/* analyze_fft1024_F32.h Converted from Teensy I16 Audio Library * * Audio Library for Teensy 3.X * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com * * Development of this audio library was funded by PJRC.COM, LLC by sales of * Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop * open source software by purchasing Teensy or other PJRC products. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice, development funding notice, and this permission * notice shall be included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ /* Moved directly I16 to F32. Bob Larkin 16 Feb 2021 * Does real input FFT of 1024 points. Output is not audio, and is magnitude * only. Multiple output formats of RMS (same as I16 version, and default), * Power or dBFS (full scale). Output can be bin by bin or a pointer to * the output array is available. Several window functions are provided by * in-class design, or a custom window can be provided from the INO. * * Functions (See comments below and #defines above: * bool available() * float read(unsigned int binNumber) * float read(unsigned int binFirst, unsigned int binLast) * int windowFunction(int wNum) * int windowFunction(int wNum, float _kdb) // Kaiser only * float* getData(void) * float* getWindow(void) * void putWindow(float *pwin) * void setOutputType(int _type) * void setNAverage(int nAverage) * * Timing, max is longest update() time: * T3.6 Windowed, Power Out, 975 uSec * T3.6 Windowed, RMS out, 1016 uSec * T3.6 Windowed, dBFS out, 1591 uSec * No Window saves 60 uSec on T3.6 for any output. * T4.0 Windowed, Ave=1, Power Out, 156 uSec * T4.0 Windowed, Ave=1, dBFS Out, 302 uSec * Scaling: * Full scale for floating point DSP is a nebulous concept. Normally the * full scale is -1.0 to +1.0. This is an unscaled FFT and for a sine * wave centered in frequency on a bin and of FS amplitude, the power * at that center bin will grow by 1024^2/4 = 262144 without windowing. * Windowing loss cuts this down. The RMS level can grow to sqrt(262144) * or 512. The dBFS has been scaled to make this max value 0 dBFS by * removing 54.2 dB. With floating point, the dynamic range is maintained * no matter how it is scaled, but this factor needs to be considered * when building the INO. */ // Fixed float/int problem in read(first, last). RSL 3 Mar 21 #ifndef analyze_fft1024_F32_h_ #define analyze_fft1024_F32_h_ #include "Arduino.h" #include "AudioStream_F32.h" #include "arm_math.h" #include "mathDSP_F32.h" #if defined(__IMXRT1062__) #include "arm_const_structs.h" #endif #define FFT_RMS 0 #define FFT_POWER 1 #define FFT_DBFS 2 #define NO_WINDOW 0 #define AudioWindowNone 0 #define AudioWindowHanning1024 1 #define AudioWindowKaiser1024 2 #define AudioWindowBlackmanHarris1024 3 class AudioAnalyzeFFT1024_F32 : public AudioStream_F32 { //GUI: inputs:1, outputs:0 //this line used for automatic generation of GUI node //GUI: shortName:FFT1024 public: AudioAnalyzeFFT1024_F32() : AudioStream_F32(1, inputQueueArray) { // __MK20DX128__ T_LC; __MKL26Z64__ T3.0; __MK20DX256__T3.1 and T3.2 // __MK64FX512__) T3.5; __MK66FX1M0__ T3.6; __IMXRT1062__ T4.0 and T4.1 #if defined(__IMXRT1062__) // Teensy4 core library has the right files for new FFT // arm CMSIS library has predefined structures of type arm_cfft_instance_f32 Sfft = arm_cfft_sR_f32_len1024; // This is one of the structures #else arm_cfft_radix4_init_f32(&fft_inst, 1024, 0, 1); // for T3.x #endif // This is always 128 block size. Any sample rate. No use of "setings" // Bob: Revisit this to use CMSIS fast fft in place of cfft. faster? useHanningWindow(); } // Inform that the output is available for read() bool available() { if (outputflag == true) { outputflag = false; return true; } return false; } // Output data from a single bin is transferred float read(unsigned int binNumber) { if (binNumber>511 || binNumber<0) return 0.0; return output[binNumber]; } // Return sum of several bins. Normally use with power output. // This produces the equivalent of bigger bins. float read(unsigned int binFirst, unsigned int binLast) { if (binFirst > binLast) { unsigned int tmp = binLast; binLast = binFirst; binFirst = tmp; } if (binFirst > 511) return 0.0; if (binLast > 511) binLast = 511; float sum = 0.0f; do { sum += output[binFirst++]; } while (binFirst <= binLast); return sum; } int windowFunction(int wNum) { if(wNum == AudioWindowKaiser1024) return -1; // Kaiser needs the kdb windowFunction(wNum, 0.0f); return 0; } int windowFunction(int wNum, float _kdb) { float kd; pWin = window; if(wNum == NO_WINDOW) pWin = NULL; else if (wNum == AudioWindowKaiser1024) { if(_kdb<20.0f) kd = 20.0f; else kd = _kdb; useKaiserWindow(kd); } else if (wNum == AudioWindowBlackmanHarris1024) useBHWindow(); else useHanningWindow(); // Default return 0; } // Fast pointer transfer. Be aware that the data will go away // after the next 512 data points occur. float* getData(void) { return output; } // You can use this to design windows float* getWindow(void) { return window; } // Bring custom window from the INO void putWindow(float *pwin) { float *p = window; for(int i=0; i<1024; i++) *p++ = *pwin++; } // Output RMS (default) Power or dBFS void setOutputType(int _type) { outputType = _type; } // Output power (non-coherent) averaging void setNAverage(int _nAverage) { nAverage = _nAverage; } virtual void update(void); private: float output[512]; float sumsq[512]; float window[1024]; float *pWin = window; audio_block_f32_t *blocklist[8]; float fft_buffer[2048]; uint8_t state = 0; bool outputflag = false; audio_block_f32_t *inputQueueArray[1]; #if defined(__IMXRT1062__) // For T4.x // const static arm_cfft_instance_f32 arm_cfft_sR_f32_len1024; arm_cfft_instance_f32 Sfft; #else arm_cfft_radix4_instance_f32 fft_inst; #endif int outputType = FFT_RMS; //Same type as I16 version init int nAverage = 1; int count = 0; // used to average for nAverage of powers // The Hann window is a good all-around window void useHanningWindow(void) { for (int i=0; i < 1024; i++) { // 2*PI/1023 = 0.006141921 window[i] = 0.5*(1.0 - cosf(0.006141921f*(float)i)); } } // Blackman-Harris produces a first sidelobe more than 90 dB down. // The price is a bandwidth of about 2 bins. Very useful at times. void useBHWindow(void) { for (int i=0; i < 1024; i++) { float kx = 0.006141921; // 2*PI/1023 int ix = (float) i; window[i] = 0.35875 - 0.48829*cosf( kx*ix) + 0.14128*cosf(2.0f*kx*ix) - 0.01168*cosf(3.0f*kx*ix); } } /* The windowing function here is that of James Kaiser. This has a number * of desirable features. The sidelobes drop off as the frequency away from a transition. * Also, the tradeoff of sidelobe level versus cutoff rate is variable. * Here we specify it in terms of kdb, the highest sidelobe, in dB, next to a sharp cutoff. For * calculating the windowing vector, we need a parameter beta, found as follows: */ void useKaiserWindow(float kdb) { float32_t beta, kbes, xn2; mathDSP_F32 mathEqualizer; // For Bessel function if (kdb < 20.0f) beta = 0.0; else beta = -2.17+0.17153*kdb-0.0002841*kdb*kdb; // Within a dB or so // Note: i0f is the fp zero'th order modified Bessel function (see mathDSP_F32.h) kbes = 1.0f / mathEqualizer.i0f(beta); // An additional derived parameter used in loop for (int n=0; n<512; n++) { xn2 = 0.5f+(float32_t)n; // 4/(1023^2)=0.00000382215877f xn2 = 0.00000382215877f*xn2*xn2; window[511 - n]=kbes*(mathEqualizer.i0f(beta*sqrtf(1.0-xn2))); window[512 + n] = window[511 - n]; } } }; #endif