双音多频调频发射机

 摘  要
 
 本文设计的是双音多频调频发射机，总的组成是：由单片机控制电路，双音多频信号编码电路，琐相环频率合成器组成的电路调频立体声芯片组成的调频电路和音频提取电路。双音多频电路产生的信号和音频提取电路提取的音频信号，分别进入调频立体声芯片的左右声道进行调频。调频电路的压控振荡电路与琐相环频率合成器组成的电路构成闭合琐相环，它的作用提供频率稳定的调频信号。 这种双音频通信具有控制简单，实施方便，传输可靠，而且造价低廉的特点。文章首先介绍了FM的通信理论，再介绍双音多频接收发送器MT8888C 的基本工作原理和常用的工作模式, 然后以实现收发DTM F 信号为例给出了MT8888C 与89C51 的典型接口电路和控制软件。其之，介绍一种采用锁相环（PLL）频率合成器(BU2618FV)和89C51单片机控制的调频发射机，并介绍介绍了锁相环集成电路（BU2618FV）的性能和典型应用。最后介绍了BA1404，BA1404 是日本ROHM 公司生产的为数不多的调频发射集成电路之一。它是将立体声调制、FM 调制和RF 放大功能集成在一个芯片上制成的。本文详细论述了具有广泛应用的立体声调频发射集成电路BA1404 的结构组成和工作原理,并给出了典型的应用电路。

关键词：双音多频；MT8888；89C51；琐相环频率合成器BU2618FV；
      调频立体声

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 Abstract [资料来源：http://THINK58.com]

 What this text designed is much frequency modulation transmitters frequently of a pair of sound , total composition is: By the control circuit of one-chip computer, pairs of sound many signal encode circuit is trivial to surround frequency circuit frequency modulation stereo frequency modulation circuit and audio frequency that chip makes up that synthesizer make up draw the circuit frequently. Pairs of sound many signal and audio frequency that the circuit produce drew the audio frequency signal that the circuit is drawn frequently, enter frequency modulation stereo chip the sound channel goes on frequency modulation from side to side separately. Frequency modulation circuit voltage-controlled to shake circuit with trivial to surround frequency circuit that synthesizer make up is it close trivial looks ring to form, its function offers the steady frequency modulation signal of frequency. These kind of audio frequency communication is it control simple to have, it is convenient to implement, it is reliable to transmit, and the characteristic with cheap fabrication cost. The article introduces communication theory of FM at first, recommend one more pair of sound receive the basic operation principle of telephone transmitter MT8888C and commonly used work pattern frequently more, then regard realizing receiving and dispatching DTM F signal as the typical interface circuit that the example provides MT8888C and 89C51 and control the software. Its, introduce one kind phase locking of adopting ring frequency synthesizer and 89C51 frequency modulation transmitter where one-chip computer control, have recommended the phase locking to surround performance of the integrated circuit (BU2618FV ) and typical application. Having introduced BA1404 finally, BA1404 is that few frequency modulation which Japan ROHM Company produces launches one of the integrated circuits. It make three-dimensional tone, FM modulate with RF enlarging function integrate at one chip making. This text has expounded the fact in detail that has structure making up and operation principle that three-dimensional tone used extensively launches integrated circuit BA1404 frequently , provide the typical application circuit. [来源：http://think58.com]

Key works:Dual Tone Multiple frequencyDTMF);phase-lockedloop(PLL);MT8888;FM stereo transmitter [资料来源：www.THINK58.com]

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 目   录
 
引言…………………………………………………………………………………………1
1 FM的通信理论……………………………………………………………………………2
   1.1调频广播的历史……………………………………………………………………4
   1.2调频广播的特点……………………………………………………………………5 [资料来源：www.THINK58.com]
   1.3调频广播的标准……………………………………………………………………6
   1.4调频系统的一般框图………………………………………………………………6
   1.5调频发射机的原理…………………………………………………………………7
2方案选择与论证 …………………………………………………………………………8
 2.1调频发射电路的选择………………………………………………………………8 [资料来源：http://THINK58.com]
   2.2调频发射电路芯片的选择  ………………………………………………………8
3 系统原理和系统硬件组成………………………………………………………………10
   3.1控制电路 …………………………………………………………………………11
   3.2 DTMF ………………………………………………………………………………15
   3.3锁相环频率合成电路BU2618FV  …………………………………………………20

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 3.4 调频立体声的调制原理 …………………………………………………………23
  3.4.1 BA1404调频立体声发射芯片的原理与应用   ……………………………………26
4 结论  ……………………………………………………………………………………29
  谢辞  ……………………………………………………………………………………31
  参考文献  ………………………………………………………………………………32 [资料来源：www.THINK58.com]

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