Method for improving AC measurement precision

Abstract

The invention discloses a method for improving AC measurement precision. The method comprises the following steps: acquiring a signal edge position in a waveform period; multiple times of sampling are carried out in adjacent intervals of the signal edge position; and calculating the calibration time of the signal edge according to the multiple sampling results. According to the invention, more accurate signal characteristic moments can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic measurement, and particularly to a method for improving the accuracy of AC measurement. Background Art

[0002] During the measurement of AC signals, the accurate positioning of the signal edge has an important impact on the measurement accuracy. The existing AC measurement technologies mainly rely on single sampling to determine the signal edge position. However, due to the influence of factors such as circuit noise and signal interference, the waveform will jitter, resulting in a large error in the measurement result of single sampling.

[0003] The traditional signal edge positioning method usually performs uniform sampling within the waveform period. This method not only requires a large number of sampling points but also easily misses the key regions where the signal changes rapidly, affecting the measurement accuracy. At the same time, due to the lack of sufficient sampling and analysis of the adjacent intervals of the signal edge, it is impossible to effectively identify and process waveform jitter, resulting in a low reliability of the measurement result.

[0004] In addition, when processing the sampled data, the existing technology often directly uses the first detected jump point as the signal edge moment, ignoring the possible jitter characteristics of the signal in the jump region. This simple processing method is difficult to obtain the accurate signal characteristic moment.

[0005] Therefore, there is an urgent need to propose a method for improving the accuracy of AC measurement to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to propose a method for improving the accuracy of AC measurement, which can obtain more accurate signal characteristic moments.

[0007] To solve the above technical problems, the present invention provides a method for improving the accuracy of AC measurement, which specifically includes the following:

[0008] Obtain the signal edge position within the waveform period;

[0009] Perform multiple samplings within the adjacent intervals of the signal edge position;

[0010] Calculate the calibration moment of the signal edge according to the results of multiple samplings.

[0011] Further, the obtaining the signal edge position within the waveform period specifically includes: searching for the signal edge position within the waveform period by using the bisection method; the signal edge includes the rising edge and the falling edge.

[0012] Further, the dichotomy method includes: sampling to obtain the current level value at a preset starting time point within the waveform period; determining the next sampling time point within the remaining time interval according to the level value; repeatedly performing sampling until a level transition is detected to obtain the signal edge position; wherein, when detecting a rising edge, searching for the transition from a low level to a high level; when detecting a falling edge, searching for the transition from a high level to a low level.

[0013] Further, the determining the next sampling time point within the remaining time interval according to the level value specifically includes: taking the midpoint of the current time interval as the next sampling time point; sampling at the next sampling time point and comparing with the level value at the previous time point; if the level value does not change, taking the remaining time interval as the new search interval and continuing to perform binary search.

[0014] Further, the performing multiple samplings within adjacent intervals of the signal edge position specifically includes: comparing the signal to be measured with a reference voltage at each sampling time; determining the logic level value at the current time according to the comparison result.

[0015] Further, the determining the logic level value at the current time according to the comparison result specifically includes: converting the logic signal into a digital signal according to the comparison result, and determining it as a low level when all the collected data are 0; determining it as a high level when all the collected data are 1.

[0016] Further, the calculating the calibration time of the signal edge according to the results of multiple samplings specifically includes: determining the start time and end time of the jitter interval according to the results of multiple samplings; performing an averaging process on the start time and end time of the jitter interval to obtain the calibration time of the signal edge.

[0017] Further, the determining the start time and end time of the jitter interval according to the results of multiple samplings specifically includes: setting a search range before and after the signal edge position and performing point-by-point scanning; performing multiple measurements on each time point; when there are different level values in the multiple measurement results, determining it as the signal jitter state; determining the time when the signal jitter state first appears as the start time of the jitter interval, and determining the time when the signal jitter state appears last as the end time of the jitter interval.

[0018] Further, before obtaining the signal edge position within the waveform period, it further includes: initializing the sliding window parameters according to the theoretical waveform signal edge time.

[0019] Further, it further includes: initializing the trie data structure; storing and managing the sampling data of multiple channels in the trie data structure; using the trie data structure for fast access to data to achieve parallel calibration of multiple channels.

[0020] Through the above technical solutions, the present invention has the following beneficial effects:

[0021] By obtaining the signal edge position within the waveform period, performing multiple samplings in the adjacent intervals of the signal edge position, and finally calculating the calibration moment of the signal edge, the problem of large measurement errors caused by single-point sampling in the prior art is overcome, and the accuracy and reliability of AC measurement are improved.

[0022] In addition, by using the dichotomy method to quickly locate the signal edge position, combining the sliding window parameter to optimize the search range, and using the trie data structure for multi-channel data management, the measurement efficiency is significantly improved, and efficient multi-channel parallel calibration is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flowchart of a method for improving the AC measurement accuracy in an embodiment of the present invention;

[0024] Figure 2 It is a specific flowchart of a method for improving the AC measurement accuracy in an embodiment of the present invention;

[0025] Figure 3 It is a square wave schematic diagram of a method for improving the AC measurement accuracy in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will describe in more detail a method for improving the AC measurement accuracy of the present invention with reference to the accompanying drawings, which shows the preferred embodiments of the present invention. It should be understood that those skilled in the art can modify the present invention described herein while still achieving the beneficial effects of the present invention. Therefore, the following description should be understood as a broad guidance for those skilled in the art and not as a limitation to the present invention.

[0027] In the following paragraphs, the present invention will be described more specifically by way of example with reference to the accompanying drawings. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, only for the purpose of facilitating and clearly assisting in explaining the objectives of the embodiments of the present invention.

[0028] As Figure 1 - Figure 2 shown, an embodiment of the present invention proposes a convenient and practical method for improving the AC measurement accuracy, which specifically includes the following steps:

[0029] S1. Obtain the signal edge position within the waveform period;

[0030] S2. Perform multiple samplings in the adjacent intervals of the signal edge position; and

[0031] S3. Calculate the calibration moment of the signal edge according to the results of multiple samplings.

[0032] In step S1, obtaining the signal edge position within the waveform period specifically includes: searching for the signal edge position within the waveform period by using the bisection method.

[0033] Specifically, the bisection method includes: sampling to obtain the current level value at a preset starting time point within the waveform period; determining the next sampling time point within the remaining time interval according to the level value; repeatedly performing sampling until a level transition is detected to obtain the signal edge position;

[0034] In a specific example, when the waveform period is 200 ns, the bisection method can generally complete the rough positioning of the signal edge within 7 - 8 iterations. Those skilled in the art know that the waveform period can be set according to actual needs, and the waveform period also includes other values besides this embodiment.

[0035] In an embodiment, the signal edge includes a rising edge and a falling edge. When detecting the rising edge, search for the transition from low level to high level; when detecting the falling edge, search for the transition from high level to low level. This two - way detection method enhances the comprehensiveness of the measurement.

[0036] Preferably, determining the next sampling time point within the remaining time interval according to the level value specifically includes: taking the mid - point of the current time interval as the next sampling time point; sampling at the next sampling time point and comparing with the level value at the previous time point; if the level value does not change, taking the remaining time interval as the new search interval and continuing to perform the bisection search. This adaptive search method improves the positioning efficiency.

[0037] In step S2, performing multiple samplings within the adjacent intervals of the signal edge position specifically includes: comparing the signal to be measured with a reference voltage at each sampling moment; determining the logical level value at the current moment according to the comparison result. In a specific example, the reference voltage can be set to 50% of the signal amplitude, and the sampling interval can be set to 10 ps. Those skilled in the art know that the reference voltage and the sampling interval can be adjusted according to actual needs.

[0038] In a specific example, in the data acquisition stage, this embodiment uses the comparator function of the PE chip. Specifically, the comparator compares the logical signal to be measured with the reference voltage and converts it into a digital signal (0 or 1). This conversion method improves the reliability of the digital signal.

[0039] Preferably, determining the logical level value at the current moment according to the comparison result specifically includes: converting the logical signal into a digital signal according to the comparison result, and when all the collected data is 0, determining it as a low level; when all the collected data is 1, determining it as a high level. This digital processing method enhances the reliability of signal processing.

[0040] In step S3, calculating the calibration moment of the signal edge according to the results of multiple samplings specifically includes: determining the start moment and the end moment of the jitter interval according to the results of multiple samplings; averaging the start moment and the end moment of the jitter interval to obtain the calibration moment of the signal edge. This statistical processing method improves the accuracy of moment determination.

[0041] Preferably, determining the start moment and the end moment of the jitter interval according to the results of multiple samplings specifically includes: setting a search range before and after the signal edge position and performing point-by-point scanning; performing multiple measurements on each moment point; when there are different level values (both 0 and 1) in the multiple measurement results, determining it as the signal jitter state (i.e., being in the jitter interval); determining the moment when the signal jitter state first appears as the start moment of the jitter interval, and the moment when the signal jitter state appears last as the end moment of the jitter interval, that is, the start and end moments of the jitter interval are determined by the first and last moments when the level values fluctuate (both 0 and 1) in multiple measurements. In a specific example, the search range can be set to 200 ps before and after each, and each moment point is measured 10 times. Those skilled in the art know that the search range and the number of measurements can be adjusted according to actual needs.

[0042] In this embodiment, before obtaining the signal edge position within the waveform period, it further includes: initializing the sliding window parameters according to the theoretical waveform signal edge moment. This preprocessing method improves the search efficiency.

[0043] Among them, the sliding window parameters include the window interval range and the start sampling moment. Those skilled in the art know that the sliding window parameters can be set according to actual needs.

[0044] In addition, this embodiment further includes: initializing the trie data structure; storing and managing the sampling data of multiple channels in the trie data structure; using the trie data structure for fast access to data to achieve parallel calibration of multiple channels. It is convenient for fast access and search of data, and is especially suitable for data processing during parallel calibration of multiple channels.

[0045] In this embodiment, a 5 MHz square wave signal is selected as the test object, as Figure 3 shown. First, calculate the basic waveform parameters: waveform period T = 1 / f = 1 / (5×10 6 ) = 200 ns. Based on this period, the available interval of the sliding window is set to 0 - 200 ns.

[0046] First, the specific parameter settings in the initialization stage are as follows: 1. Sliding window parameters: The interval range is 0 - 200 ns; the starting sampling time is 80 ns (which can be adjusted according to the rising edge time of the theoretical waveform); the theoretical rising edge position is 100 ns; 2. Initialize the trie structure. For example, the root node is the channel number; the child nodes are the sampling times; the leaf nodes are the level values (0 or 1). This structure facilitates data recording and processing during multi-channel parallel calibration.

[0047] The specific steps of the binary search based on the above parameters are as follows: First sampling: Sampling time: 80 ns; the measured level is 0 (low level); Second sampling: Calculate the new time: (80 + 200) / 2 = 140 ns; the measured level is 1 (high level); Third sampling: Calculate the new time: (80 + 140) / 2 = 110 ns; the measured level is 1 (high level); Fourth sampling: Calculate the new time: (80 + 110) / 2 = 95 ns; the measured level is 0 (low level). Through the above iteration, for example, after about 6 - 7 samplings, the signal edge position can be narrowed down to within ±5 ns.

[0048] After obtaining the rough position, the specific parameters for fine positioning are as follows: 1. Scanning settings: The scanning range extends 200 ps forward and backward; the sampling interval is 10 ps; the number of measurements per point is 10 times; 2. Measurement example (assuming the rough positioning result is 99.95 ns): The scanning interval is 99.75 - 100.15 ns; since the sampling interval is 10 ps, there are 40 sampling points within 400 ps, and each point is measured 10 times, with a total number of measurements of 16000.

[0049] Examples of specific measurement data: At 99.75 ns: All 10 measurements are 0, confirmed as a stable low level. At 99.9 ns: The measurement result is "00110010101001100101", confirmed as the starting time of the jitter interval. At 100.1 ns: All 10 measurements are 1, confirmed as a stable high level, and 100.1 ns is confirmed as the end time of the jitter interval.

[0050] Therefore, the final calibration time is calculated as: tc = (99.9 ns + 100.1 ns) / 2 = 100 ns.

[0051] Through the above method, the measurement error can be controlled within ±0.02 ns. Those skilled in the art know that the above specific values can be appropriately adjusted according to actual application requirements, and this embodiment is only one of the preferred implementation methods.

[0052] In summary, a method for improving AC measurement accuracy proposed by the present invention has the following advantages:

[0053] By obtaining the signal edge position within the waveform period, performing multiple samplings in adjacent intervals of the signal edge position, and finally calculating the calibration moment of the signal edge, the problem of large measurement errors caused by single-point sampling in the prior art is overcome, and the accuracy and reliability of AC measurement are improved.

[0054] In addition, by using the bisection method to quickly locate the signal edge position, combining the sliding window parameter to optimize the search range, and using the trie data structure for multi-channel data management, the measurement efficiency is significantly improved, and efficient multi-channel parallel calibration is achieved.

[0055] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A method for improving AC measurement accuracy, characterized in that: The details include: Get the signal edge position within the waveform period; Performing multiple sampling in adjacent intervals of the signal edge position; The calibration time of the signal edge is calculated based on the results of multiple samplings.

2. The method for improving AC measurement accuracy according to claim 1, characterized in that: The acquiring of the signal edge position within the waveform period specifically includes: searching for the signal edge position within the waveform period using a binary search method; the signal edge includes a rising edge and a falling edge.

3. The method for improving AC measurement accuracy as claimed in claim 2, characterized in that: The binary search method includes: sampling at a preset starting time point within a waveform period to obtain a current level value; determining the next sampling time point within the remaining time interval based on the level value; repeating the sampling until a level jump is detected to obtain the signal edge position; wherein, when detecting a rising edge, searching for a jump from a low level to a high level; and when detecting a falling edge, searching for a jump from a high level to a low level.

4. The method for improving AC measurement accuracy as claimed in claim 3, characterized in that: Determining the next sampling time point within the remaining time interval according to the level value specifically includes: taking the midpoint of the current time interval as the next sampling time point; sampling at the next sampling time point and comparing it with the level value at the previous moment; if the level value does not jump, taking the remaining time interval as a new search interval and continuing to perform binary search.

5. The method for improving AC measurement accuracy according to claim 1, characterized in that: The multiple sampling is performed in the adjacent intervals of the signal edge position, specifically including: at each sampling moment, comparing the signal to be measured with the reference voltage; and determining the logic level value at the current moment according to the comparison result.

6. The method for improving AC measurement accuracy as claimed in claim 5, characterized in that: Determining the logic level value at the current moment according to the comparison result specifically includes: converting the logic signal into a digital signal according to the comparison result, and determining it as a low level when the collected data are all 0s; and determining it as a high level when the collected data are all 1s.

7. The method for improving AC measurement accuracy according to claim 1, characterized in that: The calculation of the signal edge calibration time according to the results of multiple samplings specifically includes: determining the start time and the end time of the jitter interval according to the results of multiple samplings; averaging the start time and the end time of the jitter interval to obtain the signal edge calibration time.

8. The method for improving AC measurement accuracy as claimed in claim 7, characterized in that: The method of determining the start time and end time of the jitter interval based on multiple sampling results specifically includes: setting a search range before and after the signal edge position and performing point-by-point scanning; performing multiple measurements on each time point; when the multiple measurement results have different level values, determining it as a signal jitter state; determining the time when the signal jitter state appears for the first time as the start time of the jitter interval, and determining the time when the signal jitter state appears for the last time as the end time of the jitter interval.

9. The method for improving AC measurement accuracy according to claim 1, characterized in that: Before acquiring the signal edge position within the waveform period, the method further includes: initializing the sliding window parameters according to the theoretical waveform signal edge moment.

10. The method for improving AC measurement accuracy according to claim 1, characterized in that: Also includes: Initializing a dictionary tree data structure; storing and managing multi-channel sampling data in the dictionary tree data structure; The dictionary tree data structure is used to quickly access data to achieve multi-channel parallel calibration.

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