The FPGA.  The chip that makes Software Defined Radio possible. 

FPGA Chip

When I became interested in the Flex 6300 a couple of years ago, I knew nothing about the FPGA concept. (And as I am not an Engineer or a Computer Science major). I still know little. That said, I went in search of a tutorial that would serve as an introduction to the FPGA and an explanation as to why it has opened up this new world in Ham radio.  I’m an “appliance operator.  I never understood all of the Mixers/Oscillators/Roofing filters that make up the Super-Heterodyne architecture.  But hey! I could read a block diagram!  There are many videos out there.  No one video is perfect for the Ham Op, but  I found this one very useful. Maybe you will too? Try it!