Bandwidth

Bandwidth describes the difference between limiting frequencies within which the input signal can pass through the system with minimal amplitude loss — from the input at the tip of the probe or test fixture to the output data. The limiting frequencies that determine the bandwidth include both a high and a low frequency that are specified as the frequency (in Hz) at which a sinusoidal input signal is attenuated to 70.7% of its original amplitude. This point is known as the -3  dB point.

The following figure shows the four main areas that can affect the bandwidth of a digitizer.

1. Outside world to probe
2. Probe to input connector
3. Input connector to ADC
4. ADC to software