You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
301 lines
11 KiB
301 lines
11 KiB
4 years ago
|
/*
|
||
|
|
* Analyze_fft2048_iq_F32.h Assembled by Bob Larkin 8 Mar 2021
|
||
|
|
*
|
||
|
|
* Note: Teensy 4.x Only, 3.x not supported
|
||
|
|
*
|
||
|
|
* Does Fast Fourier Transform of a 2048 point complex (I-Q) input.
|
||
|
|
* Output is one of three measures of the power in each of the 2048
|
||
|
|
* output bins, Power, RMS level or dB relative to a full scale
|
||
|
|
* sine wave. Windowing of the input data is provided for to reduce
|
||
|
|
* spreading of the power in the output bins. All inputs are Teensy
|
||
|
|
* floating point extension (_F32) and all outputs are floating point.
|
||
|
|
*
|
||
|
|
* Features include:
|
||
|
|
* * I and Q inputs are OpenAudio_Arduino Library F32 compatible.
|
||
|
|
* * FFT output for every 512 inputs to overlapped FFTs to
|
||
|
|
* compensate for windowing.
|
||
|
|
* * Windowing None, Hann, Kaiser and Blackman-Harris.
|
||
|
|
* * Multiple bin-sum output to simulate wider bins.
|
||
|
|
* * Power averaging of multiple FFT
|
||
|
|
* * Soon: F32 audio outputs for I & Q
|
||
|
|
*
|
||
|
|
* Conversion Copyright (c) 2021 Bob Larkin
|
||
|
|
* Same MIT license as PJRC:
|
||
|
|
*
|
||
|
|
* From original real FFT:
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* Does complex input FFT of 2048 points. Multiple non-audio (via functions)
|
||
|
|
* 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 setNAverage(int NAve) // >=1
|
||
|
|
* void setOutputType(int _type)
|
||
|
|
* void setXAxis(uint8_t _xAxis) // 0, 1, 2, 3
|
||
|
|
*
|
||
|
|
* x-Axis direction and offset per setXAxis(xAxis) for sine to I
|
||
|
|
* and cosine to Q.
|
||
|
|
* If xAxis=0 f=fs/2 in middle, f=0 on right edge
|
||
|
|
* If xAxis=1 f=fs/2 in middle, f=0 on left edge
|
||
|
|
* If xAxis=2 f=fs/2 on left edge, f=0 in middle
|
||
|
|
* If xAxis=3 f=fs/2 on right edgr, f=0 in middle
|
||
|
|
* If there is 180 degree phase shift to I or Q these all get reversed.
|
||
|
|
*
|
||
|
|
* Timing, max is longest update() time:
|
||
|
|
* T4.0 Windowed, dBFS Out, 987 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 2048^2/4 = 1048576 without windowing.
|
||
|
|
* Windowing loss cuts this down. The RMS level can grow to sqrt(1048576)
|
||
|
|
* or 2048. The dBFS has been scaled to make this max value 0 dBFS by
|
||
|
|
* removing 60.2 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef analyze_fft2048iq_h_
|
||
|
|
#define analyze_fft2048iq_h_
|
||
|
|
|
||
|
|
// *************** TEENSY 4.X ONLY ****************
|
||
|
|
|
||
|
|
#include "Arduino.h"
|
||
|
|
#include "AudioStream_F32.h"
|
||
|
|
#include "arm_math.h"
|
||
|
|
#include "mathDSP_F32.h"
|
||
|
|
#include "arm_const_structs.h"
|
||
|
|
|
||
|
|
#define FFT_RMS 0
|
||
|
|
#define FFT_POWER 1
|
||
|
|
#define FFT_DBFS 2
|
||
|
|
|
||
|
|
#define NO_WINDOW 0
|
||
|
|
#define AudioWindowNone 0
|
||
|
|
#define AudioWindowHanning2048 1
|
||
|
|
#define AudioWindowKaiser2048 2
|
||
|
|
#define AudioWindowBlackmanHarris2048 3
|
||
|
|
|
||
|
|
class AudioAnalyzeFFT2048_IQ_F32 : public AudioStream_F32 {
|
||
|
|
//GUI: inputs:2, outputs:4 //this line used for automatic generation of GUI node
|
||
|
|
//GUI: shortName:FFT2048IQ
|
||
|
|
public:
|
||
|
|
AudioAnalyzeFFT2048_IQ_F32() : AudioStream_F32(2, 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
|
||
|
|
|
||
|
|
// 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_len2048; // This is one of the structures
|
||
|
|
useHanningWindow();
|
||
|
|
}
|
||
|
|
// There is no varient for "settings," as blocks other than 128 are
|
||
|
|
// not supported and, nothing depends on sample rate so we don't need that.
|
||
|
|
|
||
|
|
// Returns true when output data is available.
|
||
|
|
bool available() {
|
||
|
|
#if defined(__IMXRT1062__)
|
||
|
|
if (outputflag == true) {
|
||
|
|
outputflag = false; // No double returns
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
return false;
|
||
|
|
#else
|
||
|
|
// Don't know how you got this far, but....
|
||
|
|
Serial.println("Teensy 3.x NOT SUPPORTED");
|
||
|
|
return false;
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
// Returns a single bin output
|
||
|
|
float read(unsigned int binNumber) {
|
||
|
|
if (binNumber>2047 || 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 > 2047) return 0.0;
|
||
|
|
if (binLast > 2047) binLast = 2047;
|
||
|
|
float sum = 0;
|
||
|
|
do {
|
||
|
|
sum += output[binFirst++];
|
||
|
|
} while (binFirst <= binLast);
|
||
|
|
return sum;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Sets None, Hann, or Blackman-Harris window with no parameter
|
||
|
|
int windowFunction(int wNum) {
|
||
|
|
if(wNum == AudioWindowKaiser2048)
|
||
|
|
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 == AudioWindowKaiser2048) {
|
||
|
|
if(_kdb<20.0f)
|
||
|
|
kd = 20.0f;
|
||
|
|
else
|
||
|
|
kd = _kdb;
|
||
|
|
useKaiserWindow(kd);
|
||
|
|
}
|
||
|
|
else if (wNum == AudioWindowBlackmanHarris2048)
|
||
|
|
useBHWindow();
|
||
|
|
else
|
||
|
|
useHanningWindow(); // Default
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Fast pointer transfer. Be aware that the data will go away
|
||
|
|
// after the next 256 data points occur.
|
||
|
|
float* getData(void) {
|
||
|
|
// available() sets outputflag false
|
||
|
|
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<2048; i++)
|
||
|
|
*p++ = *pwin++; // Copy for the FFT
|
||
|
|
}
|
||
|
|
|
||
|
|
// Number of FFT averaged in the output
|
||
|
|
void setNAverage(int _nAverage) {
|
||
|
|
nAverage = _nAverage;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Output RMS (default), power or dBFS (FFT_RMS, FFT_POWER, FFT_DBFS)
|
||
|
|
void setOutputType(int _type) {
|
||
|
|
outputType = _type;
|
||
|
|
}
|
||
|
|
|
||
|
|
// xAxis, bit 0 left/right; bit 1 low to high; default 0X03
|
||
|
|
void setXAxis(uint8_t _xAxis) {
|
||
|
|
xAxis = _xAxis;
|
||
|
|
}
|
||
|
|
|
||
|
|
virtual void update(void);
|
||
|
|
|
||
|
|
private:
|
||
|
|
float output[2048];
|
||
|
|
float window[2048];
|
||
|
|
float *pWin = window;
|
||
|
|
float fft_buffer[4096];
|
||
|
|
float sumsq[2048]; // Avoid re-use of output[]
|
||
|
|
uint8_t state = 0;
|
||
|
|
bool outputflag = false;
|
||
|
|
audio_block_f32_t *inputQueueArray[2];
|
||
|
|
audio_block_f32_t *blocklist_i[16];
|
||
|
|
audio_block_f32_t *blocklist_q[16];
|
||
|
|
// For T4.x
|
||
|
|
// const static arm_cfft_instance_f32 arm_cfft_sR_f32_len1024;
|
||
|
|
arm_cfft_instance_f32 Sfft;
|
||
|
|
|
||
|
|
int outputType = FFT_RMS; //Same type as I16 version init
|
||
|
|
int count = 0;
|
||
|
|
int nAverage = 1;
|
||
|
|
uint8_t xAxis = 0x03;
|
||
|
|
|
||
|
|
// The Hann window is a good all-around window
|
||
|
|
void useHanningWindow(void) {
|
||
|
|
for (int i=0; i < 2048; i++) {
|
||
|
|
// 2*PI/2047 = 0.00306946
|
||
|
|
window[i] = 0.5*(1.0 - cosf(0.00306946f*(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 < 2048; i++) {
|
||
|
|
float kx = 0.00306946f; // 2*PI/2047
|
||
|
|
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
|
||
|
|
// 4/(2047^2) = 9.546063E-7;
|
||
|
|
xn2 = 9.546063E-7*xn2*xn2;
|
||
|
|
window[511 - n]=kbes*(mathEqualizer.i0f(beta*sqrtf(1.0-xn2)));
|
||
|
|
window[512 + n] = window[511 - n];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
};
|
||
|
|
#endif
|