Method and system for displaying segmented scanning frequency spectrum of EMI (Electro-Magnetic Interference) receiver

Abstract

The invention discloses an EMI receiver segmented scanning frequency spectrum display method and system, and belongs to the technical field of electromagnetic compatibility testing. The invention discloses a segmented scanning spectrum display method for an EMI receiver. Taking the amplitude-frequency test data in the plurality of test intervals as original data of a display frequency spectrum, and forming a test data set; utilizing a logarithmic coordinate system to carry out positioning of logarithmic coordinates in the X direction and linear coordinates in the Y direction on the original data; on the basis of positioning of original data in X and Y directions, a vertical line segment of a single pixel point in a logarithmic coordinate system is regarded as a pixel segment, and interval pixel segments are connected and fused to realize interval image synthesis. Therefore, test intervals are divided, discrete test data are displayed logarithmically, image processing complexity is reduced, redundant data are merged, image resource overhead is saved, the capability requirement of a processor is reduced, image processing is modularized, digitized and refined, and the display efficiency of segmented spectrum images is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic compatibility testing, and in particular relates to a segmented scanning spectrum display method and system for an EMI receiver. Background Art

[0002] The main function of the EMI measurement receiver is to receive and detect electromagnetic interference (EMI) signals. It is widely used in electromagnetic compatibility testing, troubleshooting, spectrum analysis and other fields to help identify, locate and eliminate electromagnetic interference problems.

[0003] GB / T 18655-2018 Vehicle Radio Disturbance Characteristics Standard defines five test intervals for the conducted emission voltage method measurement of components: LW (0.15-0.3MHz), MW (0.53-1.8MHz), SW (5.9-6.2MHz), FM (76-108MHz) and TV Band I (48.5-72.5MHz). The frequency resolution of LW, MW and SW is 9kHz, and the frequency resolution of FM and TV Band is 120kHz. In order to meet the standard emission limit requirements, combined with the test receiver sensitivity, the receiver channel settings such as attenuation, gain, and preamplifier may also be different. Based on the above requirements, the EMI measurement receiver is required to perform different parameter settings, channel control, frequency band scanning, data acquisition and output display for each test interval.

[0004] However, currently, a large-scale scanning method is usually adopted without distinguishing independent intervals, which prolongs the test time. At the same time, the test interval cannot be accurately corresponded to the standard limit in the scanning spectrum, and there is a lot of redundant data, which affects user observation and analysis. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method and system for displaying a segmented scanning spectrum of an EMI receiver, which solves the problems in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for displaying a segmented scanning spectrum of an EMI receiver comprises the following steps:

[0008] The amplitude-frequency test data in multiple discrete test intervals are used as the original data for displaying the spectrum and constitute a test data set;

[0009] Positioning the original data in logarithmic coordinates in the X direction and linear coordinates in the Y direction using a logarithmic coordinate system;

[0010] Based on the positioning of the original data in the X and Y directions, the vertical line segments of a single pixel point in the logarithmic coordinate system are regarded as pixel segments, and the interval pixel segments are connected and fused to achieve interval image synthesis.

[0011] Furthermore, the size of the test data set is the sum of the number of test interval data points, and the calculation formula for the test interval data points is:

[0012]

[0013] Where start is the starting frequency of the test interval; stop is the ending frequency of the test interval; rbw is the frequency resolution of the test interval.

[0014] Furthermore, the logarithmic coordinate system is the actual test spectrum image display area, the X-axis represents the frequency, which is logarithmically distributed, and the values ​​are from low to high from left to right; the Y-axis represents the amplitude, which is linearly distributed, from high to low from top to bottom; the abscissa of the logarithmic coordinate system is determined according to the minimum and maximum frequencies of the test interval, and the corresponding frequency value of each point is calculated according to the number of data points in the test interval, and the calculation formula is:

[0015]

[0016] In the formula, Frequency is the frequency corresponding to the data point; index is the data point index, ranging from 0 to points-1; points is the length of the test interval data set.

[0017] Furthermore, the abscissa calculation formula corresponding to the data set in the logarithmic coordinate system is:

[0018]

[0019] Where width is the display resolution width of the image in the LCD; pixel is the coordinate position of the data point in the data set.

[0020] Furthermore, the pixel segment accumulates multiple spectrum data points on each pixel point of the display terminal, and the corresponding horizontal coordinate values ​​of these spectrum data points in the logarithmic coordinate system are the same after rounding, and the vertical coordinate amplitude values ​​are different, forming a vertical line segment from top to bottom relative to the horizontal coordinate.

[0021] Furthermore, when synthesizing the interval image, multiple pixel segments in the interval are connected end to end, the maximum and minimum line segments are connected, and the last amplitude value is connected to the first amplitude value of the next data point.

[0022] Furthermore, when the interval image synthesis is used to update the spectrum data of the continuous test in real time, it is not necessary to update the spectrum image in the entire coordinate system. One data point is extended to the left and right of the pixel point interval of the current update interval for erasing, except for the boundary points of the test interval;

[0023] The pixel coordinates of the data points in the update interval are calculated according to formula (3). After rounding, the data points with the same coordinate values ​​are classified into the same pixel segment. The maximum and minimum values ​​in each pixel segment of the interval are counted. The interval pixel segment coordinate information is updated and the image connection of the left and right adjacent data points is completed until the spectrum images of all test intervals are connected. After the merging is completed, the latest spectrum image is output.

[0024] A segmented scanning spectrum display system for an EMI receiver, comprising:

[0025] Dataset construction module: takes the amplitude-frequency test data in multiple discrete test intervals as the original data for displaying the spectrum and forms a test data set;

[0026] Data positioning module: using a logarithmic coordinate system to position the original data in the logarithmic coordinates of the X direction and the linear coordinates of the Y direction;

[0027] And, the image synthesis module: based on the positioning of the original data in the X and Y directions, the vertical line segments of a single pixel point in the logarithmic coordinate system are regarded as pixel segments, and the interval pixel segments are connected and fused to achieve interval image synthesis.

[0028] A computer storage medium stores a readable program, and when the program is running, the above-mentioned EMI receiver segmented scanning spectrum display method can be executed.

[0029] An electronic device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0030] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned EMI receiver segmented scanning spectrum display method.

[0031] Beneficial effects of the present invention:

[0032] 1. The present invention filters the pixel data accumulated on a single pixel point according to the EMC test standard and the characteristics of the display terminal, only calculates the redundant data on the pixel point without repeating the display, retains the maximum and minimum values, reduces the complexity of the display, and saves processor overhead.

[0033] 2. The test interval of the present invention is discontinuous in frequency distribution, and the number of data points and frequency position of the interval are calculated separately in the coordinate system; when updating in segments, no graphics update of the large-scale coordinate system is performed, and only the pixel segments of the interval are updated to ensure balanced image processing performance and improve image output rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] 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, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 It is a schematic diagram of the test interval and data set of the present invention;

[0036] Figure 2 It is a schematic diagram of a pixel point interval calculation method of the present invention;

[0037] Figure 3 It is a schematic diagram of pixel segment drawing and image synthesis of the present invention;

[0038] Figure 4 It is a segmented scanning spectrum display effect diagram of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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.

[0040] Example 1

[0041] A method for displaying a segmented scanning spectrum of an EMI receiver comprises the following steps:

[0042] S1, using the amplitude-frequency test data in multiple discrete test intervals as the original data for displaying the spectrum and forming a test data set;

[0043] like Figure 1 As shown in the figure, the test data set includes multiple discrete test intervals. The data sets within the test intervals are discontinuous in frequency, and the total data length can reach millions of points. The test data set provides the raw data input of the spectrum image, which has a huge difference in length from the LCD terminal display resolution (the data set length far exceeds the actual resolution width of the screen display). The data type is a signed integer with a value of 32 bits, and is triggered irregularly through interrupts.

[0044] The size of the test data set is the sum of the number of test interval data points. The calculation formula for the test interval data points is:

[0045]

[0046] Where, start: the starting frequency of the test interval;

[0047] stop: the test interval termination frequency;

[0048] rbw: test interval frequency resolution;

[0049] points: length of the test interval data set.

[0050] S2, using a logarithmic coordinate system to locate the original data in S1 in the logarithmic coordinates (frequency) in the X direction and the linear coordinates (amplitude) in the Y direction, and determine the display position on the display terminal;

[0051] The logarithmic coordinate system is the actual test spectrum image display area, the X-axis represents the frequency, which is logarithmically distributed, and the values ​​are from low to high from left to right, and the Y-axis represents the amplitude, which is linearly distributed from high to low from top to bottom; the horizontal axis of the logarithmic coordinate system is determined according to the minimum and maximum frequencies of the test interval, and the corresponding frequency value of each point is calculated according to the number of data points in the test interval. The calculation formula is:

[0052]

[0053] Where, start: the starting frequency of the test interval;

[0054] stop: the test interval termination frequency;

[0055] index: data point index, ranging from 0 to points-1;

[0056] points: length of the test interval data set.

[0057] S3, treating the vertical line segments of single pixel points in the logarithmic coordinate system (based on the positioning of the interval data points in the XY direction in S2) as pixel segments, and connecting and merging the interval pixel segments to achieve interval image synthesis;

[0058] like Figure 3 As shown, the pixel segment constitutes the basic display unit of the test interval. The pixel segment accumulates multiple spectrum data points on each pixel point of the display terminal. The corresponding horizontal coordinate values ​​of these spectrum data points in the logarithmic coordinate system are the same after rounding, but the vertical coordinate amplitude values ​​are different. Only a vertical line segment relative to the horizontal coordinate from top to bottom can be seen by naked eye;

[0059] When synthesizing interval images, multiple pixel segments in the interval are connected end to end, the maximum and minimum line segments are connected, and the last amplitude value is connected to the first amplitude value of the next data point.

[0060] When the interval image synthesis is used to update the spectrum data of continuous testing in real time, it is not necessary to update the spectrum image in the entire coordinate system. One data point is extended to the left and right of the pixel point interval of this update interval for erasure, except for the boundary points of the test interval.

[0061] like Figure 2 As shown in the figure, the pixel interval calculation process is:

[0062] 1) The update interval is Seg, and the data point range is: from P1 to P2;

[0063] 2) The frequency range corresponding to this update interval is F1-F2, calculated according to formula (2);

[0064] 3) P1' is the left neighboring data point of P1, P2' is the right neighboring data point of P2, and the test interval data points are calculated according to formula (1);

[0065] 4) Calculate the XY coordinates of the data points P1-P2 in the data set according to formula (3). The X coordinates that are the same after rounding are classified into the same pixel segment, and mark the data points in the pixel segment with maximum and minimum values ​​according to the Y value; mark the first and last points according to the order of the data points; the line connecting the maximum and minimum values ​​constitutes the pixel segment line segment;

[0066] 5) Connect the first point of all pixel segments in Seg with the left adjacent point P1', and the last point with the first point P2' of the right adjacent pixel segment, and then output the complete test interval spectrum image;

[0067] 6) Complete the image drawing and caching of the remaining test intervals in sequence according to steps 1) to 5);

[0068] The calculation formula for the horizontal coordinate corresponding to the data set in the logarithmic coordinate system is:

[0069]

[0070] Where, width: the display resolution width of the image in the LCD

[0071] frequency: the frequency of data points in the data set;

[0072] start: the starting frequency of the test interval;

[0073] stop: the test interval termination frequency;

[0074] points: length of the test interval data set.

[0075] The data points in the update interval are calculated according to the sequence number according to formula (3), and the coordinates with the same value after rounding are classified into the same pixel segment. The maximum and minimum values ​​in each pixel segment of the interval are counted, the interval pixel segment coordinate information is updated, and the image connection of the left and right adjacent data points is completed until the spectrum images of all test intervals are connected. After the merging is completed, the latest spectrum image is output.

[0076] Based on similar inventive concepts, an embodiment of the present invention further provides a computer storage medium storing a readable program, which can execute the above-mentioned EMI receiver segmented scanning spectrum display method when the program is running.

[0077] Based on similar inventive concepts, an embodiment of the present invention provides an electronic device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0078] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned EMI receiver segmented scanning spectrum display method.

[0079] Based on similar inventive concepts, an embodiment of the present invention further provides a computer program product, including computer instructions, wherein the computer instructions instruct a computing device to execute operations corresponding to the above-mentioned method for displaying a segmented scanning spectrum of an EMI receiver.

[0080] Example 2

[0081] The pixel segment data structure is established based on C language, and the pixel segment data structure is defined as follows:

[0082] typedef struct

[0083] {

[0084] bool active; / / valid

[0085] float logAxis; / / logarithmic coordinates

[0086] uint32_t xDataIndex; / / Original horizontal coordinate index

[0087] double frequency; / / horizontal axis frequency value

[0088] float yMax; / / maximum amplitude

[0089] float yMin; / / minimum amplitude

[0090] int overlapedpCount; / / Number of overlaps

[0091] float firstY; / / The first amplitude value

[0092] float lastY; / / The last amplitude value

[0093] }pixelDataDef;

[0094] The test interval data structure is defined as follows:

[0095] typedef struct

[0096] {

[0097] double start; / / Starting frequency

[0098] double stop; / / stop frequency

[0099] double rbw; / / frequency resolution

[0100] uint32_t points; / / Number of points in interval data set

[0101] uint32_t pixelCount; / / display pixel size

[0102] pixelDataDef*pixels; / / display pixel set

[0103] }segmentDataDef;

[0104] Allocate and initialize the test interval information, pixel segment resources and coordinate system memory buffer according to the test interval and terminal display width.

[0105] 1) Establish a fully transparent image in the background coordinate system;

[0106] The background coordinate system is translated based on the Cartesian coordinate system, with the upper left corner (0, 0), the X-axis to the right, the Y-axis downward, and the X-axis frequency in a logarithmic distribution.

[0107] 2) Calculate and update the attributes of each member of the interval pixel segment in real time according to the interruption, refer to Figure 2 Perform pixel segment drawing;

[0108] Circularly calculate and update the parameters of each member of the sequence {x1,x2,x3,…,xn}, where

[0109] frequency: calculated according to formula (2);

[0110] firstY: the first amplitude value in the pixel segment;

[0111] lastY: the last amplitude value in the pixel segment;

[0112] yMax: maximum amplitude within the pixel segment;

[0113] yMin: minimum amplitude value within the pixel segment

[0114] 3)Reference Figure 3 Synthesis mode, after the interval pixel segment is updated, the previous and subsequent images are spliced, and the image is output after completion. The segmented scanning spectrum display effect is shown in the figure Figure 4 As shown, it can be seen that the test interval is logarithmically distributed in the coordinate system, and each test interval is independent; the spectrum waveform in the test interval is not distorted, and important data points in the waveform are not lost, which fully meets the standard test requirements.

[0115] Example 3

[0116] In this embodiment, a segmented scanning spectrum display system for an EMI receiver is proposed, which specifically includes:

[0117] Dataset construction module: takes the amplitude-frequency test data in multiple discrete test intervals as the original data for displaying the spectrum and forms a test data set;

[0118] Data positioning module: using a logarithmic coordinate system to position the original data in the logarithmic coordinates of the X direction and the linear coordinates of the Y direction;

[0119] And, the image synthesis module: based on the positioning of the original data in the X and Y directions, the vertical line segments of a single pixel point in the logarithmic coordinate system are regarded as pixel segments, and the interval pixel segments are connected and fused to achieve interval image synthesis.

[0120] The method of the present invention may be implemented in hardware, firmware, or as software or computer code that may be stored in a recording medium (such as a CDROM, RAM, floppy disk, hard disk, or magneto-optical disk), or as computer code that is originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded over a network and will be stored in a local recording medium, so that the method described herein may be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It is understood that a computer, processor, microprocessor controller, or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, processor, or hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0121] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for displaying a segmented scanning spectrum of an EMI receiver, characterized in that: The following steps are involved: The amplitude-frequency test data in multiple discrete test intervals are used as the original data for displaying the spectrum and constitute a test data set; Positioning the original data in logarithmic coordinates in the X direction and linear coordinates in the Y direction using a logarithmic coordinate system; Based on the positioning of the original data in the X and Y directions, the vertical line segments of a single pixel point in the logarithmic coordinate system are regarded as pixel segments, and the interval pixel segments are connected and fused to achieve interval image synthesis.

2. The EMI receiver segmented scanning spectrum display method according to claim 1, characterized in that: The size of the test data set is the sum of the number of test interval data points, and the calculation formula for the test interval data points is: Where start is the starting frequency of the test interval; stop is the ending frequency of the test interval; rbw is the frequency resolution of the test interval.

3. The EMI receiver segmented scanning spectrum display method according to claim 2, characterized in that: The logarithmic coordinate system is the actual test spectrum image display area, the X-axis represents the frequency, which is logarithmically distributed, and the values ​​are from low to high from left to right; the Y-axis represents the amplitude, which is linearly distributed, from high to low from top to bottom; the abscissa of the logarithmic coordinate system is determined according to the minimum and maximum frequencies of the test interval, and the corresponding frequency value of each point is calculated according to the number of data points in the test interval. The calculation formula is: In the formula, Frequency is the frequency corresponding to the data point; index is the data point index, ranging from 0 to points-1; points is the length of the test interval data set.

4. The method for displaying a segmented scanning spectrum of an EMI receiver according to claim 3, characterized in that: The calculation formula of the horizontal coordinate corresponding to the data set in the logarithmic coordinate system is: Where width is the display resolution width of the image in the LCD; pixel is the coordinate position of the data point in the data set.

5. The EMI receiver segmented scanning spectrum display method according to claim 1, characterized in that: The pixel segment accumulates multiple spectrum data points on each pixel point of the display terminal. The corresponding horizontal coordinate values ​​of these spectrum data points in the logarithmic coordinate system are the same after rounding, and the vertical coordinate amplitude values ​​are different, forming a vertical line segment from top to bottom relative to the horizontal coordinate.

6. The method for displaying EMI receiver segmented scanning spectrum according to claim 1 or 5, characterized in that: When synthesizing the interval image, multiple pixel segments in the interval are connected head to tail, the maximum and minimum line segments are connected, and the last amplitude value is connected to the first amplitude value of the next data point.

7. The method for displaying a segmented scanning spectrum of an EMI receiver according to claim 4, characterized in that: When the interval image synthesis is used to update the spectrum data of the continuous test in real time, it is not necessary to update the spectrum image in the entire coordinate system. One data point is extended to the left and right of the pixel point interval of the current update interval for erasing, except for the boundary points of the test interval; The pixel coordinates of the data points in the update interval are calculated according to formula (3). After rounding, the data points with the same coordinate values ​​are classified into the same pixel segment. The maximum and minimum values ​​in each pixel segment of the interval are counted. The interval pixel segment coordinate information is updated and the image connection of the left and right adjacent data points is completed until the spectrum images of all test intervals are connected. After the merging is completed, the latest spectrum image is output.

8. An EMI receiver segmented scanning spectrum display system, characterized in that: include: Dataset construction module: takes the amplitude-frequency test data in multiple discrete test intervals as the original data for displaying the spectrum and forms a test data set; Data positioning module: using a logarithmic coordinate system to position the original data in the logarithmic coordinates of the X direction and the linear coordinates of the Y direction; And, the image synthesis module: based on the positioning of the original data in the X and Y directions, the vertical line segments of a single pixel point in the logarithmic coordinate system are regarded as pixel segments, and the interval pixel segments are connected and fused to achieve interval image synthesis.

9. A computer storage medium storing a readable program, characterized in that: When the program is running, it can execute the EMI receiver segmented scanning spectrum display method described in any one of claims 1-7.

10. An electronic device, characterized in that: include: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the EMI receiver segmented scanning spectrum display method as described in any one of claims 1-7.

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