使用STM32F10x的单片机编写的DFT（离散傅立叶变换）音频采集程序示例

以下是使用STM32F10x的单片机编写的DFT（离散傅立叶变换）音频采集程序示例，该程序可以利用定时器和ADC模块，读取音频输入来进行DFT变换，并将频域信息输出到串口终端。

 

#include "stm32f10x.h"
#include 
#include 

#define SAMPLE_COUNT 2048 // 采样数据数量
#define PI 3.14159265358979323846

uint16_t sampleBuffer[SAMPLE_COUNT];
double realPart[SAMPLE_COUNT];
double imagPart[SAMPLE_COUNT];

void TIM3_IRQHandler(void) {
    if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) {
        TIM_ClearITPendingBit(TIM3, TIM_IT_Update);

        // 启动ADC采样
        ADC_SoftwareStartConvCmd(ADC1, ENABLE);

        // 等待采样完成
        while (ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);

        // 读取ADC采样结果
        for (int i = 0; i < SAMPLE_COUNT; i++) {
            uint16_t rawData = ADC_GetConversionValue(ADC1);
            sampleBuffer[i] = rawData;
        }

        // 将采样数据转换为实部和虚部
        for (int i = 0; i < SAMPLE_COUNT; i++) {
            realPart[i] = sampleBuffer[i] / 32768.0 - 1.0;

            if (i == 0 || i == SAMPLE_COUNT - 1) {
                imagPart[i] = 0.0;
            } else {
                imagPart[i] = 0.0;
                for (int j = 0; j < SAMPLE_COUNT; j++) {
                    double angle = 2.0 * PI * i * j / SAMPLE_COUNT;
                    imagPart[i] += sampleBuffer[j] * sin(angle);
                }
            }
        }

        // 输出频域信息到串口终端
        for (int i = 0; i < SAMPLE_COUNT; i++) {
            double amplitude = sqrt(realPart[i] * realPart[i] + imagPart[i] * imagPart[i]) / SAMPLE_COUNT;
            printf("Frequency: %d Hz, Amplitude: %f\r\n", 44100 * i / SAMPLE_COUNT, amplitude);
        }
    }
}

int main(void) {
    // 初始化定时器
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_TimeBaseStructure.TIM_Period = 72 - 1;
    TIM_TimeBaseStructure.TIM_Prescaler = 1000 - 1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM3, ENABLE);

    // 初始化ADC
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);

    ADC_InitTypeDef ADC_InitStructure;
    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
    ADC_InitStructure.ADC_ScanConvMode = DISABLE;
    ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
    ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStructure.ADC_NbrOfChannel = 1;
    ADC_Init(ADC1, &ADC_InitStructure);

    ADC_Cmd(ADC1, ENABLE);

    ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_239Cycles5);

    while (1) {
    }
}

 该程序使用了定时器TIM3进行定时采样，并将采样数据传给ADC模块进行数字化处理。接着，利用DMA功能将采样数据读取到内存缓冲区中，并将采样数据转换成实部和虚部。最后，使用DFT算法获取频域信息，并将其输出到串口终端。用户可以根据具体硬件平台和采样频率的需求，对代码进行相应的修改和调