1888 – 1970
Ralph Vinton Lyon Hartley was an American electronics researcher whose foundational work on information transmission preceded and influenced Claude Shannon's information theory. He formulated Hartley's law quantifying the maximum information rate of a communication channel and developed early frameworks for measuring information mathematically.
Formulated Hartley's law relating information content to the logarithm of distinguishable symbols
Introduced the 'hartley' as a unit of information (log base 10)
Invented the Hartley oscillator in 1915
Developed the Hartley transform, a real-valued alternative to the Fourier transform
Laid conceptual groundwork later formalized by Shannon's information theory