What is the principle that the signal bandwidth of the instrument is much higher than the sampling rate?
The bandwidth of the instrument is 1MHz, and the sampling frequency is 200kHz. If the signal bandwidth is below 100kHz, the sampling theorem is still satisfied. If higher than 100kHz, the built-in anti aliasing filter must be turned on. After the anti aliasing filter is turned on, the bandwidth of the instrument is bound by the aliasing filter, which is actually less than 100kHz.
The sampling frequency limits the bandwidth requirement of the input signal.
The bandwidth of the instrument reflects only the hardware characteristics of the instrument
