| Since the Short Message service on GSM network has been opened to the public, it has been widely used and brought the very high profit to the network operators. This service not only brings the convenience for the end users , but the great profit to the operator. Facing the competition from China Mobile, China Telecom, which was the biggest Telecom operator in China two years ago, is also considering providing simple data service for his customers. Therefore, an applicable and efficient system for information distribution is in great need, which will be able to send instant message to termination through the cheap and specific telephone terminal.This article introduced the appropriate solution to transform PCM signal to FSK/DTMF signal om DSP . This application system is a combination of exchange technology and computer science. It is highly appraised by experts and customers for its social and economic benefit after it was put into use by China Telecom. This paper summarizes the main points that how to produce and detect FSK/DTMF signal on DSP.Chapter one: Briefly introduces the background of the development of this system, the main functions of system and the main function modules.. Chapter two: Archetecture of this system and service procedure; internal interface; protocols..Chapter three: Basic theory of FSK and DTMF signal ;the theory of how to produce and detect FSK/DTMF, especially introduce Goertzel programming in detail.Chapter four :introduce the detail design of each modules;the main two steps to improve the performce of whole item. Chapter five: Outline of this project Attachment : Introduction of background knowledge related to this project. |
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