What is the relationship between the bandwidth of an oscilloscope and the sampling rate?
Bandwidth reflects the frequency passing ability of a signal. The larger the bandwidth, the more accurately and effectively the various frequency components (especially high-frequency components) in the signal can be amplified and displayed. If the bandwidth is not enough, a lot of high-frequency components will be lost. If there is no frequency component, the signal will naturally be displayed inaccurately and a large error will occur. The sampling rate is the frequency of signal conversion when converting analog quantities to digital quantities (that is, the number of acquisitions per second). The higher the frequency, the more signals are collected per unit time, and the more information in the signal is retained. The less information is lost, the converted digital quantity can accurately reflect the value of the signal, and then the LCD display can display the signal waveform more accurately and completely. The more sampling points, the more points will be displayed, and the clearer it will be.
There are at least two parts to a digital oscilloscope: the Y channel of the signal under test and the sampling part. The Y channel amplifies (or attenuates) the signal being measured, and the bandwidth is for the Y channel. If the Y channel can amplify all sinusoidal signals in the range of 0~10MHz uniformly without distortion, then its bandwidth is 10MHz. Since complex waveform signals are composed of sinusoidal signals with various harmonics, and the bandwidth composed of these harmonics may be very wide, so in order to ensure that complex signals are truly amplified, the larger the bandwidth of your Y channel, the better.
Just having a Y channel with sufficient bandwidth is not enough. In order to capture the waveform, you have to sample the signal amplified by the Y channel! The speed of this sampling is the sampling rate. The faster the sampling rate, the more points of the complex waveform are captured per unit time, and the final assembled and displayed waveform is closer to the real complex signal.
Therefore, although bandwidth and sampling rate are two different parameters, they are both very important for truly restoring the measured waveform.
