Sampling Front End
A high speed Sample-Hold can extend the bandwidth of the analog inputs to 20 MHz.
Below is the first prototype. It has 1st order passive or 2nd order active reconstruction filters and AC / DC coupling.
This Document explains how it works.
This Schematic shows how it is built.
Here is the final version which operates from a 9 V battery. A 10X input attenuator was added as
well as the 2nd order filters and AC/DC coupling.