WO2024131580A1 - Ultrasonic sensor chip, ultrasonic signal processing method and ultrasonic radar device - Google Patents

Abstract

An ultrasonic sensor chip (10) and an ultrasonic radar device (100), relating to the technical field of ultrasonic waves, and capable of reducing environmental interference on ultrasonic signal processing. The ultrasonic sensor chip (10) comprises: a driving circuit, a signal processing circuit and a storage module (81). The driving circuit comprises a carrier generation module (1), a modulation code generation module (2) and a phase modulation module (3). The signal processing circuit comprises a sampling module (4), a correlation calculation module (5) and a processing module (6). Output ends of the carrier generation module (1) and the modulation code generation module (2) are electrically connected to an input end of the phase modulation module (3). An output end of the sampling module (4) is electrically connected to an input end of the correlation calculation module (5). An input end of the storage module (81) is electrically connected to an output end of the driving circuit, an output end of the storage module (81) is electrically connected to the input end of the correlation calculation module (5), and a reference signal is stored in the storage module (81). An input end of the processing module (6) is electrically connected to an output end of the correlation calculation module (5).

Description

Ultrasonic sensor chip, ultrasonic signal processing method and ultrasonic radar device

This application claims the priority of the Chinese patent application filed with the State Intellectual Property Office of China on December 23, 2022, with application number 202211667704.5 and application name “Ultrasonic sensor chip, ultrasonic signal processing method and ultrasonic radar device”, the entire contents of which are incorporated by reference into this application; and claims the priority of the Chinese patent application filed with the State Intellectual Property Office of China on December 23, 2022, with application number 2022223469969.2 and application name “Ultrasonic sensor chip and ultrasonic radar device”, the entire contents of which are incorporated by reference into this application.

Technical Field

The present application relates to the field of ultrasonic technology, and in particular to an ultrasonic sensor chip, an ultrasonic signal processing method and an ultrasonic radar device.

Background technique

At present, ultrasonic radar devices can be used in vehicles, for example, to determine the distance between the vehicle and obstacles. The ultrasonic radar device transmits ultrasonic signals on the one hand and receives ultrasonic signals on the other hand, wherein the received signal is divided into time segments, which are substantially equal to half the burst length. In each time segment of the ultrasonic received signal, a peak value is determined, and the distance between the vehicle and the obstacle is determined based on the peak signal. However, clutter, noise, other ultrasonic waves, etc. in the environment will interfere with the ultrasonic system, making the existing scheme ineffective in evaluating the distance to obstacles.

Summary of the invention

An ultrasonic sensor chip, an ultrasonic signal processing method and an ultrasonic radar device can reduce the interference of the environment on the ultrasonic signal processing.

In a first aspect, an ultrasonic sensor chip is provided, comprising: a driving circuit, a signal processing circuit and a storage module, the driving circuit comprising a carrier generation module, a modulation code generation module, and a phase modulation module, the signal processing circuit comprising a sampling module, a correlation calculation module and a processing module;

The input ends of the carrier generation module and the modulation code generation module are used to couple to the microprocessor chip to receive the trigger signal, and the output ends of the carrier generation module and the modulation code generation module are electrically connected to the input end of the phase modulation module; the output end of the phase modulation module is used to couple to the first ultrasonic transducer; the input end of the sampling module is coupled to the second ultrasonic transducer, and the output end of the sampling module is electrically connected to the input end of the correlation calculation module; the input end of the storage module is electrically connected to the output end of the driving circuit, and the output end of the storage module is electrically connected to the input end of the correlation calculation module, and the reference signal is stored in the storage module; the input end of the processing module is electrically connected to the output end of the correlation calculation module, and the output end of the processing module is used to couple to the microprocessor chip to send a feedback signal; wherein,

The carrier generation module receives the trigger signal to generate a carrier and inputs the carrier into the phase modulation module;

A modulation code generation module receives a trigger signal to generate a modulation code, and inputs the modulation code to a phase modulation module;

A phase modulation module receives a modulation code and a carrier signal and performs phase modulation on the carrier to obtain a modulated wave, and outputs the modulated wave to the first ultrasonic transducer;

A sampling module, used for sampling the ultrasonic signal received by the second ultrasonic transducer, and inputting the sampled signal into the correlation calculation module;

A correlation calculation module reads the reference signal in the storage module to determine the correlation of the sampled signal, and inputs the correlation information to the processing module, wherein the correlation is related to the modulation code, and the correlation is related to the carrier;

The processing module receives the correlation information and outputs a feedback signal indicating that the correlation reaches a preset value.

In a second aspect, an ultrasonic sensor chip is provided, including: a carrier generation module for generating a carrier; a modulation code generation module for generating a modulation code; a phase modulation module for modulating the phase of the carrier according to the modulation code to obtain a modulated wave, and outputting the modulated wave to a first ultrasonic transducer; a sampling module for sampling an ultrasonic signal received by a second ultrasonic transducer to obtain a sampled signal; a correlation calculation module for determining the correlation of the sampled signal according to a reference signal, the correlation being related to the modulation code, and the correlation being related to the carrier; and a processing module for determining the sampled signal whose correlation reaches a preset value as a designated echo.

In a third aspect, an ultrasonic radar device is provided, comprising: the ultrasonic sensor chip mentioned above;

A first ultrasonic transducer, the input end of which is electrically connected to the output end of the ultrasonic sensor chip, for receiving a modulated wave and transmitting an ultrasonic signal;

The second ultrasonic transducer has an output end electrically connected to an input end of the ultrasonic sensor chip, and the ultrasonic sensor chip is used to sample the ultrasonic signal received by the second ultrasonic transducer.

In a fourth aspect, a method for processing ultrasonic signals is provided, comprising: generating a carrier wave; generating a modulation code; modulating the phase of the carrier wave according to the modulation code to obtain a modulated wave, and outputting the modulated wave to a first ultrasonic transducer; sampling the ultrasonic signal received by the second ultrasonic transducer to obtain a sampled signal; determining a correlation of the sampled signal according to a reference signal, wherein the correlation is correlated with the modulation code, and the correlation is correlated with the carrier wave; and determining the sampled signal whose correlation reaches a preset value as a designated echo.

In a fifth aspect, an ultrasonic radar device is provided, comprising: the above-mentioned ultrasonic sensor chip; a first ultrasonic transducer electrically connected to the ultrasonic sensor chip to receive a modulated wave, and used to transmit an ultrasonic signal according to the modulated wave; and a second ultrasonic transducer electrically connected to the ultrasonic sensor chip to transmit the received ultrasonic signal to the ultrasonic sensor chip.

The ultrasonic sensor chip, ultrasonic signal processing method and ultrasonic radar device in the embodiments of the present application modulate the carrier wave through the modulation code to generate a modulated wave for exciting ultrasonic emission, calculate the correlation of the received signal through the correlation calculation module, and determine whether it is a designated echo based on the calculation result, thereby reducing the adverse effects of interference, noise, etc. in the environment on ultrasonic signal processing and improving the accuracy of ultrasonic signal processing. For example, when the ultrasonic sensor is applied to the ultrasonic radar device of a vehicle, the accuracy of radar positioning can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of an ultrasonic radar device and an obstacle in an embodiment of the present application;

FIG2 is a schematic diagram of waveforms during phase modulation in an embodiment of the present application;

FIG3 is a schematic diagram of the principle of phase modulation in an embodiment of the present application;

FIG4 is a schematic diagram of spectrum changes before and after phase modulation of a carrier in an embodiment of the present application;

FIG5 is a schematic diagram of a structure of a part of the structure of the ultrasonic radar device in FIG1 ;

6 is a schematic diagram of the spectrum change of a signal including only a modulated wave received by the second ultrasonic transducer in an embodiment of the present application before and after modulation and despreading;

7 is a schematic diagram of the spectrum change of the signal including the modulated wave and the interference received by the second ultrasonic transducer in the embodiment of the present application before and after modulation and despreading;

FIG8 is another schematic diagram of a partial structure of the ultrasonic radar device in FIG1 ;

FIG9 is a schematic diagram of the correlation between the carrier and the sampling signals received at different times in an embodiment of the present application;

FIG10 is a schematic diagram of a waveform sampling in an embodiment of the present application;

FIG11 is a schematic diagram of a structure of a part of the ultrasonic radar device in FIG1 ;

FIG12 is a schematic diagram of a structure of a part of the structure of the ultrasonic radar device in FIG1 ;

FIG13 is a schematic diagram of waveform sampling with different amplitudes in an embodiment of the present application;

FIG14a is a schematic diagram of a structure of a part of the ultrasonic radar device in FIG1 ;

FIG14b is a schematic diagram of a structure of a part of the structure of the ultrasonic radar device in FIG1;

FIG15 is a schematic diagram of a structure of a part of the ultrasonic radar device in FIG1 ;

FIG16 is a schematic diagram of the relationship between a correlation and a modulation code in an embodiment of the present application;

FIG17 is a flow chart of a signal processing method in an embodiment of the present application;

FIG18 is a flow chart of another signal processing method in an embodiment of the present application;

FIG19 is a flow chart of another signal processing method in an embodiment of the present application;

FIG20 is a flow chart of another signal processing method in an embodiment of the present application;

FIG21 is a flow chart of another signal processing method in an embodiment of the present application;

FIG. 22 is a flow chart of another signal processing method in an embodiment of the present application.

Detailed ways

The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

The embodiment of the present application provides an ultrasonic sensor chip and an ultrasonic radar device. The ultrasonic sensor chip can be applied to the ultrasonic radar device. As shown in FIG1 , the ultrasonic radar device 100 includes the ultrasonic sensor chip 10 and an ultrasonic transducer 200. The ultrasonic transducer 200 includes a first ultrasonic transducer 201 and a second ultrasonic transducer 202. The input end of the first ultrasonic transducer 201 is electrically connected to the output end of the ultrasonic sensor chip 10, and is used to receive a modulated wave and transmit an ultrasonic signal. The output end of the second ultrasonic transducer 202 is electrically connected to the input end of the ultrasonic sensor chip 10. The ultrasonic sensor chip 10 is used to sample the ultrasonic signal received by the second ultrasonic transducer 202. The first ultrasonic transducer 201 and the second ultrasonic transducer 202 can be two independent devices or integrated devices. The ultrasonic sensor chip 10 includes: a driving circuit, a signal processing circuit and a storage module 81, wherein the driving circuit includes a carrier generation module 1, a modulation code generation module 2, and a phase modulation module 3, and the signal processing circuit includes a sampling module 4, a correlation calculation module 5 and a processing module 6. The input ends of the carrier generation module 1 and the modulation code generation module 2 are used to couple to the microprocessor chip 20 to receive the trigger signal, and the output ends of the carrier generation module 1 and the modulation code generation module 2 are electrically connected to the input end of the phase modulation module 3; the output end of the phase modulation module 3 is used to couple to the first ultrasonic transducer 201; the input end of the sampling module 4 is coupled to the second ultrasonic transducer 202, and the output end of the sampling module 4 is electrically connected to the input end of the correlation calculation module 5; the input end of the storage module 81 is electrically connected to the output end of the driving circuit, and the output end of the storage module 81 is electrically connected to the input end of the correlation calculation module 5, and the storage module 81 stores a reference signal; the input end of the processing module 6 is electrically connected to the output end of the correlation calculation module 5, and the output end of the processing module 6 is used to couple to the microprocessor chip 20 to send a feedback signal; wherein, The carrier generation module 1 receives a trigger signal to generate a carrier, and inputs the carrier into the phase modulation module 3; the modulation code generation module 2 receives a trigger signal to generate a modulation code, and inputs the modulation code into the phase modulation module 3; the phase modulation module 3 receives the modulation code and the carrier signal and performs phase modulation on the carrier to obtain a modulated wave, and outputs the modulated wave to the first ultrasonic transducer 201; the sampling module 4 is used to sample the ultrasonic signal received by the second ultrasonic transducer 202, and input the sampled signal into the correlation calculation module 5; the correlation calculation module 5 reads the reference signal in the storage module 81 to determine the correlation of the sampled signal, and inputs the correlation information into the processing module 6, the correlation is related to the modulation code, and the correlation is related to the carrier; the processing module 6 receives the correlation information and outputs a feedback signal that the correlation reaches a preset value. The ultrasonic radar device 100 may further include a microprocessor chip 20, the output end of the microprocessor chip 20 is electrically connected to the input end of the ultrasonic sensor chip 10, and the input end of the microprocessor chip 20 is electrically connected to the output end of the ultrasonic sensor chip 10; the ultrasonic sensor chip 10 receives a trigger signal from the microprocessor chip 20 to generate a modulated wave, and the ultrasonic sensor chip 10 is also used to send a feedback signal to the microprocessor chip 20 when a specified echo is received.

Specifically, at least one pin of the ultrasonic sensor chip 10 is electrically connected to the ultrasonic transducer 200, and at least one pin of the ultrasonic sensor chip 10 is electrically connected to the microprocessor chip 20 through a controller area network (CAN), a local interconnect network (LIN), a point-to-point (pt-to-pt), etc. When ultrasonic detection is required, the microprocessor chip 20 outputs a trigger signal to the ultrasonic sensor chip 10, and the ultrasonic sensor chip 10 responds to the trigger signal from the microprocessor chip 20 to drive the carrier generation module 1 to generate a carrier (for example, a sine wave). In addition, the modulation code generation module 2 generates a modulation code as a modulation signal. The phase modulation module 3 modulates the phase of the carrier according to the modulation code to obtain a modulation wave, that is, the phase of the carrier is adjusted according to the modulation code, and the adjusted signal is the modulation wave, which is the ultrasonic excitation signal. The phase modulation module 3 outputs the modulation wave to the first ultrasonic transducer 201, and the first ultrasonic transducer 201 vibrates under the excitation control of the modulation wave to generate a corresponding ultrasonic wave, and the ultrasonic wave will be reflected when encountering an obstacle. The second ultrasonic transducer 202 receives an ultrasonic signal, and the sampling module 4 samples the ultrasonic signal received by the second ultrasonic transducer 202 to obtain a sampled signal. For example, the sampling module 4 is an analog-to-digital converter (ADC) that converts an analog signal into a digital signal. Due to interference and noise in the environment, there may also be ultrasonic waves generated by other ultrasonic transducers. Therefore, the wave received by the second ultrasonic transducer 202 is not necessarily the ultrasonic wave emitted by the first ultrasonic transducer 201. In the embodiment of the present application, the ultrasonic wave emitted by the first ultrasonic transducer 201 is driven by a modulation wave modulated by a modulation code, and the ultrasonic wave not only has the signal characteristics of the carrier itself, but also has the signal characteristics of the modulation code. Therefore, for the ultrasonic signal received by the second ultrasonic transducer 202, after being sampled as a sampled signal, in the correlation calculation module 5, the correlation is determined according to the reference signal and the sampled signal. If it is determined in the processing module 6 that the correlation reaches the preset value, it means that the signal has the characteristics of both the carrier and the modulation code, that is, it means that the signal comes from the first ultrasonic transducer 201, rather than an interference or noise signal, so the signal is used as a designated echo, and the designated echo refers to the echo signal of the ultrasonic wave emitted by the first ultrasonic transducer 201, so as to facilitate the subsequent determination of the distance to the obstacle according to the designated echo. If it is determined in the processing module 6 that the correlation does not reach the preset value, it means that the signal is an interference or noise signal, so it will not be used as a designated echo. In the subsequent process of determining the distance to the obstacle, interference and noise are reduced, and the accuracy of ultrasonic positioning is improved.

Microprocessor chips in automobiles are usually called electronic control units (ECUs), domain controllers, and can be, for example, microcontroller units (MCUs), digital signal processing (DSPs), microprocessors, etc. Microprocessor Unit (MPU), micro central processing unit (CPU), etc. can process digital signals, analog signals, or perform signal control functions, instruction processing and calculation functions, and other micro central control chips and system-on-chip chips.

The ultrasonic sensor chip in the embodiment of the present application modulates the carrier wave through the modulation code to generate a modulated wave for exciting ultrasonic emission, calculates the correlation of the received signal through the correlation calculation module, and determines whether it is a designated echo based on the calculation result, thereby reducing the adverse effects of interference and noise in the environment on ultrasonic signal processing and improving the accuracy of ultrasonic signal processing. For example, when the ultrasonic sensor chip is used in an ultrasonic radar device of a vehicle, the accuracy of radar positioning can be improved.

In a possible implementation, the ultrasonic sensor chip 10 further includes a first timer, which can be electrically connected to the processing module 6. The first timer is used to start timing after the first ultrasonic transducer 201 emits an ultrasonic signal, or starts timing after receiving a trigger signal sent by the microprocessor chip 20, and stops timing when it is determined that a specified echo is received; the ultrasonic sensor chip 10 is also used to calculate the obstacle distance according to the timing duration of the first timer and the specified echo, and transmit the obstacle distance to the microprocessor chip 20. The processing module 6 in the ultrasonic sensor chip 10 can calculate the distance of the obstacle according to the relationship between time and ultrasonic transmission speed; after obtaining the distance information, the processing module 6 outputs data to the microprocessor chip 20, and the microprocessor chip 20 is used to make judgments and trigger prompts based on the received data, such as triggering a buzzer to emit a prompt sound, a light prompt, a display prompt, a voice prompt, etc.

In a possible implementation, the microprocessor chip 20 may include a first timer, and the microprocessor chip 20 obtains the timing duration of the first timer and the received feedback signal to obtain the obstacle distance. That is, the first timer may also be set in the microprocessor chip 20, and the timer starts timing after the microprocessor chip 20 sends a trigger signal, and the trigger signal is used to trigger the ultrasonic sensor chip 10 to generate a modulated wave, so that the first ultrasonic transducer 201 emits an ultrasonic signal, stops timing when it is determined that a specified echo is received, and can calculate the distance of the obstacle based on the relationship between time and ultrasonic transmission speed; after obtaining the distance information, a corresponding action is taken, such as triggering a buzzer to emit a prompt sound or triggering an alarm light, etc.

That is to say, in the ultrasonic radar device, the obstacle distance can be calculated by any one of the ultrasonic sensor chip 10 and the microprocessor chip 20. For example, after determining the designated echo, the ultrasonic sensor chip 10 will send a feedback signal of receiving the designated echo to the microprocessor chip 20, such as the I/O pin clock is high or low. After determining the designated echo, the ultrasonic sensor chip 10 will pull the I/O pin high or low, and the microprocessor chip 20 will calculate the time from sending the trigger signal to receiving the indication signal based on this signal, calculate the distance of the obstacle, and then control the corresponding prompt system to take action; if the ultrasonic sensor chip 10 performs the distance calculation, it can send data indicating different distances through the I/O pin after the calculation is completed, and the microprocessor chip 20 will receive this data and analyze it, and control the corresponding prompt system to take action according to the result of the analysis.

In a possible implementation, the ultrasonic radar device includes a plurality of ultrasonic sensor chips 10 , a plurality of first ultrasonic transducers 201 , and a plurality of second ultrasonic transducers 202 .

In a possible implementation, as shown in FIG. 2 and FIG. 3, the modulation code includes a first code value and a second code value, for example, the first code value is 0, and the second code value is 1. During the modulation process, the first code value is used to flip the carrier phase by 180°, and the second code value is used to keep the carrier phase unchanged. If the signal flowing in the circuit is used to illustrate, the signal input to the phase modulation module 3 by the modulation code generation circuit 1 includes a first signal and a second signal. The phase modulation module 3 receives the first signal and outputs the corresponding carrier information. The phase modulation module 3 receives the second signal and outputs the information that is 180° different from the corresponding carrier.

Specifically, the modulation code includes multiple modulation chips, each of which has a width of d, and one carrier cycle corresponds to one modulation chip width. For example, in Figure 2, the carrier is wave A with 9 sinusoidal wave cycles; the modulation code is 111001100, that is, wave B with 9 modulation chips. In the process of modulating the carrier according to the modulation code to obtain the modulated wave, when wave A encounters a modulation chip of 0, the sinusoidal wave phase flips 180°, and when encountering a modulation chip of 1, the sinusoidal wave phase remains unchanged, and the modulated wave obtained after modulation is wave C. That is, wave C = wave A * wave B, that is, wave A (111111111) * wave B (111001100) = wave C (111001100), where "*" means the above expression, that is, the carrier remains unchanged when the modulation code is 1, and the phase is reversed when the modulation code is 0. Assuming that the sequence code of wave A is 1 at the initial phase, the sequence code after the phase reversal is 0, that is, the sequence code of wave C after modulation by the modulation code is 111001100. After the above phase modulation, although the driving frequency of the carrier is not changed, the carrier after phase modulation produces a spread spectrum effect. As shown in Figure 4, before phase modulation, the carrier has only one frequency, and after modulation, multiple frequencies are generated, which is equivalent to the frequency being scattered. What needs to be known here is that this scheme does not adjust the frequency of the carrier, but only adjusts the phase of the carrier, but produces the effect of frequency modulation, which is a significant improvement over frequency modulation. See the following description for details.

In addition, the width of a chip does not necessarily correspond to one carrier cycle, and one chip may correspond to multiple carrier cycles. The principle is the same as the above one chip width equals one carrier cycle, which will not be repeated here. For other descriptions of the chip width, see the following description.

In a possible implementation, as shown in FIG5 , the ultrasonic sensor chip 10 further includes: a sampling module 4 and a related A modulation and despreading module 8 is connected between the correlation calculation module 5, the input end of the modulation and despreading module 8 is coupled to the output end of the sampling module 4, and the output end of the modulation and despreading module 8 is coupled to the input end of the correlation calculation module 5; the storage module also stores the modulation code, and the input end of the modulation and despreading module 8 is also electrically connected to the output end of the storage module 81 to read the modulation code; the reference signal is a carrier or a carrier orthogonal wave orthogonal to the carrier.

Specifically, the sampling module 4 samples the ultrasonic signal received by the second ultrasonic transducer 202, and the modulated wave obtained is wave D. The modulation and despreading module 8 modulates and despreads wave D according to wave B, and the despread sampled signal obtained is wave E. The modulation and despreading process is the same as the modulation process, that is, wave E = wave D * wave B. As shown in FIG6, if the signal received by the second ultrasonic transducer 202 only contains the modulated wave, wave D is equivalent to wave C, then wave E = wave C * wave B, and the sequence code of wave C is 111001100, and wave B is 111001100, then wave E = wave C * wave B = 111111111. The formula for correlation calculation is correlation value f = ∑M*N = M1*N1+M2*N2+…+Mn*Nn (convolution operation), M = (M1, M2,…, Mn), N = (N1, N2,…, Nn). The correlation between the demodulated sampling signal (wave E) and the timing corresponding to the carrier (wave A) is f=∑wave E*wave A. Since wave E is equal to wave A, when correlation operation is performed on two identical waves, the correlation value is very high (such as 9 in the example).

As shown in FIG7 , if the signal received by the second ultrasonic transducer 202 includes the designated echo itself (i.e., the modulated wave of the spread spectrum), the interference signal in the environment, the channel noise, or the spread spectrum signal emitted by other devices, etc., the interference signal in the environment, the channel noise, or the spread spectrum signal emitted by other devices, etc. are called undesignated echoes. There are two types of undesignated echoes, one is a spread spectrum signal, i.e., a signal containing multiple frequencies, and the other is a signal with a particularly high frequency, i.e., a single frequency signal. Here, the received interference signal is a single frequency and the other signal is a spread spectrum signal as an example for explanation.

For better understanding, here is an example:

For example, the single frequency sequence of the interference signal is recorded as wave D1, wave D1 = 111111111111111111 (twice the frequency of the carrier), then the signal of the interference signal after modulation and despreading is wave E1, wave E1 = wave D1 * wave B, wave E1 and wave A are correlated, and the correlation value is very low or relatively low (such as less than or equal to 6 in the example); even with the sliding of wave D1, by sliding despreading with the modulation code wave B, the correlation between the obtained wave E1 and wave A is still very low. The sliding despreading principle is as follows: the first 9 bits of D1 are modulated and despread with wave B to obtain E1 = 111001100, the 2nd to 10th bits of D1 are modulated and despread with wave B to obtain E1 = 111001100, the 3rd to 11th bits of D1 are modulated and despread with wave B to obtain E1 = 111001100, and so on, until D1 is completely moved. The above wave E1 is correlated with wave A one by one to check the correlation between wave E1 and wave A during any sliding process. When wave E1 is different from wave A, the correlation is always at a low level during the entire sliding process.

For another example, the interference signal is a single-frequency sequence, recorded as wave D2, wave D2 = 111111111 (the same as the carrier frequency), then wave E2 = wave D2 * wave B = 111001100, wave E2 and wave A are correlated, and the correlation value is very low (such as the highest in the example is 5). It can be seen that even if the received echo signal is consistent with the carrier, but does not conform to the modulation rule of the modulation code, the final correlation obtained is still very low, and it is not a designated echo;

For another example, the other interference signal is a spread spectrum sequence, denoted as D3. For example, wave D3=111000110, then wave E3=wave D3*wave B=111110110, and the correlation calculation between wave E3 and wave A is low (the highest is 6 in the example). It can be seen that even if the received echo signal is also a signal containing multiple frequencies, it does not conform to the modulation rules of the modulation code, and the finally obtained correlation is still very low, and it is not a designated echo. It should be noted that all echoes will be slidingly demodulated. If there are signals before and after the corresponding wave, the signal of the corresponding wave will be selected for modulation and demodulation with wave B. For example, if a signal contains waves D1, D2, and D3 in chronological order, the first 9 bits of D1 will be modulated and demodulated with wave B, and the modulated and demodulated signal will be output to the next node; the 2nd to 10th bits of D1 will continue to be modulated and demodulated with wave B... When the modulation and demodulation of the 10th to 18th bits of D1 with wave B is completed, the 11th to 18th bits of D1 and the 1st bit of D2 will be modulated and demodulated with wave B, and the 12th to 18th bits of D2 and The 1st to 2nd bits of D2 are modulated and demodulated with wave B... After the modulation and demodulation of the 1st to 9th bits of D2 with wave B is completed, the 2nd to 9th bits of D2 and the 1st bit of D3 are modulated and demodulated with wave B, and the 3rd to 9th bits of D2 and the 1st to 2nd bits of D3 are modulated and demodulated with wave B... After the modulation and demodulation of the 1st to 9th bits of D3 with wave B is completed, if there is no signal behind it, then the data modulated and demodulated with wave B by D3 becomes less and less, and the 2nd to 9th bits of D3 are modulated and demodulated with wave B, and the 3rd to 9th bits of D3 are modulated and demodulated with wave B... until the number of bits of D3 has no overlap with wave B and cannot be modulated and demodulated.

It can be known that if the ultrasonic signal received by the second ultrasonic transducer 202 contains a modulated wave, then after despreading, a wave with a frequency consistent with the carrier wave will be obtained; if the ultrasonic signal received by the second ultrasonic transducer 202 contains other non-specified echoes, then after the despreading process, both the single-frequency signal and the spread spectrum signal will be spread again (i.e., scattered), so that a wave with a frequency consistent with the carrier wave will not be obtained. As shown in Figure 7, therefore, the embodiment of the present application can realize the judgment of whether the signal is an interference signal, and the accuracy, precision, and recognition effect are excellent.

In a possible implementation, as shown in FIG8 , the reference signal is a modulated wave or a modulated orthogonal wave orthogonal to the modulated wave, for example, An input end of the correlation calculation module 5 is electrically connected to an output end of the sampling module 4 .

Specifically, in the structure shown in FIG8 , the correlation between the sampled signal and the modulated wave can be directly calculated to determine whether the signal received by the second ultrasonic transducer 202 is the signal emitted by the first ultrasonic transducer 201. For example, wave C = 111001100, since wave C = wave A*wave B, the correlation operation between wave D and wave C is equivalent to calculating the correlation between wave A*wave B and wave D, that is, calculating wave A*wave B*wave D = wave A*(wave B*wave D), and performing the correlation operation between wave D and wave C is equivalent to including the despreading process in the above scheme. The specific process is as above and will not be repeated. Only the correlation operation is discussed here.

From the above, we can see that the correlation value f=wave A*(wave B*wave D)=1111111111*(111001100*wave D).

For example, if wave D1 = 111111111111111111, and wave B*wave D = 111001100, then the correlation value f1 = 111111111*111001100, and the correlation value is very low (the highest in the example is 5);

For example, wave D2 = 111111111, wave B*wave D = 111001100, and correlation value f2 = 111111111*111001100. The correlation value is very low (the highest in the example is 5).

For example, wave D3 = 111000110, wave B*wave D = 111110101, and correlation value f3 = 111111111*111110101, and the correlation value is relatively low (the highest in the example is 7);

For example, wave D4=111001100, wave B*wave D=1111111111, correlation value f4=1111111111*111111111, and the correlation value is the highest (9 in the example).

Therefore, the embodiment corresponding to the structure shown in FIG8 can also realize the judgment of whether the signal is an interference signal. Directly using the modulated wave and the sampling signal for correlation calculation can reduce the modulation and despreading process of the sampling chip, so that the connection relationship between the hardware circuit and the circuit can be more concise. In the above patent, the correlation calculation module includes a convolution operation logic circuit to calculate the correlation.

In a possible implementation, a second timer may be provided in the ultrasonic sensor chip 10, and the second timer is related to the preset value of the correlation. As time increases, the ultrasonic echo signal becomes weaker, and the preset value of the correlation also decreases as time increases, that is, the preset value includes multiple different values. Alternatively, the second timer may not be provided, and the preset value of the correlation is related to time, and the preset value is directly stored in a memory, and multiple different values are provided in the memory, and the values are used to mark the preset value. As the clock passes, the preset values at different addresses in the memory are read, and the preset value is related to time. Generally speaking, as the clock passes, the preset value becomes smaller and smaller. In addition, the memory may also store data on the relationship between time and the preset value, and the correlation is calculated by reading the time and the preset value. The memory used to store the preset value may be the same storage module as the storage module 81 described below, but with different addresses, or it may be a storage module independent of the storage module 81 described below, but the same storage module is still an independent storage module, which is only physically divided.

When a preset value of correlation related to time is set, the storage module should also be electrically connected to the processing module 6. The processing module 6 reads the preset value information in the storage module and compares the correlation information output by the correlation calculation module with the preset value to determine whether a specified echo exists.

The technical effects of the embodiments of the present application are further described below. For example, in the embodiment corresponding to the structure shown in FIG8 , the correlation between the despread sampling signal (wave E) and the modulated wave (wave C) is used to determine whether the despread sampling signal (wave E) comes from the ultrasonic wave emitted by the first ultrasonic transducer 201. As shown in FIG9 , the despread sampling signal (wave E) includes a specified echo. During the transmission or sliding process, the echo signal is not aligned with the timing corresponding to the modulated wave (wave C), and then gradually aligned, and then gradually moves away from alignment. For example:

The clock lengths t0 and t1 mean that the timing of the despread sampling signal (wave E) and the modulation wave (wave C) are not aligned, so the correlation is low;

t2 clock length, the timing of the despread sampling signal (wave E) and the modulation wave (wave C) is aligned, so the correlation is the highest;

At the clock lengths of t3 and t4, the timing of the despread sampling signal (wave E) and the modulation wave (wave C) are not aligned, so the correlation is low.

Therefore, not only the timing corresponding to the specified modulation wave (wave C) must appear, but also the phase must be aligned to have a high correlation, otherwise the correlation is low. If the sequence is long enough, there will be no process of correlation from low to high and then from high to low. Even if it occurs, the correlations on both sides with the highest correlation are very low, which is easy to distinguish compared with the highest correlation. That is to say, in the embodiment of the present application, the moment when the specified echo is received can be determined more accurately, thereby improving the accuracy of obstacle distance calculation based on the clock length of the received specified echo.

From the above introduction, we can know that by phase modulating the carrier, the spread spectrum effect is achieved by adjusting the phase of the carrier, and then the echo During the despreading process of the signal, only the echo signals that meet the modulation and despreading rules can obtain a high correlation, that is, reach the preset value of the correlation. Any other non-specified echo signals will be spread again by the despreading process, so that a high correlation value cannot be obtained. The correlation value can be used to determine whether a designated echo appears. Due to the phase adjustment, as long as a part of any echo does not meet the rules, the calculated correlation value is relatively low. Therefore, the echo signal with a high correlation value is the designated echo signal, so that the adverse effects of interference and noise in the environment on ultrasonic signal processing can be reduced according to the determination of the designated echo signal, and the accuracy of ultrasonic signal processing can be improved.

In addition, compared with the existing technology, the embodiments of the present application also have the following beneficial effects:

1) The time when the echo appears can be clearly specified, and the judgment logic is relatively simple. In the existing correlation calculation, when the locally stored signal is correlated with the received signal, the correlation calculation generally occurs from low to high and then from high to low. Therefore, the logical judgment of which correlation value to select as the timing of the echo signal appearance is relatively complex. The timing of the echo signal appearance in this solution is relatively clear, and the judgment logic is simpler. If the length of the carrier is long enough, then during the correlation calculation, only the correlation of the specified echo waveform will be high, and the correlation of other waveforms will be very low, because the possibility of nature or other ultrasonic systems emitting highly consistent waves is very low.

2) Through the embodiment of the present application, no filtering circuit is required (before sampling or after sampling), because in the embodiment of the present application, the wave received by the second ultrasonic transducer 202 is not an echo of a single frequency, so there is no need to add a filter to filter out irrelevant waves. Irrelevant waves will be filtered out when performing correlation calculations, will not affect the final result, and save hardware circuit overhead.

3) The embodiment of the present application changes the phase of the carrier without changing the frequency, so the sampling frequency can be fixed during sampling, and the adopted frequency can be relatively low. If the frequency is adjusted in such a way that the frequency is increased, the sampling frequency must be increased, otherwise the real waveform cannot be reflected. Either the sampling frequency must be adjusted in real time, or a higher sampling frequency must be fixed, which increases the hardware overhead of sampling. If a higher sampling frequency is fixed, a lot of data will be processed in subsequent correlation calculations, peak calculations, etc., further increasing the overhead of the hardware circuit. For the embodiment of the present application, it is only necessary to fix a relatively low frequency that can reflect the carrier waveform, and the hardware is simpler.

4) In addition, it has strong anti-interference ability, allowing multiple devices to work at the same time. Because of the anti-interference ability of spread spectrum, it can allow multiple devices using unrelated spread spectrum code sequences to work at the same time without interfering with each other.

5) The embodiment of the present application can also effectively improve the influence of aftershocks, thereby improving the accuracy of obstacle judgment. In the case where the first ultrasonic transducer and the second ultrasonic transducer are the same sensor, after the ultrasonic sensor emits the ultrasonic wave, the ultrasonic excitation signal stops, but because the ultrasonic sensor cannot stop immediately, aftershocks will occur, and obstacles cannot be judged during the aftershocks, resulting in a decrease in judgment accuracy, that is, the close-range judgment is affected. The inventor found that since the aftershock vibration period will change with the passage of time, its amplitude will also change, and as described in the embodiment of the present application, a high correlation cannot be obtained. Therefore, in the case where the first ultrasonic transducer and the second ultrasonic transducer are the same sensor, the existence of aftershocks basically does not affect the judgment of the specified echo, thereby improving the detection accuracy. Moreover, in the existing case where there are aftershocks, an additional aftershock elimination circuit is basically used, such as increasing the on-resistance to the ground, increasing the suppression signal, etc., which will additionally increase the complexity of the circuit and the entire chip, while the present application does not require additional processing circuits, saving hardware expenses while simplifying the circuit.

Regarding the above-mentioned point 2), one of the beneficial effects of the present application is that no filtering circuit is required, but the present application does not exclude the solution of adding a filtering circuit.

As shown in Figure 10, since sampling may not be performed at the most ideal phase angle, there will be a certain phase angle deviation. For example, in an ideal situation, one point is sampled at 0°, 90°, 180°, and 270° respectively, but in actual situations, 20°, 110°, 200°, and 290° may appear, resulting in deviations in the final correlation result, leading to misjudgment.

For example, a sine wave samples 4 points, and the amplitude of the sine wave is 1V, then the values obtained by sampling at 0°, 90°, 180°, and 270° are 0V, 1V, 0V, and -1V (if such a pattern appears, it is considered that a sine wave with the initial phase angle described above has appeared; similarly, if -1V, 0V, 1V, and 0V appear, it is considered that a sine wave with a phase flip described above has appeared). If 0V, 1V, 0V, and -1V appear; 0V, 1V, 0V, and -1V; and -1V, 0V, 1V, and 0V appear, it means that a wave of 110 has appeared.

To simplify the description, as shown in FIG10 and Table 1, the waveform in the figure has a wave of 110, which means that the designated echo has appeared. Ideally, the sampling starts from 0° (waveform 1). If the waveform data obtained from sampling from 30° (waveform 2), 45° (waveform 3), and 90° (waveform 4) are different, the example of a cycle of 4 clock length is used for explanation. When sampling at 45°, a lower correlation is obtained, and when sampling at 90°, the correlation is 0; then, this result will be excluded, and it is considered that the designated echo has not appeared, resulting in an erroneous judgment.

Table 1

Therefore, in order to improve the problem of misjudgment caused by sampling phase angle deviation, in a possible implementation, as shown in FIG11, the correlation calculation module 5 is specifically used to calculate the first correlation between the sampling signal and the time sequence corresponding to the reference signal; calculate the second correlation between the sampling signal and the orthogonal time sequence corresponding to the reference signal; and determine the sampling signal whose sum of the first correlation and the second correlation reaches a preset value as the designated echo. That is, the storage module 81 also stores a signal orthogonal to the reference signal, and the correlation calculation module 5 also reads the signal orthogonal to the reference signal to determine the correlation.

For example, if the timing corresponding to the carrier is 0, 1, 0, -1, 0, 1, 0, -1, 0, -1, 0, 1, then the orthogonal timing corresponding to the carrier is 1, 0, -1, 0, 1, 0, -1, 0, -1, 0, 1, ∑ the timing corresponding to the carrier * the orthogonal timing corresponding to the carrier = 0, as shown in Table 2.

Table 2

Let’s take the data of Wave 1, Wave 2, Wave 3, and Wave 4 with sampling angles of 0°, 30°, 45°, and 90° as an example. See Tables 3-1 and 3-2. Correlation 1 is the correlation between the carrier and wave n, and correlation 2 is the correlation between the orthogonal sequence corresponding to the carrier and wave n, where wave n is 1, 2, 3, or 4.

Table 3-1

Table 3-2

It can be seen that no matter what the sampling phase angle is, the sum of the first correlation obtained by performing correlation operation between the despread sampling signal and the timing corresponding to the carrier and the second correlation obtained by performing correlation operation between the despread sampling signal and the orthogonal timing corresponding to the carrier remains unchanged, which is 6 in the example. Therefore, the problem of misjudgment caused by sampling phase angle deviation is improved.

In a possible implementation, as shown in FIG12, before the above correlation calculation, a modulation and despreading module may not be provided, but the correlation calculation may be performed directly on the signal output by the sampling module 4. The scheme shown in FIG12 is similar to the scheme shown in FIG11, except that in the scheme shown in FIG11, the correlation of the despread sampling signal is calculated, while in the scheme shown in FIG12, the correlation of the sampling signal output by the sampling module 4 is calculated. However, the principles of the two are similar, and both utilize the correlation calculation of the orthogonal timing to improve the misjudgment problem caused by the sampling phase deviation.

Since the farther the obstacle is from the ultrasonic system, the longer the ultrasonic transmission time is, the amplitude of the ultrasonic signal received by the second ultrasonic transducer 202 will decrease as time goes by. Exemplarily, as shown in FIG13 , the solid line waveform is the ultrasonic signal received by the second ultrasonic transducer 202 when the time from the first ultrasonic transducer 201 sending the ultrasonic signal to the second ultrasonic transducer 202 receiving the ultrasonic signal is 0, and its amplitude is the same as that of the ultrasonic signal sent by the first ultrasonic transducer 201 (actually it cannot be 0s), the dotted line waveform in the middle is the ultrasonic signal received by the second ultrasonic transducer 202 when the time is 5ms, and the dotted line waveform closest to the origin is the ultrasonic signal received by the second ultrasonic transducer 202 when the time is 10ms. It can be seen that as the time of the ultrasonic signal received by the second ultrasonic transducer 202 is later, the correlation calculated with the carrier or modulated wave is also lower. Therefore, a dynamic correlation threshold can be set, and the correlation is related to time and decreases with the increase of time, that is, the preset value of the correlation set by using the above-mentioned second timer (or directly storing the preset value related to time) is negatively correlated with the timing time of the second timer. For example, in a possible implementation, a plurality of different preset values are stored in the storage module 81, and the input end of the processing module 6 is electrically connected to the output end of the storage module 81 to read the preset value. However, setting a dynamically changing threshold requires more registers, memories, or more hardware circuit overhead.

Therefore, the embodiment of the present application also provides another solution to improve the problem of inaccurate judgment caused by the decrease in the amplitude of the ultrasonic signal over time.

In a possible implementation, as shown in FIG14a, the ultrasonic sensor chip further includes: a symbol processing module 7 disposed between the sampling module 4 and the correlation calculation module 5, the input end of the symbol processing module 7 being electrically connected to the output end of the sampling module 4, and the output end of the symbol processing module 7 being electrically connected to the input end of the correlation calculation module 5; the symbol processing module 7 is used to convert the positive value of the sampling signal into a first fixed value, and convert the negative value of the sampling signal into a second fixed value. For example, the symbol processing module 7 can be located between the correlation calculation module 5 and the modulation and despreading module 8, and for 0V in the despread sampling signal, it remains unchanged and still takes 0V; if it is a negative value such as -1V, -0.707V, -0.5V, etc., it takes a first fixed value such as -1V; if it is a positive value such as 1V, 0.707V, 0.5V, etc., it takes a second fixed value such as 1V, and similarly performs normalization processing. In this way, no matter what the sampled value is, after being processed by the symbol processing module, the output is independent of the amplitude.

As shown in Table 4-1 and Table 4-2, it is a comparative example of correlation calculation without symbol extraction based on the scheme shown in Figure 11, taking 0° phase angle sampling as an example for explanation. Table 4-1 and Table 4-2 show that the sampling amplitude decreases with the increase of time, such as 1V-0.7V-0.5V-0.3V (maximum value), then, the result of correlation calculation with the timing corresponding to the carrier and the orthogonal timing corresponding to the carrier also decreases, 6-4.2-3-1.8. Then it is necessary to adjust the dynamic correlation value, which has large hardware overhead, complex circuits, and more complex logical operations.

Table 4-1

Table 4-2

As shown in Table 5-1 and Table 5-2, after the symbol processing module, the positive and negative values are processed in the embodiment of the present application shown in FIG. 14a. It can be seen that as time increases, the sampled values used for calculation remain unchanged, so the sum of the correlations is independent of time. Therefore, a large amount of hardware circuits can be saved, the chip area is more saved, the cost is lower, and the logic operation is simpler.

Table 5-1

Table 5-2

In a possible implementation, FIG. 14b is a variation of FIG. 14a, and the symbol processing module 7 can also be arranged between the sampling module 4 and the modulation and despreading module 8, and the symbol processing module 7 is used to convert the positive value of the sampled signal into a first fixed value, convert the negative value of the sampled signal into a second fixed value, and output the converted sampled signal to the modulation and despreading module 8. This scheme is similar to the scheme shown in FIG. 14a, except that The difference is that, in the scheme shown in FIG. 14a , the symbol extracted is a modulated and despread signal, while in the variant scheme shown in FIG. 14b , the symbol extracted is a sampled signal.

In a possible implementation, as shown in FIG15, the symbol processing module 7 may also be arranged between the sampling module 4 and the correlation calculation module 5, and the symbol processing module 7 is used to convert the positive value of the sampling signal into a first fixed value, convert the negative value of the sampling signal into a second fixed value, and output the converted sampling signal to the correlation calculation module 5. The scheme shown in FIG15 is similar to the scheme shown in FIG14a and FIG14b, except that in the schemes shown in FIG14a and FIG14b, there is a modulation and despreading module, and in the scheme shown in FIG15, there is no modulation and despreading module.

The width of a code chip of the modulation code can be greater than a sine wave period of the carrier, such as a code chip corresponding to 2, 3, 4, ... n sine wave periods of the carrier. In a possible implementation, the width of a code chip of the modulation code is equal to one period of the carrier. Referring to Figure 9, when a signal related to the waveform and phase angle appears, a very high correlation will appear. However, since a sine wave has multiple sampling points, the correlation gradually begins to increase when the first sampled data of the last sine wave begins to match data, and the correlation reaches the maximum when all the sampled data match. As the wave moves, the matching degree will decrease and the correlation will decrease again. Enlarge the time axis of the correlation peak, and the correlation peak with the highest correlation will appear similar to a triangle, that is, the correlation goes from low to high, and then from high to low. As shown in Figure 16. Then, to accurately determine the timing of the correlation peak, it is necessary to compress the bottom side of the triangle as much as possible. The smaller the time, the more accurate the time. At this time, setting the modulation code chip width equal to the sine wave period of a carrier can effectively reduce the bottom side of the triangle. A sine wave samples n points, and the base of the triangle consists of 2*n clock lengths. The point with the highest correlation peak appears between the nth and n+1th clocks where the correlation peak appears, and the time determination accuracy can be controlled between plus or minus 1 clock length.

In a possible implementation, during the process of sampling the ultrasonic signal received by the second ultrasonic transducer, the sampling period is one quarter of a sine wave period of the carrier.

Specifically, as described above, due to the use of phase modulation, the sampling frequency does not need to be very high or does not need to be modulated; a sine wave can only sample 4 points, taking 0° sampling as an example, the amplitudes of the 4 points of a sine wave sampling are 0V, 1V, 0V, -1V, and the amplitudes of the sine wave after phase modulation are 0V, -1V, 0V, 1V. Therefore, through the four sampling points, it can be clearly known whether it is a sine wave of the initial phase or a sine wave after phase modulation, that is, it can be determined whether a specified echo appears, and there will be no judgment deviation due to low sampling. In the scheme of the prior art, in order to prevent misjudgment, the sampling rate must be very high, so the requirements for sampling hardware are high and the subsequent correlation calculation hardware consumption is also greater; after adopting the scheme of the embodiment of the present application, the overhead of the hardware circuit can be greatly reduced.

In a possible implementation, as shown in FIG1 , the ultrasonic sensor chip 10 may further include: a storage module 81, the storage module 81 is electrically connected to the correlation calculation module 5, and the correlation calculation module 5 may calculate the correlation according to the reference signal stored in the storage module 81. In the implementation of setting the modulation and despreading module 8, the storage module 81 stores information about the carrier and the modulation code, the modulation code is used to modulate and despread the received sampling signal, and the despread signal is then correlated with the carrier; then, the modulation and despreading module 8 is electrically connected to the storage module 81 for reading the modulation code, and modulating and despreading the sampling signal according to the modulation code, and the correlation calculation module 5 is also electrically connected to the storage module 81 for reading information related to the carrier (such as the carrier, or the carrier and sequence information orthogonal to the carrier) and performing correlation calculation. In the implementation method where the modulation and demodulation module 8 is not set, the storage module 81 stores information related to the carrier and the modulation code, and the information is the modulated wave. Because the modulated wave is obtained by phase modulation of the carrier and the modulation code, the modulated wave is also a type of information related to the carrier and the modulation code; the modulated wave and the sampling signal are correlated, and then the correlation calculation module 5 is electrically connected to the storage module 9 for reading the information related to the modulated wave (such as the modulated wave, or the modulated wave and sequence information orthogonal to the modulated wave) and performing correlation calculation.

In addition, in the implementation mode in which the modulation and despreading module 8 is provided, the storage module 81 can be electrically connected to the carrier generation module 1 and the modulation code generation module 2 to store information corresponding to the carrier and the modulation code. In the implementation mode in which the modulation and despreading module 8 is not provided, the storage module 81 can be electrically connected to the phase modulation module 3 to store information corresponding to the modulated wave.

In addition, the sampling module 4 can be an analog-to-digital converter (ADC), which samples the analog signal to generate a digital signal through the analog-to-digital conversion function of the analog-to-digital converter, that is, the analog signal of the second ultrasonic sensor is converted into a digital signal through the analog-to-digital converter for use by subsequent modules.

In a possible implementation, the correlation calculation module 5 includes a convolution operation logic circuit.

In a possible implementation manner, the first ultrasonic transducer 201 and the second ultrasonic transducer 202 are the same sensor.

The embodiment of the present application further provides an ultrasonic signal processing method, which can be applied to the above-mentioned ultrasonic sensor chip. As shown in FIG17 , the signal processing method includes:

Step 101: Generate a carrier wave;

Step 102: Generate a modulation code;

Step 103: modulate the carrier according to the modulation code to obtain a modulated wave, and output it to the first ultrasonic transducer;

Step 104: sampling the ultrasonic signal received by the second ultrasonic transducer to obtain a sampled signal;

Step 105: Determine the correlation of the sampled signal according to the reference signal, where the correlation is related to the modulation code and the correlation is related to the carrier;

Step 106: Determine the sampling signal whose correlation reaches a preset value as a designated echo.

The specific process and principle of this method are the same as those described in the above embodiment and will not be described in detail here.

In a possible implementation, as shown in FIG. 18 , before step 105 , determining the correlation of the sampling signal according to the reference signal, the method further includes: step 107 , modulating and despreading the sampling signal according to the modulation code; the reference signal is a carrier or a carrier orthogonal wave orthogonal to the carrier.

In a possible implementation, as shown in FIG. 19 , in this process, there is no need to perform a modulation and despreading process, and the reference signal is a modulated wave or a modulated orthogonal wave that is orthogonal to the modulated wave.

In a possible implementation, as shown in FIG. 20, FIG. 21 or FIG. 22, step 105, determining the correlation of the sampling signal based on the reference signal includes: step 1051, calculating the first correlation between the sampling signal and the timing corresponding to the reference signal; step 1052, calculating the second correlation between the sampling signal and the orthogonal timing corresponding to the reference signal; step 106, determining the sampling signal whose correlation reaches a preset value as the designated echo includes: determining the sampling signal whose sum of the first correlation and the second correlation reaches a preset value as the designated echo.

In a possible implementation, as shown in FIGS. 18 and 20 , the method further includes: before step 107, modulating and demodulating the sampled signal according to the modulation code, executing step 108, converting the positive value of the sampled signal into a first fixed value, and converting the negative value of the sampled signal into a second fixed value; or, as shown in FIGS. 21 and 22 , before calculating the correlation, executing step 108, converting the positive value of the sampled signal into a first fixed value, and converting the negative value of the sampled signal into a second fixed value.

In a possible implementation, as shown in FIGS. 19 to 22 , before step 105 , determining the correlation of the sampled signal according to the reference signal, the method further includes: step 108 , converting the positive value of the sampled signal into a first fixed value, and converting the negative value of the sampled signal into a second fixed value.

In a possible implementation, the modulation code includes a first code value and a second code value. During the modulation process, the first code value is used to flip the carrier phase by 180°, and the second code value is used to keep the carrier phase unchanged.

In a possible implementation manner, a chip width of the modulation code is equal to a period of the carrier.

In a possible implementation, during the process of sampling the ultrasonic signal received by the second ultrasonic transducer, the sampling period is one quarter of a sine wave period of the carrier.

In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And/or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character "/" generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, c can be single or multiple.

The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (38)

1. An ultrasonic sensor chip, characterized in that it comprises: a driving circuit, a signal processing circuit and a storage module, the driving circuit comprises a carrier generation module, a modulation code generation module, and a phase modulation module, the signal processing circuit comprises a sampling module, a correlation calculation module and a processing module;

   The input ends of the carrier generation module and the modulation code generation module are used to couple to a microprocessor chip to receive a trigger signal, and the output ends of the carrier generation module and the modulation code generation module are electrically connected to the input end of the phase modulation module; the output end of the phase modulation module is used to couple to a first ultrasonic transducer; the input end of the sampling module is coupled to a second ultrasonic transducer, and the output end of the sampling module is electrically connected to the input end of the correlation calculation module; the input end of the storage module is electrically connected to the output end of the driving circuit, and the output end of the storage module is electrically connected to the input end of the correlation calculation module, and a reference signal is stored in the storage module; the input end of the processing module is electrically connected to the output end of the correlation calculation module, and the output end of the processing module is used to couple to the microprocessor chip to send a feedback signal; wherein,

   The carrier generation module receives the trigger signal to generate a carrier, and inputs the carrier into the phase modulation module;

   The modulation code generation module receives the trigger signal to generate a modulation code, and inputs the modulation code to the phase modulation module;

   The phase modulation module receives the modulation code and the carrier signal and performs phase modulation on the carrier to obtain a modulated wave, and outputs the modulated wave to the first ultrasonic transducer;

   The sampling module is used to sample the ultrasonic signal received by the second ultrasonic transducer and input the sampled signal to the correlation calculation module;

   The correlation calculation module reads the reference signal in the storage module to determine the correlation of the sampled signal, and inputs the correlation information to the processing module, wherein the correlation is related to the modulation code, and the correlation is related to the carrier;

   The processing module receives the correlation information and outputs a feedback signal indicating that the correlation reaches a preset value.
2. The ultrasonic sensor chip according to claim 1, characterized in that

   The storage module also stores a signal orthogonal to the reference signal, and the correlation calculation module also reads the signal orthogonal to the reference signal to determine the correlation.
3. The ultrasonic sensor chip according to claim 1, characterized in that

   It also includes a sign processing module, the input end of the sign processing module is electrically connected to the output end of the sampling module, and the output end of the sign processing module is electrically connected to the input end of the correlation calculation module; the sign processing module is used to convert the positive value of the sampling signal into a first fixed value, and convert the negative value of the sampling signal into a second fixed value.
4. The ultrasonic sensor chip according to any one of claims 1 to 3, characterized in that:

   It also includes a modulation and despreading module, the input end of the modulation and despreading module is coupled to the output end of the sampling module, and the output end of the modulation and despreading module is coupled to the input end of the correlation calculation module; the storage module also stores the modulation code, and the input end of the modulation and despreading module is also electrically connected to the output end of the storage module to read the modulation code;

   The reference signal is the carrier or a carrier orthogonal wave orthogonal to the carrier.
5. The ultrasonic sensor chip according to any one of claims 1 to 3, characterized in that:

   The reference signal is the modulated wave or a modulated orthogonal wave orthogonal to the modulated wave.
6. The ultrasonic sensor chip according to claim 1 or 2, characterized in that

   The storage module stores a plurality of different preset values, and the input end of the processing module is electrically connected to the output end of the storage module to read the preset values.
7. The ultrasonic sensor chip according to any one of claims 1 to 3, characterized in that:

   The signal input to the phase modulation module by the modulation code generation circuit includes a first signal and a second signal. The phase modulation module receives the first signal and outputs the corresponding carrier information. The phase modulation module receives the second signal and outputs information that the second signal is 180° different from the corresponding carrier.
8. The ultrasonic sensor chip according to claim 7, characterized in that

   One chip width of the modulation code is equal to one period of the carrier.
9. The ultrasonic sensor chip according to claim 8, characterized in that

   In the process of sampling the ultrasonic signal received by the second ultrasonic transducer, the sampling period is one quarter of a period of the carrier.
10. The ultrasonic sensor chip according to claim 1, characterized in that

    The sampling module is an analog-to-digital converter.
11. The ultrasonic sensor chip according to claim 1, characterized in that

    The correlation calculation module includes a convolution operation logic circuit.
12. The ultrasonic sensor chip according to claim 1, characterized in that the first ultrasonic transducer and the second ultrasonic transducer are the same sensor.
13. An ultrasonic sensor chip, characterized by comprising:

    A carrier generation module, used for generating a carrier;

    A modulation code generation module, used for generating a modulation code;

    A phase modulation module, used for modulating the phase of the carrier according to the modulation code to obtain a modulated wave, and outputting the modulated wave to the first ultrasonic transducer;

    A sampling module, used for sampling the ultrasonic signal received by the second ultrasonic transducer to obtain a sampling signal;

    A correlation calculation module, used to determine the correlation of the sampled signal according to a reference signal, wherein the correlation is related to the modulation code, and the correlation is related to the carrier;

    The processing module is used to determine the sampling signal whose correlation reaches a preset value as a designated echo.
14. The ultrasonic sensor chip according to claim 13, characterized in that

    The correlation calculation module is specifically used for:

    Calculating a first correlation between the sampling signal and the timing corresponding to the reference signal;

    Calculating a second correlation between the sampling signal and the orthogonal timing corresponding to the reference signal;

    A sampling signal for which the sum of the first correlation degree and the second correlation degree reaches a preset value is determined as a designated echo.
15. The ultrasonic sensor chip according to claim 13, further comprising:

    A sign processing module is provided between the sampling module and the correlation calculation module, and is used for converting a positive value of the sampling signal into a first fixed value, and converting a negative value of the sampling signal into a second fixed value.
16. The ultrasonic sensor chip according to any one of claims 13 to 15, further comprising:

    A modulation and despreading module is provided between the sampling module and the correlation calculation module, and the modulation and despreading module is used to modulate and despread the sampling signal according to the modulation code;

    The reference signal is the carrier or a carrier orthogonal wave orthogonal to the carrier.
17. The ultrasonic sensor chip according to any one of claims 13 to 15, characterized in that:

    The reference signal is the modulated wave or a modulated orthogonal wave orthogonal to the modulated wave.
18. The ultrasonic sensor chip according to any one of claims 13 to 15, characterized in that the preset value includes a plurality of different numerical values.
19. The ultrasonic sensor chip according to any one of claims 13 to 15, characterized in that:

    The modulation code includes a first code value and a second code value. During the modulation process, the first code value is used to flip the carrier phase by 180°, and the second code value is used to keep the carrier phase unchanged.
20. The ultrasonic sensor chip according to claim 19, characterized in that

    One chip width of the modulation code is equal to one period of the carrier.
21. The ultrasonic sensor chip according to claim 20, characterized in that

    In the process of sampling the ultrasonic signal received by the second ultrasonic transducer, the sampling period is one quarter of a period of the carrier.
22. An ultrasonic signal processing method, characterized by comprising:

    Generate a carrier wave;

    generating a modulation code;

    Modulating the phase of the carrier according to the modulation code to obtain a modulated wave, and outputting the modulated wave to the first ultrasonic transducer;

    Sampling the ultrasonic signal received by the second ultrasonic transducer to obtain a sampling signal;

    Determine the correlation of the sampled signal according to the reference signal, wherein the correlation is related to the modulation code, and the correlation is related to the carrier;

    The sampling signal whose correlation reaches a preset value is determined as the designated echo.
23. The method according to claim 22, characterized in that

    Determining the correlation of the sampled signal according to the reference signal comprises:

    Calculating a first correlation between the sampling signal and the timing corresponding to the reference signal;

    Calculating a second correlation between the sampling signal and the orthogonal timing corresponding to the reference signal;

    The step of determining the sampling signal whose correlation reaches a preset value as the designated echo comprises:

    A sampling signal for which the sum of the first correlation degree and the second correlation degree reaches a preset value is determined as a designated echo.
24. The method according to claim 22, characterized in that

    Before determining the correlation of the sampled signal according to the reference signal, the method further includes:

    The positive value of the sampling signal is converted into a first fixed value, and the negative value of the sampling signal is converted into a second fixed value.
25. The method according to any one of claims 22 to 24, characterized in that

    Before determining the correlation of the sampled signal according to the reference signal, the method further includes:

    Modulating and despreading the sampled signal according to the modulation code;

    The reference signal is the carrier or a carrier orthogonal wave orthogonal to the carrier.
26. The method according to any one of claims 22 to 24, characterized in that

    The reference signal is the modulated wave or a modulated orthogonal wave orthogonal to the modulated wave.
27. The method according to any one of claims 22 to 24, characterized in that

    The preset value is related to time.
28. The method according to any one of claims 22 to 24, characterized in that

    The modulation code includes a first code value and a second code value. During the modulation process, the first code value is used to flip the carrier phase by 180°, and the second code value is used to keep the carrier phase unchanged.
29. The method according to any one of claim 28, characterized in that

    One chip width of the modulation code is equal to one period of the carrier.
30. The method according to any one of claim 29, characterized in that

    In the process of sampling the ultrasonic signal received by the second ultrasonic transducer, the sampling period is one quarter of a period of the carrier.
31. An ultrasonic radar device, characterized in that it comprises:

    The ultrasonic sensor chip according to any one of claims 1 to 12;

    A first ultrasonic transducer, wherein an input end of the first ultrasonic transducer is electrically connected to an output end of the ultrasonic sensor chip, and is used to receive the modulated wave and transmit an ultrasonic signal;

    A second ultrasonic transducer, wherein an output end of the second ultrasonic transducer is electrically connected to an input end of the ultrasonic sensor chip, and the ultrasonic sensor chip is used to sample the ultrasonic signal received by the second ultrasonic transducer.
32. The device according to claim 31, further comprising:

    A microprocessor chip, wherein the output end of the microprocessor chip is electrically connected to the input end of the ultrasonic sensor chip, and the input end of the microprocessor chip is electrically connected to the output end of the ultrasonic sensor chip; the ultrasonic sensor chip receives the trigger signal of the microprocessor chip to generate the modulated wave, and the ultrasonic sensor chip is also used to send the feedback signal of receiving the specified echo to the microprocessor chip.
33. The device according to claim 31, characterized in that

    The microprocessor chip includes a first timer, and the microprocessor chip obtains the obstacle distance by obtaining the timing duration of the first timer and the received feedback signal.
34. The device according to any one of claims 31 to 33 is characterized by comprising a plurality of the ultrasonic sensor chips, a plurality of the first ultrasonic transducers and a plurality of the second ultrasonic transducers.
35. An ultrasonic radar device, characterized by comprising:

    The ultrasonic sensor chip according to any one of claims 13 to 21;

    a first ultrasonic transducer, electrically connected to the ultrasonic sensor chip to receive the modulated wave, and used to transmit an ultrasonic signal according to the modulated wave;

    The second ultrasonic transducer is electrically connected to the ultrasonic sensor chip to transmit the received ultrasonic signal to the ultrasonic sensor chip.
36. The device according to claim 35, further comprising:

    The microprocessor chip is electrically connected to the ultrasonic sensor chip; the ultrasonic sensor chip receives the trigger signal of the microprocessor chip to generate the modulated wave, and the ultrasonic sensor chip is also used to send a feedback signal of receiving a specified echo to the microprocessor chip.
37. The device according to claim 36, characterized in that

    The microprocessor chip includes a first timer, and the microprocessor chip is further used to calculate the obstacle distance according to the timing duration of the first timer and the feedback signal of the designated echo.
38. The device according to any one of claims 35 to 37, characterized in that it comprises a plurality of the ultrasonic sensor chips, a plurality of the first ultrasonic transducers and a plurality of the second ultrasonic transducers.