With perfectionist audio, a perfect digital chain is often described as “bit-perfect”. When two player applications are both bit-perfect; there should be no audible difference between them (when the rest of the chain remains unchanged of course). People now realize this is wrong; they hear differences between players such as Amarra, Decibel and Itunes. Actually this observation is not heavily discussed; most people can hear it. So clearly bit-perfect alone is not enough to describe the quality of a digital audio player. When describing a DAC; bit-perfect is not a point of discussion, however another parameter called ‘jitter’ is (check wiki for background on jitter).
Amateur radio (also called ham radio) is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication. The term “amateur” is used to specify persons interested in radio technique solely with a personal aim and without direct pecuniary interest, and to differentiate it from commercial broadcasting, public safety (such as police and fire), or professional two-way radio services (such as maritime, aviation, taxis, etc.). (from wikipedia)