双音频调频解调机

双音频调频解调机

文档编号:JD1058 文档字数:19466,页数:33,

摘要
本调频收音机主要由FM/AM收音机芯片CXA1191M，PLL频率合成器BU2614，双音频解码芯片MT8870和单片机AT89C51组成。在许多单片机应用系统中，常常利用电信号与非电信号，来传送控制信号和数据信息，以实现遥控或遥测的功能，例如光信号、超声波信号、电脉冲信号等。而本FM有线/无线遥控广播系统中，使用双音频电信号接收，实现对FM有线/无线广播的远程控制管理。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，也是一种较为常用的通信方式。为实现单片机控制的双音频解码，本收音机采用了双音频译码芯片MT8870，从调频信号中解调出音频信号，并从音频信号中分离出双音频信号进入双音频解码电路实行信令解码，从而利用调频信道进行低速率的控制指令的传输。主要以单片机芯片AT89C51为控制核心，实现指定频率范围的搜索和双音频指令的终端显示。

关键词：接收机；锁相；双音频；译码

Abstract
This FM receiver mainly by FM/AM radio chip CAX1191M, PLL frequency synthesizer BU2614 and monolithic integrated circuit AT89C51 composition. In many monolithic integrated circuits application system, uses the electrical signal and the non-electric signal frequently, transmits the control signal and the data message, by realizes the remote control or the telemetering function, for example light signal, ultrasonic wave signal,electricity pulse signal and so on. But this FM wired/In the wireless remote control broadcast system, uses the double audio frequency electrical signal transmission receive, realizes wired to FM/Radiobroadcasting long-distance control management. This kind of double audio frequency correspondence has the control simply,implementation convenient, the transmission is reliable, moreover construction cost inexpensive characteristic, also is one more commonly used mailing address. The realization monolithic integrated circuit system double audio frequency, this radio has used double audio frequency decoding chip MT8870, demodulates the tonic train signalling from the frequency-modulated signal, and separates the double tonic train signalling from the tonic train signalling to enter the double audio frequency decoding electric circuit implementation letter command to decode, thus carries on the low gear rate using the frequency modulation channel the control command transmission. Mainly take monolithic integrated circuit chip AT89C51 as the control core,the realization assigns thefrequency range the search and the double audio frequency instruction terminal demonstration.

Key words : Receiver；Phase-lock； Double audio frequency；Decoding

目录
摘要 1
Abstract 2
引言 3
1 系统概述 4
1.1 接收机的设计方案比较 5
1.2 系统的性能要求 5
1.2.1选择性要求 5
2 系统的系统设计 6
2.1 系统框图的设计及原理介绍 6
2.2 硬件电路的介绍 6
2.2.1调频广播接收机 6
2.2.2 锁相部分 9
2.2.3 双音频解码部分 14
2.2.4 单片机及显示部分 19
3 系统的软件设计 27
4 电路设计制作及调试 28
4.1电路设计制作 28
4.2 调试 29
5 结论 31
谢辞 32
参考文献 33

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