Robert S Mathes

US Patent:

39912736, Nov 9, 1976

Filed:

Oct 4, 1943

Appl. No.:

2/504899

Inventors:

Robert C. Mathes - Maplewood NJ

Assignee:

Bell Telephone Laboratories, Incorporated - Murray Hill NJ

International Classification:

H04K 104

US Classification:

179 15FS

Abstract:

1. In a secret telephone transmission system in which speech waves are analyzed into component speech-defining low frequency signals which are coded in stepped wave form, a group of frequency modulators of the same type and same average frequency, means to impress said signals of stepped wave form on the respective frequency modulators to produce a plurality of frequency modulated waves of the same average frequency, and means to translate said last waves into frequency modulated waves accurately positioned at different frequency levels comprising a separate amplitude modulator for shifting the frequency of each such frequency modulated wave, and means to supply to said amplitude modulators carrier waves of accurately spaced frequency comprising a source of base frequency waves of highly constant frequency and a harmonic generator for fixing the frequencies of said supplied carrier waves.