How to distinguish between analog bandwidth and digital real-time bandwidth of oscilloscope

Virtual oscilloscopes are becoming increasingly popular due to their unique advantages in waveform triggering, storage, display, measurement, waveform data analysis and processing. Since there is a large performance difference between virtual oscilloscopes and analog oscilloscopes, if used improperly, large measurement errors will occur, thus affecting the test task.

Differentiate between analog bandwidth and digital real-time bandwidth

Bandwidth is one of the most important indicators of an oscilloscope. The bandwidth of an analog oscilloscope is a fixed value, while the bandwidth of a virtual oscilloscope has two types: analog bandwidth and digital real-time bandwidth. The maximum bandwidth that a virtual oscilloscope can achieve for a repetitive signal using sequential sampling or random sampling technology is the digital real-time bandwidth of the oscilloscope. The digital real-time bandwidth is related to the maximum digitization frequency and the waveform reconstruction technology factor K (digital real-time bandwidth = maximum digitization rate/K), and is generally not given directly as an indicator. From the definitions of the two bandwidths, it can be seen that the analog bandwidth is only suitable for the measurement of repetitive periodic signals, while the digital real-time bandwidth is suitable for the measurement of both repetitive signals and single-shot signals. The manufacturer claims that the bandwidth of the oscilloscope can reach so many megabytes, which actually refers to the analog bandwidth, and the digital real-time bandwidth is lower than this value. For example, the bandwidth of TEK's TES520B is 500MHz, which actually means that its analog bandwidth is 500MHz, while the maximum digital real-time bandwidth can only reach 400MHz, which is much lower than the analog bandwidth. Therefore, when measuring a single signal, it is necessary to refer to the digital real-time bandwidth of the virtual oscilloscope, otherwise it will bring unexpected errors to the measurement.