when was fm invented
On December 26, 1933, he was awarded four patents for FM radio (The other two were applied for in 1927 and 1930, but weren't for wide-band). He discovered in early 1934 that his invention was almost free of static. Armstrong took a few more years to give FM high fidelity, but by 1938 or 1939 he had improved FM to the point that it was our FM radio, minus the stereo sound.