Whitepaper
Evaluating Oscilloscope Bandwidths for Your Application
This application note details how to select an oscilloscope bandwidth appropriate for both digital and analog applications. It contrasts Gaussian and maximally-flat frequency responses, noting that the former allows faster rise times while the latter provides more accurate in-band signal measurement. For digital signals, the paper advocates determining the “knee” frequency (fknee) of fast edges – calculated as 0.5/rise time (10-90%) or 0.4/rise time (20-80%) – and multiplying it by a factor between 1.0 (for 20% accuracy) to 1.9 (for 3% accuracy) to determine required bandwidth. Using a 100MHz clock signal with 500ps rise times as an example, the paper demonstrates how scopes of differing bandwidths (100 MHz, 500 MHz, 1 GHz, and 2 GHz) impact measurement accuracy.