语音/文字短信无线发射机设计

语音/文字短信无线发射机是嵌入式智能家居系统的重要部件，采用锁相环式频率合成器技术，利用MC145152 和MC12022 芯片组成锁相环。输出载波频率35MHz，稳定度达到4×10-5，准确度达到3×10-5。由变容二极管V149 和集成压控振荡器芯片MC1648 实现对载波的调频调制。末级功放选用三极管2SC1970，工作在丙类放大状态，输出功率达到20mW。采用PT2262 编码器芯片和AT89S52单片机实现文字短信数据传输业务，以及对机号的选择与控制等功能。音频输入和文字短信数据输入可自动转换，显示采用128×64 点阵型液晶显示。
关键词： 无线电发射机、锁相环、编码器、单片机
Design of Wireless transmitter for Sound and Letter note Huang Zhiwei Liu hong Jiang Chenjun Fu xianchen （The College of Electrical Engineering , Nanhua University ,Hengyang 421001, China） Abstract: The wireless transmitter of sound and letter note is a important part of embedded intelligent home system. It adopts the phase-locked loop pattern of frequency synthesizing technology and uses the MC145152 and MC12022 chips to compose the phase-locked loop. The frequency of the carrier-wave is at 35MHz. The stabilization of the carrier-wave can be 4×10-5, the accuracy can be 3×10-5. The frequency modulation of the carrier-wave are realized by the capacity-changing diode V149 and the integration voltage-control oscillator MC1648 chip. The end power amplifier uses the transistor 2SC1970 to make it work in the third magnifying state, the output power reaches 20mW. It uses PT2262 encoder to realize the data transmission operation as well as the platform-choosing function. The AT89S52 is used as the controlling part of the whole system.The input of the Sound and
Letter note can be automatically transformed. The display adopts 128×64 lattice LCD to show.
Key word: wireless transmitter, PLL, encoder, microcontroller