Time domain gate filtering signal processing method and device

Abstract

The invention discloses a time domain gate filtering signal processing method and a time domain gate filtering signal processing device, which are used for solving the technical problems that a traditional time domain gate technology design method excessively depends on skill level and experience requirements of operators, and the automation degree is low, so that the signal processing efficiency is poor. The method comprises the following steps: acquiring a straight-through parameter frequency domain signal and a reflecting plate parameter frequency domain signal; generating a subtraction time domain signal according to the straight-through parameter frequency domain signal and the reflecting plate parameter frequency domain signal; performing target detection on the subtraction time domain signal by adopting a preset unit average constant false alarm rate algorithm, and determining starting and ending time of a time domain gate; constructing a time domain gate function based on the time domain gate starting and ending time, and performing linear frequency modulation Z transformation on the time domain gate function to generate a frequency domain and time domain gate function; and performing signal processing on the frequency domain signal of the to-be-detected sample by adopting the frequency domain and time domain gate function and the time domain gate starting and ending time, and outputting a time domain gate filtering signal.

Description

Technical Field

[0001] The present invention relates to the technical field of signal analysis, and in particular to a time domain gate filtering signal processing method and device. Background Art

[0002] Time domain gate technology is a technology widely used in vector frequency domain data post-processing, especially in vector network analyzers (VNA). Its core lies in the application of bandpass filters in the time domain, which can accurately remove or retain signal responses in a specific time period.

[0003] In reflection measurement, since the reflected signals generated by each impedance discontinuity point in the system arrive at the measurement reference plane with different time delays in the time domain, the time domain gate technology can accurately analyze the reflected signals of specific discontinuities. Therefore, the time domain gate technology can effectively eliminate the interference reflections generated by non-terminal loads (such as test equipment, connecting cables, etc.), thereby significantly improving the accuracy and reliability of the measurement.

[0004] Traditional time domain gate technology design methods mostly use observation methods, which require operators to compare and observe the specific position of the sample to be tested in the time domain to determine the position and size of the time domain gate, and then determine the time domain start and end time and gate width, construct a time domain gate function, and then obtain the signal after time domain gate technology filtering based on the time domain gate function. This process is too dependent on the operator's skill level and experience requirements, and has a low degree of automation, resulting in poor signal processing efficiency. Summary of the invention

[0005] The present invention provides a time domain gate filter signal processing method and device, which are used to solve the technical problem that the design method of traditional time domain gate technology is too dependent on the skill level and experience requirements of operators, and has a low degree of automation, resulting in poor signal processing efficiency.

[0006] A first aspect of the present invention provides a time domain gate filtering signal processing method, comprising:

[0007] Obtaining a through parameter frequency domain signal and a reflector parameter frequency domain signal;

[0008] Generate a subtraction time domain signal according to the through parameter frequency domain signal and the reflector parameter frequency domain signal;

[0009] Using a preset unit average constant false alarm rate algorithm to perform target detection on the subtracted time domain signal, and determine the start and end time of the time domain gate;

[0010] Based on the start and end time of the time domain gate, a time domain gate function is constructed, and a linear frequency modulation Z transform is performed on the time domain gate function to generate a frequency domain time domain gate function;

[0011] The frequency domain time domain gate function and the time domain gate start and end time are used to perform signal processing on the frequency domain signal of the sample to be tested, and a time domain gate filtering signal is output.

[0012] Optionally, the step of generating a subtraction time domain signal according to the through parameter frequency domain signal and the reflector parameter frequency domain signal comprises:

[0013] Performing windowing processing on the direct parameter frequency domain signal and the reflector parameter frequency domain signal respectively, and outputting a windowed direct parameter frequency domain signal and a windowed reflector parameter frequency domain signal;

[0014] Performing linear frequency modulation inverse Z transform on the windowed direct-pass parameter frequency domain signal and the windowed reflector parameter frequency domain signal respectively to generate a windowed direct-pass parameter time domain signal and a windowed reflector parameter time domain signal;

[0015] A subtraction operation is performed on the windowed direct parameter time domain signal and the windowed reflector parameter time domain signal, and a subtraction time domain signal is output.

[0016] Optionally, the step of using a preset unit average constant false alarm rate algorithm to perform target detection on the subtracted time domain signal and determining the start and end time of the time domain gate includes:

[0017] Segmenting the subtracted time domain signal according to a preset unit length to determine a plurality of training time domain sub-signals;

[0018] Performing unit averaging processing on each of the training time-domain sub-signals respectively, and outputting initial unit average values ​​corresponding to each of the training time-domain sub-signals;

[0019] Performing mean processing on each of the initial unit average values ​​to determine a target unit average value;

[0020] Calculate a threshold factor using the target unit average value and the preset unit length;

[0021] comparing the threshold factor and the subtracted time domain signal;

[0022] If the subtracted time domain signal is greater than the threshold factor, the start and end times corresponding to the reflector peaks in the subtracted time domain signal are used as the start and end times of the time domain gate.

[0023] Optionally, the step of using the frequency domain time domain gate function and the time domain gate start and end time to perform signal processing on the frequency domain signal of the sample to be tested and outputting a time domain gate filter signal includes:

[0024] Constructing a unit impulse signal based on the start and end time of the time domain gate;

[0025] Performing a convolution operation on the unit impulse signal and the frequency-domain and time-domain gate function to determine a time-domain gate normalization coefficient;

[0026] Based on the time domain gate normalization coefficient, the frequency domain signal of the sample to be tested and the frequency domain time domain gate function are convolved and normalized to output a time domain gate filter signal.

[0027] Optionally, the time domain gate start and end time include a time domain gate start time position and a time domain gate end time position; the time domain gate function is specifically:

[0028] ;

[0029] in, is the time domain gate function; f c is the center frequency of the frequency signal of the sample to be tested, which is 33.25 GHz; t start is the starting time position of the time domain gate; t stop is the time position of the time domain gate termination; t is the time domain gate time.

[0030] Optionally, the processing process of the time domain gate filtering signal is specifically as follows:

[0031] ;

[0032] in, is the time domain gate filtered signal; is the frequency domain and time domain gate function; is convolution; is the frequency domain signal of the sample to be tested; nc is the time domain gate normalization coefficient.

[0033] A second aspect of the present invention provides a time domain gate filtering signal processing device, comprising:

[0034] A signal acquisition module is used to acquire a direct parameter frequency domain signal and a reflector parameter frequency domain signal;

[0035] A subtraction time domain signal generation module is used to generate a subtraction time domain signal according to the through parameter frequency domain signal and the reflector parameter frequency domain signal;

[0036] A target detection module, used to perform target detection on the subtracted time domain signal using a preset unit average constant false alarm rate algorithm to determine the start and end time of the time domain gate;

[0037] A transformation module, used to construct a time domain gate function based on the start and end time of the time domain gate, and perform a linear frequency modulation Z transform on the time domain gate function to generate a frequency domain time domain gate function;

[0038] The signal processing module is used to perform signal processing on the frequency domain signal of the sample to be tested by using the frequency domain time domain gate function and the time domain gate start and end time, and output a time domain gate filter signal.

[0039] A third aspect of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the time-domain gate filtering signal processing method as described in any one of the above items.

[0040] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the steps of the time-domain gate filtering signal processing method as described in any one of the above items.

[0041] A fifth aspect of the present invention provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions, wherein when the program instructions are executed by a computer, the computer executes the steps of the time-domain gate filtering signal processing method as described in any one of the above items.

[0042] It can be seen from the above technical solutions that the present invention has the following advantages:

[0043] The above technical scheme of the present invention provides a time domain gate filter signal processing method, first, obtain a direct parameter frequency domain signal and a reflector parameter frequency domain signal; then, generate a subtraction time domain signal according to the direct parameter frequency domain signal and the reflector parameter frequency domain signal; use a preset unit average constant false alarm rate algorithm to perform target detection on the subtraction time domain signal to determine the start and end time of the time domain gate; based on the start and end time of the time domain gate, construct a time domain gate function, and perform a linear frequency modulation Z transform on the time domain gate function to generate a frequency domain time domain gate function; finally, use the frequency domain time domain gate function and the start and end time of the time domain gate to perform signal processing on the frequency domain signal of the sample to be tested, and output a time domain gate filter signal; based on the above scheme, use a preset unit average constant false alarm rate algorithm to perform target detection on the subtraction time domain signal, determine the start and end time of the time domain gate, and construct a time domain gate function based on the start and end time of the time domain gate, and then obtain the time domain gate filter signal according to the time domain gate function. The process does not need to rely on the skill level and experience requirements of the operator, and can realize the automatic construction of the time domain gate function, thereby improving the signal processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0045] Figure 1 A flowchart of the steps of a time domain gate filtering signal processing method provided in the first embodiment of the present invention;

[0046] Figure 2 A schematic diagram of the structure of a free space measurement system provided in Embodiment 1 of the present invention;

[0047] Figure 3 A comparison diagram of a windowed direct parameter time domain signal and a windowed reflector parameter time domain signal provided in the first embodiment of the present invention;

[0048] Figure 4 A time chart of the position of the reflector plate marked by the CA-CFAR algorithm provided in the first embodiment of the present invention;

[0049] Figure 5 A schematic diagram of constructing a time domain gating function provided in the first embodiment of the present invention;

[0050] Figure 6 A frequency domain comparison diagram using the time domain gate technology provided in the first embodiment of the present invention;

[0051] Figure 7 A flowchart of the steps of a time domain gate filtering signal processing method provided in the second embodiment of the present invention;

[0052] Figure 8 A schematic diagram of a process for automatically constructing a time domain gating function provided in the second embodiment of the present invention;

[0053] Fig. 9 A schematic diagram of the flow of time domain gate filtering signal processing provided in the second embodiment of the present invention;

[0054] Fig.10 This is a structural block diagram of a time domain gate filtering signal processing device provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0055] The embodiment of the present invention provides a time domain gate filter signal processing method and device, which is used to solve the technical problem that the design method of traditional time domain gate technology is too dependent on the skill level and experience requirements of the operator, and has a low degree of automation, resulting in poor signal processing efficiency.

[0056] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Terminology explanation:

[0058] Constant False-Alarm Rate (CFAR): refers to a common form of adaptive algorithm used in radar systems to detect target echoes against a background of noise, clutter, and interference.

[0059] Chirp Z-transform (CZT): A generalization of the Discrete Fourier Transform (DFT) that allows sampling of arbitrary spirals in the Z plane. With CZT, frequencies can be sampled more densely to approximate a continuous spectrum.

[0060] Kaiser Window: The Kaiser Window is approximately an elongated elliptical window, which maximizes the ratio of main lobe energy to side lobe energy.

[0061] See also Figure 1 , Figure 1 A flowchart of the steps of a time domain gate filtering signal processing method provided in Embodiment 1 of the present invention.

[0062] The present invention provides a time domain gate filtering signal processing method, comprising:

[0063] Step 101: Obtain a through parameter frequency domain signal and a reflector parameter frequency domain signal.

[0064] Please note that Figure 2 , the through parameter frequency domain signal is the parameter frequency domain signal of the free space system when no objects are placed in the through state, and the reflector parameter frequency domain signal is the parameter frequency domain signal of the reflector placed in the space on both sides of the sample to be tested, and the reflector is measured respectively; among them, Figure 2 The free space system shown is composed of a pair of point focusing lens antennas, a vector network analyzer and a mode converter. The present invention uses a free space measurement system to measure the parameters of the sample to be tested and the reflectors placed on both sides, that is, the free space measurement system is used to measure the direct parameter frequency domain signal and the reflector parameter frequency domain signal.

[0065] In this embodiment, the number of measurement sampling points of the signal can be set as needed. For example, the number of measurement sampling points can be set to 2001, but the present invention is not limited thereto.

[0066] Step 102: Generate a subtraction time domain signal according to the through parameter frequency domain signal and the reflector parameter frequency domain signal.

[0067] Specifically, the through parameter frequency domain signal and the reflector parameter frequency domain signal are windowed, and the windowed through parameter frequency domain signal and the windowed reflector parameter frequency domain signal are output; the windowed through parameter frequency domain signal and the windowed reflector parameter frequency domain signal are subjected to a linear frequency modulation inverse Z transform (ICZT, Inverse Chirp-Z Transform) to generate a windowed through parameter time domain signal and a windowed reflector parameter time domain signal; wherein the transformation formula of the linear frequency modulation Z transform can be expressed as:

[0068] ;

[0069] in, is the result of CZT transformation; is the input signal sequence; is the sampling point; n is the sequence of the current input signal; N is the length of the input signal; A is the starting point; W is the spiral line; K is the sequence of the current output signal; M is the length of the output signal; is the radius of the starting position; is the phase angle of the starting position; is the stretching rate of the helix W; is the adjacent phase angle interval of the spiral line W.

[0070] For further information, see Figure 3 After the linear frequency modulation inverse Z transform of the windowed direct parameter frequency domain signal and the windowed reflector parameter frequency domain signal, the following can be obtained: Figure 3 The windowed direct parameter time domain signal and the windowed reflector parameter time domain signal shown are obtained by subtracting the direct time domain signal (windowed direct parameter time domain signal) from the two reflector time domain signals (windowed reflector parameter time domain signal) to obtain the subtracted time domain signal (subtracted time domain signal). The subtracted time domain signal can be expressed as:

[0071] ;

[0072] in, is the subtraction time domain signal; is the time domain signal of the windowed reflector parameter; is the windowed pass parameter time domain signal.

[0073] Step 103: Use a preset unit average constant false alarm rate algorithm to perform target detection on the subtracted time domain signal to determine the start and end time of the time domain gate.

[0074] The preset cell average constant false alarm rate algorithm is a cell average constant false alarm rate (CA-CFAR) algorithm, which is a commonly used constant false alarm rate (CFAR) detection algorithm and is widely used in radar and target detection systems.

[0075] Specifically, the subtracted time domain signal is divided according to the preset unit length to determine a plurality of training time domain sub-signals; unit average processing is performed on each training time domain sub-signal respectively, and an initial unit average value corresponding to each training time domain sub-signal is output; mean processing is performed on each initial unit average value to determine a target unit average value; the target unit average value and the preset unit length are used to calculate the threshold factor; wherein the preset unit length includes the training unit length and the protection unit length, and the calculation process of the threshold factor can be expressed as:

[0076] ;

[0077] Where, T is the threshold factor; is the training unit length; P fa is the false alarm probability, ; Z is the average value of the target unit, which represents the clutter noise power statistic of the unit to be detected (subtracted time domain signal).

[0078] For further information, see Figure 4 , take the subtracted time domain signal as the cell under test CUT (Cell Under Test), compare the threshold factor and the cell under test CUT; if the cell under test CUT is greater than the threshold factor, it indicates that there is a target signal in the subtracted time domain signal, that is, there is a reflector peak, and the start and end times corresponding to the reflector peak in the subtracted time domain signal are used as the start and end times of the time domain gate; if the cell under test CUT is less than or equal to the threshold factor, it indicates that there is no target signal in the subtracted time domain signal; wherein, the comparison process of the threshold factor and the cell under test CUT, that is, the threshold factor and the subtracted time domain signal can be expressed as:

[0079] ;

[0080] Among them, CUT is the unit to be detected (subtracted time domain signal); T is the threshold factor.

[0081] In this embodiment, the training unit length and the protection unit length can be set as needed. For example, the training unit length can be 120, and the protection unit length can be 30. The present invention is not limited to this.

[0082] Step 104: construct a time domain gate function based on the start and end time of the time domain gate, and perform a linear frequency modulation Z transform on the time domain gate function to generate a frequency domain time domain gate function.

[0083] The start time position of the time domain gate and the end time position of the time domain gate.

[0084] Please note that Figure 5 , the time domain gate function is constructed according to the start and end time of the time domain gate. The approximate formula of the time domain gate function can be expressed as:

[0085] ;

[0086] in, is the time domain gate function; f c The center frequency of the frequency signal of the sample to be tested, that is, the center frequency in the range of 26.5~40GHz ;t start is the starting time position of the time domain gate; t stop is the time position of the time domain gate termination; t is the time domain gate time.

[0087] Furthermore, the constructed time domain gate function Use CZT (Chirp-Z Transform) to transform to frequency domain and time domain gate function .

[0088] Step 105: Use the frequency domain time domain gate function and the time domain gate start and end time to process the frequency domain signal of the sample to be tested, and output a time domain gate filtered signal.

[0089] Specifically, based on the start and end time of the time domain gate, a unit impulse signal is constructed; wherein the unit impulse signal The expression after normalization in the frequency domain is:

[0090] ;

[0091] in, is the unit impulse signal; f is the working frequency band of the sample to be tested, and its value range is 26.5-40Ghz; f c is the center frequency of the frequency signal of the sample to be tested; is the center point of the time domain gate, .

[0092] Furthermore, a convolution operation is performed on the unit impulse signal and the frequency domain time domain gate function to determine the time domain gate normalization coefficient; wherein the calculation process of the time domain gate normalization coefficient can be expressed as:

[0093] ;

[0094] Among them, nc is the time domain gate normalization coefficient; is the frequency domain and time domain gate function; is the unit impact signal; is convolution.

[0095] For further information, see Figure 6 Based on the time domain gate normalization coefficient, the frequency domain signal of the sample to be tested and the frequency domain time domain gate function are convolved and normalized to output the time domain gate filter signal, that is, the convolved frequency domain signal is normalized and compensated to obtain the final frequency domain signal after the time domain gate technology (time domain gate filter signal) as shown in Figure 6 As shown; wherein, the processing process of the time domain gate filtering signal can be expressed as:

[0096] ;

[0097] in, is the time domain gate filtered signal; is the frequency domain and time domain gate function; is convolution; is the frequency domain signal of the sample to be tested; nc is the time domain gate normalization coefficient.

[0098] In an embodiment of the present invention, the present invention provides a time domain gate filter signal processing method, first, obtain a direct parameter frequency domain signal and a reflector parameter frequency domain signal; then, generate a subtraction time domain signal according to the direct parameter frequency domain signal and the reflector parameter frequency domain signal; use a preset unit average constant false alarm rate algorithm to perform target detection on the subtraction time domain signal to determine the start and end time of the time domain gate; based on the start and end time of the time domain gate, construct a time domain gate function, and perform a linear frequency modulation Z transform on the time domain gate function to generate a frequency domain time domain gate function; finally, use the frequency domain time domain gate function and the start and end time of the time domain gate to perform signal processing on the frequency domain signal of the sample to be tested, and output a time domain gate filter signal; based on the above scheme, use a preset unit average constant false alarm rate algorithm to perform target detection on the subtraction time domain signal, determine the start and end time of the time domain gate, and construct a time domain gate function based on the start and end time of the time domain gate, and then obtain the time domain gate filter signal according to the time domain gate function. The process does not need to rely on the skill level and experience requirements of the operator, and can realize the automatic construction of the time domain gate function, thereby improving the signal processing efficiency.

[0099] See also Figure 7 , Figure 7 A flowchart of the steps of a time domain gate filtering signal processing method provided in Embodiment 2 of the present invention.

[0100] The present invention provides a time domain gate filtering signal processing method, comprising:

[0101] Step 701: Obtain a through parameter frequency domain signal and a reflector parameter frequency domain signal.

[0102] It should be noted that the parameter frequency domain signal of the free space system in the straight-through state without any objects placed therein and the original frequency domain signal of the reflectors placed on both sides of the sample to be tested are measured, that is, the straight-through parameter frequency domain signal and the reflector parameter frequency domain signal are obtained.

[0103] Step 702: perform windowing processing on the direct parameter frequency domain signal and the reflector parameter frequency domain signal respectively, and output a windowed direct parameter frequency domain signal and a windowed reflector parameter frequency domain signal.

[0104] It should be noted that the Kaiser window function is used to multiply the measured direct parameter frequency domain signal and the reflector parameter frequency domain signal respectively to perform windowed data preprocessing to obtain the windowed direct parameter frequency domain signal and the windowed reflector parameter frequency domain signal to reduce spectrum leakage and the resulting truncation effect.

[0105] Step 703: Perform linear frequency modulation inverse Z transform on the windowed direct parameter frequency domain signal and the windowed reflector parameter frequency domain signal respectively to generate a windowed direct parameter time domain signal and a windowed reflector parameter time domain signal.

[0106] It should be noted that, by using the ICZT transformation technology, the windowed direct parameter frequency domain signal and the windowed reflector parameter frequency domain signal are subjected to linear frequency modulation inverse Z transformation to obtain the windowed direct parameter time domain signal and the windowed reflector parameter time domain signal.

[0107] Step 704: perform a subtraction operation on the windowed direct parameter time domain signal and the windowed reflector parameter time domain signal, and output a subtraction time domain signal.

[0108] It should be noted that the time domain signal of the direct pass (windowed direct pass parameter time domain signal) is subtracted from the time domain signal of the two reflectors (windowed reflector parameter time domain signal) to obtain the subtracted time domain signal (subtracted time domain signal).

[0109] Step 705: Use a preset unit average constant false alarm rate algorithm to perform target detection on the subtracted time domain signal to determine the start and end time of the time domain gate.

[0110] Further, step 705 may include the following sub-steps:

[0111] S51, dividing the subtracted time domain signal according to a preset unit length to determine a plurality of training time domain sub-signals;

[0112] S52, performing unit average processing on each training time-domain sub-signal respectively, and outputting an initial unit average value corresponding to each training time-domain sub-signal;

[0113] S53, performing mean processing on the average values ​​of each initial unit to determine the target unit average value;

[0114] S54, using the target unit average value and the preset unit length to calculate the threshold factor;

[0115] S55, comparing the threshold factor and the subtraction time domain signal;

[0116] S56: If the subtracted time domain signal is greater than the threshold factor, the start and end times corresponding to the reflector peaks in the subtracted time domain signal are used as the start and end times of the time domain gate.

[0117] It should be noted that the cell-averaging constant false alarm rate (CA-CFAR) target detection is performed on the time domain signal obtained by subtraction, that is, the subtracted time domain signal. The specific algorithm steps are as follows: first, the size of the training area and the protection area is determined. Assume that the training unit length is defined as 120, protection unit length is 30. Next, the signal strength average value of the training unit (the average value of the target unit) is calculated as the clutter noise power statistic Z of the unit to be detected (the subtracted time domain signal). The threshold factor is calculated using the training unit length and the average value of the target unit. The subtracted time domain signal is used as the unit to be detected CUT. Finally, the unit to be detected CUT and the threshold factor are compared. If the unit to be detected CUT is greater than the threshold factor, it indicates that the unit to be detected CUT has a target signal, that is, the peak value of the reflector. The start and end times corresponding to the peak value of the reflector are used as the start and end times of the time domain gate.

[0118] Step 706: construct a time domain gate function based on the start and end time of the time domain gate, and perform a linear frequency modulation Z transform on the time domain gate function to generate a frequency domain time domain gate function.

[0119] For example, see Figure 8 First, the parameter frequency domain signal of the direct pass without any object placed in the free space system and the original frequency domain signal of the reflectors placed on both sides of the sample to be tested are measured, that is, the direct pass parameter frequency domain signal and the reflector parameter frequency domain signal are obtained, then, the direct pass parameter frequency domain signal and the reflector parameter frequency domain signal are respectively preprocessed with windowed data to obtain the windowed direct pass parameter frequency domain signal and the windowed reflector parameter frequency domain signal; the windowed direct pass parameter frequency domain signal and the windowed reflector parameter frequency domain signal are respectively transformed into the windowed direct pass parameter time domain signal and the windowed reflector parameter time domain signal, and the time domain signal of the reflectors on both sides is subtracted from the direct pass time domain signal, that is, the windowed direct pass parameter time domain signal and the windowed reflector parameter time domain signal are subtracted, and the subtracted time domain signal is output, and then based on the preset unit average constant false alarm rate algorithm, the start and end times corresponding to the reflector peaks in the subtracted time domain signal are marked and used as the start and end times of the time domain gate, and finally, the time domain gate function is constructed according to the start and end times of the time domain gate.

[0120] Step 707: Use the frequency domain time domain gate function and the time domain gate start and end time to process the frequency domain signal of the sample to be tested, and output a time domain gate filtered signal.

[0121] Further, step 707 may include the following sub-steps:

[0122] S71, constructing a unit impact signal based on the start and end time of the time domain gate;

[0123] S72, performing a convolution operation on the unit impulse signal and the frequency domain and time domain gate function to determine a time domain gate normalization coefficient;

[0124] S73. Based on the time domain gate normalization coefficient, convolve and normalize the frequency domain signal of the sample to be tested and the frequency domain time domain gate function, and output a time domain gate filter signal.

[0125] Please note that Fig. 9 , based on the time domain gate function frequency domain signal (frequency domain time domain gate function) obtained in the above steps and the frequency domain signal of the sample to be tested, the result after time domain gating is obtained. Since the convolution within the frequency range will cause part of the time domain gate function value to leak out of the band, there will be large errors near the start and end frequencies and the end frequency. In order to eliminate the influence of this error on the final result, it is necessary to perform normalization compensation processing on the convolved signal (that is, the result of the convolution of the time domain gate function frequency domain signal (frequency domain time domain gate function) and the frequency domain signal of the sample to be tested) to improve the accuracy and reliability of signal processing. Specifically, based on the unit impulse signal and the frequency domain time domain gate function obtained at the center time of the time domain gate function, the time domain gate normalization coefficient is calculated, and the time domain gate normalization coefficient is used to normalize the convolved signal, and finally the frequency domain signal (time domain gate filter signal) after the time domain gate technology is obtained.

[0126] As a comparison of technical effects, it can be combined with existing technologies for reference. In free space measurement systems, usually before the measurement process, in order to remove the influence of clutter outside the target area and the sample to be measured, the time domain gate technology needs to be used to select the original signal. Time domain gate technology is a technology widely used in vector frequency domain data post-processing and is a technology provided in vector network analyzers (VNAs). The core of time domain gate technology lies in its application as a bandpass filter in the time domain, which can accurately remove or retain signal responses in a specific time period. In reflection measurement, since the reflected signals generated by each impedance discontinuity in the system arrive at the measurement reference plane with different time delays in the time domain, the time domain gate technology can accurately analyze the reflected signals at specific discontinuities. Therefore, the time domain gate technology can effectively remove the interference reflections generated by non-terminal loads (such as test equipment, connecting cables, etc.), thereby significantly improving the accuracy and reliability of the measurement.

[0127] The traditional time-domain gate technology design method is mainly implemented in vector network analysis through the following steps: first, the frequency response of the original frequency-domain system is converted to the time domain using the inverse linear frequency modulation Z transform (ICZT), and the time-domain signal is observed to determine the time-domain range of the object to be tested, and then the start and end time and gate width of the time-domain gate are determined to construct the time-domain gate function; then, the time-domain gate function is transformed back to the frequency domain through the linear frequency modulation Z transform (CZT); finally, the frequency-domain signal of the sample to be tested is convolved with the time-domain gate function to obtain the filtered signal. However, this process relies on the observation method, requiring the operator to determine the position and size of the time-domain gate by comparing the specific position of the sample to be tested in the time domain. At the same time, the process is complicated and requires high skill levels and experience of the operator. In addition, the periodicity of the CZT transform, the truncation effect of filtering or time-domain gate functions, and the trade-offs of constructing different shapes of time-domain gate functions need to be considered. Difficult parameter adjustment is also a major challenge. Once the time-domain data is downloaded to the computer, it is often difficult for users to further process or adjust the gate parameters, limiting the flexibility of data processing and the depth of subsequent analysis.

[0128] In view of the above problems, the present invention proposes a time domain gate filter signal processing method, which is designed for the automatic selection of time domain gate technology. The automatic time domain gate technology detects the reflectors placed on both sides of the sample to be tested through the constant false alarm rate (CFAR), detects the time domain positions of the radiation plates on both sides, and determines the start time and end time of the time domain gate and constructs a time domain gate function. The time domain signal of the constructed time domain gate function is converted to a frequency domain signal, and finally convolved with the frequency domain signal of the sample to be tested to obtain the signal after time domain gate filtering. Specifically, first measure the original frequency domain signals of the system's direct pass and the reflectors placed on both sides of the sample to be tested; then, load the Kaiser window for data preprocessing, and use the ICZT transform to convert the frequency domain signal into a time domain signal; subtract the direct pass signal from the reflector signal, and use the CFAR algorithm to mark the peak values ​​of the time domain signals of the reflectors on both sides; determine the results obtained in the third step as the start and end times for constructing the time domain gate function, and construct the time domain gate function; finally, transform the constructed time domain gate function into the frequency domain, convolve it with the frequency domain signal of the sample to be tested, and perform normalization processing to finally obtain the frequency domain signal after the time domain gate technology.

[0129] Compared with the prior art, the present invention introduces a constant false alarm rate (CFAR) to detect the time domain time of the reflectors on both sides of the sample to be tested, and then automatically determines the start and end time of the time domain gate, thereby constructing a time domain gate function, realizing the automatic construction of the time domain gate function, and finally realizing automatic time domain gate technology, which can conveniently and quickly construct the time domain gate function of the sample to be tested, avoiding the need to rely on human experience to construct the time domain gate function, and solving the problem that the traditional time domain gate technology cannot automatically determine the start and end time of the time domain gate function.

[0130] In an embodiment of the present invention, the present invention provides a time domain gate filter signal processing method, first, obtain a direct parameter frequency domain signal and a reflector parameter frequency domain signal; then, generate a subtraction time domain signal according to the direct parameter frequency domain signal and the reflector parameter frequency domain signal; use a preset unit average constant false alarm rate algorithm to perform target detection on the subtraction time domain signal to determine the start and end time of the time domain gate; based on the start and end time of the time domain gate, construct a time domain gate function, and perform a linear frequency modulation Z transform on the time domain gate function to generate a frequency domain time domain gate function; finally, use the frequency domain time domain gate function and the start and end time of the time domain gate to perform signal processing on the frequency domain signal of the sample to be tested, and output a time domain gate filter signal; based on the above scheme, use a preset unit average constant false alarm rate algorithm to perform target detection on the subtraction time domain signal, determine the start and end time of the time domain gate, and construct a time domain gate function based on the start and end time of the time domain gate, and then obtain the time domain gate filter signal according to the time domain gate function. The process does not need to rely on the skill level and experience requirements of the operator, and can realize the automatic construction of the time domain gate function, thereby improving the signal processing efficiency.

[0131] See also Fig.10 , Fig.10 This is a structural block diagram of a time domain gate filtering signal processing device provided in Embodiment 3 of the present invention.

[0132] The present invention provides a structural block diagram of a time domain gate filtering signal processing device, comprising:

[0133] The signal acquisition module 1001 is used to acquire the direct parameter frequency domain signal and the reflector parameter frequency domain signal;

[0134] A subtraction time domain signal generation module 1002 is used to generate a subtraction time domain signal according to the direct parameter frequency domain signal and the reflector parameter frequency domain signal;

[0135] The target detection module 1003 is used to perform target detection on the subtracted time domain signal by using a preset unit average constant false alarm rate algorithm to determine the start and end time of the time domain gate;

[0136] The transformation module 1004 is used to construct a time domain gate function based on the start and end time of the time domain gate, and perform a linear frequency modulation Z transform on the time domain gate function to generate a frequency domain time domain gate function;

[0137] The signal processing module 1005 is used to perform signal processing on the frequency domain signal of the sample to be tested by using the frequency domain time domain gate function and the time domain gate start and end time, and output a time domain gate filter signal.

[0138] Further, the subtraction time domain signal generation module 1002 is specifically used for:

[0139] Performing windowing processing on the direct parameter frequency domain signal and the reflector parameter frequency domain signal respectively, and outputting a windowed direct parameter frequency domain signal and a windowed reflector parameter frequency domain signal;

[0140] Performing linear frequency modulation inverse Z transform on the windowed direct parameter frequency domain signal and the windowed reflector parameter frequency domain signal respectively to generate a windowed direct parameter time domain signal and a windowed reflector parameter time domain signal;

[0141] A subtraction operation is performed on the windowed direct parameter time domain signal and the windowed reflector parameter time domain signal, and a subtraction time domain signal is output.

[0142] Furthermore, the target detection module 1003 is specifically used for:

[0143] The subtracted time domain signal is divided according to a preset unit length to determine a plurality of training time domain sub-signals;

[0144] Perform unit averaging processing on each training time-domain sub-signal respectively, and output the initial unit average value corresponding to each training time-domain sub-signal;

[0145] Perform mean processing on the average values ​​of each initial unit to determine the target unit average value;

[0146] The threshold factor is calculated using the target unit average value and the preset unit length;

[0147] comparing threshold factors and subtracting time domain signals;

[0148] If the subtracted time domain signal is greater than the threshold factor, the start and end times corresponding to the reflector peaks in the subtracted time domain signal are used as the start and end times of the time domain gate.

[0149] Further, the signal processing module 1005 is specifically used for:

[0150] Based on the start and end time of the time domain gate, a unit impact signal is constructed;

[0151] Perform convolution operation on the unit impulse signal and the frequency domain and time domain gate function to determine the time domain gate normalization coefficient;

[0152] Based on the time domain gate normalization coefficient, the frequency domain signal of the sample to be tested and the frequency domain time domain gate function are convolved and normalized to compensate, and the time domain gate filtering signal is output.

[0153] Furthermore, the start and end time of the time domain gate includes the start time position of the time domain gate and the end time position of the time domain gate; the time domain gate function is specifically:

[0154] ;

[0155] in, is the time domain gate function; f c is the center frequency of the frequency signal of the sample to be tested, which is 33.25 GHz; t start is the starting time position of the time domain gate; t stopis the time position of the time domain gate termination; t is the time domain gate time.

[0156] Furthermore, the processing process of the time domain gate filtering signal is specifically as follows:

[0157] ;

[0158] in, is the time domain gate filtered signal; is the frequency domain and time domain gate function; is convolution; is the frequency domain signal of the sample to be tested; nc is the time domain gate normalization coefficient.

[0159] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0160] An embodiment of the present invention further provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory; when the computer program is executed by the processor, the processor executes the steps of the time domain gate filtering signal processing method as described in any of the above embodiments.

[0161] An embodiment of the present invention further provides a computer-readable storage medium on which a computer program / instruction is stored. When the computer program / instruction is executed by a processor, the steps of the time-domain gate filtering signal processing method as in any of the above embodiments are implemented.

[0162] An embodiment of the present invention further provides a computer program product, including a computer program / instruction, which implements the steps of the time-domain gate filtering signal processing method in any of the above embodiments when the computer program / instruction is executed by a processor.

[0163] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0164] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0165] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A time domain gate filtering signal processing method, characterized in that: include: Obtaining a through parameter frequency domain signal and a reflector parameter frequency domain signal; Generate a subtraction time domain signal according to the through parameter frequency domain signal and the reflector parameter frequency domain signal; Using a preset unit average constant false alarm rate algorithm to perform target detection on the subtracted time domain signal, and determine the start and end time of the time domain gate; Based on the start and end time of the time domain gate, a time domain gate function is constructed, and a linear frequency modulation Z transform is performed on the time domain gate function to generate a frequency domain time domain gate function; The frequency domain time domain gate function and the time domain gate start and end time are used to perform signal processing on the frequency domain signal of the sample to be tested, and a time domain gate filtering signal is output.

2. The time domain gate filtering signal processing method according to claim 1, characterized in that: The step of generating a subtraction time domain signal according to the through parameter frequency domain signal and the reflector parameter frequency domain signal comprises: Performing windowing processing on the direct parameter frequency domain signal and the reflector parameter frequency domain signal respectively, and outputting a windowed direct parameter frequency domain signal and a windowed reflector parameter frequency domain signal; Performing linear frequency modulation inverse Z transform on the windowed direct-pass parameter frequency domain signal and the windowed reflector parameter frequency domain signal respectively to generate a windowed direct-pass parameter time domain signal and a windowed reflector parameter time domain signal; A subtraction operation is performed on the windowed direct parameter time domain signal and the windowed reflector parameter time domain signal, and a subtraction time domain signal is output.

3. The time domain gate filtering signal processing method according to claim 1, characterized in that: The step of using a preset unit average constant false alarm rate algorithm to perform target detection on the subtracted time domain signal and determine the start and end time of the time domain gate includes: Segmenting the subtracted time domain signal according to a preset unit length to determine a plurality of training time domain sub-signals; Performing unit averaging processing on each of the training time-domain sub-signals respectively, and outputting initial unit average values ​​corresponding to each of the training time-domain sub-signals; Performing mean processing on each of the initial unit average values ​​to determine a target unit average value; Calculate a threshold factor using the target unit average value and the preset unit length; comparing the threshold factor and the subtracted time domain signal; If the subtracted time domain signal is greater than the threshold factor, the start and end times corresponding to the reflector peaks in the subtracted time domain signal are used as the start and end times of the time domain gate.

4. The time domain gate filtering signal processing method according to claim 1, characterized in that: The step of using the frequency domain time domain gate function and the time domain gate start and end time to process the frequency domain signal of the sample to be tested and outputting the time domain gate filter signal comprises: Constructing a unit impulse signal based on the start and end time of the time domain gate; Performing a convolution operation on the unit impulse signal and the frequency-domain and time-domain gate function to determine a time-domain gate normalization coefficient; Based on the time domain gate normalization coefficient, the frequency domain signal of the sample to be tested and the frequency domain time domain gate function are convolved and normalized to output a time domain gate filter signal.

5. The time domain gate filtering signal processing method according to claim 1, characterized in that: The start and end time of the time domain gate includes the start time position of the time domain gate and the end time position of the time domain gate; the time domain gate function is specifically: ； in, is the time domain gate function; f c is the center frequency of the frequency signal of the sample to be tested, which is 33.25 GHz; t start is the starting time position of the time domain gate; t stop is the time position of the time domain gate termination; t is the time domain gate time.

6. The time domain gate filtering signal processing method according to claim 4, characterized in that: The processing process of the time domain gate filtering signal is specifically as follows: ； in, is the time domain gate filtered signal; is the frequency domain and time domain gate function; is convolution; is the frequency domain signal of the sample to be tested; nc is the time domain gate normalization coefficient.

7. A time domain gate filter signal processing device, characterized in that: include: A signal acquisition module is used to acquire a direct parameter frequency domain signal and a reflector parameter frequency domain signal; A subtraction time domain signal generation module is used to generate a subtraction time domain signal according to the through parameter frequency domain signal and the reflector parameter frequency domain signal; A target detection module, used to perform target detection on the subtracted time domain signal using a preset unit average constant false alarm rate algorithm to determine the start and end time of the time domain gate; A transformation module, used to construct a time domain gate function based on the start and end time of the time domain gate, and perform a linear frequency modulation Z transform on the time domain gate function to generate a frequency domain time domain gate function; The signal processing module is used to perform signal processing on the frequency domain signal of the sample to be tested by using the frequency domain time domain gate function and the time domain gate start and end time, and output a time domain gate filter signal.

8. A computer device, characterized in that: It comprises a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the time domain gate filtering signal processing method according to any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the time-domain gate filtering signal processing method according to any one of claims 1 to 6 is implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program stored on a non-transitory computer-readable storage medium, wherein the computer program comprises program instructions, wherein when the program instructions are executed by a computer, the computer is caused to execute the time-domain gate filtering signal processing method as described in any one of claims 1-6.

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