“…The key pieces of information theory needed to do this were published by Claude Shannon in 1948 ( 12 ) and 1949 ( 27 ). Then, in 1959 Pierce and Cutler used information theory to define an efficiency measure for satellite communications ( 28 , 29 ),
where P /N is the `signal-to-noise ratio', the power P dissipated at the receiver in joules per second, versus the thermal noise power N interfering with the signal there. This formula was derived from Claude Shannon's famous channel capacity equation,
in which the bandwidth W defines the range of frequencies used in the communications as, for example, by a radio station ( 12 , 13 , 27 ).…”