CN116930937A - Ultrasonic transducer chip, signal processing method and automobile ultrasonic radar device - Google Patents
Ultrasonic transducer chip, signal processing method and automobile ultrasonic radar device Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
- G01S15/06—Systems determining the position data of a target
- G01S15/08—Systems for measuring distance only
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/88—Sonar systems specially adapted for specific applications
- G01S15/93—Sonar systems specially adapted for specific applications for anti-collision purposes
- G01S15/931—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
- G01S7/52004—Means for monitoring or calibrating
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- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Abstract
The embodiment of the application provides an ultrasonic transducer chip, a signal processing method and an automobile ultrasonic radar device, wherein the ultrasonic transducer chip comprises: the sampling circuit is used for sampling the ultrasonic signals; the digital down-conversion module is used for carrying out digital down-conversion processing on the sampling signals; a low-pass filter for low-pass filtering the mixed signal; the amplitude calculation module is used for calculating the amplitude according to the filtered signal; the envelope calibration module is used for calibrating the envelope amplitude curve, wherein the envelope calibration module calibrates the envelope amplitude curve at least between a driving stage and a transition period of a aftershock stage; and the threshold comparison circuit is used for comparing the final envelope curve with an envelope curve threshold. In the embodiment of the application, the envelope amplitude curve can be calibrated between the transition periods of the driving stage and the aftershock stage, so that system misjudgment possibly caused by waveform fluctuation in the transition period is avoided, and the accuracy of obstacle detection is improved.
Description
The present application claims priority from the chinese patent application filed at 2023, 4 and 10, with application number 202310375784.5, application name "a signal processing circuit, processing method and processing chip for ultrasonic transducer", which is incorporated herein by reference in its entirety.
Technical Field
The application relates to the technical field of electronics, in particular to an ultrasonic transducer chip, a signal processing method and an automobile ultrasonic radar device.
Background
Ultrasonic ranging, as a typical non-contact measurement method, is widely used in many fields such as vehicle obstacle detection, industrial automation control, construction engineering measurement, and the like. Taking vehicle obstacle detection as an example, after transmitting an ultrasonic wave having a frequency of 20KHz or more (which is a non-audible range), an ultrasonic transducer may sense an echo signal reflected from an external obstacle and analyze the echo signal to determine a distance between the ultrasonic transducer and the obstacle, i.e., a detection distance. Based on the detected distance, a corresponding prompt message (for example, warning sound is output through a buzzer or obstacle distance is displayed through a display screen) can be provided for the user to assist the user in driving safely.
Specifically, when distance detection is required, after the main control circuit of the ultrasonic transducer chip receives a trigger signal from a host computer (such as an ECU (electronic control Unit) or the like), the driving circuit is controlled to generate an ultrasonic driving signal, and the driving signal is used for driving the ultrasonic transducer to emit ultrasonic waves (the process is called as a driving stage); after the driving stage, the driving signal stops driving the ultrasonic transducer, but the ultrasonic transducer cannot immediately stop vibrating, but a periodic vibration signal (the process is called as a 'aftershock stage') is generated, and in the aftershock stage, the echo processing circuit cannot identify an echo signal (a signal reflected by an obstacle when the transmitted ultrasonic waves encounter the obstacle) because the intensity of the vibration signal is high; after the aftershock phase, the echo processing circuitry may identify the echo signals (this process is referred to as the "receive phase").
In the signal processing process, the driving signal in the driving stage, the oscillating signal in the aftershock stage and the echo signal in the receiving stage are all input into the echo processing circuit for processing. However, the applicant has found that, due to the phase difference or frequency difference between the driving signal and the oscillating signal, a strong waveform fluctuation occurs between the received driving signal and the oscillating signal, which causes a fluctuation of the received signal, and in serious cases, misjudgment of the detection distance occurs.
It should be noted that the information disclosed in the background section of the present application is only for enhancement of understanding of the general background of the present application and should not be taken as an admission or any form of suggestion that this information forms the prior art that is well known to a person skilled in the art.
Disclosure of Invention
In view of the above, the present application provides an ultrasonic transducer chip, a signal processing method, and an automotive ultrasonic radar apparatus, so as to solve the problem in the prior art that a strong waveform fluctuation occurs between a received driving signal and an oscillating signal due to a phase difference or a frequency difference between the driving signal and the oscillating signal, and the waveform fluctuation causes a fluctuation of the received signal, and in severe cases, misjudgment occurs to a detection distance.
In a first aspect, an embodiment of the present application provides an ultrasonic transducer chip for electrically connecting with an ultrasonic transducer, where the chip receives signals divided into: the chip comprises a driving stage, a aftershock stage and a receiving stage, wherein the chip comprises:
the sampling circuit is electrically connected with the ultrasonic transducer and is used for sampling the ultrasonic signal to obtain a sampling signal;
the digital down-conversion module is electrically connected with the sampling circuit and is used for receiving the sampling signal output by the sampling circuit and carrying out digital down-conversion processing on the sampling signal to obtain a mixed signal corresponding to the ultrasonic signal;
The low-pass filter is electrically connected with the digital down-conversion module and is used for receiving the mixed signal output by the digital down-conversion module and carrying out low-pass filtering on the mixed signal to obtain a filtered signal;
the amplitude calculation module is electrically connected with the low-pass filter and is used for receiving a filtered signal output by the low-pass filter, calculating the amplitude according to the filtered signal and outputting an envelope amplitude curve;
the envelope calibration module is electrically connected with the amplitude calculation module and is used for receiving the envelope amplitude curve output by the amplitude calculation module, and performing calibration processing on the envelope amplitude curve to output a final envelope curve, wherein the envelope calibration module is used for calibrating the envelope amplitude curve at least between the driving stage and the transition period of the aftershock stage and outputting the final envelope curve of the transition period;
and the threshold comparison circuit is electrically connected with the envelope calibration module and is used for receiving a final envelope curve output by the envelope calibration module, and comparing the final envelope curve with an envelope curve threshold value to output a threshold value comparison result.
In a second aspect, an embodiment of the present application provides an ultrasonic signal processing method, applied to an ultrasonic transducer chip, where the chip is used for being electrically connected to an ultrasonic transducer, and the chip receives signals in the following manner: a driving stage, a aftershock stage and a receiving stage, the method comprising:
Sampling the ultrasonic signal to obtain a sampling signal;
performing digital down-conversion processing on the sampling signal to obtain a mixed signal corresponding to the ultrasonic signal;
performing low-pass filtering on the mixed signal to obtain a filtered signal;
calculating the amplitude according to the filtering signal, and outputting an envelope amplitude curve;
calibrating the envelope magnitude curve to output a final envelope curve, wherein the envelope magnitude curve is calibrated at least between the drive phase and the transition period of the aftershock phase and the final envelope curve of the transition period is output;
and comparing the final envelope curve with an envelope curve threshold value to output a threshold value comparison result.
In a third aspect, an embodiment of the present application provides an ultrasonic radar apparatus for an automobile, including:
the chip of the first aspect;
an ultrasonic transducer;
wherein the chip is electrically connected with the ultrasonic transducer.
In the embodiment of the application, the envelope amplitude curve can be calibrated between the transition periods of the driving stage and the aftershock stage, so that overlarge fluctuation of waveforms in the transition period and system misjudgment possibly caused by fluctuation are avoided, and the accuracy of obstacle detection is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic view of an application scenario provided in an embodiment of the present application;
fig. 2A and fig. 2B are schematic diagrams illustrating a ranging principle of an ultrasonic system according to an embodiment of the present application;
FIG. 3 is a schematic diagram of an envelope magnitude curve before calibration according to an embodiment of the present application;
fig. 4 is a schematic diagram of a distance measurement principle of another ultrasonic system according to an embodiment of the present application;
fig. 5 is a schematic structural diagram of an echo processing circuit according to an embodiment of the present application;
FIG. 6 is a schematic diagram of a distance measurement principle of another ultrasonic system according to an embodiment of the present application;
FIG. 7 is a schematic diagram of a distance measurement principle of another ultrasonic system according to an embodiment of the present application;
FIG. 8 is a schematic diagram of threshold comparison according to an embodiment of the present application;
FIG. 9 is a diagram of a calibrated final envelope curve according to an embodiment of the present application;
Fig. 10 is a schematic diagram of a distance measurement principle of another ultrasonic system according to an embodiment of the present application;
FIG. 11 is a schematic diagram of a distance measurement principle of another ultrasonic system according to an embodiment of the present application;
fig. 12 is a flow chart of an ultrasonic signal processing method according to an embodiment of the present application;
fig. 13 is a schematic structural diagram of an ultrasonic radar device for an automobile according to an embodiment of the present application.
Detailed Description
For a better understanding of the technical solution of the present application, the following detailed description of the embodiments of the present application refers to the accompanying drawings.
It should be understood that the described embodiments are merely some, but not all, embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The terminology used in the embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be understood that the term "and/or" as used herein is merely one way of describing an association of associated objects, meaning that there may be three relationships, e.g., a and/or b, which may represent: the first and second cases exist separately, and the first and second cases exist separately. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
Referring to fig. 1, a schematic view of an application scenario is provided in an embodiment of the present application. In fig. 1, a vehicle 100 and an obstacle 200 are shown, wherein a plurality of ultrasonic transducers 101 are provided at the tail of the vehicle 100, when a user (possibly in the case of automatic driving) controls the vehicle 100 to reverse (possibly in any scene of lateral parking and front obstacle recognition), the ultrasonic transducers 101 can transmit ultrasonic waves and receive echo signals (the ultrasonic transducers can be two independent devices comprising an ultrasonic transmitting transducer and an ultrasonic receiving transducer or can be one device with functions of transmitting ultrasonic waves and receiving ultrasonic waves), and further the distance between the ultrasonic transducers 101 (i.e. the vehicle 100) and the obstacle 200 can be calculated, and corresponding prompt information (for example, warning sound is output through a buzzer or the obstacle distance is displayed through a display screen) can be provided for the user to assist the safe driving.
It should be noted that fig. 1 is only one possible application scenario listed in the embodiment of the present application, and should not be taken as a limitation on the protection scope of the present application. For example, the ultrasonic ranging may be applied to an application scene such as industrial automation control and construction engineering survey in addition to the detection of an obstacle by a vehicle, and in other application scenes, the obstacle may be referred to as a "detected object"; the ultrasonic transducer may be provided at a side portion or a front portion of the vehicle in addition to the rear portion of the vehicle to detect an obstacle at the side portion or the front portion of the vehicle; in addition to 4 ultrasonic transducers, a greater or lesser number of ultrasonic transducers or the like may be provided, and the embodiment of the present application is not particularly limited.
Referring to fig. 2A and fig. 2B, schematic diagrams of ranging principle of an ultrasonic system according to an embodiment of the present application are provided. As shown in fig. 2A and 2B, the ultrasonic system includes an electric control unit (Electronic Control Unit, ECU), an ultrasonic transducer chip, and an ultrasonic transducer, wherein the ultrasonic transducer chip includes a main control circuit, a driving circuit, and an echo processing circuit. The ECU is in communication connection with the main control circuit, the output end of the main control circuit is electrically connected with the input end of the driving circuit, the output end of the driving circuit is electrically connected with the input end of the ultrasonic transducer, the output end of the ultrasonic transducer is electrically connected with the input end of the echo processing circuit, and the output end of the echo processing circuit is electrically connected with the input end of the main control circuit.
Specifically, in the ultrasonic system shown in fig. 2A, the input end and the output end of the ultrasonic transducer are provided, respectively. As shown in fig. 2A, two ports below the ultrasonic transducer are electrically connected as input ends to the output ends of the driving circuit, and two ports above the ultrasonic transducer are electrically connected as output ends to the input ends of the echo processing circuit. In the ultrasound system shown in fig. 2B, the same set of ports is used as both the input and output of the ultrasound transducer. As shown in fig. 2B, two ports below the ultrasonic transducer may be electrically connected as an input to the output of the driving circuit, and may be electrically connected as an output to the input of the echo processing circuit. It should be noted that the inclusion of two ports at the input and/or output of the ultrasound transducer of fig. 2A and 2B is merely an exemplary illustration and may be provided as a greater or lesser number of ports. In addition, in different implementations, there are some other forms of variations in the functional units of the ultrasound system and/or the connection relationships between the functional units, see in particular the description of the other parts of the application.
When the distance detection is needed, after the main control circuit of the ultrasonic transducer chip receives a trigger signal from the ECU, the driving circuit is controlled to generate an ultrasonic driving signal, and the driving signal is used for driving the ultrasonic transducer to emit ultrasonic waves (the process is called a driving stage); after the driving stage, the driving signal stops driving the ultrasonic transducer, but the ultrasonic transducer cannot immediately stop vibrating, but a periodic vibration signal (the process is called as a 'aftershock stage') is generated, and in the aftershock stage, the echo processing circuit cannot identify an echo signal (a signal reflected by an obstacle when the transmitted ultrasonic waves encounter the obstacle) because the intensity of the vibration signal is high; after the aftershock phase, the echo processing circuitry may identify the echo signals (this process is referred to as the "receive phase").
In the signal processing process, the driving signal in the driving stage, the oscillating signal in the aftershock stage and the echo signal in the receiving stage are all input into the echo processing circuit for processing. In particular, in the case that an ultrasonic transducer is used as both a driving transducer and a receiving transducer, a driving signal in a driving stage is directly input into the echo processing circuit, and an oscillation signal and an echo signal of the ultrasonic transducer are also input into the echo processing circuit. After receiving the ultrasonic signal, the echo processing circuit can extract an envelope amplitude curve of the ultrasonic signal, further, compare the envelope amplitude curve with a preset envelope curve threshold value to obtain a threshold value comparison result, and judge whether an obstacle is detected or not and determine the distance of the obstacle according to the threshold value comparison result. Specifically, the threshold comparison result may include a first logic and a second logic. Illustratively, the first logic is 1 and the second logic is 0; alternatively, the first logic is 0 and the second logic is 1. In other parts of this document, a logic "1" may also be referred to as a high level, and a logic "0" may also be referred to as a low level.
In general, the amplitude values of the envelope amplitude curves in the driving stage and the oscillation stage are larger than the maximum input value range of the sampling circuit, and the envelope amplitude curves in the driving stage and the oscillation stage are truncated in the waveform diagram of the envelope amplitude curves. However, in practical applications, there may be a strong waveform fluctuation between the received driving signal and the oscillation signal due to a phase difference or a frequency difference between the driving signal and the oscillation signal, and the waveform fluctuation may cause erroneous judgment of the detection distance.
Illustratively, an envelope magnitude curve is shown in fig. 3, which includes a driving phase, a aftershock phase, and a receiving phase. The envelope magnitude curve is truncated in the driving stage and the aftershock stage, but there is an obvious dip in the envelope magnitude curve between the driving stage and the aftershock stage, which can cause a signal to have larger fluctuation, and if the dip is lower than the threshold of the envelope curve, misjudgment on the detection distance can be caused.
Specifically, as described above, it may be determined whether an obstacle is detected by comparing the envelope magnitude curve with the envelope curve threshold. In the application scenario shown in fig. 3, when the envelope magnitude curve is smaller than the envelope curve threshold, the threshold comparison result is a high level, and when the envelope magnitude curve is larger than the envelope curve threshold, the threshold comparison result is a low level. Thus, a first low level is detected between t1-t2, a second low level is detected between t3-t4, and a third low level is detected between t5-t 6.
It will be appreciated that the third low level is a low level signal corresponding to the echo signal, and therefore, the detected obstacle and the obstacle distance can be determined by the third low level signal. In addition, since the first low level is the low level detected during the drive phase, one possible solution is that the system can directly ignore the low level signal. However, for the second low level, a system misjudgment is caused, that is, the system misjudges that the second low level is a low level signal corresponding to the echo signal, and then determines the obstacle distance according to the low level signal. Obviously, the determination result is erroneous, and the second low level is caused by the recess between the driving stage and the aftershock stage.
In view of the above problems, an embodiment of the present application provides an ultrasonic transducer chip, which can calibrate an envelope amplitude curve between a driving stage and a transition stage of a aftershock stage, so as to avoid excessive fluctuation of waveforms in the transition stage, and possible system erroneous judgment caused by the fluctuation, and improve accuracy of obstacle detection. The detailed description is provided below in connection with specific implementations.
Referring to fig. 4, a schematic diagram of a distance measurement principle of another ultrasonic system according to an embodiment of the present application is provided. As shown in fig. 4, on the basis of the ultrasonic system shown in fig. 2A, the echo processing circuit in the ultrasonic transducer chip further includes a sampling circuit, a digital down-conversion module, a low-pass filter, an amplitude calculation module, and an envelope calibration module; the master circuit further includes a threshold comparison circuit. It should be noted that the ultrasonic transducer chip according to the embodiment of the present application may be applied to the ultrasonic system shown in fig. 2B, and for simplicity of description, only the ultrasonic system shown in fig. 2A is used as an example.
With continued reference to fig. 4, the input end of the sampling circuit is electrically connected to the output end of the ultrasonic transducer, the output end of the sampling circuit is electrically connected to the input end of the digital down-conversion module, the output end of the digital down-conversion module is electrically connected to the input end of the low-pass filter, the output end of the low-pass filter is electrically connected to the input end of the amplitude calculation module, the output end of the amplitude calculation module is electrically connected to the input end of the envelope calibration module, and the output end of the envelope calibration module is electrically connected to the input end of the threshold comparison circuit.
The sampling circuit is used for sampling the received ultrasonic signals to obtain sampling signals. As described above, the driving signal in the driving stage, the oscillating signal in the aftershock stage and the echo signal in the receiving stage are all input to the echo processing circuit for processing, so the sampling signal includes the driving signal in the driving stage, the oscillating signal in the aftershock stage and the echo signal in the receiving stage.
In one possible implementation, the sampling frequency of the sampling circuit may be increased in order to restore the received ultrasonic signal as much as possible. Specifically, the sampling frequency of the sampling circuit is greater than the oscillation frequency of the ultrasonic signal itself. For example, if the driving circuit transmits an ultrasonic signal at a frequency f0, the sampling circuit samples the ultrasonic signal at a sampling frequency n×f0, where n > 1. Illustratively, n may be 4, 8, etc.
In a specific implementation, the sampling circuit may be an analog-to-digital converter (Analog to Digital Converter, ADC). Of course, those skilled in the art may set other types of sampling circuits according to actual needs, and the embodiment of the present application is not limited thereto.
The digital down-conversion module is used for receiving the sampling signal output by the sampling circuit and performing digital down-conversion processing on the sampling signal to obtain a mixed signal corresponding to the ultrasonic signal. Specifically, the sampling signal may be subjected to digital down-conversion processing based on the local signal, so as to obtain a corresponding mixed signal, where the mixed signal includes a high-frequency signal and a low-frequency signal, where the low-frequency signal is a desired signal, and therefore, the high-frequency signal in the mixed signal needs to be filtered in a subsequent step to obtain the desired low-frequency signal. In addition, in practical applications, since the ultrasonic signal is usually a complex signal, it is necessary to perform digital down-conversion processing on the sampled signal based on two mutually orthogonal local signals, respectively, to obtain two mixed signals.
Referring to fig. 5, a schematic structural diagram of an echo processing circuit according to an embodiment of the present application is provided. As shown in fig. 5, in the embodiment of the present application, the digital down-conversion module specifically includes a first frequency conversion module and a second frequency conversion module, where the first frequency conversion module and the second frequency conversion module are respectively electrically connected to the sampling circuit, and are configured to receive the sampling signal output by the sampling circuit. The first frequency conversion module is used for carrying out digital down conversion processing on the sampling signal based on a local signal sin (2 x pi x fo x t) to obtain a first mixed signal; the second frequency conversion module is configured to perform digital down conversion processing on the sampled signal based on the local signal cos (2×pi×fo×t) to obtain a second mixed signal. It can be understood that the local signal sin (2×pi×fo×t) and the local signal cos (2×pi×fo×t) are mutually orthogonal, that is, the first frequency conversion module and the second frequency conversion module respectively perform digital down conversion processing on the sampling signal based on the mutually orthogonal local signals.
Further, the ultrasonic transducer chip further includes a storage unit, and the local signal may be stored in the storage unit. Specifically, the storage unit is electrically connected to the digital down-conversion module, and the digital down-conversion module may directly obtain the local signal in the storage unit, as shown in fig. 6. Alternatively, the storage unit is electrically connected to the main control circuit, and when the digital down conversion module needs the local signal, the main control circuit may acquire the local signal from the storage unit and then forward the local signal to the digital down conversion module, as shown in fig. 7.
In a specific implementation, the storage unit may be a unit or element with storage properties in various forms, such as RAM (random access memory), ROM (read-only memory), registers, buffers, and the like.
The low-pass filter is used for receiving the mixed signal output by the digital down-conversion module and performing low-pass filtering on the mixed signal to obtain a filtered signal. It will be appreciated that when the digital down conversion module outputs two mixed signals, two low pass filters should be included accordingly.
With continued reference to fig. 5, in an embodiment of the present application, the low-pass filter includes a first low-pass filter and a second low-pass filter. The first low-pass filter is electrically connected with the first frequency conversion module and is used for receiving a first mixed signal output by the first frequency conversion module, and carrying out low-pass filtering on the first mixed signal to obtain a first filtered signal, namely a low-frequency signal in the first mixed signal; the second low-pass filter is electrically connected with the second frequency conversion module and is used for receiving the second mixed signal output by the second frequency conversion module and carrying out low-pass filtering on the second mixed signal to obtain a second filtered signal, namely a low-frequency signal in the second mixed signal.
The amplitude calculation module is used for receiving the filtered signal output by the low-pass filter, calculating the amplitude according to the filtered signal and outputting an envelope amplitude curve. It will be appreciated that when the low pass filter outputs two filtered signals, the magnitude calculation may be performed from the two filtered signals.
With continued reference to fig. 5, in an embodiment of the present application, the amplitude calculating module is electrically connected to the first low-pass filter and the second low-pass filter (the electrical connection may be a direct electrical connection or an indirect electrical connection through the downsampling module, which is described below), and is configured to receive the first filtered signal and the second filtered signal output by the first low-pass filter and the second low-pass filter, respectively, and perform amplitude calculation according to the first filtered signal and the second filtered signal, so as to obtain an envelope amplitude curve.
In a specific implementation, the formula may be:an envelope magnitude curve is calculated. Where P is the amplitude of the envelope amplitude curve,i is the amplitude of the first filtered signal and Q is the amplitude of the second filtered signal. It should be noted that when the echo signal processing circuit includes a downsampling module, I is the amplitude of the first downsampled signal, and Q is the amplitude of the second downsampled signal.
And the envelope calibration module is used for receiving the envelope amplitude curve output by the amplitude calculation module, and performing calibration processing on the envelope amplitude curve to output a final envelope curve. As can be seen from the description of fig. 3 above, the erroneous determination of the detection distance is mainly due to waveform fluctuations between the driving phase and the transition period of the aftershock phase, and therefore, the envelope calibration module calibrates the envelope magnitude curve at least between the driving phase and the transition period of the aftershock phase and outputs the final envelope curve of the transition period. Specifically, the start point of the transition period is located at the end point of the driving period, and the end point of the transition period is a specified time after the end point of the driving period or a point corresponding to a specified number of periods. Typically, the specified time or number of cycles is related to the duration of the aftershock phase, and the specific value thereof may be determined empirically or through testing.
In addition, outside the transition period, the envelope calibration module can directly output the envelope amplitude curve directly outwards to form a final envelope curve because the envelope amplitude curve does not have severe waveform fluctuation. Of course, the envelope calibration module may also calibrate the envelope magnitude curve to obtain the final envelope curve during the transition period, which is not particularly limited in the embodiment of the present application.
With continued reference to fig. 3, in the embodiment of the present application, there is a significant dip in the envelope magnitude curve between the transition periods of the driving phase and the aftershock phase, which causes strong waveform fluctuation, and the dip may cause the system to misjudge the detection distance. Thus, the envelope calibration module emphasizes the need to calibrate the dip. Further analysis, the dip is distinguished from other locations (drive phase and early aftershock phase) in that the amplitude of the envelope amplitude curve is small. Thus, it can be determined whether the calibration process for the envelope magnitude curve is required based on the magnitude of the envelope magnitude curve.
Specifically, a first amplitude threshold value can be set, the amplitude of the envelope amplitude curve is compared, and if the amplitude of the envelope amplitude curve is smaller than the preset first amplitude threshold value, the envelope amplitude curve is calibrated; if the amplitude of the envelope amplitude curve is larger than a preset first amplitude threshold, the envelope amplitude curve is not calibrated.
Further, in order to make the final envelope curve after the calibration process smoother, a second amplitude threshold value may be further set on the basis of the first amplitude threshold value, wherein the first amplitude threshold value is greater than the second amplitude threshold value. If the amplitude of the envelope amplitude curve is smaller than a preset first amplitude threshold and larger than or equal to a second amplitude threshold, calibrating the envelope amplitude curve by adopting a first calibration offset strategy; and if the amplitude of the envelope amplitude curve is smaller than the second amplitude threshold, calibrating the envelope amplitude curve by adopting a second calibration offset strategy.
In one possible implementation, the first amplitude threshold is the amplitude maximum of the envelope amplitude curve and/or the second amplitude threshold is one half of the amplitude maximum of the envelope amplitude curve. Of course, those skilled in the art may adapt the first amplitude threshold value and/or the second amplitude threshold value according to actual needs, which is not particularly limited in the embodiment of the present application.
In a specific implementation, the first calibration offset strategy is: p_final= (p_ev+p_cal1)/2, the second calibration offset strategy is: p_final= (p_ev+p_cal2)/2. Wherein, P_final is the magnitude of the final envelope curve output by the envelope calibration module, P_ev is the magnitude of the envelope magnitude curve output by the magnitude calculation module, P_cal1 is the first calibration factor, and P_cal2 is the second calibration factor. Illustratively, the first calibration factor is 1.25 x p_max and the second calibration factor is 1.5 x p_max; where p_max is the maximum amplitude value of the envelope amplitude curve. Of course, the specific values of the first calibration factor and the second calibration factor can be adjusted according to actual needs by those skilled in the art, but it should be ensured that the first calibration factor is smaller than the second calibration factor, so that the final envelope curve after the calibration process is smoother.
With continued reference to fig. 4, in the embodiment of the present application, a threshold comparison circuit is further provided in the main control circuit, and the threshold comparison circuit is configured to receive the final envelope curve output by the envelope calibration module, and compare the final envelope curve with the envelope curve threshold to output a threshold comparison result. Specifically, the threshold comparison result may include a first logic and a second logic. Illustratively, the first logic is 1 and the second logic is 0; alternatively, the first logic is 0 and the second logic is 1. In other parts of this document, a logic "1" may also be referred to as a high level, and a logic "0" may also be referred to as a low level.
Referring to fig. 8, a threshold comparison schematic diagram is provided in an embodiment of the present application. As shown in fig. 8, the envelope value of the final envelope curve and the envelope curve threshold are input to the threshold comparison circuit at the same time, and the high-low level signal is output by comparing the magnitudes of the final envelope curve and the envelope curve threshold. In the embodiment of the application, when a low level appears in the threshold comparison result, the detection of the obstacle is judged. Of course, the determination logic in the threshold comparison circuit may be adjusted to determine that an obstacle is detected when a high level appears in the threshold comparison result, which is not particularly limited in the embodiment of the present application.
Referring to fig. 9, a schematic diagram of a calibrated final envelope curve is provided according to an embodiment of the present application. Comparing fig. 3 and fig. 9, it can be seen that after the calibration process of the envelope calibration module, the dip between the transition periods of the driving stage and the aftershock stage tends to be gentle, the amplitude of the dip is higher than the threshold of the envelope curve, so that misjudgment on the detection distance is not caused, the dip is smoother, and good processing is obtained.
Specifically, when the envelope magnitude curve is smaller than the envelope curve threshold, the threshold comparison result is a low level, and when the envelope magnitude curve is larger than the envelope curve threshold, the threshold comparison result is a high level. Thus, a first low level is detected between t1-t4 and a second low level is detected between t5-t 6. Since the first low level is the low level detected by the drive phase, the system can directly ignore the low level signal. It will be appreciated that the second low level is a low level signal corresponding to the echo signal, and therefore, by means of the second low level signal, it is possible to determine that an obstacle is detected and to determine the obstacle distance.
In summary, the ultrasonic transducer chip provided by the embodiment of the application can calibrate the envelope amplitude curve between the transition periods of the driving stage and the aftershock stage, so as to avoid erroneous system judgment caused by waveform fluctuation in the transition period and improve the accuracy of obstacle detection.
As described above, in order to restore the received ultrasonic signal as much as possible, the oversampling may be performed, that is, the sampling frequency of the sampling circuit is greater than the oscillation frequency of the ultrasonic signal itself. However, the data volume obtained by oversampling is larger, and the data processing volume of a subsequent circuit is increased while the ultrasonic signal is better restored, so that the response speed of the system is reduced, the power consumption of the system is increased, and the like.
Referring to fig. 10, a schematic diagram of a distance measurement principle of another ultrasonic system according to an embodiment of the present application is provided. As shown in fig. 10, the embodiment of the present application further provides a downsampling module between the low-pass filter and the amplitude calculating module based on the ultrasonic system shown in fig. 4. Specifically, the input end of the downsampling module is electrically connected with the output end of the low-pass filter and is used for receiving a filtered signal output by the low-pass filter and downsampling the filtered signal to obtain a downsampled signal; the output end of the downsampling module is electrically connected with the input end of the amplitude calculating module and is used for outputting downsampling signals to the amplitude calculating module so that the amplitude calculating module can calculate the amplitude according to the downsampling signals and output an envelope amplitude curve. The embodiment of the application can reduce the data processing amount while restoring the received ultrasonic signals as much as possible, namely, the effects of improving the detection precision and reducing the data processing amount are achieved.
In one possible implementation, when the sampling frequency of the sampling circuit is n×f0, the sampling frequency of the downsampling module is f0, that is, one point is extracted as a downsampled signal every n points. In general, an ultrasonic transducer emits an ultrasonic signal at a frequency f0, a sampling circuit samples at a sampling frequency n×f0, and a downsampling module downsamples at the sampling frequency f 0. It will be appreciated that the down-sampling module and the ultrasonic transducer are at the same frequency. The arrangement reduces the complexity of the circuit.
It will be appreciated that when the low pass filter outputs two filtered signals, two downsampling modules should be included accordingly.
With continued reference to fig. 5, in an embodiment of the present application, the downsampling module specifically includes a first downsampling module and a second downsampling module. The input end of the first downsampling module is electrically connected with the output end of the first low-pass filter and is used for receiving a first filtering signal output by the first low-pass filter and downsampling the first filtering signal to obtain a first downsampling signal; the input end of the second downsampling module is electrically connected with the output end of the second low-pass filter and is used for receiving a second filtered signal output by the second low-pass filter and downsampling the second filtered signal to obtain a second downsampled signal. The amplitude calculation module is electrically connected with the first downsampling module and the second downsampling module respectively, and is used for receiving the first downsampling signal output by the first downsampling module and the second downsampling signal output by the second downsampling module, calculating the amplitude according to the first downsampling signal and the second downsampling signal and outputting an envelope amplitude curve.
Referring to fig. 11, a schematic diagram of a distance measurement principle of another ultrasonic system according to an embodiment of the present application is provided. As shown in fig. 11, the embodiment of the present application is further provided with a front-end circuit between the sampling circuit and the ultrasonic transducer on the basis of the ultrasonic system shown in fig. 4. The input end of the front-end circuit is electrically connected with the output end of the ultrasonic transducer, and the output end of the front-end circuit is electrically connected with the input end of the sampling circuit. Specifically, the pre-circuit may include an amplifier and a filter, and the received ultrasonic signal may be amplified by the amplifier, filtered by the filter to obtain an ultrasonic signal of a specified frequency, and the filtering may be a high-pass, low-pass or band-pass filtering. It should be noted that, those skilled in the art may further add or subtract functions in the front-end circuit according to actual needs; or to remove the pre-circuit, to which embodiments of the application are not particularly limited.
In addition, in some application scenarios, the voltage of the driving signal output by the driving circuit is low, and the ultrasonic transducer may not be driven to emit ultrasonic waves, or the low driving voltage or current makes the distance of obstacle detection closer. Therefore, a transformer is further arranged between the output end of the driving circuit and the input end of the ultrasonic transducer, and the voltage/current of the driving signal can be increased through the transformer, so that the ultrasonic transducer is driven to emit ultrasonic waves. It should be noted that the echo signal received by the ultrasonic transducer may be directly transmitted to the echo processing circuit via the output terminal, without being processed by the transformer.
It should be noted that, the ultrasonic transducer in the above embodiment may be two independent devices including an ultrasonic transmitting transducer and an ultrasonic receiving transducer, or may be one device having both functions of transmitting ultrasonic waves and receiving ultrasonic waves; in addition, the ECU may be other micro-processing units having data processing capability, which is not particularly limited in the embodiment of the present application.
Corresponding to the above embodiment, the embodiment of the present application further provides an ultrasonic signal processing method, where the method may be applied to the ultrasonic transducer chip described in the above embodiment, and the ultrasonic transducer chip is used for being electrically connected to an ultrasonic transducer.
Referring to fig. 12, a flow chart of an ultrasonic signal processing method according to an embodiment of the present application is shown. As shown in fig. 12, it mainly includes the following steps.
Step S1201: sampling the ultrasonic signal to obtain a sampling signal;
step S1202: performing digital down-conversion processing on the sampling signal to obtain a mixed signal corresponding to the ultrasonic signal;
step S1203: low-pass filtering is carried out on the mixed signal to obtain a filtered signal;
step S1204: calculating the amplitude according to the filtered signal, and outputting an envelope amplitude curve;
Step S1205: calibrating the envelope magnitude curve to output a final envelope curve, wherein the envelope magnitude curve is calibrated at least between a driving stage and a transition period of a aftershock stage and the final envelope curve of the transition period is output;
step S1206: and comparing the final envelope curve with an envelope curve threshold value to output a threshold value comparison result.
In one possible implementation manner, step S1205 specifically includes: and comparing the amplitude value of the envelope amplitude curve, and if the amplitude value of the envelope amplitude curve is smaller than a preset first amplitude threshold value, performing calibration processing on the envelope amplitude curve.
In one possible implementation manner, if the amplitude of the envelope amplitude curve is smaller than a preset first amplitude threshold, performing calibration processing on the envelope amplitude curve specifically includes: if the amplitude of the envelope amplitude curve is smaller than a preset first amplitude threshold and larger than or equal to a second amplitude threshold, calibrating the envelope amplitude curve by adopting a first calibration offset strategy; if the amplitude of the envelope amplitude curve is smaller than the second amplitude threshold, calibrating the envelope amplitude curve by adopting a second calibration offset strategy; wherein the first amplitude threshold is greater than the second amplitude threshold.
In one possible implementation, the first amplitude threshold is the amplitude maximum of the envelope amplitude curve and/or the second amplitude threshold is one half of the amplitude maximum of the envelope amplitude curve.
In one possible implementation, the first calibration offset strategy is: p_final= (p_ev+p_cal1)/2, the second calibration offset strategy is: p_final= (p_ev+p_cal2)/2; wherein P_final is the magnitude of the final envelope curve, P_ev is the magnitude of the envelope magnitude curve, P_cal1 is the first calibration factor, and P_cal2 is the second calibration factor.
In one possible implementation, the first calibration factor is 1.25×p_max, and the second calibration factor is 1.5×p_max; wherein p_max is the maximum value of the amplitude of the envelope amplitude curve.
In one possible implementation, the start point of the transition period is located at the end point of the driving period, and the end point of the transition period is a point corresponding to a specified time or a specified number of periods after the end point of the driving period.
In one possible implementation, the envelope magnitude curve is directly output outward to form the final envelope curve outside the transition period.
In one possible implementation, the ultrasonic transducer is driven to emit an ultrasonic signal at a frequency f0, and the ultrasonic signal is sampled at a sampling frequency of n×f0, where n > 1, to obtain a sampled signal.
In one possible implementation manner, after the filtered signal is obtained, the filtered signal is first downsampled to obtain a downsampled signal; and then, carrying out amplitude calculation according to the downsampled signal, and outputting an envelope amplitude curve.
In one possible implementation manner, the performing digital down-conversion processing on the sampling signal to obtain a mixed signal corresponding to the ultrasonic signal includes: respectively adopting mutually orthogonal local signals to convert the sampling signals into a first mixed signal and a second mixed signal; the low-pass filtering the mixed signal to obtain a filtered signal includes: respectively carrying out low-pass filtering on the first mixed signal and the second mixed signal to obtain a first filtered signal and a second filtered signal; the step of downsampling the filtered signal to obtain a downsampled signal includes: respectively downsampling the first filtering signal and the second filtering signal to obtain a first downsampled signal and a second downsampled signal; the calculating the amplitude according to the downsampled signal, outputting an envelope amplitude curve, including: and calculating the amplitude according to the first downsampling signal and the second downsampling signal, and outputting the envelope amplitude curve.
It should be noted that, for brevity, details of the embodiments of the present application may be referred to the description of the foregoing embodiments, and are not repeated herein.
Corresponding to the embodiment, the embodiment of the application also provides an automobile ultrasonic radar device.
Referring to fig. 13, a schematic structural diagram of an ultrasonic radar device for an automobile is further provided in an embodiment of the present application. As shown in fig. 13, the automotive ultrasonic radar apparatus includes an ultrasonic transducer chip and an ultrasonic transducer, wherein the ultrasonic transducer chip and the ultrasonic transducer are electrically connected.
It should be noted that, the specific content of the ultrasonic transducer chip and the ultrasonic transducer according to the embodiments of the present application may be referred to the description of the foregoing embodiments, and for brevity of description, the description is omitted herein.
Corresponding to the above embodiment, the embodiment of the present application further provides a computer readable storage medium, where the computer readable storage medium may store a program, where when the program runs, the device where the computer readable storage medium is located may be controlled to execute some or all of the steps in the above method embodiment. In particular, the computer readable storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (random access memory, RAM), or the like.
Corresponding to the above embodiments, the present application also provides a computer program product comprising executable instructions which, when executed on a computer, cause the computer to perform some or all of the steps of the above method embodiments.
In the embodiments of the present application, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relation of association objects, and indicates that there may be three kinds of relations, for example, a and/or B, and may indicate that a alone exists, a and B together, and B alone exists. Wherein A, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of the following" and the like means any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or plural.
Those of ordinary skill in the art will appreciate that the various elements and algorithm steps described in the embodiments disclosed herein can be implemented as a combination of electronic hardware, computer software, and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.
In several embodiments provided by the present application, any of the functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
The foregoing is merely exemplary embodiments of the present application, and any person skilled in the art may easily conceive of changes or substitutions within the technical scope of the present application, which should be covered by the present application. The protection scope of the present application shall be subject to the protection scope of the claims.
Claims (23)
1. An ultrasonic transducer chip for being electrically connected with an ultrasonic transducer, wherein the chip receives signals and is divided into: the driving stage, the aftershock stage and the receiving stage, wherein the chip comprises:
the sampling circuit is electrically connected with the ultrasonic transducer and is used for sampling the ultrasonic signal to obtain a sampling signal;
the digital down-conversion module is electrically connected with the sampling circuit and is used for receiving the sampling signal output by the sampling circuit and carrying out digital down-conversion processing on the sampling signal to obtain a mixed signal corresponding to the ultrasonic signal;
the low-pass filter is electrically connected with the digital down-conversion module and is used for receiving the mixed signal output by the digital down-conversion module and carrying out low-pass filtering on the mixed signal to obtain a filtered signal;
the amplitude calculation module is electrically connected with the low-pass filter and is used for receiving a filtered signal output by the low-pass filter, calculating the amplitude according to the filtered signal and outputting an envelope amplitude curve;
The envelope calibration module is electrically connected with the amplitude calculation module and is used for receiving the envelope amplitude curve output by the amplitude calculation module, and performing calibration processing on the envelope amplitude curve to output a final envelope curve, wherein the envelope calibration module is used for calibrating the envelope amplitude curve at least between the driving stage and the transition period of the aftershock stage and outputting the final envelope curve of the transition period;
and the threshold comparison circuit is electrically connected with the envelope calibration module and is used for receiving a final envelope curve output by the envelope calibration module, and comparing the final envelope curve with an envelope curve threshold value to output a threshold value comparison result.
2. The chip of claim 1, wherein the envelope calibration module is specifically configured to:
and comparing the amplitude value of the envelope amplitude curve, and if the amplitude value of the envelope amplitude curve is smaller than a preset first amplitude threshold value, performing calibration processing on the envelope amplitude curve.
3. The chip of claim 2, wherein the envelope calibration module is specifically configured to:
if the amplitude of the envelope amplitude curve is smaller than a preset first amplitude threshold and larger than or equal to a second amplitude threshold, calibrating the envelope amplitude curve by adopting a first calibration offset strategy;
If the amplitude of the envelope amplitude curve is smaller than the second amplitude threshold, calibrating the envelope amplitude curve by adopting a second calibration offset strategy;
wherein the first amplitude threshold is greater than the second amplitude threshold.
4. A chip according to claim 3, characterized in that the first amplitude threshold value is the amplitude maximum value of the envelope amplitude curve and/or the second amplitude threshold value is one half of the amplitude maximum value of the envelope amplitude curve.
5. The chip of claim 4, wherein the first calibration offset strategy is: p_final= (p_ev+p_cal1)/2, the second calibration offset strategy is: p_final= (p_ev+p_cal2)/2;
wherein p_final is the magnitude of the final envelope curve output by the envelope calibration module, p_ev is the magnitude of the envelope magnitude curve output by the magnitude calculation module, p_cal1 is a first calibration factor, and p_cal2 is a second calibration factor.
6. The chip of claim 5, wherein the first calibration factor is 1.25 x p_max and the second calibration factor is 1.5 x p_max;
wherein p_max is the maximum value of the amplitude of the envelope amplitude curve.
7. The chip of claim 1, wherein the start of the transition period is located at an end point of the driving period, and the end point of the transition period is a point corresponding to a specified time or a specified number of cycles after the end point of the driving period.
8. The chip of claim 1, wherein the envelope calibration module outputs the envelope magnitude curve directly outward to form the final envelope curve outside of the transition period.
9. The chip of any one of claims 1-8, further comprising a drive circuit for electrically connecting with the ultrasonic transducer to drive the ultrasonic transducer to emit an ultrasonic signal at a frequency of f 0; the sampling circuit is used for being electrically connected with the ultrasonic transducer and sampling the ultrasonic signal according to the sampling frequency of n x f0 to obtain a sampling signal, wherein f0 is the frequency of the ultrasonic signal, and n is more than 1.
10. The chip of claim 9, further comprising a downsampling module electrically connected between the low-pass filter and the amplitude calculation module, the downsampling module electrically connected to the low-pass filter for receiving a filtered signal output by the low-pass filter and downsampling the filtered signal to obtain a downsampled signal; the amplitude calculation module is electrically connected with the downsampling module and is used for receiving the downsampling signals output by the downsampling module, calculating the amplitude according to the downsampling signals and outputting an envelope amplitude curve.
11. The chip of claim 10, wherein the digital down conversion module comprises:
the first frequency conversion module is electrically connected with the sampling circuit and is used for receiving the sampling signal output by the sampling circuit and converting the sampling signal into a first mixing signal;
the second frequency conversion module is electrically connected with the sampling circuit and is used for receiving the sampling signal output by the sampling circuit and converting the sampling signal into a second mixing signal;
the local signals adopted by the first frequency conversion module and the second frequency conversion module are mutually orthogonal;
the low-pass filter includes:
the first low-pass filter is electrically connected with the first frequency conversion module and is used for receiving a first mixing signal output by the first frequency conversion module and carrying out low-pass filtering on the first mixing signal to obtain a first filtering signal;
the second low-pass filter is electrically connected with the second frequency conversion module and is used for receiving a second mixing signal output by the second frequency conversion module and carrying out low-pass filtering on the second mixing signal to obtain a second filtering signal;
the downsampling module comprises:
the first downsampling module is electrically connected with the first low-pass filter and is used for receiving a first filtered signal output by the first low-pass filter and downsampling the first filtered signal to obtain a first downsampled signal;
The second downsampling module is electrically connected with the second low-pass filter and is used for receiving a second filtered signal output by the second low-pass filter and downsampling the second filtered signal to obtain a second downsampled signal;
the amplitude calculation module is electrically connected with the first downsampling module and the second downsampling module respectively, and is used for receiving a first downsampling signal output by the first downsampling module and a second downsampling signal output by the second downsampling module, calculating the amplitude according to the first downsampling signal and the second downsampling signal, and outputting the envelope amplitude curve.
12. An ultrasonic signal processing method is applied to an ultrasonic transducer chip, the chip is used for being electrically connected with an ultrasonic transducer, and the chip receiving signals are divided into: a driving stage, a aftershock stage and a receiving stage, wherein the method comprises the following steps:
sampling the ultrasonic signal to obtain a sampling signal;
performing digital down-conversion processing on the sampling signal to obtain a mixed signal corresponding to the ultrasonic signal;
performing low-pass filtering on the mixed signal to obtain a filtered signal;
Calculating the amplitude according to the filtering signal, and outputting an envelope amplitude curve;
calibrating the envelope magnitude curve to output a final envelope curve, wherein the envelope magnitude curve is calibrated at least between the drive phase and the transition period of the aftershock phase and the final envelope curve of the transition period is output;
and comparing the final envelope curve with an envelope curve threshold value to output a threshold value comparison result.
13. The method according to claim 12, wherein said calibrating said envelope magnitude curve outputs a final envelope curve, comprising in particular:
and comparing the amplitude value of the envelope amplitude curve, and if the amplitude value of the envelope amplitude curve is smaller than a preset first amplitude threshold value, performing calibration processing on the envelope amplitude curve.
14. The method according to claim 13, wherein if the magnitude of the envelope magnitude curve is smaller than a preset first magnitude threshold, performing a calibration process on the envelope magnitude curve, specifically includes:
if the amplitude of the envelope amplitude curve is smaller than a preset first amplitude threshold and larger than or equal to a second amplitude threshold, calibrating the envelope amplitude curve by adopting a first calibration offset strategy;
If the amplitude of the envelope amplitude curve is smaller than the second amplitude threshold, calibrating the envelope amplitude curve by adopting a second calibration offset strategy;
wherein the first amplitude threshold is greater than the second amplitude threshold.
15. The method according to claim 14, characterized in that the first amplitude threshold value is the amplitude maximum value of the envelope amplitude curve and/or the second amplitude threshold value is one half of the amplitude maximum value of the envelope amplitude curve.
16. The method of claim 15, wherein the first calibration offset strategy is: p_final= (p_ev+p_cal1)/2, the second calibration offset strategy is: p_final= (p_ev+p_cal2)/2;
wherein P_final is the magnitude of the final envelope curve, P_ev is the magnitude of the envelope magnitude curve, P_cal1 is the first calibration factor, and P_cal2 is the second calibration factor.
17. The method of claim 16, wherein the first calibration factor is 1.25 x p_max and the second calibration factor is 1.5 x p_max;
wherein p_max is the maximum value of the amplitude of the envelope amplitude curve.
18. The method of claim 12, wherein the start of the transition period is at an end point of the drive period, and the end point of the transition period is a specified time after the end point of the drive period or a point corresponding to a specified number of cycles.
19. The method of claim 12, wherein the envelope magnitude curve is output directly outward to form the final envelope curve outside of the transition period.
20. A method according to any one of claims 12-19, characterized in that the ultrasonic transducer is driven to emit an ultrasonic signal at a frequency f0 and the ultrasonic signal is sampled at a sampling frequency n x f0 to obtain a sampled signal, where n > 1.
21. The method of claim 20, wherein after obtaining the filtered signal, downsampling the filtered signal to obtain a downsampled signal; and then, carrying out amplitude calculation according to the downsampled signal, and outputting an envelope amplitude curve.
22. The method of claim 21, wherein the step of determining the position of the probe is performed,
the digital down-conversion processing is performed on the sampling signal to obtain a mixed signal corresponding to the ultrasonic signal, including: respectively adopting mutually orthogonal local signals to convert the sampling signals into a first mixed signal and a second mixed signal;
the low-pass filtering the mixed signal to obtain a filtered signal includes: respectively carrying out low-pass filtering on the first mixed signal and the second mixed signal to obtain a first filtered signal and a second filtered signal;
The step of downsampling the filtered signal to obtain a downsampled signal includes: respectively downsampling the first filtering signal and the second filtering signal to obtain a first downsampled signal and a second downsampled signal;
the calculating the amplitude according to the downsampled signal, outputting an envelope amplitude curve, including: and calculating the amplitude according to the first downsampling signal and the second downsampling signal, and outputting the envelope amplitude curve.
23. An automotive ultrasonic radar apparatus, comprising:
the chip of any one of claims 1-11;
an ultrasonic transducer;
wherein the chip is electrically connected with the ultrasonic transducer.
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| CN202310895917.1A Pending CN116930937A (en) | 2023-04-10 | 2023-07-20 | Ultrasonic transducer chip, signal processing method and automobile ultrasonic radar device |
| CN202310895916.7A Pending CN117008105A (en) | 2023-04-10 | 2023-07-20 | Signal processing circuit, signal processing method, ultrasonic signal processing chip and radar device |
| CN202310898776.9A Pending CN117055015A (en) | 2023-04-10 | 2023-07-20 | Ultrasonic transducer chip, signal processing method and automobile ultrasonic radar device |
| CN202310895935.XA Pending CN116990788A (en) | 2023-04-10 | 2023-07-20 | Signal processing circuit, ultrasonic signal processing chip, and radar apparatus |
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| CN202310898776.9A Pending CN117055015A (en) | 2023-04-10 | 2023-07-20 | Ultrasonic transducer chip, signal processing method and automobile ultrasonic radar device |
| CN202310895935.XA Pending CN116990788A (en) | 2023-04-10 | 2023-07-20 | Signal processing circuit, ultrasonic signal processing chip, and radar apparatus |
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