FM Shortwave Receiver
Abstract
This paper describes the difference between FM-AM and FM advantages. Second, the program describes the arguments and selecting the receiver, then the hardware design and adopted in the design of narrow-band FM / IF chip MC3361B complete mixing, and demodulation in place. PLL frequency synthesizer means to generate a stable local oscillator to D / A conversion method control input tuned circuit resonant frequency, in order to achieve electrical tuning. Using MCS-51 series MCU on the Serial Input PLL Frequency Synthesizer MC145L55-2 than a preset sub-band, through the D / A output control voltage. Added to the 8279 keyboard and display circuit, in order to achieve a variety of program-controlled serial E2POM search, storage and carrier radio show. Finally, through data testing and analysis, complete design requirements.
Key words:microcontroller; diode; transistor; integrated amplifier