Top, Base and Amplitude Top and Base are measures of the high and low levels of a signal, excluding any noise or ringing present on those levels. These differ from the Maximum and Minimum which do include any noise or ringing on those levels. Amplitude measures the difference in the Top and Base measurements, giving you the total magnitude or strength of the electronic signal. In this case it is calculated as Top - Base. More information on Top, Base & Amplitude - Measurement and Math Channels >>