When choosing an oscilloscope, the most important consideration is bandwidth. When should sampling rate be considered?
Depending on the object being measured, and provided the bandwidth is sufficient, it is hoped that the minimum sampling interval (the reciprocal of the sampling rate) can capture the signal details you need. There are some empirical formulas about sampling rate in the industry, but they are basically based on the bandwidth of the oscilloscope. In practical applications, it is best not to use an oscilloscope to measure signals of the same frequency. If you are selecting a model, for sine waves, choose an oscilloscope whose bandwidth is 3 times the frequency of the sine signal being measured. Above that, the sampling rate is 4 to 5 times the bandwidth, which is actually 12 to 15 times the signal. For other waveforms, it is necessary Ensure the sampling rate is sufficient to capture signal details. If you are using an oscilloscope, you can verify whether the sampling rate is sufficient by the following methods: Stop the waveform and zoom in. If you find changes in the waveform (such as certain amplitudes), the sampling rate is not enough, otherwise it is okay. Point display can also be used to analyze whether the sampling rate is sufficient.
What are the applications for glitch/pulse width triggering?
There are generally two typical applications for glitch/pulse width triggering. One is synchronous circuit behavior, such as using it to synchronize serial signals, or for applications with very serious interference that cannot use edge triggering to correctly synchronize signals. Pulse width triggering is an option. ; The other is used to find anomalies in the signal, such as narrow glitches caused by interference or competition. Since the anomaly appears occasionally, it must be captured by glitch triggering (the other method is the peak detection method, but the peak detection method The method may be limited by its maximum sampling rate, and at the same time, it can generally be seen but not measured). If the pulse width of the object under test is 50ns, and there are no problems with the signal, that is, there is no signal distortion or narrower caused by interference, competition, etc., the signal can be synchronized using edge triggering without using glitch triggering. .
