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arduinoFFT
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Fix bug in example 1. Negative numbers were stored in unsigned var

pull/8/head
Enrique Condes 2016-12-30 16:35:36 -06:00
rodzic 11a37ab10f
commit 3e56804d95
1 zmienionych plików z 13 dodań i 13 usunięć
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26
Examples/FFT_01/FFT_01.ino
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@ -15,24 +15,24 @@
You should have received a copy of the GNU General Public License You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. along with this program. If not, see <http://www.gnu.org/licenses/>.
*/ */
#include "arduinoFFT.h" #include "arduinoFFT.h"
arduinoFFT FFT = arduinoFFT(); /* Create FFT object */ arduinoFFT FFT = arduinoFFT(); /* Create FFT object */
/* /*
These values can be changed in order to evaluate the functions These values can be changed in order to evaluate the functions
*/ */
const uint16_t samples = 64; //This value MUST ALWAYS be a power of 2 const uint16_t samples = 64; //This value MUST ALWAYS be a power of 2
double signalFrequency = 1000; double signalFrequency = 1000;
double samplingFrequency = 5000; double samplingFrequency = 5000;
uint8_t amplitude = 100; uint8_t amplitude = 100;
/* /*
These are the input and output vectors These are the input and output vectors
Input vectors receive computed results from FFT Input vectors receive computed results from FFT
*/ */
double vReal[samples]; double vReal[samples];
double vImag[samples]; double vImag[samples];
#define SCL_INDEX 0x00 #define SCL_INDEX 0x00
@ -47,13 +47,13 @@ void setup()
Serial.println("Ready"); Serial.println("Ready");
} }
void loop() void loop()
{ {
/* Build raw data */ /* Build raw data */
double cycles = (((samples-1) * signalFrequency) / samplingFrequency); //Number of signal cycles that the sampling will read double cycles = (((samples-1) * signalFrequency) / samplingFrequency); //Number of signal cycles that the sampling will read
for (uint8_t i = 0; i < samples; i++) for (uint8_t i = 0; i < samples; i++)
{ {
vReal[i] = uint8_t((amplitude * (sin((i * (Theta * cycles)) / samples))) / 2.0);/* Build data with positive and negative values*/ vReal[i] = int8_t((amplitude * (sin((i * (Theta * cycles)) / samples))) / 2.0);/* Build data with positive and negative values*/
//vReal[i] = uint8_t((amplitude * (sin((i * (6.2831 * cycles)) / samples) + 1.0)) / 2.0);/* Build data displaced on the Y axis to include only positive values*/ //vReal[i] = uint8_t((amplitude * (sin((i * (6.2831 * cycles)) / samples) + 1.0)) / 2.0);/* Build data displaced on the Y axis to include only positive values*/
} }
Serial.println("Data:"); Serial.println("Data:");
@ -68,20 +68,20 @@ void loop()
PrintVector(vImag, samples, SCL_INDEX); PrintVector(vImag, samples, SCL_INDEX);
FFT.ComplexToMagnitude(vReal, vImag, samples); /* Compute magnitudes */ FFT.ComplexToMagnitude(vReal, vImag, samples); /* Compute magnitudes */
Serial.println("Computed magnitudes:"); Serial.println("Computed magnitudes:");
PrintVector(vReal, (samples >> 1), SCL_FREQUENCY); PrintVector(vReal, (samples >> 1), SCL_FREQUENCY);
double x = FFT.MajorPeak(vReal, samples, samplingFrequency); double x = FFT.MajorPeak(vReal, samples, samplingFrequency);
Serial.println(x, 6); Serial.println(x, 6);
while(1); /* Run Once */ while(1); /* Run Once */
// delay(2000); /* Repeat after delay */ // delay(2000); /* Repeat after delay */
} }
void PrintVector(double *vData, uint8_t bufferSize, uint8_t scaleType) void PrintVector(double *vData, uint8_t bufferSize, uint8_t scaleType)
{ {
for (uint16_t i = 0; i < bufferSize; i++) for (uint16_t i = 0; i < bufferSize; i++)
{ {
double abscissa; double abscissa;
/* Print abscissa value */ /* Print abscissa value */
switch (scaleType) switch (scaleType)
{ {
case SCL_INDEX: case SCL_INDEX:
abscissa = (i * 1.0); abscissa = (i * 1.0);