Pseudo-random signal coding construction method and system based on amplitude modulation and phase modulation collaborative control

Abstract

The application belongs to the technical field of geophysical exploration, and provides a pseudo-random signal coding construction method and system based on amplitude modulation and phase modulation collaborative control. According to the required frequency of exploration, a plurality of standard square waves with a target frequency as a base frequency are constructed, an initial signal is generated by superposition, and a bipolar square wave is constructed by binary of the initial signal. The amplitude and phase parameters are adjusted, and the optimal variable combination is found, so that the mean square error of the amplitude of each target frequency in the signal spectrum after binary is minimized. The signal generated by the optimal variable combination is used as the final time domain transmission signal sequence. The application controls the amplitude and phase of square waves with different frequencies collaboratively, and generates a pseudo-random signal containing the required frequency components by superposition.

Description

Technical Field

[0001] This invention belongs to the field of geophysical exploration technology, specifically relating to a pseudo-random signal encoding construction method and system based on amplitude modulation and phase modulation coordinated control. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Artificial source frequency domain electromagnetic method is a geophysical exploration method that detects underground electrical structures by measuring the response of electromagnetic fields excited by artificial sources at different frequencies. Its core advantage lies in utilizing the characteristic that electromagnetic fields of different frequencies have different penetration depths (skin effect). By changing the transmission frequency, detection at different depths can be achieved, thereby obtaining vertical information about the geoelectric structure. It has been widely used in mineral resource exploration, oil and gas exploration, hydrogeological surveys, and engineering and environmental exploration.

[0004] In frequency-domain electromagnetic exploration, the design of the transmitted signal is crucial, directly determining the depth, resolution, and data quality of the probe. A scientifically customized transmitted signal can effectively suppress environmental noise, enhance the strength of the useful signal, and be optimized for specific geological targets. This is because different exploration tasks (such as deep structural surveys or shallow fine exploration) have drastically different requirements for the frequency range and energy distribution of the signal. For example, probing deep high-resistivity layers requires enhancing the energy of low-frequency signals, while resolving thin layers relies on high-frequency components. Therefore, customizing the waveform, frequency combination, and transmission timing of the transmitted signal according to the electromagnetic interference level of the work area, the electrical characteristics of the target, and the required exploration depth is a key prerequisite for ensuring exploration success and obtaining high-quality data. However, there are still significant shortcomings in the customized design of transmitted signals. Existing customization methods mainly control the spectral distribution of the transmitted signal through phase modulation, resulting in a small solution space and difficulty in obtaining optimal solutions when constructing complex waveforms. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a pseudo-random signal encoding construction method and system based on amplitude and phase modulation coordinated control. This invention generates a pseudo-random signal containing the desired frequency components by coordinating amplitude and phase control of square waves of different frequencies.

[0006] According to some embodiments, the present invention adopts the following technical solution: A pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control includes the following steps: Based on the frequency required for exploration, multiple standard square waves with the target frequency as the fundamental frequency are constructed, superimposed to generate an initial signal, and the initial signal is binaryized to construct a bipolar square wave. Adjust the amplitude and phase parameters to find the optimal combination of variables so that the mean square error of the amplitude of each target frequency in the binary signal spectrum is minimized; The signal generated by the optimal combination of variables is used as the final time-domain transmitted signal sequence.

[0007] As an alternative implementation, the fundamental frequency, amplitude, and phase of the standard square wave with the target frequency as the fundamental frequency are respectively... , , Amplitude All values ​​are within (0,1], phase All values ​​are within (0, 2π].

[0008] As an alternative implementation, the process of generating the initial signal includes:

[0009] In the formula, K The number of target frequencies. , ,…, These are standard square waves with different fundamental frequencies. A standard square wave is a signal with a 50% duty cycle, equal duration of positive and negative amplitudes, fixed amplitude, and periodic variation.

[0010] As an alternative implementation, the process of binarying the initial signal to construct a bipolar square wave includes:

[0011] In the formula, J Let be the amplitude of the signal in the time domain, and be a constant. t These are the time sampling points.

[0012] As an alternative implementation method, adjusting the amplitude and phase parameters to find the optimal combination of variables that minimizes the mean square error of the amplitude at each target frequency in the binary signal spectrum includes: standard square wave amplitude All values ​​are taken within (0,1], and are divided into p equal parts, changing by 1 / p each time; phase All values ​​are taken within (0, 2π], and are divided into q parts at equal intervals, with each change being 2π / q. After each adjustment of amplitude and phase, an initial superimposed signal is generated, then a binary signal is generated, and then the spectrum of the binary signal is obtained through Fourier transform. The mean square error of the frequency domain amplitude of each target frequency is calculated.

[0013] As a further defined implementation method, the formula for calculating the root mean square error is:

[0014] In the formula, The frequency domain amplitude of each target frequency in the spectrum of the binary signal. This represents the average value of the frequency domain amplitude.

[0015] As an alternative implementation method, the process of adjusting the amplitude and phase parameters to find the optimal combination of variables includes: selecting the amplitude that minimizes the mean square error. , ,…, and phase , ,…, The combination is the optimal solution.

[0016] A pseudo-random signal encoding construction system based on amplitude modulation and phase modulation coordinated control includes: The square wave construction module is configured to construct multiple standard square waves with the target frequency as the fundamental frequency according to the frequency required for exploration, superimpose them to generate an initial signal, and binary the initial signal to construct a bipolar square wave; The optimization module is configured to adjust the amplitude and phase parameters to find the optimal combination of variables that minimizes the mean square error of the amplitude at each target frequency in the binary signal spectrum; the signal generated by the optimal combination of variables is used as the final time-domain transmitted signal sequence.

[0017] An electronic device includes a processor and a memory, the memory storing computer instructions that, when executed by the processor, cause the electronic device to perform actions according to the method described above.

[0018] A computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the operation according to the method described above.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention constructs a transmission signal through amplitude modulation and phase modulation coordinated control. Compared with phase modulation alone, it greatly expands the understanding space and the constructed transmission signal has a smaller mean square error.

[0020] The frequencies in the signal constructed by this invention can be arbitrary and do not need to be a fixed combination of frequencies. Furthermore, since the amplitude of the standard square wave used for superposition is constantly adjusted, the number of frequencies no longer needs to be odd and can be arbitrary.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 A flowchart of a pseudo-random signal encoding construction method based on phase modulation and amplitude modulation coordinated control; Figure 2 The first part shows the time series and spectrum of the initial superimposed signal generated in step 1 using the optimal amplitude and phase combination. (a) is the time series and (b) is the spectrum. Figure 3 In order to be in Figure 2 The above are the time series and spectrum of a high-order (3rd order, 39 frequencies) pseudo-random signal after binarization based on the signal shown. (a) is the time series and (b) is the spectrum. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] Where there is no conflict, the embodiments and features described in this application may be combined with each other.

[0028] Example 1 A pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control, taking the construction of a third-order 39-frequency high-order pseudo-random signal as an example, includes the following steps: (1) In the formula, K The number of target frequencies is given. For the above 3rd order, 39-frequency high-order pseudo-random signal, K =39. , ,…, The following are standard square waves with different fundamental frequencies, as shown in Table 1. A standard square wave is a signal with a 50% duty cycle, equal duration of positive and negative amplitudes, fixed amplitude, and periodic variation, as shown in Table 1.

[0029] Table 1

[0030] The fundamental frequency, amplitude, and phase are respectively , , Amplitude All values ​​are within (0,1], phase All values ​​are taken within (0, 2π]. Assume that the initial amplitude of each of the 39 frequencies is 1 and the phase is 2π.

[0031] The binarization process of superimposed signals is as follows: (2) In the formula, J Let be the amplitude of the signal in the time domain, and be a constant. t Let be the time sampling point. The minimum fundamental frequency is 0.25Hz, and the minimum common period is 4s. J =1, the sampling rate is 30000Hz, therefore t =1 / 120000,2 / 120000,…, 4s.

[0032] 2. Adjust the amplitude and phase parameters to find the optimal combination of variables (amplitude and phase) so that the mean square error of the amplitude of each target frequency in the binary signal spectrum is minimized.

[0033] Specifically, it is divided into 100 equal parts, changing by 1 / 100 each time; phase All values ​​are taken within (0, 2π], and the result is divided into 100 equal parts, with π / 50 changing each time.

[0034] After each adjustment of amplitude and phase, an initial superimposed signal is first generated through step 1, followed by the generation of a binary signal. Then, the spectrum of the binary signal is obtained through Fourier transform, and the mean square error of the frequency domain amplitude at each target frequency is calculated. For a third-order 39-frequency signal, the formula for calculating its mean square error is as follows: (3) In the formula, The frequency domain amplitude of each target frequency in the spectrum of the binary signal. This represents the average value of the frequency domain amplitudes mentioned above.

[0035] 3. Select the amplitude that minimizes the mean square error. , ,…, and phase , ,…, The optimal combination is obtained by taking the combination as the optimal solution. Then, the initial superimposed signal is generated by step 1, and then the final time-domain transmitted signal sequence is generated by binary transformation.

[0036] The minimum standard deviation is approximately 0.001. Figure 2 The initial superimposed signal is generated using the optimal combination of amplitude and phase. Figure 3 The final transmitted signal time series and spectrum after binary transformation show that the amplitude of each target frequency is basically the same in the frequency domain, which meets the requirements.

[0037] Example 2 Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of one or more computer-usable storage media (including, but not limited to, disk storage, etc.) containing computer-usable program code. CD - ROM It takes the form of a computer program product implemented on (such as optical memory, etc.).

[0038] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0039] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0040] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art without creative effort within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control, characterized in that, Includes the following steps: Based on the frequency required for exploration, multiple standard square waves with the target frequency as the fundamental frequency are constructed, superimposed to generate an initial signal, and the initial signal is binaryized to construct a bipolar square wave. Adjust the amplitude and phase parameters to find the optimal combination of variables so that the mean square error of the amplitude of each target frequency in the binary signal spectrum is minimized; The signal generated by the optimal combination of variables is used as the final time-domain transmitted signal sequence.

2. The pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control as described in claim 1, characterized in that, The fundamental frequency, amplitude, and phase of the standard square wave with the target frequency as the fundamental frequency are respectively: , , Amplitude All values ​​are within (0,1], phase All values ​​are within (0, 2π].

3. The pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control as described in claim 1, characterized in that, The process of generating the initial signal includes: In the formula, K The number of target frequencies. , ,…, These are standard square waves with different fundamental frequencies. A standard square wave is a signal with a 50% duty cycle, equal duration of positive and negative amplitudes, fixed amplitude, and periodic variation.

4. The pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control as described in claim 1, characterized in that, The process of binarying the initial signal to construct a bipolar square wave includes: In the formula, J Let be the amplitude of the signal in the time domain, and be a constant. t These are the time sampling points.

5. The pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control as described in claim 1, characterized in that, The process of adjusting amplitude and phase parameters to find the optimal combination of variables that minimizes the mean square error of amplitude at each target frequency in the binary signal spectrum includes: standard square wave amplitude All values ​​are taken within (0,1], and are divided into p equal parts, changing by 1 / p each time; phase All values ​​are taken within (0, 2π], and are divided into q parts at equal intervals, with each change being 2π / q. After each adjustment of amplitude and phase, an initial superimposed signal is generated, then a binary signal is generated, and then the spectrum of the binary signal is obtained through Fourier transform. The mean square error of the frequency domain amplitude of each target frequency is calculated.

6. The pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control as described in claim 5, characterized in that, The formula for calculating the root mean square error is: In the formula, The frequency domain amplitude of each target frequency in the spectrum of the binary signal. This represents the average value of the frequency domain amplitude.

7. The pseudo-random signal encoding construction method based on amplitude modulation and phase modulation coordinated control as described in claim 1, characterized in that, The process of adjusting the amplitude and phase parameters to find the optimal combination of variables includes: selecting the amplitude that minimizes the mean square error. , ,…, and phase , ,…, The combination is the optimal solution.

8. A pseudo-random signal encoding construction system based on amplitude modulation and phase modulation coordinated control, characterized in that, include: The square wave construction module is configured to construct multiple standard square waves with the target frequency as the fundamental frequency according to the frequency required for exploration, superimpose them to generate an initial signal, and binary the initial signal to construct a bipolar square wave; The optimization module is configured to adjust the amplitude and phase parameters to find the optimal combination of variables that minimizes the mean square error of the amplitude at each target frequency in the binary signal spectrum; the signal generated by the optimal combination of variables is used as the final time-domain transmitted signal sequence.

9. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing computer instructions that, when executed by the processor, cause the electronic device to perform the actions of the method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions that, when executed by a processor, perform the actions of the method according to any one of claims 1-7.

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