基于通信系統(tǒng)的信號源設計

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摘要 信號源是通信設備和系統(tǒng)設計、調(diào)試和維護中不可缺少的儀器，實現(xiàn)信號源的設計有很多方案，本設計采用硬件設計方案，具有結構簡單、成本低、體積小、使用方便及實用性強等特點。本文對于信號源的研究主要在于對基本信號的研究，其中包括常用的基本信號中的正弦信號、脈沖信號、三角波信號和時鐘信號，還包括通信系統(tǒng)中常用的DTMF信號和CMI碼，也包括了模擬調(diào)制信號以及數(shù)字調(diào)制信號。
在常用基本信號的產(chǎn)生中，本文先用RC橋式振蕩器產(chǎn)生可調(diào)的正弦波；得到正弦波后，讓其經(jīng)過一個遲滯型電壓比較器，得到可調(diào)的方波；最后將輸出的方波通過積分器，即可到三角波信號。時鐘信號的產(chǎn)生是通過分頻器來實現(xiàn)的，將4.096MHz的時鐘信號通過分頻器可以得到不同頻率的時鐘信號。對于通信系統(tǒng)中常用的DTMF信號，本文采用數(shù)字方法來產(chǎn)生與檢測。產(chǎn)生的信號經(jīng)過D/A轉換器可得連續(xù)時間DTMF信號，本文采用的檢測方法為戈澤爾算法。CMI碼則使用了硬件搭設的方法，首先搭設一個由4個雙D觸發(fā)器組成的15位偽隨機碼產(chǎn)生電路，然后將輸出的偽隨機碼輸入搭設好的編碼電路得到CMI編碼。
在模擬調(diào)制信號產(chǎn)生與解調(diào)中，AM信號調(diào)制是直接將原信號加上直流分量然后再乘以一個載波來是實現(xiàn)的，其解調(diào)的方法是包絡檢波法。DSB信號的調(diào)制與AM相近，只是不加直流分量，解調(diào)是采用的相干解調(diào)法。對于數(shù)字調(diào)制信號，3種數(shù)字調(diào)制信號，均采用了模擬相乘法來進行調(diào)制，他們的解調(diào)也都是采用了相干解調(diào)法。
關鍵詞： 信號源 通信 DTMF 仿真 Multisim Matlab
Design of the Signal Generator Based on Communication System
Abstract Signal generator is an essential equipment applied in communication device, system design, commissioning and maintenance. Designing and implementing a signal generator has many schemes. This design adopts the scheme of hardware design, which has the characteristics of simple structure, low cost, small size, easy to use and strong practicability etc.. In this paper, the study of signal generator lies mainly in the study of basic signal, including common basic signals such as a sinusoidal signal, a pulse signal, a triangular wave signal and a clock signal, the DTMF signal and the CMI code commonly used in a communication system, and the analog modulation signal and a digital modulation signal.
For the generation of common basic signal, we first generate an adjustable sine wave with the RC bridge oscillator. We let it pass through a hysteretic voltage comparator to get a tunable square wave after getting the sine wave. Finally, we let the square wave pass through an integrator to obtain a triangle wave signal. Generating a clock signal is realized by the divider. We can obtain the clock signals of different frequencies when letting a clock signal frequency of 4.096MHz pass through the divider. The DTMF signal is commonly used in communication system. In this paper, we generate and detect the signal with digital method. The continuous time DTMF signal can be got by letting the digital signal pass through the D / A converter. Detection methods used in this paper is the Goertzel algorithm. The generation of CMI code adopts the method of hardware erection. Firstly, we erect a 15-bit pseudo-random code generator circuit by four D flip-flops. Then we can let the exporting pseudo-random code pass through the encoding circuit to get the CMI code.
In terms of the generation and demodulation of an analog modulated signal, AM modulation signal can be achieved by coupling directly to the DC component of the original signal and then being multiplied by a carrier, which can be demodulated with envelope detector method. DSB modulation and AM modulation signal is analogous, but the former don’t contain a DC component, and the demodulation method is coherent demodulation. For digital modulation signals, three kinds of digital modulation signals are used to modulate the analog multiplication, they are also demodulated by coherent demodulation.
Key words: Signal generator Signal communication DTMF Simulation Multisim Matlab
目 錄
第一章 緒 論 1
1.1 信號源綜述 1
1.1.1 信號源簡介 1
1.1.2 信號源發(fā)展的現(xiàn)狀、水平和趨勢 1
1.2 課題的研究意義 2
1.3 信號源設計方案現(xiàn)狀 3
1.4 仿真軟件概述 3
1.4.1 NI Multisim 概述 3
1.4.2 Matlab概述 4
第二章 常用的基礎信號 5
2.1 常用信號信號總電路的設計 5
2.2 正弦波的產(chǎn)生 7
2.2.1 RC橋式正弦波振蕩器電路構成 7
2.2.2 RC橋式振蕩器的穩(wěn)幅過程 8
2.2.3 RC橋式正弦振蕩電路的設計與仿真 8
2.3 脈沖波的產(chǎn)生 10
2.3.1 脈沖波產(chǎn)生原理 10
2.3.2 脈沖波設計與仿真 11
2.4 三角波的產(chǎn)生 12
2.5 時鐘信號的產(chǎn)生 13
2.5.1 時鐘信號總電路設計 13
2.5.2 時鐘信號電路仿真 14
第三章 通信系統(tǒng)中常用的信號 19
3.1 信令簡介 19
3.1.1 信令的概念 19
3.1.2 用戶終端發(fā)出的信令 19
3.1.3 交換機發(fā)出的信令 20
3.2 雙音多頻信號 20
3.2.1 DTMF信號原理 20
3.2.2 DTMF信號的產(chǎn)生 20
3.2.3 DTMF信號的檢測 21
3.2.4 Matlab仿真程序分析 22
3.3 CMI碼 24
3.3.1 CMI簡要介紹 24
3.3.2 偽隨機碼發(fā)生器電路設計 24
3.3.3 CMI編碼電路設計 25
3.3.4 CMI解碼電路設計 28
第四章 模擬調(diào)制信號 30
4.1 調(diào)幅（AM） 30
4.1.1 AM調(diào)制原理 30
4.1.2 AM解調(diào)原理（包絡檢波） 30-b..