CN106770671A - Ultrasonic echo processing unit and method in a kind of ultrasonic detection device - Google Patents

Abstract

The invention discloses an ultrasonic echo processing device and method in an ultrasonic detection device, comprising a microprocessor, a picosecond timing chip, a waveform shaping circuit, a control gate circuit, a filter amplification circuit, a zero-crossing detection circuit, an AND gate circuit, The first counter, the second counter and the third counter; the picosecond-level timing chip provides the transmitted pulse signal, and starts timing when the transmitted pulse signal is sent to the ultrasonic transmitting probe, and the gate circuit compares the ultrasonic echo signal with the original transmitted signal , in the case of complete coincidence, the second counter outputs an effective signal to the picosecond-level timing chip to make it stop timing, and the timing result is obtained, and the microprocessor calculates the propagation time of the ultrasonic wave in the measured object according to the timing result. The present invention calculates and obtains the propagation time of the ultrasonic echo information in the measured object on the basis of obtaining accurate ultrasonic echo information, thereby ensuring the detection accuracy of material feature detection based on the ultrasonic echo information.

Description

Ultrasonic echo processing device and method in an ultrasonic detection device

technical field

The invention relates to related technologies of ultrasonic testing instruments and equipment, in particular to an ultrasonic echo processing device and method in an ultrasonic testing device.

Background technique

Due to the difference in the propagation speed of ultrasonic waves in substances composed of different components, this characteristic can be used to detect the characteristics of the material composition. Usually, the ultrasonic wave passes through the measured object, and then the correlation of the measured object is obtained according to the information of the ultrasonic echo. Features, such as ultrasonic concentration detection, ultrasonic flaw detection, ultrasonic distance measurement, etc. The most important information of the ultrasonic echo is the time difference, that is, the time difference between the time when the ultrasonic wave passes through the object and the first echo is detected by the receiving probe. Depending on the type and size of the object to be measured, the frequency of the ultrasonic wave used, the time difference of the ultrasonic echo, and the accuracy requirements are very different. For example, the time difference of the ultrasonic concentration detection is usually only 10 microseconds, and its time accuracy requires to the level of nanoseconds or even picoseconds, otherwise the reliability of the measurement results is not high. Therefore, how to accurately obtain the time difference is the technical key of this type of application. For example, in the relative blood volume detection based on ultrasound, the system uses ultrasound with a frequency of 2-5MHz, the width of the measured blood container is about 2cm, and the echo time difference is about 15μs. Different concentrations of blood correspond to different echo time differences. Hemodialysis patients During the dialysis process, with the continuous change of the ultrafiltration volume, the blood concentration changes accordingly, and the relative change of the overall blood volume can be evaluated according to the time difference information of the ultrasonic echo, because the relative change of the blood volume before and after dialysis is only 10%-20% , the corresponding overall change in echo time difference is only 1.5-3μs. In order to show immediate small changes, the measurement of ultrasonic echo time difference needs to reach the level of nanoseconds or even picoseconds.

The improvement of ultrasonic echo time measurement accuracy depends on at least two basic aspects, one is the selection of time measurement method, and the other is the acquisition of the first ultrasonic echo peak. In terms of time measurement methods, the traditional time measurement methods include cycle N time measurement method, phase-locked loop time measurement method, single-chip timer direct time measurement method, pulse counting method, etc. The highest time measurement accuracy can only reach the 100ns level. It cannot meet the requirements of relative blood volume detection based on ultrasound. The second aspect of improving the accuracy of ultrasonic echo timing is to accurately obtain the first peak of the echo, and the accurate acquisition of the first peak of the echo includes: neither mistaking the interference signal as the first echo, nor Do not miss the first round or even the second round of echo; in order to detect the echo, it is necessary to first perform zero-crossing detection on the echo signal, which is realized by a zero-crossing comparator, but the ultrasonic wave will be reflected or Refraction phenomenon, low-level interference echo is inevitable, so the zero-crossing detection will also treat the interference signal as an ultrasonic echo, so threshold discrimination is usually required after zero-crossing detection, through hysteresis comparator or other threshold discrimination methods, filtering Except for the interference echo with too low amplitude; the actual ultrasonic echo needs the vibration process, so the first round of echo has a very small amplitude, and it is likely not to reach a fixed threshold. In this way, the threshold discrimination method is often The first round or even the second round of echoes will be missed, the measured time difference will become longer, and the sound velocity will become "slower". The measurement result corresponding to the reincarnation wave is equivalent to the total time difference, equal to invalid. Therefore, the zero-crossing detection and threshold value discrimination methods adopted in the prior art may still cause great deviations in the measurement results.

The invention patent with the patent publication number CN102697522A discloses an online relative blood volume detection device and its detection method, wherein the online relative blood volume detection device is equipped with a processor, a timer, an ultrasonic transmitting and receiving circuit, a zero-crossing detection circuit, etc. , the device calculates the relative blood volume by measuring the propagation time of ultrasonic waves in the blood. The propagation time is the most important data of the device, usually only a dozen microseconds, and the resolution needs to reach the level of 10 picoseconds, but this In the detection method of the invention patent, the stop timing signal for the timer is obtained through the zero-crossing detection circuit. When an interference signal appears in the ultrasonic echo, the stop signal output by the zero-crossing detection will deviate, and the interference clutter in the ultrasonic echo is It is a very common phenomenon, so the reliability of the test results is obviously not enough.

Contents of the invention

The first object of the present invention is to overcome the shortcomings and deficiencies of the prior art, to provide a simple structure, low cost ultrasonic echo processing device in the ultrasonic detection device, through which the ultrasonic echo processing device can obtain accurate ultrasonic echo The propagation time of the ultrasonic echo information in the measured object is calculated on the basis of the information, and the ultrasonic echo signal with interference clutter or missing the first ultrasonic echo peak or even the second ultrasonic echo peak is not used. Therefore, the accurate propagation time of the ultrasonic waves in the measured object can be obtained, which ensures the detection accuracy of the material feature detection based on the ultrasonic echo information.

The second purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and provide an ultrasonic echo processing method in an ultrasonic detection device based on the above ultrasonic echo processing device.

The first object of the present invention is achieved through the following technical solutions: an ultrasonic echo processing device in an ultrasonic detection device, including a microprocessor, a picosecond timing chip, a waveform shaping circuit, a control gate circuit, a filter amplifier circuit, a zero-crossing A detection circuit, an AND circuit, a first counter, a second counter and a third counter;

The data IO port of the picosecond timing chip is connected to the microprocessor, and receives the control instruction sent by the microprocessing through the data IO port and sends the timing result to the microprocessor; the start timing signal input terminal of the picosecond timing chip is connected to Microprocessor, the microprocessor sends the start timing signal to the picosecond level timing chip through the start timing signal input end, starts the picosecond level timing chip to start timing; the pulse signal output end of the picosecond level timing chip is connected to the waveform shaping circuit The input terminal and the output terminal of the waveform shaping circuit are respectively connected to the input terminal of the first counter and the input terminal of the third counter, and the pulse signals output by the waveform shaping circuit are counted by the first counter and the third counter;

The input end of the control gate circuit is respectively connected to the pulse signal output end of the picosecond level timing chip, the output end of the first counter and the end connected to the start timing signal input end of the microprocessor and the picosecond level timing chip; The output end of the circuit is connected to the ultrasonic transmitting probe through the drive amplifier circuit; when the control gate circuit receives the start timing signal sent by the microprocessor and the count of the first counter does not reach the first count limit, the picosecond timing chip The output pulse signal is sent to the driving amplifier circuit, and then sent to the ultrasonic transmitting probe after passing through the driving amplifier circuit;

The ultrasonic receiving probe is connected to the input end of the zero-crossing detection circuit through the filter amplifier circuit, and the output end of the zero-crossing detection circuit and the output end of the waveform shaping circuit are respectively connected to two input ends of the AND gate circuit;

The output terminal of the AND gate circuit is connected to the input terminal of the second counter, and the pulse signal output by the AND gate circuit is counted by the second counter; the output terminal of the third counter is connected to the counting control terminal of the second counter, and the output terminal of the third counter is The output signal controls the second counter to stop counting;

The lowest bit state output terminal in the second counter is connected to the counting control terminal of the third counter, and the third counter is started to count by the second counter;

The output end of the second counter is connected to the stop timing signal input end of the picosecond timing chip. When the count of the second counter reaches the second count limit, the picosecond timing chip receives the stop timing signal through the stop timing signal input end.

Preferably, the output end of the filter amplifier circuit is connected to the microprocessor through the amplitude acquisition circuit.

Preferably, the model of the picosecond timing chip is TDC-GP2.

Preferably, the microprocessor is an MSP430 single-chip microcomputer.

The second object of the present invention is achieved through the following technical solutions: an ultrasonic echo processing method in an ultrasonic detection device based on the ultrasonic echo processing device in the above-mentioned ultrasonic detection device, the steps are as follows:

S1. The microprocessor sends the starting timing signal to the control gate circuit and the picosecond timing chip, and the picosecond timing chip starts timing after receiving the starting timing signal; at the same time, the pulse signal sent by the pulse signal output terminal of the picosecond timing chip passes through the waveform The shaping circuit sends the shaping to the first counter, the third counter and the AND gate circuit respectively;

S2. The first counter starts counting after receiving the signal sent by the waveform shaping circuit. When the control gate circuit receives the starting timing signal sent by the microprocessor and the counting of the first counter does not reach the first counting limit, it will count in picoseconds. The pulse signal emitted by the chip is transmitted to the driving amplifier circuit, and then sent to the ultrasonic transmitting probe through the driving amplifier circuit, and the ultrasonic transmitting probe transmits the ultrasonic signal; when the first counter counts to the first counting limit, the control gate circuit stops counting the picosecond The pulse signal sent by the first-level timing chip is sent to the driving amplifier circuit, and the ultrasonic transmitting probe stops emitting ultrasonic signals;

S3. After the ultrasonic signal emitted by the ultrasonic transmitting probe passes through the object to be measured, it is received by the ultrasonic receiving probe. After receiving the ultrasonic echo signal, the ultrasonic receiving probe sends it to the filter amplifier circuit. Zero detection circuit, the zero-crossing detection circuit sends the signal after zero-crossing detection to the AND gate circuit;

S4. After the two input terminals of the AND gate circuit receive the signals sent by the zero-crossing detection circuit and the waveform shaping circuit, they perform an AND operation on the signals input by the two input terminals, and send the operation result to the second counter, and the second counter Count the signals output by the AND gate circuit;

S5. After the second counter starts counting, start the third counter to count the signal output by the waveform shaping circuit, and when the count of the third counter reaches the third count limit, control the second counter to close and stop counting; when the second counter When the count reaches the second counting limit before closing, the picosecond timing chip receives a stop timing signal from the second counter, and the picosecond timing chip stops timing;

S6. The picosecond-level timing chip obtains the timing result according to the time interval between the start of timing and the stop of timing, and then sends the timing result to the microprocessor, and the microprocessor calculates the propagation of the ultrasonic signal in the measured object according to the timing result time.

Preferably, the first count limit of the first counter, the second count limit of the second counter and the third count limit of the third counter are the same.

Preferably, the first counting limit of the first counter is 1 greater than the second counting limit of the second counter, and 2 greater than the third counting limit of the third counter.

Preferably, the microprocessor calculates the propagation time T of the ultrasonic signal in the object under test according to the timing result as:

T=Tc-n*Tt;

Where n is the second counting limit of the second counter, Tc is the timing result obtained by the picosecond timing chip, and Tt is the period of the pulse signal output from the pulse signal output terminal of the picosecond timing chip.

Preferably, in the step S6, when the microprocessor does not receive the timing result from the picosecond timing chip within a certain period of time A, it controls the picosecond timing chip to reset and re-transmit the pulse signal, and then returns to step S1;

If within a certain period of time B, the microprocessor still does not receive the timing result from the picosecond-level timing chip, then the pulse signal re-emitted by the picosecond-level timing chip is controlled to be the pulse signal after changing the phase; wherein B is greater than A.

Preferably, the output end of the filter amplifier circuit in the ultrasonic echo processing device in the ultrasonic detection device is connected to the microprocessor through the amplitude acquisition circuit; the signal amplified by the filter amplifier circuit is sent to the amplitude acquisition circuit, and the amplitude acquisition circuit is used for filtering The amplifying circuit amplifies and processes the signal for amplitude acquisition, and sends the signal obtained by the amplitude acquisition to the microprocessor, and the microprocessor judges the relevant characteristics of the measured substance according to the signal sent by the amplitude acquisition circuit.

Compared with the prior art, the present invention has the following advantages and effects:

(1) The ultrasonic echo processing device of the present invention includes a microprocessor, a picosecond timing chip, a waveform shaping circuit, a control gate circuit, a filter amplifier circuit, a zero-crossing detection circuit, an AND gate circuit, a first counter, and a second counter and a third counter. In the present invention, a picosecond-level timing chip is used for timing, and the propagation time of the ultrasonic wave in the object to be measured is obtained according to the timing result of the chip. Since the timing accuracy of the chip can reach the picosecond level, the ultrasonic wave is greatly improved. The precision with which travel times in objects are calculated. In addition, after the present invention obtains the ultrasonic echo signal through the ultrasonic receiving probe, the AND operation is performed on the ultrasonic echo signal after filtering, amplifying and zero-crossing detection and the shaped pulse signal emitted by the picosecond timing chip through an AND circuit, so as to obtain The coincidence and comparison of the two signals is realized. Only when the two signals are all consistent, the second counter controls the picosecond timing chip to stop timing. If there are interference waveforms mixed in the ultrasonic echo signal, it will be excluded because the wave width or interval cannot be matched. If one or several echo peaks are missed, the second counter will not be fully counted within the specified time of one round of testing. That is, it is turned off and is invalid. Therefore, no matter whether there is an extra interference waveform on the basis of the normal echo or a normal echo is missed, the picosecond timing chip cannot get the stop timing signal. It can be seen that the propagation time of the ultrasonic wave in the object under test of the present invention, that is, the time from the start of timing to the reception of the first echo by the picosecond timing chip, is calculated on the basis of obtaining accurate and effective time difference raw data. Interfering clutter or ultrasonic echo signals that miss the first or even the second ultrasonic echo peak will not be used. Since the present invention adopts waveform comparison, counting and time length limitation triple screening technology for interference clutter to eliminate interference, and does not directly set a limit value for the first ultrasonic echo with a smaller amplitude, so the present invention will neither Interference is regarded as the first ultrasonic echo peak, and the situation of the first or even the second ultrasonic echo peak will not be missed, which greatly improves the accuracy of ultrasonic echo information acquisition and ensures that the material based on ultrasonic echo information The detection accuracy of feature detection. It effectively overcomes the problem of using the zero-crossing detection and threshold discrimination methods in the prior art to treat the interference clutter as the first ultrasonic echo, or to miss the first ultrasonic echo peak or even the second ultrasonic echo peak, resulting in propagation time Detect inaccurate technical issues.

(2) The circuit adopted by the ultrasonic echo processing device of the present invention only needs to add several small digital circuit chips to the existing ultrasonic detection device, so it has the advantages of simple structure and low cost.

(3) In the present invention, when there is interference or one or more echo peaks are missed in the ultrasonic echo signal, since the ultrasonic echo signal and the shaped pulse signal emitted by the picosecond timing chip will not completely match, the first The counting of the second counter will be closed when the second counting limit is not reached. In this case, the picosecond timing chip will not be able to receive the stop timing signal from the second counter. When the microprocessor in the present invention does not receive the timing result from the picosecond-level timing chip within a certain period of time, it controls the picosecond-level timing chip to reset and re-transmit the pulse signal to perform the next round of detection until the echo is obtained and Ultrasonic echo signals that perfectly match the transmitted pulses make the second counter count up to the second count limit. When the microprocessor does not receive the timing results from the picosecond timing chip for a longer time, control the picosecond The pulse signal re-emitted by the timing chip is the pulse signal after changing the phase. Therefore, the timing results obtained by the picosecond-level timing chip in the present invention are all obtained on the basis of accurate and effective time difference raw data, which greatly improves the detection accuracy of the material characteristic detection of ultrasonic echo information.

Description of drawings

Fig. 1 is a structural diagram of an ultrasonic echo processing device in an ultrasonic detection device of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example

This embodiment discloses an ultrasonic echo processing device in an ultrasonic detection device, as shown in Figure 1, including a microprocessor, a picosecond timing chip, a waveform shaping circuit, a control gate circuit, a filter amplifier circuit, and a zero-crossing detection circuit , AND gate circuit, first counter, second counter and third counter.

The data IO port of the picosecond timing chip is connected to the microprocessor, and the control command sent by the microprocessor is received through the data IO port and the timing result is sent to the microprocessor; the start timing signal input terminal of the picosecond timing chip is connected to the microprocessor, The microprocessor sends the start timing signal to the picosecond timing chip through the start timing signal input terminal, and starts the picosecond timing chip to start timing. In this embodiment, the picosecond timing chip is a TDC-GP2 chip, and the microprocessor is an MSP430 single-chip microcomputer. The SPI interface of the TDC-GP2 chip includes a data IO port, which is connected to the SPI interface of the MSP430 microcontroller through the SPI bus. The TDC-GP2 chip receives the control instruction sent by the microprocessor through the data input port of the SPI interface, wherein the control instruction includes an initialization setting control instruction and a TDC-GP2 chip measurement mode control instruction. In this embodiment, the microprocessor controls the work of the TDC-GP2 chip In measurement mode 2, the measurable range is 500ns-4ms. The start timing signal input terminal of the picosecond timing chip is the START signal input terminal, and the stop timing signal input terminal of the picosecond timing chip is the STOP signal input terminal.

The pulse signal output terminal of the picosecond timing chip is connected to the input terminal of the waveform shaping circuit, and the output terminals of the waveform shaping circuit are respectively connected to the input terminal of the first counter and the input terminal of the third counter, and the first counter and the third counter respectively The pulse signal output by the waveform shaping circuit is counted.

The input end of the control gate circuit is respectively connected to the pulse signal output end of the picosecond timing chip, the output end of the first counter, and the end connected between the microprocessor and the start timing signal input end of the picosecond timing chip; the output end of the control gate circuit Connect the ultrasonic transmitting probe through the drive amplifier circuit; when the control gate circuit receives the start timing signal sent by the microprocessor and the count of the first counter does not reach the first count limit, the pulse signal output by the picosecond timing chip is sent to The driving amplifier circuit is sent to the ultrasonic transmitting probe 1 after passing through the driving amplifier circuit.

The ultrasonic receiving probe 2 is connected to the input end of the zero-crossing detection circuit through the filter amplifier circuit, and the output end of the zero-crossing detection circuit and the output end of the waveform shaping circuit are respectively connected to the two input ends of the AND gate circuit; wherein the ultrasonic transmitting probe 1 and the ultrasonic receiving The probes 2 are respectively arranged on both sides of the measured object 3 .

The output end of the AND gate circuit is connected to the input end of the second counter, and the pulse signal output by the AND gate circuit is counted by the second counter; the output end of the third counter is connected to the counting control end of the second counter, and the output end of the third counter is The signal controls the second counter to stop counting; when the counting of the third counter reaches the third counting limit, an effective signal is output to the counting control terminal of the second counter to control the second counter to stop counting.

The lowest bit state output terminal in the second counter is connected to the counting control end of the third counter, and the third counter is started to count by the second counter; when the second counter counts a number, the second counter lowest bit status output terminal outputs effective signal, thereby starting the third counter to start counting, and realizing the purpose of starting the third counter through the second counter.

The output end of the second counter is connected to the stop timing signal input end of the picosecond timing chip. When the count of the second counter reaches the second count limit, the picosecond timing chip receives the stop timing signal through the stop timing signal input end. Wherein the second counting limit value of the second counter counting in this embodiment is set according to the counting value obtained under the condition that the ultrasonic echo signal received by the AND gate circuit and the signal after the transmitting pulse signal are all consistent with each other, so as to ensure that When the ultrasonic echo signal received by the AND gate circuit matches the reshaped signal of the transmitted pulse signal, the second counter counts up to the second count limit, thereby outputting a valid signal to the picosecond timing chip stop timing signal input terminal. In the case that the ultrasonic echo signal received by the AND gate circuit does not completely match the transmitted pulse signal, the count of the second counter will not reach the second count limit, and at this time the second counter will not output a valid signal to the picosecond The picosecond-level timing chip will not receive the stop timing signal.

In this embodiment, the picosecond timing chip obtains the timing result according to the start timing signal received from the microprocessor and the stop timing signal received from the output of the second counter, and the timing result is passed through the data in the SPI interface. The output is sent to the microprocessor. After the microprocessor receives the timing result, it calculates the propagation time of the ultrasonic signal in the measured object according to the timing result, and obtains the relevant characteristics of the measured object through the propagation time of the ultrasonic signal in the measured object. For example, the measured object is When using blood, the relative blood volume can be obtained according to the propagation time of the ultrasonic signal in the blood.

In this embodiment, the first count limit of the first counter, the second count limit of the second counter, and the third count limit of the third counter are the same. Or the first count limit of the first counter is 1 greater than the second count limit of the second counter and 2 greater than the third count limit of the third counter. Wherein the first counting limit of the first counter is less than 15, in this embodiment the first counting limit of the first counter is 5, the second counting limit of the second counter is 4, the third counting limit of the third counter value 3.

In addition, in the above-mentioned ultrasonic echo processing device of this embodiment, the output end of the filter amplifier circuit is connected to the microprocessor through the amplitude acquisition circuit, and the amplitude acquisition circuit performs amplitude acquisition on the signal amplified and processed by the filter amplifier circuit, and the signal obtained by the amplitude acquisition It is sent to the microprocessor, and the microprocessor judges the relevant characteristics of the measured substance according to the signal sent by the amplitude acquisition circuit. For example, when the measured substance is blood, the microprocessor judges whether there are air bubbles in the blood according to the signal sent by the amplitude acquisition circuit, which is used for processing such as eliminating the influence of air bubbles.

This embodiment also discloses an ultrasonic echo processing method in the ultrasonic detection device realized by the ultrasonic echo processing device in the above ultrasonic detection device, the steps are as follows:

S1. The microprocessor sends the starting timing signal to the control gate circuit and the picosecond timing chip, and the picosecond timing chip starts timing after receiving the starting timing signal; at the same time, the pulse signal sent by the pulse signal output terminal of the picosecond timing chip passes through the waveform The shaping circuit sends the shaping to the first counter, the third counter and the AND gate circuit respectively.

S2. The first counter starts counting after receiving the signal sent by the waveform shaping circuit. When the control gate circuit receives the starting timing signal sent by the microprocessor and the counting of the first counter does not reach the first counting limit, it will count in picoseconds. The pulse signal emitted by the chip is transmitted to the driving amplifier circuit, and then sent to the ultrasonic transmitting probe through the driving amplifier circuit, and the ultrasonic transmitting probe transmits the ultrasonic signal; when the first counter counts to the first counting limit, the control gate circuit stops counting the picosecond The pulse signal emitted by the timing chip is transmitted to the drive amplifier circuit, and the ultrasonic emitting probe stops emitting ultrasonic signals.

S3. After the ultrasonic signal emitted by the ultrasonic transmitting probe passes through the object to be measured, it is received by the ultrasonic receiving probe. After receiving the ultrasonic echo signal, the ultrasonic receiving probe sends it to the filter amplifier circuit. A zero detection circuit, the zero-crossing detection circuit sends the signal after the zero-crossing detection to the AND gate circuit.

S4. After the two input terminals of the AND gate circuit receive the signals sent by the zero-crossing detection circuit and the waveform shaping circuit, they perform an AND operation on the signals input by the two input terminals, and send the operation result to the second counter, and the second counter Count the signals output by the AND gate circuit;

S5. After the second counter starts counting, start the third counter to count the signal output by the waveform shaping circuit, and when the count of the third counter reaches the third count limit, control the second counter to close and stop counting; when the second counter When the counting of the counter before closing reaches the second counting limit, the picosecond timing chip receives a stop timing signal from the second counter, and the picosecond timing chip stops timing.

S6. The picosecond-level timing chip obtains the timing result according to the time interval between the start of timing and the stop of timing, and then sends the timing result to the microprocessor, and the microprocessor calculates the propagation of the ultrasonic signal in the measured object according to the timing result time. In this step, the microprocessor calculates the propagation time T of the ultrasonic signal in the object under test according to the timing result as:

T=Tc-n*Tt;

Where n is the second counting limit of the second counter, Tc is the timing result obtained by the picosecond timing chip, and Tt is the period of the pulse signal output from the pulse signal output terminal of the picosecond timing chip. The propagation time T of the ultrasonic signal in the object under test is Tc minus n echo cycles, that is, the time from when the start timing signal is sent to when the first echo of the ultrasonic signal is received.

In the above step S5, the AND gate circuit performs an AND operation on the signals sent by the zero-crossing detection circuit and the waveform shaping circuit received by the two input terminals, that is, the two signals are matched and compared, and when the two signals are all matched , the second counter can normally complete counting, that is, it can count up to the second counting limit before it is turned off, thereby triggering the picosecond-level timing chip to stop timing.

In this embodiment, if the counting of the second counter in step S5 does not reach the second counting limit and stops counting, then the picosecond timing chip cannot receive the stop timing signal from the second counter. At this time, the step When the microprocessor in S6 does not receive the timing result from the picosecond timing chip within a certain period of time A, it controls the picosecond timing chip to reset and retransmits the pulse signal; if within a certain period of time B, the microprocessor still fails Receiving the timing result from the picosecond timing chip means that multiple rounds of detection have failed. At this time, the pulse signal that controls the picosecond timing chip to re-emit is the pulse signal after changing the phase. where B is greater than A. The values of A and B are determined according to the length of the ultrasonic path of the measured object. Assuming that the theoretical estimated value of the ultrasonic propagation time of the measurement path is t, then A can be set to 3 times to 5 times of t, and B can be set to A 3 times to 5 times.

The ultrasonic echo processing method in this embodiment also includes the following steps: the signal amplified by the filter amplifier circuit is sent to the amplitude acquisition circuit, and the amplitude acquisition circuit performs amplitude acquisition on the signal amplified by the filter amplifier circuit, and the amplitude acquisition is obtained The signal is sent to the microprocessor, and the microprocessor judges the relevant characteristics of the measured substance according to the signal sent by the amplitude acquisition circuit. For example, when the measured substance is blood, the microprocessor judges whether there are air bubbles in the blood according to the signal sent by the amplitude acquisition circuit, which is used for processing such as eliminating the influence of air bubbles.

In this embodiment, the picosecond-level timing chip provides the pulse signal required for the ultrasonic transmitting probe to emit, and starts timing after receiving the start timing signal sent by the microprocessor, and the control gate circuit according to the start timing signal and the first counter The counting result controls whether the signal emitted by the picosecond-level timing chip is transmitted to the ultrasonic transmitting probe. Since the counting result of the first counter must not reach the first counting limit at the beginning, the picosecond-level timing chip starts counting when it receives the start timing signal At the same time, the output pulse signal will be transmitted to the ultrasonic transmitting probe through the gate control circuit for transmission. After the ultrasonic receiving probe receives the ultrasonic echo signal, it performs filter amplification and zero-crossing detection in sequence and then sends it to the AND gate circuit. If the two signals are completely consistent, the second counter can count up to the second count limit before it is closed. At this time, the second counter outputs a valid signal to the picosecond timing chip to stop the timing signal input. At the end, the picosecond-level timing chip stops timing, and calculates the timing result, and then sends it to the microprocessor. The relevant characteristics of the measured object. In the present invention, a picosecond-level timing chip is used for timing, and the propagation time of the ultrasonic wave in the object to be measured is obtained according to the timing result of the chip. Since the timing accuracy of the chip can reach the picosecond level, the ultrasonic wave is greatly improved. Accuracy of travel time calculations in objects. In addition, after the ultrasonic echo signal is obtained by the ultrasonic receiving probe, the ultrasonic echo signal after filtering, amplification and zero-crossing detection is compared with the shaped pulse signal transmitted by the picosecond timing chip, that is, the original transmitted pulse signal. , only when the two signals are all consistent, the second counter controls the picosecond timing chip to stop timing. If there are interference waveforms mixed in the ultrasonic echo signal, it will be excluded because the wave width or interval cannot be matched. Therefore, no matter whether there is an extra interference waveform on the basis of the normal echo or the normal echo is missed, the picosecond timing chip cannot get the stop timing signal. It can be seen that the propagation time of the ultrasonic waves in the object under test in this embodiment, that is, the time from the start of timing to the reception of the first echo by the picosecond-level timing chip, is calculated on the basis of obtaining accurate and effective time difference raw data. Ultrasonic echo signals with interfering clutter or missing the first or even the second ultrasonic echo peak will not be used.

Since this embodiment adopts triple screening technology of waveform comparison, counting and duration limitation for interference clutter to eliminate interference, and does not directly set a limit value for the first ultrasonic echo with a small amplitude, so the method of this embodiment can It will not regard interference as the first ultrasonic echo peak, nor will it miss the first or even the second ultrasonic echo peak, which greatly improves the accuracy of ultrasonic echo information acquisition and ensures The detection accuracy of the material characteristic detection of the information. It effectively overcomes the problem of using the zero-crossing detection and threshold discrimination methods in the prior art to treat the interference clutter as the first ultrasonic echo, or to miss the first ultrasonic echo peak or even the second ultrasonic echo peak, resulting in propagation time Detect inaccurate technical issues.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (10)

1. Ultrasonic echo processing device in an ultrasonic detection device, it is characterized in that, comprises microprocessor, picosecond timing chip, waveform shaping circuit, control gate circuit, filter amplifier circuit, zero-crossing detection circuit, AND gate circuit, a first counter, a second counter and a third counter; The data IO port of the picosecond timing chip is connected to the microprocessor, and receives the control instruction sent by the microprocessing through the data IO port and sends the timing result to the microprocessor; the start timing signal input terminal of the picosecond timing chip is connected to Microprocessor, the microprocessor sends the start timing signal to the picosecond level timing chip through the start timing signal input end, starts the picosecond level timing chip to start timing; the pulse signal output end of the picosecond level timing chip is connected to the waveform shaping circuit The input terminal and the output terminal of the waveform shaping circuit are respectively connected to the input terminal of the first counter and the input terminal of the third counter, and the pulse signals output by the waveform shaping circuit are counted by the first counter and the third counter; The input end of the control gate circuit is respectively connected to the pulse signal output end of the picosecond level timing chip, the output end of the first counter and the end connected to the start timing signal input end of the microprocessor and the picosecond level timing chip; The output end of the circuit is connected to the ultrasonic transmitting probe through the drive amplifier circuit; when the control gate circuit receives the start timing signal sent by the microprocessor and the count of the first counter does not reach the first count limit, the picosecond timing chip The output pulse signal is sent to the driving amplifier circuit, and then sent to the ultrasonic transmitting probe after passing through the driving amplifier circuit; The ultrasonic receiving probe is connected to the input end of the zero-crossing detection circuit through the filter amplifier circuit, and the output end of the zero-crossing detection circuit and the output end of the waveform shaping circuit are respectively connected to two input ends of the AND gate circuit; The output terminal of the AND gate circuit is connected to the input terminal of the second counter, and the pulse signal output by the AND gate circuit is counted by the second counter; the output terminal of the third counter is connected to the counting control terminal of the second counter, and the output terminal of the third counter is The output signal controls the second counter to stop counting; The lowest bit state output terminal in the second counter is connected to the counting control terminal of the third counter, and the third counter is started to count by the second counter; The output end of the second counter is connected to the stop timing signal input end of the picosecond timing chip. When the count of the second counter reaches the second count limit, the picosecond timing chip receives the stop timing signal through the stop timing signal input end. 2 . The ultrasonic echo processing device in the ultrasonic detection device according to claim 1 , wherein the output end of the filtering and amplifying circuit is connected to a microprocessor through an amplitude acquisition circuit. 3 . 3 . The ultrasonic echo processing device in the ultrasonic detection device according to claim 1 , wherein the model of the picosecond timing chip is TDC-GP2. 4 . 4. The ultrasonic echo processing device in the ultrasonic detection device according to claim 1, wherein the microprocessor is an MSP430 single-chip microcomputer. 5. an ultrasonic echo processing method in the ultrasonic detection device realized based on the ultrasonic echo processing device in the ultrasonic detection device of claim 1, is characterized in that, the steps are as follows: S1. The microprocessor sends the starting timing signal to the control gate circuit and the picosecond timing chip, and the picosecond timing chip starts timing after receiving the starting timing signal; at the same time, the pulse signal sent by the pulse signal output terminal of the picosecond timing chip passes through the waveform The shaping circuit sends the shaping to the first counter, the third counter and the AND gate circuit respectively; S2. The first counter starts counting after receiving the signal sent by the waveform shaping circuit. When the control gate circuit receives the starting timing signal sent by the microprocessor and the counting of the first counter does not reach the first counting limit, it will count in picoseconds. The pulse signal emitted by the chip is transmitted to the driving amplifier circuit, and then sent to the ultrasonic transmitting probe through the driving amplifier circuit, and the ultrasonic transmitting probe transmits the ultrasonic signal; when the first counter counts to the first counting limit, the control gate circuit stops counting the picosecond The pulse signal sent by the first-level timing chip is sent to the driving amplifier circuit, and the ultrasonic transmitting probe stops emitting ultrasonic signals; S3. After the ultrasonic signal emitted by the ultrasonic transmitting probe passes through the object to be measured, it is received by the ultrasonic receiving probe. After receiving the ultrasonic echo signal, the ultrasonic receiving probe sends it to the filter amplifier circuit. Zero detection circuit, the zero-crossing detection circuit sends the signal after zero-crossing detection to the AND gate circuit; S4. After the two input terminals of the AND gate circuit receive the signals sent by the zero-crossing detection circuit and the waveform shaping circuit, they perform an AND operation on the signals input by the two input terminals, and send the operation result to the second counter, and the second counter Count the signals output by the AND gate circuit; S5. After the second counter starts counting, start the third counter to count the signal output by the waveform shaping circuit, and when the count of the third counter reaches the third count limit, control the second counter to close and stop counting; when the second counter When the count reaches the second counting limit before closing, the picosecond timing chip receives a stop timing signal from the second counter, and the picosecond timing chip stops timing; S6. The picosecond-level timing chip obtains the timing result according to the time interval between the start of timing and the stop of timing, and then sends the timing result to the microprocessor, and the microprocessor calculates the propagation of the ultrasonic signal in the measured object according to the timing result time. 6. The ultrasonic echo processing method in the ultrasonic detection device according to claim 5, wherein the first counting limit of the first counter, the second counting limit of the second counter and the third counting of the third counter The limits are the same. 7. The ultrasonic echo processing method in the ultrasonic detection device according to claim 5, wherein the first count limit value of the first counter is greater than the second count limit value of the second counter by 1, and is greater than the second count limit value of the third counter. The third count limit is 2 greater. 8. The ultrasonic echo processing method in the ultrasonic detection device according to claim 5, wherein the microprocessor calculates the propagation time T of the ultrasonic signal in the measured object according to the timing result as: T=Tc-n*Tt; Where n is the second counting limit of the second counter, Tc is the timing result obtained by the picosecond timing chip, and Tt is the period of the pulse signal output from the pulse signal output terminal of the picosecond timing chip. 9. The ultrasonic echo processing method in the ultrasonic detection device according to claim 5, characterized in that, in the step S6, the microprocessor does not receive the timing result from the picosecond timing chip within a certain period of time A , control the picosecond-level timing chip to reset and re-transmit the pulse signal, and then return to step S1; If within a certain period of time B, the microprocessor still does not receive the timing result from the picosecond-level timing chip, then the pulse signal re-emitted by the picosecond-level timing chip is controlled to be the pulse signal after changing the phase; wherein B is greater than A. 10. The ultrasonic echo processing method in the ultrasonic detection device according to claim 5, wherein the output end of the filter amplifier circuit in the ultrasonic detection device is connected to the microprocessor through an amplitude acquisition circuit The signal amplified and processed by the filter amplifier circuit is sent to the amplitude acquisition circuit, and the amplitude acquisition circuit performs amplitude acquisition on the signal amplified by the filter amplifier circuit, and sends the signal obtained by the amplitude acquisition to the microprocessor, and the microprocessor collects the signal according to the amplitude The signal sent by the circuit judges the relevant characteristics of the measured substance.