Lucky joined Bell Labs in 1961, where his initial assignment was in the Data Theory Department under William R Bennett. In 1964 he made his best known invention, the adaptive equalizer, and in the years to follow he was promoted a number of times, becoming in 1982 the executive director of the communications sciences research division. This division comprised essentially all of the Bell Labs research on wireless, optical systems, and other communications systems topics, as well as some of the Bell Labs research on physics and computer science. Two Nobel Prizes were won by researchers in the division. Lucky left Bell Labs in 1992 and joined Bellcore, the research laboratory for the divested Bell Telephone companies, where he was corporate vice president, responsible for management of research. A few years later Bellcore was sold to SAIC and renamed Telcordia Technologies. Robert Lucky retired from Telcordia in 2002.
In the early 1960s the highest speed for modems on telephone lines was 2400 bits per second. Higher speeds were not possible because of intersymbol interference. Each dialed connection would have a different distorting effect on the series of pulses sent to convey digital information, smearing successive pulses and entangling them, resulting in errors in detection. Lucky invented a way to adaptively undo the smearing effects by automatic adjustment of a variable filter, using a tapped delay line with adjustable gains at each tap. The equalizer used a steepest descentalgorithm to minimize distortion. It was initially trained by a series of known pulses, but during actual data transmission it relied upon decision-directed adjustment, which assumed that decisions about pulses were largely correct and could be used for reconstruction of the ongoing error. The first adaptive equalizer, in 1964, used 13 adjustable gains, each set by 8 relays. The rack of equipment was about 5 feet high. Its use immediately made possible data transmission at 9600 bits per second – four times the highest previously attainable speed. Shortly thereafter, the relays were replaced with transistor switches, then in succeeding years the equalizer was implemented with a special purpose integrated circuit. Today adaptive equalization is built into almost every modem and is simply a subroutine in the instruction program for an embedded microprocessor.
He is the author of a textbook, Principles of Data Communications. He wrote a popularized account of information theory in Silicon Dreams. A compilation of his essays was published under the title Lucky Strikes Again. Since 1982 he has written a bi-monthly column, Reflections, in IEEE Spectrum Magazine, which features his essays on technology and engineering culture.
Later career
Since retirement in 2002, Lucky has been a member of the Defense Science Board, chairman of the board of ANSER, Inc., a member of the Laboratory Operations Board of the United States Department of Energy, chairman of Marconi Society, and a member of advisory board of TTI/Vanguard. The governor of New Jersey appointed him to the Authority for the Redevelopment of Fort Monmouth, and he was elected chairman of that Authority.
