使用C语言写一个Goertzel算法

好的，Goertzel算法是一种数字信号处理算法，用于计算单个离散频率的幅度。以下是使用C语言实现Goertzel算法的代码示例：

#include <stdio.h>
#include <math.h>

double goertzel(double *samples, int sample_rate, double frequency, int sample_count) {
    double s_prev = 0.0;
    double s_prev2 = 0.0;
    double coeff = 2.0 * cos(2.0 * M_PI * frequency / (double)sample_rate);
    double s;
    
    for(int i = 0; i < sample_count; i++) {
        double sample = samples[i];
        s = sample + coeff * s_prev - s_prev2;
        s_prev2 = s_prev;
        s_prev = s;
    }
    
    double normalized_frequency_power = s_prev2 * s_prev2 + s_prev * s_prev - coeff * s_prev2 * s_prev;
    double power = normalized_frequency_power / (double)sample_count;
    return power;
}

int main() {
    double samples[] = {1.0, -1.0, 1.0, -1.0};
    int sample_rate = 44100;
    double frequency = 1000.0;
    int sample_count = 4;
    double power = goertzel(samples, sample_rate, frequency, sample_count);
    printf("Goertzel power: %f\n", power);
    return 0;
}

这段代码演示了如何使用Goertzel算法计算频率为1000HZ的信号的幅度。您可以将示例数据替换为您自己的数据，并调整频率和采样率以适应您的应用程序。