Harold Stephen Black
Born Apr 14 1898 - Died Dec 11 1983
Wave Translation System
Negative Feedback Amplifier
Patent Number(s) 2,102,671
Research engineer Harold S. Black revolutionized telecommunications by inventing systems that eliminated feedback distortion in telephone calls. The major task confronting the lab at that time was elimination of distortion. After six years of persistence, Black conceived the principles and equations for his negative feedback amplifier in a flash commuting to work aboard the ferry. Basically, the concept involved feeding systems output back to the input as a method of system control.
Negative feedback had wider applications than transcontinental and transAtlantic telecommunications, including industrial, military, and consumer electronics, weaponry, analog computers, and such biomechanical devices as pacemakers.
Born in Leominster, Massachusetts, Black graduated from Worcester Polytechnic Institute in 1921; years later he received an honorary doctorate in engineering from Worcester Tech. Following graduation Black joined Western Electric's West Street Labs, the forerunner of Bell Telephone Laboratories, in New York City. Black worked on a negative feedback system to aid the blind and deaf from 1966 until his death.