Some General Notes on Design Schematic

        Here you will find a list of every schematic block and some comments on it.  Remember this design has incorporated many extra features not necessary to the basic operation of an ECM.  Generally you will find extra I/O for items that we didn't originally think of.  Also you may notice that there are extra buffers and resistors.  These are generally used for easy gain manipulation if needed later.  Many of the resistors associated with these stages are through hole for ease of modification.  Not that SMT parts are all that difficult to deal with, but for one thing these old eyes of mine sure appreciate the little larger components.