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OpenAudio_ArduinoLibrary/examples/TestFFT4096iqEM/TestFFT4096iqEM.ino

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// TestFFT2048iqEM.ino for Teensy 4.x
// *** EXTERNAL MEMORY VERSION of 4095 FFT ***
// Bob Larkin 9 March 2021
// Generate Sin and Cosine pair and input to IQ FFT.
// Serial Print outputs of all 4096 bins.
//
// Public Domain
#include "OpenAudio_ArduinoLibrary.h"
#include "AudioStream_F32.h"
// Memory for IQ FFT
float32_t fftOutput[4096]; // Array to allow fftBuffer[] to be available for new in data
float32_t window[2048]; // Half size window storage
float32_t fftBuffer[8192]; // Used for FFT, 4096 real, 4096 imag, interleaved
float32_t sumsq[4096]; // Required if power averaging is being done
int jj;
// GUItool: begin automatically generated code
AudioSynthSineCosine_F32 sine_cos1; //xy=76,532
// Optional
// (float32_t* _pOutput, float32_t* _pWindow, float32_t* _pFFT_buffer, float32_t* _pSumsq)
//AudioAnalyzeFFT4096_IQEM_F32 FFT4096iqEM1(fftOutput, window, fftBuffer); //xy=243,532
AudioAnalyzeFFT4096_IQEM_F32 FFT4096iqEM1(fftOutput, window, fftBuffer, sumsq); // w/ power ave
AudioOutputI2S_F32 audioOutI2S1; //xy=246,591
AudioConnection_F32 patchCord1(sine_cos1, 0, FFT4096iqEM1, 0);
AudioConnection_F32 patchCord2(sine_cos1, 1, FFT4096iqEM1, 1);
// GUItool: end automatically generated code
void setup(void) {
Serial.begin(9600);
delay(1000);
// The 4096 complex FFT needs 32 F32 memory for real and 32 for imag.
// Set memory to more than 64, depending on other useage.
AudioMemory_F32(100);
Serial.println("FFT4096IQem Test");
sine_cos1.amplitude(1.0f); // Initialize Waveform Generator
// Engage the identical BP Filters on sine/cosine outputs (true).
sine_cos1.pureSpectrum(true);
// Pick T4.x bin center
// sine_cos1.frequency(689.0625f);
// or pick any old frequency
sine_cos1.frequency(1000.0f);
// elect the output format, FFT_RMS, FFT_POWER, or FFT_DBFS
FFT4096iqEM1.setOutputType(FFT_DBFS);
// Select the wndow function, designed by FFT object
//FFT4096iqEM1.windowFunction(AudioWindowNone);
//FFT4096iqEM1.windowFunction(AudioWindowHanning4096);
//FFT4096iqEM1.windowFunction(AudioWindowKaiser4096, 55.0f);
FFT4096iqEM1.windowFunction(AudioWindowBlackmanHarris4096);
// Uncomment to Serial print window function
// for (int i=0; i<2048; i++) Serial.println(*(window+i), 7);
// xAxis, See leadin discussion at analyze_fft4096_iqem_F32.h
FFT4096iqEM1.setXAxis(0X03); // 0X03 default
// In order to average powers, a buffer for sumsq[4096] must be
// globally declared and that pointer, sumsq, set as the last
// parameter in the object creation. Then the following will
// cause averaging of 4 powers:
FFT4096iqEM1.setNAverage(4);
jj = 0; // This is to delay data gathering to get steady state
}
void loop(void) {
static bool doPrint=true;
// Print output, once
if( FFT4096iqEM1.available() && jj++>2 && doPrint ) {
if(jj++ < 3)return;
for(int i=0; i<4096; i++)
{
// Serial.print((int)((float32_t)i * 44100.0/4096.0)); // Print freq
Serial.print(i); // FFT Output index (0, 4095)
Serial.print(" ");
Serial.println(*(fftOutput + i), 8 );
}
doPrint = false;
}
if(doPrint)
{
Serial.print(" Audio MEM Float32 Peak: ");
Serial.println(AudioMemoryUsageMax_F32());
}
delay(100);
}