## { s(Q|X) = -K SUM(p*ln(p)) }: "Symbols, Signals and Noise" by J. R. Pierce

(Original Review, 1980-12-05)

Final answer to question, "How many joules to send a bit?"

The unit of information is determined by the choice of the arbitrary scale factor K in Shannon's entropy formula:

{ s(Q|X) = -K SUM(p*ln(p)) }

If K is made equal to 1/ln(2), then S is said to be measured in "bits" of information.

If you're into stuff like this, you can read the full review.