Thanks for your support of Rhode Island Radio Website!
Mr Charles D Lindridge was married to Florence Edgette. 3
Because he was deeply interested in the problem of a telephone repeater, Mr. Lindridge passed up the family business of selling musical instruments, and left England in 1906. He got a job in the plant department of New York Telephone Company and in his spare time worked on a repeater. He remembers well seeing, in 1907, Lee DeForest demonstrate his "audion." Transferring in that year to Providence, Mr. Lindridge began making experimental tubes and in 1912 published an article on repeaters in which he noted the phenomenon of feedback. During World War I Mr. Lindridge served in the Signal Corps and was commissioned Second
Lieutenant.
In 1908 Charles D Lindridge is living at 40 Haskins St and working as an engineer at 112 Union St which was the Telephone Building at the time. There is also a Edward Lindridge who is listed as a Telephont operator living at the same address, brother?5
One interesting fact is seen in 1915. Lindridge seems to have been associated with another famous Rhode Island engineer, Harold P Donle. The company name Donle-Lindridge is seen in a 1915 Providence Directory at 632 Industrial Trust Building.
In 19124, 19162, and 19176 Lindridge is listed as a telephone engineer working at 15 Snow St and living at 149 Lenox Ave.
He entered the Laboratories in 1919 and worked nearly a year on repeater development. Following this, he was assigned to carrier telephony, then in the early stages of development. From 1923 to 1925 he was en- gaged on equipment development for toll switchboards, and then joined the group which developed the equipment for carrier systems. He has had a part in the development of radio control terminals, of the Types C, J, N, and O systems, and of carrier pilot channel equipment. During World War II he worked on spiral -four carrier systems, Sonar, and on an important development which is still classified. In retirement, Mr. Lindridge sees a chance to combine two of his interests, by developing electronic musical instruments. He and his wife expect to remain in their home in Montclair. 1
By 1955 an American, Charles D. Lindridge, had already invented the first EXCITER (a unit that EXCITES upper harmonics), when he presented a unit for improving the sound of music and speech. He enriched signal sources with artificially generated upper harmonics and found that both sound quality, transparency and perceived positioning of musical instruments could be considerably improved using this effect. He was granted an American patent on his circuit design under the number US 2,866,849.
Mr Charles D Lindridge was married to Florence Edgette. 
