Oversampling - What is oversampling good for?
It increases the sampling frequency for a perfect vibration graph.
When we plot a signal, we take samples of the signal at a certain sampling frequency. Choosing a Band fmax value gives us a sampling frequency 2.5x higher than the Band fmax value. But if the frequency of the measured signal is close to the Band fmax value, we only get two and a half samples per period.
In this case, the sampling frequency is too low and we get a graph that does not look like the measured signal at all. This is why we use oversampling. We increase the sampling frequency without changing the Band fmax value. A higher sampling frequency allows us to take more samples from a period of the measured signal. This gives us a better looking graph. We could increase the Band fmax value itself, which also increases the sampling frequency. However, the measured signal may contain higher frequencies which we do not want to see in the graph. Increasing the Band fmax value would show these high frequencies in the graph, because they would be below the new Band fmax value.