调频收音机的设计和控制

The Design and Control of FM Receive

本调频收音机的设计是以SONY公司FM/AM收音机集成芯片CXA10 19S为核心 ,完成混频、中放 ,鉴频 ,功放等功能 ;采用MCS - 5 1系列单片机控制变容二极管的输入电压以实现输入回路的调谐与高度稳定的本振 ,提高镜像抑制比 ;采用E2 PRAM实现电台存储 ;通过DC -DC直流变换器实现全电路 3V供电 ;通过D/A输出控制电压 ,加上 82 79键盘显示电路 ,从而实现多种程控搜索、电台存储 ,载波显示 ,时钟的控制及显示 ;利用片内电子音量控制功能 ,使输出音量得到了提升 ;为提高灵敏度 ,抑制噪声 ,增加了调频静噪调谐电路 ,使该收音机的收音质量得到了很大改善 .

In this paper, We used the FM/AM receiver integrated chip CXA1019 of SONY company to finish mixing, intermediate-frequency amplification, frequency discrimination, power amplification; We used MCS-51 signal- microcomputer to control the input voltage of varicap then we can turn in the input circuit, gain stable frequency and high image-holdback ratio; We used E 2PRAM to save radios; used DC-DC changer to supply the whole circuit (3V) with one power supply; By means of the output voltage of D/A and the keyboard-display circuit of 8279, we can auto-search the radios, save the radios, display the carrier frequency and display the clock; We used the electric sound volume in the chip to control the sound volume; In order to raise the sensibility and holdback crackling, We added the circuit of quiet syntonize; Through the mass of the radio had much progress.