Mask testing adds a feature to the traditional function of an oscilloscope: quickly determining whether an input signal is acceptable. When an unqualified signal is captured, we can stop, take screenshots, etc. This article will introduce the mask test function of the ZDS4000 series oscilloscope, and give an application case.
Template test interface introduction

Figure 1 ZDS4000 series mask test interface In automated testing, the mask test function is very practical, we can define a standard signal, and then set a pass or fail area around the standard signal, and then compare the input signal with the standard signal, you can Judge the pass or fail of the input signal.
Figure 1 is the test interface of the mask test of the ZDS4000 oscilloscope. The gray area around the waveform is the mask touch area, that is, the unqualified area, and the black area is the qualified area. As shown in Figure 2 below, when the waveform touches the template touch area, it will be displayed in red, and it is judged to be an unqualified waveform, that is, "Fail", and the waveform that does not touch the template touch area is "Pass". The information displayed in the upper right corner is some status information during the template testing process.

Figure 2 Template test failure interface Template test setting steps The setting steps of template setting are as follows:
Enter the analysis interface through [Analyze] on the oscilloscope panel, select [Mask Test], and turn on [Function Enable] to the "ON" state;
Select the waveform channel to be tested through the [Channel Source] menu, as shown in Figure 3:

Figure 3 Template test channel settings Enter the template generation interface through [Template Generation]. By adjusting the [Vertical Tolerance] and [Horizontal Tolerance], the size of the template touch area can be changed. After adjusting the template touch area, we can pass the [ Generate] menu can generate a template test area. We can import and export templates through [Template Import] and [Template Export], as shown in Figure 4:

Figure 4. Template generation setting Template test condition setting, that is, when the input waveform touches the template area, the corresponding operation is performed. We can set the stop conditions, whether to take screenshots after touching, sound prompts and other operations, as shown in Figure 5:

Figure 5 Template test condition settings After completing the above settings, we can click [Operation] to start the template pass test, and you can view the status information during the test through the information display menu, as shown in Figure 6:

Figure 6 Mask test status information Mask test application case Customer requirements: test a fluctuating signal of about 5V for a long time. If the input signal fluctuates beyond the range of 4V to 6V, the customer hopes to capture the abnormality through the oscilloscope and save it as a screenshot.
According to customer requirements, we can use the mask test function of the ZDS4000 oscilloscope. We first input a 5V DC signal, and then adjust the [Vertical Tolerance], the upper limit is 6V, and the lower limit is 4V, click to generate a template, as shown in Figure 7 . Then in the template test condition setting, we can set the [Failure Action] to save the screenshot. In this way, the customer's test requirements can be realized.

Figure 7 Summary of case mask area diagram This paper mainly introduces the mask test function of ZDS series oscilloscope, gives detailed setting steps, and gives the specific application of mask test combined with customer cases.