Edwin Howard Armstrong (1890-1954) is the largely unsung electrical
engineer and inventor of three of the basic electronic circuits underlying all
modern radio, radar, and television. Upon graduating from high school, Armstrong
began to commute by motorcycle to Columbia University's school of engineering.
In the summer of 1912, while a junior at Columbia, he made his first major
invention: a new regenerative circuit in which part of the current at the plate
was fed back to the grid to strengthen incoming signals. This single circuit
yielded not only the first radio amplifier but also the key to the
continuous-wave transmitter that is still at the heart of all radio operations.
Armstrong received his engineering degree in 1913, filed for a patent, and
returned to Columbia as an instructor and as assistant to the professor and
inventor, Michael Pupin.
During World War I, Armstrong was commissioned a Captain and sent to Paris.
While working under his direction in the Paris laboratory of the U.S. Signal
Corps, Corporal Harold M. Lewis kept this notebook in which he recorded the
invention of Armstrong's superheterodyne circuit, the basis for most radio,
television and radar receivers. On August 13, 1918, Armstrong first explained to
Lewis his new short wave amplification system; the complete circuit designs and
the first working model were finished between August 14 and September 3, 1918.
Thus, Armstrong had created a circuit capable of handling radio signals at much
higher frequencies than were then possible. Lewis went on to a career in radio
engineering and patented nearly sixty inventions of his own. Upon the success of
early radio broadcasting after the war, Armstrong became a millionaire, but
continued at Columbia University as a professor and eventual successor to Pupin.
In 1941 he was given the highest honor in U.S. science, the Franklin Medal.
In 1933, Armstrong brought forth a wide-band frequency modulation (FM)
system that in field tests gave clear reception through the most violent storms
and, as a dividend, offered the highest fidelity sound yet heard in radio. But
in the depressed 1930s the major radio industry was in no mood to take on a new
system requiring basic changes in both transmitters and receivers. Armstrong
found himself blocked on almost every side. It took him until 1940 to get a
permit for the first FM station, erected at his own expense, on the Hudson River
Palisades at Alpine, N.J. It would be another two years before the Federal
Communications Commission granted him a few frequency allocations. Armstrong
spent the rest of his life fighting infringements on his patents. Drained of
resources and exhausted, Armstrong committed suicide on January 31, 1954. His
estate eventually won $10,000,000 from multiple corporations in patent
infringement actions. The Armstrong Papers were given to Columbia in 1977 by the
Armstrong Memorial Research Foundation.