A method for testing performance of an oscilloscope through a LabVIEW software platform

Abstract

The present application relates to the field of electronic information technology, and relates to a method for testing performance of an oscilloscope through a LabVIEW software platform, which utilizes a signal generator to generate a Lissajous signal, utilizes a digital oscilloscope to receive two signals with fixed frequency ratio and phase difference generated by the signal generator, then fits the two signals to generate a Lissajous figure, collects data by means of a LabVIEW software platform designed automatic acquisition program, and generates a clear Lissajous figure observable in details by using Orign drawing software. In this process, only the noise interference of the oscilloscope itself will affect the curve smoothness of the final Lissajous figure, so the final result can reflect the performance of the oscilloscope to a certain extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic information technology, in particular to a method for testing performance of an oscilloscope through a LabVIEW software platform. BACKGROUND

[0002] An oscilloscope is a widely used electronic measuring instrument. It can transform invisible electrical signals into visible images, which is convenient for people to study the change process of various electrical phenomena. In the process of using the oscilloscope, the oscilloscope data is distorted to varying degrees due to internal noise and other reasons. In order to ensure the accuracy of the oscilloscope data, the performance of the oscilloscope needs to be detected. The common repair method is to test and repair the possible fault parts according to the working principle of the oscilloscope and the distortion phenomenon. In order to ensure the accuracy of the oscilloscope data, the most effective method at present is to calibrate the oscilloscope before starting to collect data.

[0003] The oscilloscope is usually calibrated by using the probe calibration method. DC calibration is the most commonly used calibration method for the oscilloscope. The output of the comparison calibration signal (standard DC voltage) is compared with the actual test voltage of the calibration signal of the oscilloscope, which is used to correct the gain and bias deviation of the probe test DC voltage. The DC calibration process is to determine the values of the linear equation y = mx + b coefficients m and b.

[0004] DC calibration is a method for calibrating the oscilloscope by comparing the calibration signal, so as to ensure the accuracy of the oscilloscope data. The DC calibration of the probe needs to be performed at least once a year, and more frequently, it needs to be performed several months or even several days. However, the DC calibration has high requirements for the calibration signal, needs a standard DC voltage, and the calibration principle and operation are relatively complex. SUMMARY

[0005] The present application provides a method for testing performance of an oscilloscope through a LabVIEW software platform, which can overcome some or some defects of the prior art.

[0006] According to the method for testing performance of an oscilloscope through a LabVIEW software platform, the following steps are included:

[0007] Step 1: a blank vi file is newly created in LabVIEW;

[0008] Step 2: a VISA function is set in the program block panel of the blank vi file;

[0009] Step 3: the added VISA function is functionally connected;

[0010] Step 4: data reading of CH1 and CH2, adding related controls and connecting; the data format of reading data is data header + waveform data; all corresponding string data are converted into array form output through string to byte array conversion;

[0011] Step 5: creating XY graph; converting the data of CH1 and CH2 to dynamic data to create XY graph;

[0012] Step 6: connecting the output terminal of the signal generator with CH1 and CH2 of the analog channel input area of the digital oscilloscope in sequence through the USB data line;

[0013] Step 7: connecting the USB DEVICE of the digital oscilloscope with the USB data interface of the computer through the USB data line;

[0014] Step 8: powering on the signal generator and setting the output as a sine wave with frequency ratio and phase difference;

[0015] Step 9: powering on the digital oscilloscope and setting the display as the synthesized waveform of the analog data of channels CH1 and CH2;

[0016] Step 10: running the labVIEW control program written, automatically collecting oscilloscope data and saving test data;

[0017] Step 11: sending the data into the software Origin to generate Lissajous figure;

[0018] Step 12: observing the smoothness of the Lissajous figure obtained by data collection, and comparing and analyzing the experimental figure and the theoretical Lissajous figure generated by the signal generator to judge the accuracy of the oscilloscope data collection.

[0019] As preferred, in step 2, the VISA function includes two VISA writes, two VISA reads, one VISA open and one VISA close function.

[0020] As preferred, in step 3, a textbox is added in the write buffer of the VISA write control and corresponding content is written, and the length of the read waveform data is less than 2048 total bytes; a USB interface is added before the VISA open function.

[0021] The beneficial effects of the present application are as follows:

[0022] After the data acquisition is completed, on the vi front panel, click Save Data to save the Lissajous figure data collected by the oscilloscope as a data file, and use Origin software to draw the Lissajous figure data into a high-precision Lissajous figure, so that various details of the figure can be clearly observed. For the obtained Lissajous figure, it can be observed that the collected Lissajous figure is not smooth enough, and the theoretical figure should be a smooth curve. The reason for this phenomenon is that there is noise in the oscilloscope, and the noise causes distortion of the final figure during data collection. By this method, the distortion points of the obtained Lissajous figure curve can be analyzed to more clearly judge the performance of the oscilloscope in collecting data. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A flowchart of the method for testing the performance of the oscilloscope through the LabVIEW software platform in the embodiment;

[0024] Figure 2 A program diagram of VISA in the embodiment;

[0025] Figure 3 A data reading program diagram in the embodiment;

[0026] Figure 4 A schematic diagram of creating an XY graph in the embodiment;

[0027] Figure 5 A program diagram of reading CH1 and CH2 in the embodiment. DETAILED DESCRIPTION

[0028] For a further understanding of the present application, reference will be made to the following description taken in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments are merely illustrative of the present application and are not limiting.

[0029] EMBODIMENT

[0030] As shown in the Figure 1 , the embodiment provides a method for testing the performance of an oscilloscope through a LabVIEW software platform, which comprises the following steps:

[0031] Step 1: Turn on the computer, open the LabVIEW software, and create a blank vi file in LabVIEW (LabVIEW 2015);

[0032] Step 2: Set the VISA function in the program block diagram panel of the blank vi file; including two VISA write, two VISA read, one VISA open, and one VISA close function;

[0033] Step 3: Functionally connect the added VISA function; add a textbox in the write buffer of the VISA write control and write the corresponding content, and the length of the read waveform data is less than 2048 total bytes; add a USB interface before the VISA open function (e.g. Figure 2 The program diagram of VISA is shown in the figure);

[0034] Step 4: Data reading of CH1 and CH2, adding related controls and connecting (the steps are the same as above); the data format of reading data is data header + waveform data; convert all corresponding string data into array form by string to byte array conversion, then the corresponding waveform data can be seen on the waveform chart control (note that when writing the program, the total number of bytes in VISA reading must be greater than the number of bytes of waveform data, 2048>1400) (e.g. Figure 3 The data reading program diagram is shown in the figure);

[0035] Step 5: Create XY chart; convert the data of CHI and CH2 to dynamic data, create XY chart, and through the XY chart, the Lissajous figure under different frequencies and phase difference conditions can be more intuitively observed (e.g. Figure 4 The creation of XY chart is shown in the figure);

[0036] Step 6: Connect the output terminal of the signal generator and the CH1 and CH2 order of the analog channel input area of the digital oscilloscope through the USB data line;

[0037] Step 7: Connect the USB DEVICE of the digital oscilloscope and the USB data interface of the computer through the USB data line;

[0038] Step 8: Power on the signal generator and set the output to a sine wave with frequency ratio and phase difference;

[0039] Step 9: Power on the digital oscilloscope and set the display to the combined waveform of channel CH1 and CH2 analog data;

[0040] Step 10: Run the labVIEW control program written, automatically collect oscilloscope data, and save the test data;

[0041] Step 11: For the convenience of observing details, send the data into the software Origin to generate Lissajous figure;

[0042] Step 12: Observe the smoothness of the Lissajous figure obtained by data acquisition, and compare and analyze the experimental figure and the theoretical Lissajous figure generated by the signal generator to judge the accuracy of the oscilloscope data acquisition.

[0043] In summary, according to the idea of the present embodiment, an automatic acquisition program is designed by using LabVIEW software, data is collected by means of an oscilloscope, and the smoothness of the collected Lissajous figure is observed, so as to analyze the performance of the oscilloscope. The specific implementation can be divided into the following steps:

[0044] I. The program for reading CH1 and CH2 of MSO2302A digital oscilloscope is completed on the LabVIEW software platform. The specific program diagram is shown in Figure 5

[0045] II. The signal generator and the oscilloscope are connected by a USB data line, and the oscilloscope and the computer are connected, and relevant debugging is performed. This includes setting the signal generator to generate two sinusoidal signals with a set frequency ratio and a fixed phase difference, setting the channel selection of the oscilloscope to CH1 and CH2, so as to synthesize the Lissajous figure.

[0046] III. The "Run" button in the vi front panel of the LabVIEW software platform is clicked, and after the Lissajous figure is observed in the "XY graph" in the vi front panel, the data is exported, and the exported data is sent to the Orign software for processing to obtain a Lissajous figure.

[0047] IV. The smoothness of the curve in the Lissajous figure is observed, so as to analyze the size of the noise of the oscilloscope itself affecting the collected data, and further analyze the performance of the oscilloscope.

[0048] Feasibility analysis: This method uses the AFG-2225 signal generator to generate Lissajous signals, uses the MSO2000A / DS2000A series digital oscilloscope to receive two signals with fixed frequency ratio and phase difference generated by the signal generator, then fits them to generate a Lissajous figure, uses the LabVIEW software platform to design an automatic acquisition program to collect data, and uses the Orign drawing software to generate a clear Lissajous figure. In this process, only the noise of the oscilloscope itself will affect the smoothness of the curve of the final Lissajous figure, so the final result can reflect the performance of the oscilloscope to a certain extent.

[0049] By using this method, the performance of an oscilloscope can be analyzed only by using common signal generators and computers in the laboratory, and the requirements for the operating environment are small. The results can also be more intuitive and explicit to reflect whether the oscilloscope is disturbed by its own noise during data collection, so as to analyze the performance of the oscilloscope. The operation is simple, easy to understand, the results are accurate, and the degree of automation is high.

[0050] ​The above describes the present application and its embodiments in a schematic manner, and the description is not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the present application, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by the above, without departing from the spirit of the present application, similar structural modes and embodiments can be designed without creativity, and all of them shall belong to the protection scope of the present application.

Claims

1. A method for testing oscilloscope performance using the LabVIEW software platform, characterized in that: Includes the following steps: Step 1: Create a new blank .vi file in LabVIEW; Step 2: Set the VISA function in the block diagram panel of the blank vi file; The VISA functions include two VISA write functions, two VISA read functions, one VISA open function, and one VISA close function. Step 3: Connect the added VISA functions; Step 4: Read data from CH1 and CH2, add relevant controls and connections; read data in header + waveform format; convert all corresponding string data into array format for output through string to byte array conversion; Step 5: Create an XY plot; convert the CHI and CH2 data to dynamic data and create an XY plot; Step 6: Connect the output terminals of the signal generator to CH1 and CH2 of the analog channel input area of ​​the digital oscilloscope in sequence using a USB data cable; Step 7: Connect the digital oscilloscope's USB device to the computer's USB data interface using a USB data cable; Step 8: Power on the signal generator and set the output to a sine wave with frequency ratio and phase difference; Step 9: Power on the digital oscilloscope and set the display to show the synthesized waveform of analog data from channels CH1 and CH2; Step 10: Run the pre-written LabVIEW control program to automatically acquire oscilloscope data and save the test data; Step 11: Input the data into the software Origin to generate Lissajous figures; Step 12: Observe the smoothness of the Lissajous figures obtained from the data acquisition, and compare and analyze the degree of agreement between the experimental figures and the theoretical Lissajous figures generated by the signal generator to judge the accuracy of the data acquired by the oscilloscope. In step 3, add a text box to the write buffer of the VISA write control and write the corresponding content. The total number of bytes of the waveform data read is less than 2048. Add a USB interface before the VISA open function.

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