// 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; float *pPwr; // 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); }