Understanding the impact of digitizer noise on oscilloscope measurements

摘要

One of the most common sources of errors in measurements is the presence of vertical noise, which can decrease the accuracy of signal measurement and lead to such problems as inaccurate measurements as frequencies change. You can use ENOB (effective-number-of-bits) testing to more accurately evaluate the performance of digitizing systems, including oscilloscopes. The ENOB figure summarizes the noise and frequency response of a system. Resolution typically degrades significantly as frequency increases, so ENOB versus frequency is a useful specification. Unfortunately, when an ENOB specification is provided, it is often at just one or two points rather than across all frequencies.