Editing Superheterodyne receiver (section)

=== Patent battles ===

French engineer [[Lucien Lévy]] filed a patent application for the superheterodyne principle in August 1917 with brevet n° 493660.<ref name="Koster_2016"/> Armstrong also filed his patent in 1917.<ref name="Howarth_2017"/><ref name="luxor"/><ref name="Sarkar_2006"/>  Levy filed his original disclosure about seven months before Armstrong's.<ref name="Klooster_2009"/>
German inventor [[Walter H. Schottky]] also filed a patent in 1918.<ref name="Koster_2016"/>

At first the US recognised Armstrong as the inventor, and his US Patent 1,342,885 was issued on 8 June 1920.<ref name="Klooster_2009"/> After various changes and court hearings Lévy was awarded US patent No 1,734,938 that included seven of the nine claims in Armstrong's application, while the two remaining claims were granted to Alexanderson of GE and Kendall of AT&T.<ref name="Klooster_2009"/>
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