Oscilloscope Practice Special 2: Afterglow Time

　　In the last issue, we shared the infinite persistence function of the ZDS2022 oscilloscope. The one-click infinite persistence function makes it easier than ever to measure noise and jitter, capture incidental events, and more. With this function, we can get better waveform observation results, and observe waveform anomalies and details more comprehensively. Then the question is, when capturing waveforms at a high refresh rate, the infinite persistence mode may accumulate many abnormal waveforms, which overlap, making it difficult for us to observe specific anomalies in a targeted manner.

　　What should we do when we encounter this problem? In fact, we can solve our concerns by setting the persistence time.

　　The ZDS2022 oscilloscope defines the function of "setting persistence time" in the [Display] menu. The persistence time can be set to ten modes: off, 100ms, 200ms, etc.

　　Here we will share some knowledge about persistence display. In an oscilloscope, the waveform on each screen is composed of the superposition of several frames of waveforms.

　　Assuming that the total capture time of each screen waveform is 50ms, when we set the persistence time to 200ms, the final result displayed on the screen is the result of the superposition of the 4-screen waveform traces, and the superimposed 4-screen waveforms are dynamically refreshed in real time. On the other hand, in infinite persistence mode, the screen displays the result of the superposition of the historical waveforms from the beginning to the current.

　　On the ZDS2022 oscilloscope, we can control the duration of the afterglow display, which makes the waveform observation more purposeful and avoids the problems caused by afterglow accumulation, bringing great convenience and flexibility to the test and measurement work.