Electronically-switched multifrequency generator with transducer control

作者： Dewitt G. Ong , Dale H. Nelson , Joseph J. Nahas , Brian A. Wittman , Paul C. Davis

DOI:

关键词: Telephone line 、 Keypad 、 Electrical engineering 、 Generator (computer programming) 、 Engineering 、 Tone (musical instrument) 、 Solid-state 、 Signal 、 Transducer 、 Electronic engineering 、 Transfer (computing)

摘要: In a multifrequency generator providing tone signaling for telephone, the common switching functions are performed by solid state circuitry (1200). Improved signal transfer between telephone line and transmit receive transducer of is provided arranging solid-state switches (1201, 1401) in gain configuration to increase level speech signal. The signals digitally synthesized use an integrated R-C oscillator (600) as reference. Button down button up debouncing contact closure from single per keypad provided.