Background

Edwin Howard Armstrong was born on December 18, 1890, in Chelsea, Manhattan, New York, and was the oldest of John and Emily (Smith) Armstrong's three children. Armstrong’s father was a publisher who became vice-president in charge of the American branch of Oxford University Press; his mother graduated from Hunter College and taught for ten years in New York public schools before her marriage in 1888.

Education

When Armstrong was twelve, the family moved to Yonkers, New York, where he attended high school and became interested in radiotelegraphy. He entered Columbia University at nineteen and studied electrical engineering under Michael Idvorsky Fie.

Career

While still an undergraduate, Armstrong made the first of his many inventions, one of four that proved to be particularly significant: the triode feedback (regenerative) circuit. That invention, and the negative-bias grid circuit invented by Frederick Lowenstein, ultimately led to wide utilization of the as yet little-exploited triode (invented in 1906 by Lee De Forest), but Armstrong became embroiled in patent litigation and received only modest royalties.

Armstrong remained at Columbia for the rest of his life, serving as research assistant to Michael Pupin and, on the latter's death in 1934, as professor of electrical engineering. He had one of those turbulent careers typical of so many inventors, especially those working in new and rapidly developing industries. Driven by a thirst for historical vindication and love of legal combat, perhaps more than by the desire for money, inventors have plagued each other's lives to a remarkable degree.

Armstrong took out his first patent before he finished college in 1913, and patents and disputes over them always seem to have occupied an inordinate amount of his time and effort. His early and long association with Professor Pupin gave Armstrong direct access to one of the best and most fertile minds in the electrical field. Armstrong's academic base also kept him free of connection with any of the many companies then vying for dominance in the radio field; he was one of the few men to successfully maintain such independence.

In 1917, after serving as an assistant at Columbia for some years, Armstrong became a U.S. Army Signal Corps officer when the United States entered World War I. He was sent to France and while there developed his second important invention, the superheterodyne circuit, an improvement on the heterodyne circuit that was invented in 1905 by Reginald Aubrey Fessenden. In the heterodyne circuit, the received signal is mixed with a locally generated signal to produce an audible “beat” note at a frequency equal to the difference between those of the two signals; Armstrong’s method, which greatly improved the sensitivity and stability of radio receivers, extended the technique to much higher frequencies and shifted the beat note above the audible range.

Upon returning to America, Armstrong was once again beset by patent interference proceedings, although his personal fortunes took a turn for the better: he sold his feedback and superheterodyne patents to Westinghouse Electric & Manufacturing Company (retaining royalty-earning licensing rights for the use of amateurs); he resumed his position at Columbia University.

In 1921 Armstrong made his third important discovery, super regeneration - a method of overcoming the regenerative receiver’s principal limitation, the tendency to burst into oscillations just as the point of maximum amplification was reached. RCA purchased the patent, but it did not yield the company much in royalties since it was unsuited for broadcast receivers; it did not come into its own until special applications were developed many years later. However, RCA profited greatly from the “superhet,” to which it had acquired the rights through a cross-license with Westinghouse. Armstrong found himself a millionaire.

The next decade of his life was marred by the long battle with De Forest over the feedback patents. The case was taken to the U.S. Supreme Court but Armstrong lost on a legal technicality. Before that decision had been handed down, however, Armstrong had completed and patented his greatest invention, frequency modulation (FM). Once again he was beset by difficulties: the U.S. radio industry resisted the introduction of FM broadcasting, FM production was interrupted when the United States entered World War II, and the Federal Communications Commission dealt FM a stunning blow in 1945 when it relegated it to a new frequency band and put restrictions on transmitter power, thus making over fifty existing transmitters and half a million receivers obsolete. At the same time, FM came to be widely used in military and other mobile communications, radar, telemetering, and the audio portion of television; but widespread adoption of FM broadcasting came only after Armstrong’s death.

Exhausted by a five-year suit for patent infringement against RCA and almost destitute as his FM patents began to expire, Armstrong committed suicide and died on February 1, 1954 at the aged of 63 in Manhattan, New York City, New York. Armstrong was buried in Locust Grove Cemetery, Merrimac, Massachusetts.

Achievements

• 

  No inventor contributed more profoundly to the art of electronic communication as Edwin Armstrong. He is one of the two dozen honored in the Pantheon of the International Telecommunications Union in Geneva.
  
  Armstrong's first important contribution was his realization of the value of Lee De Forest's audion vacuum tube as a means of amplifying current. To Armstrong this realization appeared to rank alongside the invention of the audion itself. Armstrong's second contribution was the feedback circuit, another means of amplifying current, which he (and others independently) worked out in 1912. He also discovered that the audion could be used to generate high-frequency oscillations; again, there were several contemporary claims to this discovery. While serving as a signal officer in World War I, Armstrong developed in 1918 the superheterodyne circuit, in which incoming high-frequency signals were beaten against low-frequency signals from a local oscillator so that they could be detected.
  
  In 1921 Armstrong made his third important discovery, super regeneration—a method of overcoming the regenerative receiver’s principal limitation, the tendency to burst into oscillations just as the point of maximum amplification was reached. His last great contribution was frequency modulation (FM), a method of overcoming static in broadcasting, on which he worked from 1924 to 1933 in the face of indifference and even hostility from large manufacturers and broadcasters.
  
  Armstrong had received many honors, including the highest awards of the two U.S. electrical engineering societies, the American Institute of Electrical Engineers (Edison Medal, 1942) and the Institute of Radio Engineers (Medal of Honor, 1918, reaffirmed in 1934 when he tried to return it after losing the legal fight against De Forest); the Franklin Medal (1941); and, for his war work, the U.S. Medal for Merit (1945).
  
  He was inducted into the National Inventors Hall of Fame and included in the International Telecommunication Union's roster of great inventors. In recognition of his work, the Radio Club of America established an annual award, the Armstrong Medal.

Works

• book

  • The Legacies of Edwin Howard Armstrong.

Politics

Politically, he was described by one of his associates as "a revolutionist only in technology — in politics he was one of the most conservative of men".

Views

Quotations: "Men substitute words for reality and then argue about the words."

"Not only did he teach by accomplishment, but he taught by the inspiration of a marvelous imagination that refused to accept the permanence of what appeared to others to be insuperable difficulties: an imagination of the goals of which, in a number of instances, are still in the realms of speculation."

"I could never accept findings based almost exclusively on mathematics. It ain't ignorance that causes all the trouble in this world. It's the things people know that ain't so."

"Anyone who has had actual contact with the making of the inventions that built the radio art knows that these inventions have been the product of experiment and work based on physical reasoning, rather than on the mathematicians' calculations and formulae. Precisely the opposite impression is obtained from many of our present day text books and publications."

"The world, I think, will wait a long time for Nikola Tesla's equal in achievement and imagination."

Membership

While studying at Columbia University in New York City, Armstrong became a member of the Epsilon Chapter of the Theta Xi engineering fraternity.

Personality

Physical Characteristics: At the age of eight, Armstrong contracted Sydenham's chorea (then known as St. Vitus' Dance), an infrequent but serious neurological disorder precipitated by rheumatic fever. For the rest of his life, Armstrong was afflicted with a physical tic exacerbated by excitement or stress.

Interests

• Armstrong was an avid tennis player until an injury in 1940, and drank an Old Fashioned with dinner.

Connections

In 1923 Edwin Armstrong married Marion MacInnis, secretary to David Sarnoff, then general manager of the Radio Corporation of America. In 1955, Marion Armstrong founded the Armstrong Memorial Research Foundation, and participated in its work until her death in 1979 at the age of 81.

Father:

John Armstrong

Mother:

Emily (Smith) Armstrong

Spouse:

Marion MacInnis

teacher:

Mihajlo Idvorski Pupin

Armstrong studied (and later worked) under Professor Michael Pupin at the Hartley Laboratories, a separate research unit at Columbia.

References

• Man of High Fidelity: Edwin Howard Armstrong.
• The Legacies of Edwin Howard Armstrong.