By Greg Tate, Spectrum Sales Manager Asia, and Oliver Rovini, Spectrum Technical Leader
When selecting a digitiser for acquiring electronic signals, the primary specifications considered tend to be sampling rate, bandwidth and resolution. The first two parameters help define the maximum frequency content the digitiser can capture.
For accurate and repeatable measurements, as a general guide users typically try to sample their signal at least ten times faster than its highest frequency content. For example, a 10MHz signal would be sampled at around 100MS/s to ensure the digitised signal has sufficient time resolution to be accurately reproduced. Similarly, to be certain that signals are not being unintentionally attenuated (with amplitude information being lost), users generally aim for the digitiser’s analogue bandwidth to be at least two to five times above their highest signal frequency content. So, depending on the test, measuring a 10MHz signal typically requires a bandwidth of 20-50MHz.