计算施加FFT后的信号幅度

Question

我正在使用Arduino Due和噪声传感器，我应用FFT库来提取频率，它工作得很好。但是我不知道如何计算振幅并在控制台上打印它们？

这是代码：

#include "arduinoFFT.h"
#define SAMPLES 32             
#define SAMPLING_FREQUENCY 1000 
arduinoFFT FFT = arduinoFFT();
unsigned int sampling_period_us;
unsigned long microseconds;
double vReal[SAMPLES];
double vImag[SAMPLES];
void setup() {
Serial.begin(9600);
sampling_period_us = round(1000000*(1.0/SAMPLING_FREQUENCY));
}
void loop() {
/*SAMPLING*/
for(int i=0; i<SAMPLES; i++)
{
microseconds = micros();    
vReal[i] = analogRead(0);
vImag[i] = 0;
while(micros() < (microseconds + sampling_period_us)){
}
}
/*FFT*/
FFT.Windowing(vReal, SAMPLES, FFT_WIN_TYP_HAMMING, FFT_FORWARD);
FFT.Compute(vReal, vImag, SAMPLES, FFT_FORWARD);
FFT.ComplexToMagnitude(vReal, vImag, SAMPLES);
double peak = FFT.MajorPeak(vReal, SAMPLES, SAMPLING_FREQUENCY);

Serial.println(peak);     
for(int i=0; i<(SAMPLES/2); i++)
{

Serial.print((i * 1.0 * SAMPLING_FREQUENCY) / SAMPLES, 1);
Serial.print(" ");
//Serial.println(vReal[i], 1);    //View only this line in serial plotter to visualize the bins
}
delay(1000);  
while(1);       
}

Answer 1

串行绘图仪没有许多样本到绘图功能。

如果要正确查看每个窗口的振幅，则需要使用以下代码

for(int i=0; i<(SAMPLES/2); i++)
{
//  Serial.print((i * 1.0 * SAMPLING_FREQUENCY) / SAMPLES, 1);
for(int i=0; i<20; i++)//Adjust the 20 to make space between each samples.
Serial.print(0);
Serial.print(vReal[i]); 
}

然后调整串行绘图仪的大小以适合您的窗口。

我希望这有所帮助。