The innovative Digital Guitar Research technology uses digital electronics to control string vibrations and create unique performance characteristics.  This patented process allows a solid body guitar to behave like a fine acoustic instrument. The patented system can also emulate a different solid body electric guitar.  It can also create unlimited sustain by injecting a controlled amount of energy back into the strings. 

To do all this, the Digital Guitar Research system senses the vibrating string forces acting on the guitar body, and then generates reactive forces pushing back on the strings - just as a real acoustic instrument body would react to these same forces.  The result is a virtual instrument which can emulate different types of real instruments.  It also allows the player to create completely new and unique virtual instruments with playing characteristics that have never been realized before.

The details of how this is done are described in US Patent 7,453,040.  The link to the US Patent office site is www.uspto.gov