Transponders, Encoders, Codecs?

[jgags6]

Im sorry but I dont really know what these things are, all i know is they have to do with channels and picture quality. Could someone explain. Thanks alot.

 

[BobaBird]

A transponder is a satellite channel (more detailed explanation) that carries one analog video channel. DBS operators send 3 or 4 digital HD channels over a transponder. An encoder translates the source format (analog, MPEG2) into another (MPEG2, MPEG4). These formats are also known as codecs (COde/DECode), or the protocol used to build and read the digitized results.