The Detection Of DTMF Signal Based On The EP4CE55

Recently, DTMF is widely used in communication systems, such as Voice Mail, Telephone Banking, ATM Terminals and so on. The emergence of DTMF signaling scheme solved much problems of transferring dialing information in the communication system, such as slow transmission speed, suffering sever distortion, poor signal stability and so on. As one of the most important segments in DTMF communication system, filters take a critical part. Its performance decides whether the receiver can recognize and decode the input DTMF signal accurately or not. If the Encode and Decode of DTMF signals can be integrated into the FPGA development systems, it does not only eliminate the dependence of DTMF signal on appropriation chips, but also can reduce the cost of circuit design, as well as can simplify the system, at that time it will be overcome the disadvantages of poor signal stability and the power consumption, therefore, the detection of DTMF signal is a very valuable application project, takes as theThis thesis describes the system of DTMF signal detection, as well as introduces the hardware platform and the software platform, the hardware platform is based on EP4CE55F23C8N and the software platform based on Quartus Ⅱ11.0, also represents a design method which using mixed design in Verilog HDL and schematic. In the decoding part, the Goertzel optimization algorithm is adopted. Compared with the algorithm of FFT, the Goertzel optimization algorithm can reduce the computation of the system and cut back the complexity of operations. Also, In order to make the DTMF signal detection becomes intuitive and accurate, the VB software is used to verify the validity of Goertzel algorithm, and the Matlab software is adopted to test the waveform of simulation. The result of the experimental shows that the DTMF decoding algorithm integrated in the system based on FPGA can make the whole DTMF signal detection system not only stable and reliable but also cost-effective outstanding, as well as show the advantage of FPGA.This thesis is composed of the following seven chapters.The first chapter is the introduction. This part briefly introduces the background and significance of the DTMF signal detection firstly, and then represents the history of DTMF signals and the forecast of DTMF technology, finally, it elaborates the main content of the research in detial.In the second chapter, the detection principle of DTMF signal and the analysis of Goertzel algorithmic are included. At first, the principle of DTMF signal is briefly introduced, and then describes the Goertzel algorithm principle and the parameters of Goertzel algorithm, as well as the complexity of the Goertzel algorithm.The third chapter is the overall system design. Firstly, this chapter generally introduces the overall structure of the DTMF signal detection system, Secondly, it respectively presents the design of the storage module,conversion module and operation module.Then it depictes the softwareof Quartus Ⅱ11.0,Finally, it summarizes all of this work.Chapter4discusses the hardware design of the Detecti on of DTMF Signal Based on the EP4CE55.This part mainly describes the external clock circuits, and briefly representes the performance of FPGA and external clock circuit.The software design of the system is presented in chapter five.From the point of view of modular design, more detailed exposition are carried out for module design,such as the clock adjustment module,data initial value module Goertzel algorithm operation module and energy storage module, also some part programs and graphs of module design are being given.The sixth chapter discusses the numerical simulation and waveform simulation. Primarily, it introduces the test value of Goertzel algorithm by VB software, then, it describes the result of the waveform simulation for the DTMF signal detection by the Matlab software, finally, it summarizes the simulation test.The stage of completion of the work is proposed in chapter seven. The prospect to in-depth research is mentioned.