ADC chip of the data sampling card may perform enable control by a timing signal of a timing controller, so as to achieve the effect of flexibly controlling a sampling interval, as shown in fig. 2.
In an embodiment, as shown in fig. 4, the ultrasound signal acquisition system provided in the above embodiment may further include a storage controller and a data storage device, where the storage controller is respectively connected to the data storage device and the data acquisition module, and the storage controller is configured to send the digital signal output by the data acquisition module to the data storage device for temporary storage of data.
In this embodiment, after the timing controller generates the excitation timing signal, the external ultrasonic signal generating device generates an excitation pulse segment, and the excitation pulse segment passes through modules such as an ultrasonic transducer to form an ultrasonic echo sequence. Subsequently, the ultrasonic echo sequence transmitted into the system is acquired and stored under the action of a data sampling card, is transferred into data storage equipment through a storage controller, and is transmitted into a signal processing device in time through a high-speed return interface to be subjected to waveform display and cross-correlation sound velocity analysis, so that a sound velocity value under each excitation is obtained, and the change rule of the sound velocity along with environmental factors such as temperature, magnetic field and the like can be conveniently and automatically analyzed by matching with the acquisition value of an environmental signal.
Further, the memory controller provided in this embodiment may be further connected to the timing control module, and the memory controller is further configured to provide temporary storage and reading of the timing control data for the timing control module.
Specifically, the application method of the ultrasound signal acquisition system based on the time sequence control provided by the invention comprises the following steps:
step 1: and turning on a system power supply, starting the signal processing system, connecting the time schedule controller and the data sampling card with corresponding interfaces of an external ultrasonic signal generating device, and well performing power-on initialization and emptying of the data storage equipment.
If the ultrasonic probe works in the pulse mode, a user needs to adjust the position of the high-level part of the sampling control time sequence signal of the data sampling card in the time sequence controller according to actual conditions and measurement experience, so that a sampling window is aligned to an ultrasonic signal pulse segment required by the user, as shown in fig. 2, based on the hardware condition of the time sequence controller of the embodiment, the adjustment precision of two ends of the sampling window can reach 78ps.
In practice, the time interval between the generation of the ultrasonic excitation and the reception of the actual echo needs to be considered, for example, the size of the sample is L, and the sound velocity is L in a normal-temperature field-free environmentv 0 Then the delay value τ of the sampling card control timing signal relative to the ultrasound excitation timing signal can be preset to further align the sampling window with the valid interval:
τ=2L/v 0
then, the window position fine adjustment with the accuracy of 78ps can be performed according to the actual experiment result and the acquisition condition.
And 2, step: and setting the time sequence of the ultrasonic excitation signal, the working mode of the sampling system and the control time sequence of the data sampling card in the time sequence controller.
And step 3: waiting for the arrival of a trigger signal of an outgoing master control station which indicates the start of the test, and when the arrival of the trigger signal of an external master control station, synchronously generating a plurality of paths of time sequence signals by the core time sequence controller, and simultaneously starting the ultrasonic signal generating device, the data sampling card and other devices needing to be controlled.
And 4, step 4: taking a pulse working mode as an example, the data sampling card continuously starts and stops sampling according to the level of the input timing sequence signal, as shown in fig. 2, accurately acquires an ultrasonic pulse segment required by a user, transmits the acquired data to the storage controller in real time, and writes the acquired data into the data storage device by the storage controller.
And 5: and the high-speed return interface continuously reads the acquired data from the data storage device through the storage controller and transmits the data to the signal processing system after the sampling is stopped until the next excitation comes or the whole sampling process is stopped, and at the moment, a user can see the real-time returned ultrasonic signal waveform in the signal processing system.
And 6: according to different sampling system working modes, the signal processing system performs sound velocity calculation at different moments, and after the whole sampling process is stopped in the transient high-speed acquisition mode and the signal corresponding to single excitation is completely returned in the steady-state cyclic acquisition mode.
And 7: the user performs further processing based on the analysis of the signal processing system and ends the measurement.
It will be understood by those skilled in the art that the foregoing is only an exemplary embodiment of the present invention, and is not intended to limit the invention to the particular forms disclosed, since various modifications, substitutions and improvements within the spirit and scope of the invention are possible and within the scope of the appended claims.
Claims (10)
1. An ultrasonic signal acquisition system based on time sequence control is used for acquiring ultrasonic echo signals and is characterized by comprising a time sequence control module and a data acquisition module, wherein,
the time sequence control module is used for generating a plurality of paths of time sequence signals under the control of an external trigger signal, wherein one path of time sequence signal A is sent to an external ultrasonic signal generating device, the time sequence signal A is synchronous with the trigger signal and controls the time and the pulse width of an excitation pulse section generated by the ultrasonic signal generating device through the rising time and the pulse width of the time sequence signal A, and the other path of time sequence signal B is sent to the data acquisition module and is used for controlling the data acquisition module to acquire a sampling interval of an ultrasonic echo sequence under the excitation pulse section and convert the sampling interval into a digital signal to be output to an external signal processing system for signal processing;
the data acquisition module is used for starting to sample the ultrasonic echo sequence at each rising moment of the time sequence signal B and stopping sampling the ultrasonic echo sequence at each falling moment of the time sequence signal B; the time sequence signal B is delayed by tau time relative to the time sequence signal A and is used for controlling the alignment of the sampling starting time of the data acquisition module and the occurrence time of the ultrasonic echo sequence, the falling time of the time sequence signal B is set according to the storage space of the data acquisition module, and when the storage space is limited, the falling time of the time sequence signal B is set at the ending time of the ultrasonic echo signal under each excitation pulse segment.
2. The timing control based ultrasound signal acquisition system according to claim 1, wherein the timing signal B is calculated with respect to the timing signal a by the time instant τ:
τ=2L/v 0
in the formula (I), the compound is shown in the specification,Lrepresenting the size of the sample to be tested;v 0 and representing the sound velocity of the sample to be measured in the normal-temperature field-free environment.
3. The ultrasonic signal acquisition system based on time sequence control according to claim 1, wherein the time sequence control module adopts a time sequence controller composed of an FPGA chip and a peripheral circuit thereof, a counter, a Carry4 Carry chain and two ideelaye 2 delay chains under the control of a 200MHz main clock are adopted inside the FPGA chip, and one of the ideelaye 2 delay chain and the Carry4 Carry chain constitutes an external trigger jitter compensation module.
4. The timing control based ultrasound signal acquisition system of claim 3, wherein the data acquisition module employs an ADS54J42EVM acquisition card.
5. The ultrasonic signal acquisition system based on time sequence control according to claim 3, further comprising a storage controller and a data storage device, wherein the storage controller is respectively connected with the data storage device and the data acquisition module, and the storage controller is used for sending the digital signal output by the data acquisition module to the data storage device for temporary data storage.
6. The timing control based ultrasound signal acquisition system according to claim 5, wherein the memory controller is connected to the timing control module, the memory controller further configured to provide temporary storage and reading of timing control data for the timing control module.
7. The timing control based ultrasound signal acquisition system of claim 5, wherein the memory controller is implemented with a MIG IP core inside the FPGA chip.
8. The timing control based ultrasound signal acquisition system according to claim 5, wherein the data storage device employs MT41K256M16HA-125 DDR3 memory chip.
9. The timing control based ultrasound signal acquisition system of claim 1, wherein the signal processing system is configured to perform sinc interpolation and resampling on the digital signal according to shannon's sampling theorem and then perform signal processing on the resampled signal according to user selection.
10. The ultrasonic signal acquisition system based on time sequence control according to claim 1, wherein the ultrasonic signal generation device comprises a pulse generator and two ultrasonic transducers, the pulse generator is used for generating corresponding excitation pulse segments according to the time sequence signal a, one of the ultrasonic transducers is used for emitting ultrasonic signals to one end face of the sample according to the excitation pulse segment, and the other ultrasonic transducer is used for measuring an ultrasonic echo sequence emitted from the other end face opposite to one end face of the sample.
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