He was the 3rd most prolific inventor in the history of America after Edison and Thompson. Ernst F. W. Alexanderson was granted a total of 344 patents, a truly incredible number. More here.He was born in Upsaala, Sweden in 1878. His parents were educated, a judge and a professor, it was clear that he would be educated but not how great his contributions would be. He studied electrical engineering at the Royal Institute of Technology and the Technical University in Berlin. It was there that he read a book titled class Alternating Current Phenomena written by Dr. Charles Steinmetz. He was so enamored of the book that he went to the US to meet Steinmetz at GE. You can read the book here.
Steinmetz got him a job in the lab at GE in 1902. It was at General Electric that he began his prolific inventing streak which included the Alexanderson Alternator. It was the Alexanderson Alternator that made brodacasting at higher frequencies possible.
back then the latest and greatest was the spark gap transmitter. These had limitations. they generated a carrier wave, but one at too low frequency to carry much data. Most of them werelimited to about 60 Hertz. None other than Reginald Fessenden came to GE in 1904 and asked for one that could generate a wave at a frequency of 100,000 Hertz.
Two years later Alexanderson had constructed a 2 kW, 100 kHz alternator. It's the one that Fessenden installed at Brant Rock, MA. Gugliemo Marconi bought two of them for his station in New Jersey. This was the Rolls Royce of it's day.In 1932 General Electric Company and RCA seperated. Alexanderson divided his time between the two branches as a consultant and refocused on Television. He continued to be a pioneer. He oversaw the construction of powerful radio stations in Sweeden, Long island and Hawaii He invented several more critical components for television, directional broadcasts, microwave, radar... the list goes on. Later in life he became an engineer for NBC working out of WGY.
He was elected to the Royal Academy of Science in Sweden, received the Medal of Honor from the IRE in 1919, Knighthood in Poland in 1924, The Edison Medal from the American IEE in 1944, the Royal Danish Medal in 1946, and in 1983 he was inducted into the Inventors Hall of fame. More here.