2018 Electronic Competition Question F-Wireless Microphone Amplification System (Xidian University)

This system uses MSP430 as the control core, uses RDA5820 integrated FM transceiver chip to build an analog frequency modulation circuit, and realizes arbitrary setting of the carrier frequency. It uses an adder and demodulation circuit to create a receiver that can mix sound amplification, and uses RSSI channel occupancy detection Algorithm enables the microphone to automatically detect channel occupancy when turned on and avoid interfering signals.
The wireless microphone is powered by dual dry batteries +3V. It can output a carrier frequency between 88MHz and 108MHz, and can be set arbitrarily in steps of 200KHz. The maximum frequency deviation can be set from 50kHz to 100kHz, and the audio bandwidth is 40 Hz to 15 kHz. When using two microphones at the same time, the carrier frequency can be automatically selected to avoid interfering signals within 0.7 seconds after powering on; the receiving part adopts a self-designed and produced circuit, with a receiving distance of more than 25 meters, achieving a maximum output power of more than 0.6W for microphone amplification and Mixed sound.
After final cascading and debugging, the system achieved all the requirements of the question. Some indicators such as communication distance, automatic avoidance response time, maximum audio output power, etc. all exceed the question requirements.