
Primary Source
Edwin H. Armstrong, of Paris, France Method of Receiving High-Frequency Oscillations Patent # 1,342,885 Application filed Feb. 8, 1919 – Patented June 8, 1920
Radio Inquiry Unit
Radio Inquiry Unit While serving in the U.S. Army during World War I, Armstrong synthesized three ideas to create his superheterodyne circuit for selectively amplifying a very high fr…
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