User manual for an audio processing system based on Arm Cortex-M4 MCU with noise reduction and FM transmission via QN8027 module.
This document describes a real-time audio processing system built around the Arm Cortex-M4 MCU. It captures, processes, and transmits audio signals wirelessly using an FM module (QN8027). The system includes microphone amplification, ADC sampling, DSP filtering, DAC conversion, and FM transmission modules. Key features include low distortion, high SNR, and wide dynamic range. The manual details hardware design, software algorithms (including adaptive filtering), and circuit implementation.
The system is designed for practical applications such as wireless microphones and is suitable for educational or prototyping use. It uses high-performance components like MAX541 DAC, MAX297 filter, and QN8027 FM transmitter. The design includes two microphones for noise cancellation and uses CMSIS-DSP for processing. Performance metrics like SNR, sampling rate, and frequency range are specified and tested. This manual is written in Chinese.
| ADC Resolution | 16-bit |
|---|---|
| DAC Resolution | 16-bit |
| Low-Pass Filter | 3500Hz elliptical |
| FM Carrier Frequency Range | 88MHz~108MHz |
| Maximum Frequency Deviation | 75Hz |
| Channel Spacing | 200KHz |
| Maximum Audio Output Power | 0.5W |
| Communication Distance | 10~20 meters |
| SNR | 6.02B-7.2 |
| Filter Type | Bandpass |
| Filter Design Method | Equiripple |
The maximum audio output power is 0.5W.
The FM carrier frequency range is 88MHz to 108MHz.
Noise is reduced using adaptive filtering with two microphones to cancel environmental noise.