Digital phase sensitive rectification method, system and apparatus

Abstract

The application relates to the technical field of measuring electric variables, and provides a digital phase-sensitive rectification method, a system and a computing device.The system comprises: an analog-to-digital conversion module which converts an alternating current signal into a discrete signal; a plurality of phase rectification modules which respectively perform full-wave rectification on the discrete signal for one period with different reference phases as starting points and obtain rectification values through accumulation of rectified waveform data; an amplitude analysis module which obtains an amplitude linear representation value based on the rectification values of a response signal; a phase offset analysis module which obtains a phase offset based on the rectification values with one reference phase as a basic phase; and a measured signal analysis module which obtains a measured linear representation value of a measured signal based on the amplitude linear representation value and the phase offset.The application can filter out correlation interference.

Description

Technical Field

[0001] This invention relates to the field of electrical variable measurement technology, and in particular to digital phase-sensitive rectification methods, systems and devices. Background Technology

[0002] In modern engineering technology, weak signal detection has always been a key research topic in the field of detection. The electrical signals that characterize weak signals (pressure, impedance, etc.) are often subject to interference from external factors and the hardware conditions of the equipment itself.

[0003] The interference that characterizes weak electrical signals mainly falls into the following two categories:

[0004] Uncorrelated interference: Uncorrelated interference is mostly external conducted and radiated interference, such as interference from mains power, high-frequency charging and discharging equipment, and communication equipment. This interference can be periodic or non-periodic, and can be low-frequency or high-frequency. Most of this type of interference does not have a significant impact on the amplitude and phase frequency characteristics of the signal. Generally, the interference signal can be attenuated or removed by processing methods such as modulation and demodulation, passband filtering, or digital integration.

[0005] Correlation interference: Correlation interference is mostly from the same source or at the same frequency. It not only causes the signal amplitude to deviate from the expected value, but also causes a significant phase shift compared to the original signal. Existing filtering methods are not only ineffective against this type of interference, but may even exacerbate its effects.

[0006] First, co-channel interference and strong signal coupling: the frequency of co-channel interference and the target signal completely overlaps, and existing filters cannot selectively separate the two.

[0007] Second, the irreversibility of phase shift: the interference signal changes the instantaneous phase point of the response signal, causing the phase information of the target signal to be permanently covered. Even if the interference component is filtered out, the residual phase distortion cannot be restored.

[0008] Third, group delay exacerbates phase distortion: the filter introduces additional group delay near the cutoff band, and the filter phase response becomes significantly nonlinear, which further causes time shift of the signal waveform on the basis of the already distorted phase caused by the interference.

[0009] Fourth, device nonlinearity induces intermodulation interference: the nonlinear characteristics of electronic devices (such as power amplifier saturation) can cause intermodulation products between the interference signal and the target signal.

[0010] Fifth, time-domain processing causes inter-symbol interference: forced filtering will destroy the time-domain continuity of the signal, resulting in blurred symbol boundaries, and amplifying the bit errors caused by phase jumps in a multipath environment;

[0011] Sixth, phase sensitivity and orthogonality are disrupted: Interference causes an imbalance in the I / Q components of the received signal, resulting in a shift in the demodulation phase reference. The filter cannot restore the disrupted orthogonality.

[0012] While existing phase-sensitive rectifiers are also used for filtering, they are typically used for narrowband filtering, and they cannot filter out correlation interference, and may even exacerbate it.

[0013] The core of existing phase-sensitive rectifiers is to shift the target frequency component to the baseband by multiplying the input signal and the reference signal (or using equivalent switching logic), and then outputting the DC component through low-pass filtering to extract the amplitude and phase signals. This technology has the following main drawbacks:

[0014] First, the multiplication operation depends on phase matching: the phase-sensitive rectifier multiplies the input signal with the reference signal through the multiplier. If the interference signal and the reference signal have the same frequency but have a fixed phase difference (such as coherent interference), the multiplication result will produce a baseband component, which cannot be distinguished by the subsequent low-pass filter. For example, when the phase difference of the interference signal is close to that of the target signal, the output DC component is contaminated, resulting in a decrease in the signal-to-noise ratio.

[0015] Second, the frequency domain limitation of low-pass filtering: the filtering unit can only suppress high-frequency harmonics and uncorrelated noise, but correlated interference shares the same frequency band as the target signal, and the filter cannot separate the two from the frequency domain.

[0016] Third, constraints on correlator characteristics: Phase-sensitive rectification is essentially a correlation operation, and its suppression effect depends on the non-correlation between the interference and the reference signal; if the interference has a strong correlation (such as the aiming narrowband interference in spread spectrum communication), the demodulation process will retain part of it;

[0017] Fourth, correlated interference is difficult to separate: coherent interference (such as power frequency harmonics or co-frequency interference) is highly coupled to the signal in the time or frequency domain, and existing algorithms (such as synchronization mechanisms based on phase-locked loops) lack the ability to dynamically identify and isolate correlated components. Although some systems introduce adaptive filtering, the real-time adjustment of parameters is insufficient to respond to rapidly changing correlated interference, and stray components are easily left behind.

[0018] In summary, existing filtering methods fail to achieve the expected results in handling correlation interference of weak signals, and cannot meet the monitoring and inspection needs of engineering sites and equipment operation. Summary of the Invention

[0019] In view of this, the present invention provides a digital phase-sensitive rectification system. The present invention also relates to a digital phase-sensitive rectification method and computing device to overcome the technical shortcomings of existing technologies that cannot effectively filter out correlation interference.

[0020] According to a first aspect of the present invention, a digital phase-sensitive rectification system is provided, comprising: an analog-to-digital converter module configured to convert an AC signal into a discrete signal, the AC signal including an excitation signal and a response signal;

[0021] Multiple phase rectification modules are configured to perform full-wave rectification of the discrete signal for one cycle starting from different reference phases and to accumulate the rectified waveform data to obtain the rectified value.

[0022] The amplitude analysis module is configured to obtain a linear amplitude characterization value based on the rectified value of the response signal, wherein the square of the linear amplitude characterization value is a linear combination of the squares of the rectified values ​​of the response signals at different reference phases.

[0023] The phase offset analysis module is configured to use a reference phase as the base phase and obtain the phase offset based on the rectified value. The trigonometric function of the phase offset is a linear combination of the product of the trigonometric function of the reference phase and its rectified value and the rectified value of the base phase.

[0024] The measured signal analysis module is configured to obtain the measured linear characterization value based on the amplitude linear characterization value and the phase offset, wherein the measured linear characterization value and the measured signal have a linear relationship; the measured linear characterization value is the component of the amplitude linear characterization value in the component direction; the component direction is the sum of the phase difference between the phase offset of the excitation signal and the phase offset of the response signal and the phase difference between the reference phase and the fundamental phase.

[0025] In one possible implementation, the digital phase-sensitive rectifier system further includes:

[0026] The measured signal acquisition module is configured to acquire the measured signal based on the linear relationship between the measured linear characterization value and the measured signal.

[0027] In one possible implementation, the phase rectification module includes a positive half-cycle waveform accumulation unit, a negative half-cycle waveform accumulation unit, and a first linear combination unit:

[0028] The positive half-cycle waveform accumulation unit is configured to take the reference phase as the starting point, regard half a cycle from 0 to π as the positive half-cycle, keep the waveform of the positive half-cycle unchanged, accumulate the waveform data of the positive half-cycle, and obtain the positive half-cycle waveform data.

[0029] The negative half-cycle waveform accumulation unit is configured to take the reference phase as the starting point, regard the half-cycle of π - 2π as the negative half-cycle, invert the waveform of the negative half-cycle, accumulate the waveform data of the negative half-cycle, and obtain the negative half-cycle waveform data.

[0030] The first linear combination unit is configured to sum the positive half-cycle waveform data of each reference phase obtained by the positive half-cycle waveform accumulation unit and the negative half-cycle waveform data obtained by the negative half-cycle waveform accumulation unit to obtain the rectified value corresponding to each reference phase.

[0031] In one possible implementation, the amplitude analysis module includes a first digital operation unit, a second linear combination unit, and a second digital operation unit:

[0032] The first digital processing unit is configured to square the rectified values ​​of different reference phases corresponding to the response signal to obtain the rectified squares of different reference phases;

[0033] The second linear combination unit is configured to sum the rectified squares of different reference phases to obtain a quadratic linear combination;

[0034] The second digital processing unit is configured to obtain a linear representation of the amplitude of the response signal by taking the square root of a linear combination of the squares of the response signal.

[0035] In one possible implementation, the phase offset analysis module includes a basic phase acquisition unit, a rectification ratio acquisition unit, and a third digital calculation unit:

[0036] The basic phase acquisition unit is configured to set a reference phase as the basic phase;

[0037] The rectification ratio obtaining unit is configured to obtain the rectification ratio as the ratio of the rectified value of another reference phase relative to the rectified value of the base phase obtained by the base phase obtaining unit;

[0038] The third digital processing unit is configured to perform an arctangent operation on the rectification ratio to obtain the phase offset.

[0039] In one possible implementation, the measured signal analysis module includes a component direction acquisition unit and a component unit:

[0040] The component direction acquisition unit is configured to use the sum of the offset phase difference and the reference phase difference as the component direction; the reference phase difference is the phase difference between the reference phase and the base phase; the offset phase difference is the difference between the phase offset corresponding to the response signal and the phase offset corresponding to the excitation signal.

[0041] The component unit is configured to obtain the sinusoidal component of the amplitude linear characterization value of the response signal in the component direction as the measured linear characterization value.

[0042] In one possible implementation, the digital phase-sensitive rectification system includes two phase rectification modules, the reference phases of the two phase rectification modules being π / 2 out of phase.

[0043] According to a second aspect of the present invention, a digital phase-sensitive rectification method is provided, comprising:

[0044] Analog-to-digital conversion step: Converting an AC signal into a discrete signal through analog-to-digital conversion, wherein the AC signal includes an excitation signal and a response signal;

[0045] Rectification steps: Perform full-wave rectification of the discrete signal for one cycle starting from different reference phases, and accumulate the rectified waveform data to obtain the rectified value;

[0046] Amplitude analysis steps: Obtain a linear amplitude characterization value based on the rectified value of the response signal, wherein the square of the linear amplitude characterization value is a linear combination of the squares of the rectified values ​​of the response signals at different reference phases;

[0047] Phase offset analysis steps: Using a reference phase as the base phase, obtain the phase offset based on the rectified value. The trigonometric function of the phase offset is a linear combination of the product of the trigonometric function of the reference phase and its rectified value and the rectified value of the base phase.

[0048] The linear characterization analysis steps for the measured signal are as follows: The measured linear characterization value is obtained based on the amplitude linear characterization value and the phase offset. The measured linear characterization value and the measured signal have a linear relationship. The measured linear characterization value is the component of the amplitude linear characterization value in the component direction. The component direction is the sum of the phase difference between the phase offset of the excitation signal and the phase offset of the response signal, and the phase difference between the reference phase and the fundamental phase.

[0049] In one possible implementation, the digital phase-sensitive rectification method further includes:

[0050] Steps for obtaining the measured signal: Based on the linear relationship between the measured linear characterization value and the measured signal, the measured signal is obtained through the measured linear characterization value.

[0051] In one possible implementation, the rectification step includes:

[0052] Starting from the reference phase, the half-cycle from 0 to π is considered the positive half-cycle, and the half-cycle from π to 2π is considered the negative half-cycle. The rectified value of the AC signal corresponding to a reference phase is obtained by the following formula:

[0053]

[0054] in, For reference phase index; This is an index for the number of samples per half-cycle; For the first One reference phase; Reference phase The corresponding rectified value; For the first Discrete values ​​of a subsampled discrete signal, wherein the discrete values ​​are waveform data related to the amplitude and phase of the AC signal.

[0055] In one possible implementation, the amplitude analysis step includes:

[0056] The linear amplitude representation of the response signal is obtained by taking the rectified values ​​of multiple reference phases corresponding to the response signal using the following formula.

[0057]

[0058] in, This is a linear representation of the amplitude. For the first The linear coefficients corresponding to each reference phase.

[0059] In one possible implementation, the phase offset analysis step includes:

[0060] The excitation phase offset and response phase offset are obtained from multiple rectified values ​​corresponding to multiple reference phases of the excitation and response signals using the following formula:

[0061]

[0062] in, , Based on the phase, For the first The reference phase difference between each reference phase and the base phase. For the first The phase offset of the AC signal corresponding to each reference phase; The rectified value corresponding to the base phase.

[0063] In one possible implementation, the rectification step includes:

[0064] The rectified value is obtained by performing full-wave rectification of the discrete signal for one cycle using two reference phases that differ by π / 2, and then accumulating the rectified waveform data.

[0065] In one possible implementation, the steps of the linear characterization analysis of the measured signal include:

[0066] The measured linear characterization value of the signal under test is obtained from the amplitude linear characterization value of the response signal, the excitation phase offset, the response phase offset, the reference phase, and the fundamental phase using the following formula:

[0067]

[0068] in, , For the first The response phase offset corresponding to each reference phase For the first Excitation phase offset corresponding to each reference phase For the first The offset phase difference corresponding to each reference phase; The amplitude is a linear representation of the response signal. It is a function based on the form of the excitation signal; For the first The measured linear characterization value of the measured signal corresponding to each reference phase.

[0069] In one possible implementation, the measured linear characterization value is obtained based on the amplitude linear characterization value and the phase offset using the following formula:

[0070] .

[0071] According to a third aspect of the present invention, a computing device is provided, comprising an analog-to-digital converter, a memory, and a processor:

[0072] The analog-to-digital converter is connected to the processor via wired or wireless connection and is configured to convert AC signals into discrete signals.

[0073] The memory is used to store computer-executable instructions;

[0074] The processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of the digital phase-sensitive rectification method described above.

[0075] The analog-to-digital conversion module of the digital phase-sensitive rectification system of this invention converts the response signal and excitation signal with correlated interference into discrete signals, thus disrupting the phase continuity of the interference signal. Multiple phase rectification modules perform full-wave and periodic rectification accumulation on the discrete signal starting from different reference phases. This multi-reference phase rectification disrupts the phase consistency of the interference signal, dispersing the phase interference energy and facilitating the separation of co-frequency interference. The amplitude analysis module obtains a linear amplitude characterization value from the rectified response values ​​of multiple reference phases, achieving linear characterization of the signal amplitude through energy equivalent conversion and noise suppression. Phase offset... The analysis module obtains the phase offset of the response signal and excitation signal relative to the base phase through a trigonometric function of the rectified value. It is insensitive to amplitude fluctuations and eliminates the influence of correlation interference through phase information. The measured signal analysis module projects the linear amplitude representation value onto the direction of offset phase difference + reference phase difference. By comparing the difference between the response phase offset and the excitation phase offset, it eliminates the common interference components of the two, making the component direction aligned with the principal components of the target signal, while correlation interference is filtered out due to directional misalignment. The measured signal acquisition unit can accurately obtain the measured signal through the linear relationship between the measured signal and the measured linear representation.

[0076] The digital phase-sensitive rectification method of this invention converts the response signal into a discrete signal, and performs phase rectification by accumulating full-wave and periodic rectification starting from different reference phases to obtain rectified values. Then, it obtains the amplitude linear characterization value through the rectified values ​​of multiple reference phases of the response signal, and obtains the excitation phase offset and response phase offset through the rectified values. Then, it obtains the measured linear characterization value based on the amplitude linear characterization value, the offset phase difference, and the reference phase difference, and finally obtains the measured signal according to the linear relationship. The randomization of interference is achieved by rotating the phase of multiple reference phases, and then the deterministic characteristics of the measured signal are used for extraction. It does not require prior knowledge of the specific characteristics of the interference, and filtering can be achieved only by relying on the phase correlation between the measured signal and the reference signal. Attached Figure Description

[0077] Figure 1 This is a flowchart illustrating an embodiment of the digital phase-sensitive rectification method described in this invention;

[0078] Figure 2 This is a flowchart illustrating a preferred embodiment of the digital phase-sensitive rectification method described in this invention;

[0079] Figure 3 This is a waveform diagram of an embodiment of the response signal described in this invention;

[0080] Figure 4 This is a schematic diagram of the waveform after rectification starting from a reference phase, as described in this invention.

[0081] Figure 5This invention is described in conjunction with Figure 4 A schematic diagram of the waveform after rectification, with another reference phase differing by π / 2 as the starting point;

[0082] Figures 6-8 These are waveform diagrams of the target signal, interference signal, and response signal, respectively, in a specific embodiment of the digital phase-sensitive rectification method described in this invention. The horizontal axis represents the phase, and the vertical axis represents the amplitude.

[0083] Figure 9 and Figure 10 These are waveform diagrams of the interference signal and the response signal, respectively, of the second specific embodiment of the digital phase-sensitive rectification method described in this invention.

[0084] Figure 11 and Figure 12 These are waveform diagrams of the interference signal and the response signal of the third specific embodiment of the digital phase-sensitive rectification method described in this invention;

[0085] Figures 13-15 These are waveform diagrams of the target signal, interference signal, and response signal, respectively, in the fourth specific embodiment of the digital phase-sensitive rectification method described in this invention. The horizontal axis represents the phase, and the vertical axis represents the amplitude.

[0086] Figures 16-18 These are waveform diagrams of the target signal, interference signal, and response signal, respectively, in the fifth specific embodiment of the digital phase-sensitive rectification method described in this invention. The horizontal axis represents the phase, and the vertical axis represents the amplitude.

[0087] Figure 19 and Figure 20 These are waveform diagrams of the interference signal and the response signal of the sixth specific embodiment of the digital phase-sensitive rectification method described in this invention;

[0088] Figure 21 and Figure 22 These are waveform diagrams of the interference signal and the response signal of the seventh specific embodiment of the digital phase-sensitive rectification method described in this invention;

[0089] Figure 23 This is a schematic block diagram of an embodiment of the digital phase-sensitive rectifier system described in this invention;

[0090] Figure 24 This is a schematic block diagram of a preferred embodiment of the digital phase-sensitive rectifier system described in this invention;

[0091] Figure 25 This is a schematic block diagram of one embodiment of the computing device described in this invention;

[0092] Figure 26 This is a schematic block diagram of another embodiment of the computing device described in this invention;

[0093] The components are as follows: 10. Digital phase-sensitive rectification system; 1. Analog-to-digital converter module; 2. Multiple phase rectification modules; 21. Basic phase rectification module; 22. Quadrature phase rectification module; 3. Amplitude analysis module; 4. Phase offset analysis module; 5. Measured signal analysis module; 6. Measured signal acquisition module; 200. Computing device; 201. AC signal; 202. Discrete signal; 203. Rectified signal; 204. Amplitude information; 205. Phase information; 206. Measured signal; 210. Analog-to-digital converter; 220. Memory; 230. Processor; 240. Access device; 250. Network; 260. Bus; 270. Database. Detailed Implementation

[0094] Many specific details are set forth in the following description to provide a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this specification. Therefore, this specification is not limited to the specific implementations disclosed below.

[0095] The terminology used in one or more embodiments of this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the one or more embodiments of this specification. The singular forms “a” and “the” as used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items.

[0096] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this specification, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this specification, and similarly, second may also be referred to as first. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0097] The response signal is a composite signal of the interference signal and the target signal. The target signal is an electrical signal that characterizes the measured signal without interference. The measured signal can be a weak signal such as internal resistance or impedance, or a weak signal that has a linear relationship with internal resistance and / or impedance, such as the pressure of a pressure-sensitive element.

[0098] The existing method for obtaining the measured signal involves filtering the response signal to obtain the target signal, and then using the target signal to obtain the measured signal. For example, the measured signal is the internal resistance, the measured system is a battery, and the battery outputs a voltage response signal after receiving a current excitation signal. The voltage response signal is a composite signal of electromagnetic interference and the target signal, while the target signal is a voltage signal without interference that characterizes the battery's internal resistance. The existing method for obtaining the internal resistance involves filtering the voltage response signal to obtain the target signal, and then obtaining the internal resistance based on the target signal. The internal resistance is the ratio of the voltage amplitude of the target signal to the current amplitude of the current excitation signal. However, because correlation interference distorts the phase and amplitude through a triple mechanism of spectrum encroachment, nonlinear intermodulation, and device saturation, the existing filtering method not only fails to accurately obtain the target signal but also accelerates distortion, thus making it even more difficult to accurately obtain the measured signal.

[0099] To improve the accuracy of obtaining the measured signal from a response signal with correlated interference, this invention provides a digital phase-sensitive rectification method, such as... Figure 1 As shown, the digital phase-sensitive rectification method includes:

[0100] Step S1: Convert the AC signal into a discrete signal through analog-to-digital conversion. The AC signal includes at least one excitation signal and at least one response signal. The response signal is a measurable electrical signal generated by the system under test corresponding to the measured signal under the action of a signal related to the excitation signal. For example, the measured signal is a resistance, and the signal related to the excitation signal is an excitation current. The excitation signal is a voltage signal generated by the excitation current passing through a sampling resistor. The discrete signal includes an excitation discrete signal and a response discrete signal.

[0101] Step S2: Perform full-wave rectification on the discrete signal starting from different reference phases to obtain multiple rectified signals, including excitation rectified signals and response rectified signals; starting from the reference phase, accumulate the rectified signals of one cycle to obtain the rectified value corresponding to the reference phase, including excitation rectified value and response rectified value.

[0102] Step S3: Obtain the amplitude linear characterization value of the response signal based on the rectified response values ​​of multiple reference phases corresponding to the response signal. The amplitude linear characterization value is linearly related to the amplitude of the response signal. The square of the amplitude linear characterization value is a linear combination of the squares of the rectified response values ​​of different reference phases.

[0103] Step S4: Using a reference phase as the base phase, obtain the phase offset of the AC signal relative to the base phase based on the rectified value of the base phase, other reference phases and their rectified values. The phase offset includes the excitation phase offset and the response phase offset. The trigonometric function of the phase offset is a linear combination of the product of the trigonometric function of the reference phase and its rectified value and the rectified value of the base phase.

[0104] Step S5: Obtain the measured linear characterization value of the signal under test based on the amplitude linear characterization value of the response signal, the response phase offset, the excitation phase offset, the reference phase, and the base phase. The difference between the response phase offset and the excitation phase offset is used as the offset phase difference; the phase difference between the reference phase and the base phase is used as the reference phase difference; the sum of the offset phase difference and the reference phase difference is used as the component direction; the measured linear characterization value is the component of the amplitude linear characterization value of the response signal in the component direction; the measured linear characterization value has a linear relationship with the signal under test.

[0105] Step S6: Based on the linear relationship between the measured linear representation value and the measured signal, the measured signal is obtained through the measured linear representation value. For example, the linear relationship between the measured linear representation value and the measured signal can be obtained through the standard resistance value of the standard resistor and the measured linear representation value obtained through steps S1-S5 of this invention. Of course, it can also be obtained through supervised machine learning training methods.

[0106] The digital phase-sensitive rectification method described in this invention performs rectification accumulation starting from different reference phases. Because the interference signal is randomly correlated with the reference phase, its rectified value will cancel each other out during multiple phase rotations; while the measured signal, because it has a fixed relationship with the reference phase, will retain its rectified value. After accumulation, the random characteristics of the interference signal are further weakened.

[0107] The digital phase-sensitive signal rectification method of the present invention extracts the amplitude by means of the response rectified values ​​corresponding to multiple reference phases and extracts the phase offset by means of the response rectified values ​​and excitation rectified values ​​corresponding to multiple reference phases, forming a dual suppression mechanism in the time domain (phase rectification) and frequency domain (amplitude statistics), which has a significant filtering effect, especially on periodic or narrowband interference.

[0108] This invention utilizes the phase and amplitude correlation of signals affected by correlation interference to extract useful components from complex signals.

[0109] In one feasible embodiment, step S2 includes:

[0110] Starting from the reference phase, the half-cycle from 0 to π is considered as the positive half-cycle, and the half-cycle from π to 2π is considered as the negative half-cycle. The rectified value of the reference phase is obtained through the following equation (1):

[0111] (1)

[0112] in, For reference phase index; This is an index for the number of samples per half-cycle; For the first One reference phase; Reference phase The corresponding rectified value; For the first Discrete values ​​of a subsampled discrete signal, wherein the discrete values ​​are waveform data related to the amplitude and phase of the AC signal.

[0113] In one feasible embodiment, step S3 includes:

[0114] The amplitude linear characterization value of the response signal is obtained by taking the rectified values ​​of multiple reference phases corresponding to the response signal through the following equation (2).

[0115] (2)

[0116] in, This is a linear representation of the amplitude. For the first The linear coefficients corresponding to each reference phase can be obtained through supervised machine learning training. When multiple reference phases are... When a reference phase is constructed that is 90° out of phase, The rectified values ​​of each reference phase corresponding to the response signal can be used to obtain the linear amplitude characterization value of the response signal through the above formula (2).

[0117] In one feasible embodiment, step S4 includes:

[0118] The excitation phase offset and response phase offset are obtained by using the following equation (3) based on the multiple rectified values ​​corresponding to the multiple reference phases of the excitation signal and the response signal:

[0119] (3)

[0120] in, , Based on the phase, For the first The reference phase difference between each reference phase and the base phase. For the first The phase offset of the AC signal corresponding to each reference phase; The rectified value corresponding to the base phase; the rectified value of each reference phase of the excitation signal can be obtained by the above formula (3) to obtain the excitation phase offset corresponding to each reference phase; the rectified value of each reference phase of the response signal can be obtained by the above formula (3) to obtain the response phase offset corresponding to each reference phase.

[0121] In one feasible embodiment, step S5 includes:

[0122] The measured linear characterization value of the signal under test is obtained from the amplitude linear characterization value of the response signal, the excitation phase offset, the response phase offset, the reference phase, and the fundamental phase using the following equation (4):

[0123] (4)

[0124] in, , For the first The response phase offset corresponding to each reference phase For the first Excitation phase offset corresponding to each reference phase For the first The offset phase difference corresponding to each reference phase; The amplitude is a linear representation of the response signal. It is a function based on the form of the excitation signal; For the first The measured linear characterization value of the measured signal corresponding to each reference phase.

[0125] In one feasible embodiment, the excitation signal is a sinusoidal signal. In step S5, the measured linear characterization value of the signal under test is obtained based on the amplitude linear characterization value of the response signal, the excitation phase offset, the response phase offset, the reference phase, and the fundamental phase using the following formula (5):

[0126] (5)

[0127] In other words, the linear representation of the target signal's amplitude is the amplitude of the response signal along its component directions. The sinusoidal component on.

[0128] In another feasible embodiment, the excitation signal is a square wave signal. In step S5, the measured linear characterization value of the signal under test is obtained based on the amplitude linear characterization value of the response signal, the excitation phase offset, the response phase offset, the reference phase, and the fundamental phase using the following formula (6):

[0129] (6)

[0130] in, For odd-numbered harmonic orders.

[0131] In the third feasible implementation, the excitation signal is a triangular wave signal. In step S5, the measured linear characterization value of the signal under test is obtained based on the amplitude linear characterization value of the response signal, the excitation phase offset, the response phase offset, the reference phase, and the fundamental phase using the following formula (7):

[0132] (7)

[0133] in, The normalization coefficient is... This is the amplitude attenuation coefficient.

[0134] The above provides three embodiments of the measured signal under different excitation signals, but the present invention is not limited thereto, and the excitation signal can also be other forms of periodic signal.

[0135] In the above embodiments, ideally, the measured signals corresponding to each reference phase obtained through the same base phase should be the same. To further reduce errors, in one feasible embodiment, the digital phase-sensitive rectification method further includes:

[0136] The final measured signal is obtained through data processing (e.g., data averaging) based on the phase offset of each reference phase, the measured linear characterization value, and / or the measured signal:

[0137] After obtaining the phase offset of the AC signal corresponding to each reference phase, average it.

[0138] After obtaining the measured linear characterization values ​​of the measured signal corresponding to each reference phase, the values ​​are averaged.

[0139] Or / and after obtaining the measured signal corresponding to each reference phase, perform averaging.

[0140] In a low-frequency signal detection system with a known frequency, the interference in the test system based on internal resistance mainly comes from the induced electromotive force generated at the signal end by the alternating magnetic field generated by the excitation current through spatial coupling. Its frequency is the same as the target signal, but its phase lags behind the target signal by π / 2. It is combined with the target signal to form a response signal with uncertain phase and amplitude. Since the phase difference between the interference signal and the target signal is π / 2, the digital phase-sensitive rectification method described in this invention uses two reference phases with a phase difference of π / 2 to detect the target signal from the response signal.

[0141] In a preferred embodiment, such as Figures 2-5 As shown, the digital phase-sensitive rectification method includes:

[0142] Step S10: Convert the AC signal into a discrete signal through analog-to-digital conversion. The AC signal includes an excitation signal and a response signal. The excitation signal is a sine wave signal, and the discrete signal includes an excitation discrete signal and a response discrete signal.

[0143] Step S20: The excitation discrete signal and the response discrete signal are rectified using a first reference phase and a second reference phase, respectively, to obtain rectified signals. The rectified signals include the excitation rectified signal and the response rectified signal corresponding to the first reference phase, and the excitation rectified signal and the response rectified signal corresponding to the second reference phase. Starting from the first reference phase and the second reference phase, the rectified signals for one cycle are accumulated to obtain the excitation rectified value and the response rectified value corresponding to the first reference phase, and the excitation rectified value and the response rectified value corresponding to the second reference phase. The phase difference between the second reference phase and the first reference phase is π / 2.

[0144] Step S30: Obtain the amplitude linear characterization value of the response signal based on the response rectified values ​​of the first reference phase and the second reference phase corresponding to the response signal. The square of the amplitude linear characterization value of the response signal is a linear combination of the squares of the response rectified values ​​of the two reference phases.

[0145] Step S40: Using the first reference phase as the base phase, obtain the phase offset of the AC signal relative to the base phase based on the rectified value of the base phase, the second reference phase, and its rectified value. The phase offset includes an excitation phase offset and a response phase offset. The trigonometric function of the phase offset is a linear combination of the product of the trigonometric function of the reference phase and its rectified value and the rectified value of the base phase. Preferably, this includes: using the first reference phase as the base phase, obtaining the rectification ratio between the rectified value of the second reference phase and the rectified value of the base phase, and performing an arctangent operation on the rectification ratio to obtain the phase offset of the AC signal relative to the base phase.

[0146] Step S50: Based on the amplitude linear characterization value of the response signal, the response phase offset, the excitation phase offset, the reference phase, and the base phase, obtain the measured linear characterization value of the signal under test. Use the difference between the response phase offset and the excitation phase offset as the offset phase difference, and use the phase difference between the reference phase and the base phase as the reference phase difference. The reference phase difference is π / 2. The sum of the offset phase difference and the reference phase difference is the component direction. The measured linear characterization value is the sinusoidal component of the amplitude linear characterization value of the response signal in the component direction.

[0147] Step S60: Obtain the measured signal based on the linear relationship between the measured linear characterization value and the measured signal.

[0148] In one feasible embodiment, step S20 includes:

[0149] Taking the first reference phase and the second reference phase as starting points respectively, the half-cycle from 0 to π is considered as the positive half-cycle, and the half-cycle from π to 2π is considered as the negative half-cycle. The rectified values ​​of the first reference phase and the second reference phase are obtained through the following equations (8) and (9):

[0150] (8)

[0151] (9)

[0152] in, This is the first reference phase; The rectified value corresponding to the first reference phase; This is the rectified value corresponding to the second reference phase.

[0153] In one feasible embodiment, step S30 includes:

[0154] The two rectified values ​​of the two reference phases corresponding to the response signal are used to obtain the linear amplitude characterization value of the response signal through the following equation (10):

[0155] (10)

[0156] in, The rectified value of the response signal corresponding to the first reference phase (response rectified value); This is the rectified response value corresponding to the second reference phase.

[0157] In one feasible embodiment, step S40 includes:

[0158] The excitation phase offset and response phase offset are obtained by equations (11) and (12) based on the rectified values ​​of the excitation signal and response signal corresponding to the first reference phase and the second reference phase:

[0159] (11)

[0160] (12)

[0161] in, This is the excitation phase offset; In response to phase offset; This is the excitation rectified value corresponding to the first reference phase; This is the excitation rectified value corresponding to the second reference phase.

[0162] In one feasible embodiment, in step S50:

[0163] The measured linear characterization value of the signal under test is obtained from the amplitude linear characterization value of the response signal, the excitation phase shift, and the response phase shift using the following equation (13):

[0164] (13)

[0165] in, , This represents the phase difference.

[0166] In the above embodiments, the number of samplings per half cycle affects the accuracy of the detection of the measured signal. Too few samplings will cause aliasing distortion, amplitude attenuation and phase misjudgment, reducing the accuracy of the measured signal detection. Too many samplings will cause data redundancy and resource consumption, high-frequency noise amplification, nonlinear error aggravation, quantization noise distribution deterioration, etc., which will also reduce the accuracy of the measured signal detection.

[0167] To obtain the optimal number of samplings per half-cycle, in one feasible embodiment, the digital phase-sensitive rectification method further includes:

[0168] The number of samplings in half a cycle satisfies the following equations (14) and (15):

[0169] (14)

[0170] (15)

[0171] in, The sampling rate is for half a cycle; The highest frequency component, The lowest frequency component, the highest frequency component and lowest frequency component The highest and lowest frequency components of the analog-to-digital conversion can be used, or the signal can be obtained by simulating the output response signal of the system under test. This represents the number of samples per half cycle.

[0172] In one feasible embodiment, the digital phase-sensitive rectification method further includes:

[0173] The first highest frequency component is obtained by scanning the output response signal of the system under test using a wideband (e.g., white noise excitation) method.

[0174] The response signal is captured at a sampling rate that is a multiple of the first highest frequency component, preferably, the multiple is not less than 2;

[0175] Perform FFT verification on the response signal to obtain the second highest frequency component and the first lowest frequency component that meet the signal sampling quality requirements of FFT verification (no mixing, no spectral leakage, spectral resolution meets accuracy requirements, etc.);

[0176] The second highest frequency component is reduced by a step size of a first predetermined percentage to obtain multiple third highest frequency components, and the signal-to-noise ratio change of each third highest frequency component is monitored. Preferably, the first predetermined percentage is not greater than 50%.

[0177] The optimal third highest frequency component is obtained by using the first optimal function of signal-to-noise ratio change according to the following equation (16). :

[0178] and (16)

[0179] in, It is the third highest frequency component; It is the second highest frequency component; The signal-to-noise ratio corresponding to the third highest frequency component; The signal-to-noise ratio corresponding to the second highest frequency component; The signal-to-noise ratio variation threshold is preferably defined as follows: Not less than 0.95.

[0180] The first lowest frequency component is increased by a step size of a second set percentage of the first lowest frequency component to obtain multiple second lowest frequency components, and the signal-to-noise ratio change of each second lowest frequency component is monitored.

[0181] The second lowest frequency component is obtained by using the second optimal function of signal-to-noise ratio change in the following equation (17). ;

[0182] and (17)

[0183] in, This is the first lowest frequency component; It is the second lowest frequency component; The signal-to-noise ratio corresponding to the second lowest frequency component; The signal-to-noise ratio corresponding to the first lowest frequency component; The signal-to-noise ratio variation threshold is preferably defined as follows: Not less than 0.95.

[0184] The following specific embodiments were implemented to demonstrate the technical effects of the present invention:

[0185] Example 1:

[0186] like Figure 6 As shown, the target signal is a sine wave signal with an amplitude of 1, such as... Figure 7As shown, the interference signal of correlation interference is an interference signal with a phase lead and an amplitude of 1. The response signal of the composite target signal and interference signal is as follows: Figure 8 As shown, due to correlation interference, the amplitude and phase of the response signal change relative to the target signal. The data obtained using steps S10-S60 of this invention are shown in Table 1:

[0187] Table 1

[0188]

[0189] The precision rectified value of the target signal obtained by using a precision rectifier circuit based on an operational amplifier is 229.1773. The error between the measured linear characterization value and the precision rectified value of the target signal is 3.8 × 10⁻⁶. -5 This demonstrates that the digital phase-sensitive rectifier of the present invention can accurately obtain the target signal without interference from the response signal with correlated interference, thereby ensuring the accuracy of the measured signal.

[0190] The rectified value of the target signal obtained after filtering the response signal using a phase-sensitive rectifier filter of the prior art (such as LTC1968) is 324.1056. The error between this value and the true rectified value of the target signal (229.1773) is about 41.4%, which is much larger than the error of the present invention. This shows that the digital phase-sensitive rectification method of the present invention has high accuracy compared with the prior art.

[0191] Example 2:

[0192] like Figure 6 As shown, the target signal is a sine wave signal with an amplitude of 1, such as... Figure 9 As shown, the interference signal of correlation interference is an interference signal with a phase lead and an amplitude of 2. The response signal of the composite target signal and interference signal is as follows. Figure 10 As shown, due to correlation interference, the amplitude and phase of the response signal change relative to the target signal. The data obtained using steps S10-S60 of this invention are shown in Table 2:

[0193] Table 2

[0194]

[0195] The precision rectified value of the target signal obtained by using a precision rectifier circuit based on an operational amplifier is 229.1773. The error between the measured linear characterization value and the precision rectified value of the target signal is 3.8 × 10⁻⁶. -5 This demonstrates that the digital phase-sensitive rectifier of the present invention can accurately obtain the target signal without interference from the response signal with correlated interference, thereby ensuring the accuracy of the measured signal.

[0196] The rectified value of the target signal obtained after filtering the response signal using a phase-sensitive rectifier filter (such as LTC1968) is 512.4752, while the actual rectified value of the target signal is 229.1773. This shows that the existing technology can no longer detect the target signal from the response signal, further proving the high accuracy of the digital phase-sensitive rectification method of the present invention in detecting the target signal.

[0197] Example 3:

[0198] like Figure 6 As shown, the target signal is a sine wave signal with an amplitude of 1, such as... Figure 11 As shown, the interference signal of the correlation interference is an interference signal with a phase lead and an amplitude of 3. The response signal of the composite target signal and interference signal is as follows. Figure 12 As shown, due to correlation interference, the amplitude and phase of the response signal change relative to the target signal. The data obtained using steps S10-S60 of this invention are shown in Table 3:

[0199] Table 3

[0200]

[0201] The precision rectified value of the target signal obtained by using a precision rectifier circuit based on an operational amplifier is 229.1773. The error between the measured linear characterization value and the precision rectified value of the target signal is 3.8 × 10⁻⁶. -5 This demonstrates that the digital phase-sensitive rectifier of the present invention can accurately obtain the target signal without interference from the response signal with correlated interference, thereby ensuring the accuracy of the measured signal.

[0202] The rectified value of the target signal obtained after filtering the response signal using a phase-sensitive rectifier filter (such as LTC1968) of the existing technology is 724.7494, while the actual rectified value of the target signal is 229.1773. This shows that the existing technology can no longer detect the target signal from the response signal, further proving the high accuracy of the digital phase-sensitive rectification method of the present invention in detecting the target signal.

[0203] Example 4:

[0204] like Figure 13 As shown, the target signal is a square wave signal with an amplitude of 1, such as... Figure 14 As shown, the interference signal of the correlation interference is an interference signal with a phase lead and an amplitude of 3. The response signal of the composite target signal and interference signal is as follows. Figure 15 As shown, due to correlation interference, the amplitude and phase of the response signal change relative to the target signal. The data obtained using steps S10-S60 of this invention are shown in Table 4:

[0205] Table 4

[0206]

[0207] The precision rectified value of the target signal obtained by using a precision rectifier circuit based on an operational amplifier is 76.0000. The measured linear characterization value is the same as the precision rectified value of the target signal. This shows that the digital phase-sensitive rectification of the present invention can accurately obtain the target signal without interference from the response signal with correlated interference, thereby ensuring the accuracy of the measured signal.

[0208] The rectified value of the target signal obtained after filtering the response signal using a phase-sensitive rectifier filter of existing technology (such as LTC1968) is 75.8000, while the actual rectified value of the target signal is 76.0000, which further proves the high accuracy of the digital phase-sensitive rectification method of the present invention in detecting the target signal.

[0209] Example 5

[0210] like Figure 16 As shown, the target signal is a triangular wave signal with an amplitude of 1, such as... Figure 17 As shown, the interference signal of correlation interference is an interference signal with a phase lead and an amplitude of 1. The response signal of the composite target signal and interference signal is as follows: Figure 18 As shown, due to correlation interference, the amplitude and phase of the response signal change relative to the target signal. The data obtained using steps S10-S60 of this invention are shown in Table 5:

[0211] Table 5

[0212]

[0213] The precision rectified value of the target signal obtained by using a precision rectifier circuit based on an operational amplifier is 38.0000. The measured linear characterization value is the same as the precision rectified value of the target signal. This shows that the digital phase-sensitive rectification of the present invention can accurately obtain the target signal without interference from the response signal with correlated interference, thereby ensuring the accuracy of the measured signal.

[0214] The rectified value of the target signal obtained after filtering the response signal using a phase-sensitive rectifier filter of the prior art (such as LTC1968) is 56.9474, and the error between it and the true rectified value of the target signal of 38.0000 is about 50.0%. This shows that the digital phase-sensitive rectification method of the present invention has high accuracy compared with the prior art.

[0215] Example 6:

[0216] like Figure 16 As shown, the target signal is a triangular wave signal with an amplitude of 1, such as... Figure 19As shown, the interference signal of correlation interference is an interference signal with a phase lead and an amplitude of 2. The response signal of the composite target signal and interference signal is as follows. Figure 20 As shown, due to correlation interference, the amplitude and phase of the response signal change relative to the target signal. The data obtained using steps S10-S60 of this invention are shown in Table 6:

[0217] Table 6

[0218]

[0219] The precision rectified value of the target signal obtained by using a precision rectifier circuit based on an operational amplifier is 38.0000. The measured linear characterization value is the same as the precision rectified value of the target signal. This shows that the digital phase-sensitive rectification of the present invention can accurately obtain the target signal without interference from the response signal with correlated interference, thereby ensuring the accuracy of the measured signal.

[0220] The rectified value of the target signal obtained after filtering the response signal using a phase-sensitive rectifier filter of existing technology (such as LTC1968) is 88.6316, while the actual rectified value of the target signal is 38.0000, which further proves the high accuracy of the digital phase-sensitive rectification method of the present invention in detecting the target signal.

[0221] Example 7:

[0222] like Figure 16 As shown, the target signal is a triangular wave signal with an amplitude of 1, such as... Figure 21 As shown, the interference signal of the correlation interference is an interference signal with a phase lead and an amplitude of 3. The response signal of the composite target signal and interference signal is as follows. Figure 22 As shown, due to correlation interference, the amplitude and phase of the response signal change relative to the target signal. The data obtained using steps S10-S50 of this invention are shown in Table 7:

[0223] Table 7

[0224]

[0225] The precision rectified value of the target signal obtained by using a precision rectifier circuit based on an operational amplifier is 38.0000. The measured linear characterization value is the same as the precision rectified value of the target signal. This shows that the digital phase-sensitive rectification of the present invention can accurately obtain the target signal without interference from the response signal with correlated interference, thereby ensuring the accuracy of the measured signal.

[0226] The rectified value of the target signal obtained after filtering the response signal using a phase-sensitive rectifier filter of existing technology (such as LTC1968) is 123.4737, while the actual rectified value of the target signal is 38.0000. This shows that the existing technology can no longer detect the target signal from the response signal, further proving the high accuracy of the digital phase-sensitive rectification method of the present invention in detecting the target signal.

[0227] Figure 23 This is a schematic block diagram of an embodiment of the digital phase-sensitive rectifier system described in this invention, as shown below. Figure 23 As shown, the digital phase-sensitive rectification system 10 includes an analog-to-digital conversion module 1, multiple phase rectification modules 2, an amplitude analysis module 3, a phase shift analysis module 4, a measured signal analysis module 5, and a measured signal acquisition module 6.

[0228] The analog-to-digital conversion module 1 is configured to convert an AC signal into a discrete signal, the AC signal including at least one excitation signal and at least one response signal; the discrete signal including an excitation discrete signal and a response discrete signal.

[0229] The plurality of phase rectification modules 2 are configured to perform full-wave rectification on the discrete signal after analog-to-digital conversion by the analog-to-digital conversion module 1 starting from different reference phases to obtain multiple rectified signals, and to accumulate the rectified signals of one cycle to obtain multiple rectified values ​​corresponding to multiple reference phases. The rectified signals include excitation rectified signals and response rectified signals, and the rectified values ​​include excitation rectified values ​​and response rectified values.

[0230] The amplitude analysis module 3 is configured to obtain a linear amplitude characterization value of the response signal amplitude based on the response rectified values ​​of multiple reference phases corresponding to the response signal rectified by the phase rectification module 2. The linear amplitude characterization value is linearly related to the amplitude of the response signal. The square of the linear amplitude characterization value is a linear combination of the squares of the response rectified values ​​of different reference phases.

[0231] The phase offset analysis module 4 is configured to use a reference phase as the base phase, and obtain the phase offset of the AC signal relative to the base phase based on the rectified value of the base phase after rectification by the phase rectification module 2, the rectified values ​​of other reference phases, and other reference phases. The phase offset includes the excitation phase offset and the response phase offset. The trigonometric function of the phase offset is a linear combination of the product of the trigonometric function of the reference phase and its rectified value and the rectified value of the base phase.

[0232] The measured signal analysis module 5 is configured to obtain a measured linear characterization value of the measured signal based on the amplitude linear characterization value of the response signal obtained by the amplitude analysis module 3 and the response phase offset, excitation phase offset, reference phase, and fundamental phase obtained by the phase offset analysis module 4. The measured linear characterization value and the measured signal have a linear relationship; the measured linear characterization value is the component of the amplitude linear characterization value of the response signal in the component direction; the component direction is the sum of the offset phase difference and the reference phase difference; the reference phase difference is the phase difference between the reference phase and the fundamental phase; the offset phase difference is the difference between the response phase offset and the excitation phase offset.

[0233] The measured signal acquisition module 6 is configured to obtain the measured signal based on the measured linear characterization value obtained by the measured signal analysis module 5.

[0234] In one feasible embodiment, the digital phase-sensitive rectification system further includes a data processing module, which is configured to average the phase offset of the AC signal corresponding to each reference phase obtained by the phase offset analysis module; average the measured linear characterization value of the measured signal corresponding to each reference phase obtained by the measured signal analysis module; and / or average the measured signal corresponding to each reference phase obtained by the measured signal acquisition module.

[0235] In one feasible embodiment, the digital phase-sensitive rectifier system further includes a sampling count acquisition module, which is configured to set the sampling count of the AC signal.

[0236] In the above embodiments, the phase rectification module can be divided into different units according to requirements. In one feasible embodiment, the phase rectification module includes a full-wave rectification unit and an accumulation unit. The full-wave rectification unit is used to perform full-wave rectification on the discrete signal to obtain a rectified signal. The accumulation unit is used to accumulate the rectified signal of one cycle starting from the reference signal to obtain the rectified value.

[0237] In another feasible embodiment, the phase rectification module includes a positive half-cycle waveform accumulation unit, a negative half-cycle waveform accumulation unit, and a first linear combination unit, which are used to rectify and accumulate AC signals of the positive half-cycle and negative half-cycle periods and to obtain rectified values ​​through linear combination, respectively.

[0238] The interference in the response signal output by the system under test with a weak impedance signal mainly comes from the spatial coupling of the alternating magnetic field generated by the excitation current. The phase difference between the interference signal and the target signal is ±π / 2. Therefore, in a preferred embodiment of the present invention, as... Figure 24 As shown, the digital phase-sensitive rectification system includes a basic phase rectification module 21 and a quadrature phase rectification module 22:

[0239] The basic phase rectification module 21 is configured to rectify the AC signal starting from the first reference phase;

[0240] The quadrature phase rectifier module 22 is configured to rectify the AC signal starting from a second reference phase that differs from the first reference phase by π / 2.

[0241] In one feasible embodiment, the amplitude analysis module includes a first digital operation unit, a second linear combination unit, and a second digital operation unit, which are respectively used to square the rectified value, sum and square root to obtain the linear characterization value of the amplitude.

[0242] In one feasible embodiment, the phase offset analysis module includes a basic phase acquisition unit, a rectification ratio acquisition unit, and a third digital calculation unit, which are used to obtain the basic phase, rectification ratio, and phase offset, respectively.

[0243] In one feasible embodiment, the measured signal analysis module includes a component direction acquisition unit and a component unit, which are used to acquire the component direction and the measured linear characterization value, respectively.

[0244] The above is a schematic scheme of the digital phase-sensitive rectification system of this embodiment. It should be noted that the technical solution of this digital phase-sensitive rectification system and the technical solution of the digital phase-sensitive rectification method described above belong to the same concept. For details not described in detail in the technical solution of the digital phase-sensitive rectification system, please refer to the description of the technical solution of the digital phase-sensitive rectification method described above.

[0245] Figure 25 This invention illustrates an application scenario of the digital phase-sensitive rectification method described in this invention. Figure 25 In the application scenario, the computing device 200 can acquire the AC signal 201 of the system under test and convert it into a discrete signal 202. Then, the computing device rectifies the discrete signal with different reference phases to obtain a rectified signal 203 and a rectified value. Next, the computing device obtains amplitude information 204 (the amplitude linearity representation value of the response signal amplitude) and phase information 205 (phase offset) based on the rectified value. Finally, the computing device determines the measured linearity representation value of the signal under test based on the amplitude linearity representation value and phase offset of the response signal, thereby obtaining the measured signal 206.

[0246] It should be noted that the aforementioned computing devices can be software, installed in servers, terminal devices, or other hardware devices. They can be implemented as multiple software programs or software modules to provide distributed services, or as a single software program or software module. No specific limitations are made here.

[0247] The aforementioned computing devices can be a combination of software and hardware, such as... Figure 26As shown, the computing device includes an analog-to-digital converter 210, a memory 220, and a processor 230.

[0248] The analog-to-digital converter 210 is connected to the processor 230 via wired or wireless connection and is configured to convert AC signals into discrete signals.

[0249] The memory 220 is used to store computer-executable instructions;

[0250] The processor 230 is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of the digital phase-sensitive rectification method described in the various embodiments.

[0251] The aforementioned computing devices can be implemented as a distributed cluster consisting of multiple servers or terminal devices, or as a single server or a single terminal device.

[0252] The computing device 200 also includes an access device 240 that enables the computing device 200 to communicate via one or more networks 250. Examples of such networks include Public Switched Telephone Network (PSTN), Local Area Network (LAN), Wide Area Network (WAN), Personal Area Network (PAN), or combinations of communication networks such as the Internet. The access device 240 may include one or more of any type of wired or wireless network interface (e.g., a network interface card (NIC)), such as an IEEE 802.11 Wireless Local Area Network (WLAN) wireless interface, a Wi-MAX (Worldwide Interoperability for Microwave Access) interface, an Ethernet interface, a Universal Serial Bus (USB) interface, a cellular network interface, a Bluetooth interface, or a Near Field Communication (NFC) interface.

[0253] In one embodiment of this specification, the aforementioned components of the computing device 200 and Figure 26 Other components, not shown, can also be connected to each other, for example, via bus 260. It should be understood that... Figure 26The block diagram of the computing device shown is for illustrative purposes only and is not intended to limit the scope of this specification. Those skilled in the art can add or replace other components as needed; for example, the computing device 200 may also include a database 270 for storing data.

[0254] The computing device 200 can be any type of stationary or mobile computing device, including chips, mobile computers or mobile computing devices (e.g., tablet computers, personal digital assistants, laptop computers, notebook computers, netbooks, etc.), mobile phones (e.g., smartphones), wearable computing devices (e.g., smartwatches, smart glasses, etc.) or other types of mobile devices, or stationary computing devices such as desktop computers or personal computers (PCs). The computing device 200 can also be a mobile or stationary server.

[0255] The computer instructions include computer program code, which may be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0256] The above is a schematic diagram of a computing device. It should be noted that the technical solution of this computing device and the aforementioned digital phase-sensitive rectification method share the same concept. Details not described in detail in the computing device's technical solution can be found in the description of the aforementioned digital phase-sensitive rectification method.

[0257] The preferred embodiments disclosed above are merely illustrative of this specification. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the embodiments described herein. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the embodiments, thereby enabling those skilled in the art to better understand and utilize this specification. This specification is limited only by the claims and their full scope and equivalents.

Claims

1. A digital phase-sensitive rectification method, characterized in that, include: Analog-to-digital conversion step: Converting an AC signal into a discrete signal through analog-to-digital conversion, wherein the AC signal includes an excitation signal and a response signal; Rectification steps: Perform full-wave rectification of the discrete signal for one cycle starting from different reference phases, and accumulate the rectified waveform data to obtain the rectified value; Amplitude analysis steps: Obtain a linear amplitude characterization value based on the rectified value of the response signal, wherein the square of the linear amplitude characterization value is a linear combination of the squares of the rectified values ​​of the response signals at different reference phases; Phase offset analysis steps: Using a reference phase as the base phase, obtain the phase offset based on the rectified value. The trigonometric function of the phase offset is a linear combination of the product of the trigonometric function of the reference phase and its rectified value and the rectified value of the base phase. The linear characterization analysis steps of the measured signal are as follows: the linear characterization value of the measured signal is obtained based on the amplitude linear characterization value and the phase offset, and the linear characterization value of the measured signal has a linear relationship with the measured signal. The measured linear characterization value is the component of the amplitude linear characterization value in the component direction; The component direction is the sum of the phase difference between the phase offset of the excitation signal and the phase offset of the response signal and the phase difference between the reference phase and the base phase; The rectification step includes: The rectified value is obtained by performing full-wave rectification of the discrete signal for one cycle with two reference phases differing by π / 2 and accumulating the rectified waveform data. The steps of the linear characterization analysis of the measured signal include: The measured linear characterization value of the signal under test is obtained from the amplitude linear characterization value of the response signal, the excitation phase offset, the response phase offset, the reference phase, and the fundamental phase using the following formula: in, , For the first The response phase offset corresponding to each reference phase For the first Excitation phase offset corresponding to each reference phase For the first The offset phase difference corresponding to each reference phase; The amplitude is a linear representation of the response signal. It is a function based on the form of the excitation signal; For the first The measured linear characterization value of the measured signal corresponding to each reference phase.

2. The digital phase-sensitive rectification method according to claim 1, characterized in that, Also includes: Steps for obtaining the measured signal: Based on the linear relationship between the measured linear characterization value and the measured signal, the measured signal is obtained through the measured linear characterization value.

3. The digital phase-sensitive rectification method according to claim 1, characterized in that, The rectification step includes: Starting from the reference phase, the half-cycle from 0 to π is considered the positive half-cycle, and the half-cycle from π to 2π is considered the negative half-cycle. The rectified value of the AC signal corresponding to a reference phase is obtained by the following formula: in, For reference phase index; This is an index for the number of samples per half-cycle; For the first One reference phase; Reference phase The corresponding rectified value; For the first Discrete values ​​of a subsampled discrete signal; Or / and the amplitude analysis step includes: The linear amplitude representation of the response signal is obtained by taking the rectified values ​​of multiple reference phases corresponding to the response signal using the following formula. in, This is a linear representation of the amplitude. For the first The linear coefficients corresponding to each reference phase; Or / and the phase shift analysis step includes: The excitation phase offset and response phase offset are obtained from multiple rectified values ​​corresponding to multiple reference phases of the excitation and response signals using the following formula: in, , Based on the phase, For the first The reference phase difference between each reference phase and the base phase. For the first The phase offset of the AC signal corresponding to each reference phase; The rectified value corresponding to the base phase.

4. The digital phase-sensitive rectification method according to claim 3, characterized in that, The steps of the linear characterization analysis of the measured signal include: The measured linear characterization value is obtained based on the amplitude linear characterization value and the phase offset using the following formula: 。 5. A digital phase-sensitive rectification system implementing the digital phase-sensitive rectification method according to any one of claims 1-4, characterized in that, include: An analog-to-digital converter module is configured to convert an AC signal into a discrete signal, the AC signal including an excitation signal and a response signal; Multiple phase rectification modules are configured to perform full-wave rectification of the discrete signal for one cycle starting from different reference phases and to accumulate the rectified waveform data to obtain the rectified value. The amplitude analysis module is configured to obtain a linear amplitude characterization value based on the rectified value of the response signal, wherein the square of the linear amplitude characterization value is a linear combination of the squares of the rectified values ​​of the response signals at different reference phases. The phase offset analysis module is configured to use a reference phase as the base phase and obtain the phase offset based on the rectified value. The trigonometric function of the phase offset is a linear combination of the product of the trigonometric function of the reference phase and its rectified value and the rectified value of the base phase. The measured signal analysis module is configured to obtain the measured linear characterization value based on the amplitude linear characterization value and the phase offset, wherein the measured linear characterization value and the measured signal have a linear relationship. The measured linear characterization value is the component of the amplitude linear characterization value in the component direction; the component direction is the sum of the phase difference between the phase offset of the excitation signal and the phase offset of the response signal and the phase difference between the reference phase and the fundamental phase.

6. The digital phase-sensitive rectifier system according to claim 5, characterized in that, Also includes: The measured signal acquisition module is configured to acquire the measured signal based on the linear relationship between the measured linear characterization value and the measured signal.

7. The digital phase-sensitive rectifier system according to claim 5, characterized in that, The phase rectification module includes a positive half-cycle waveform accumulation unit, a negative half-cycle waveform accumulation unit, and a first linear combination unit: The positive half-cycle waveform accumulation unit is configured to take the reference phase as the starting point, regard the half-cycle from 0 to π as the positive half-cycle, keep the waveform of the positive half-cycle unchanged, accumulate the waveform data of the positive half-cycle, and obtain the positive half-cycle waveform data. The negative half-cycle waveform accumulation unit is configured to take the reference phase as the starting point, regard the half-cycle of π - 2π as the negative half-cycle, invert the waveform of the negative half-cycle, accumulate the waveform data of the negative half-cycle, and obtain the negative half-cycle waveform data. The first linear combination unit is configured to sum the positive half-cycle waveform data of each reference phase obtained by the positive half-cycle waveform accumulation unit and the negative half-cycle waveform data obtained by the negative half-cycle waveform accumulation unit to obtain the rectified value corresponding to each reference phase. Or / and the amplitude analysis module includes a first digital operation unit, a second linear combination unit, and a second digital operation unit: The first digital processing unit is configured to square the rectified values ​​of different reference phases corresponding to the response signal to obtain the rectified squares of different reference phases; The second linear combination unit is configured to sum the rectified squares of different reference phases to obtain a quadratic linear combination; The second digital processing unit is configured to take the square root of the square linear combination of the response signals to obtain a linear representation of the amplitude of the response signals; Or / and the phase offset analysis module includes a basic phase acquisition unit, a rectification ratio acquisition unit, and a third digital calculation unit: The basic phase acquisition unit is configured to set a reference phase as the basic phase; The rectification ratio obtaining unit is configured to obtain the rectification ratio as the ratio of the rectified value of another reference phase relative to the rectified value of the base phase obtained by the base phase obtaining unit; The third digital processing unit is configured to perform an arctangent operation on the rectification ratio to obtain the phase offset.

8. The digital phase-sensitive rectifier system according to claim 7, characterized in that, The measured signal analysis module includes a component direction acquisition unit and a component unit: The component direction acquisition unit is configured to use the sum of the offset phase difference and the reference phase difference as the component direction; the reference phase difference is the phase difference between the reference phase and the base phase; the offset phase difference is the difference between the phase offset corresponding to the response signal and the phase offset corresponding to the excitation signal. The component unit is configured to obtain the sinusoidal component of the amplitude linear characterization value of the response signal in the component direction as the measured linear characterization value.

9. The digital phase-sensitive rectifier system according to claim 5, characterized in that, It includes two phase rectification modules, and the reference phases of the two phase rectification modules differ by π / 2.

10. A computing device, characterized in that, Includes analog-to-digital converters, memory, and processors: The analog-to-digital converter is connected to the processor via wired or wireless connection and is configured to convert AC signals into discrete signals. The memory is used to store computer-executable instructions; The processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of the digital phase-sensitive rectification method according to any one of claims 1 to 4.

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