Another innovation during the 1930s was the introduction of a competing transmission technology, "wide-band frequency modulation" (FM), which was developed in the United States by Edwin Howard Armstrong. This was promoted as being superior to AM transmissions, in particular due to its high-fidelity and near immunity to static interference. On June 17, 1936 Armstrong formally demonstrated his FM system to the FCC. Doolittle was impressed with FM's potential, and in early 1939 announced plans to convert the Meriden experimental high frequency station, now operating under the call sign W1XPW, into an FM broadcasting station.