@ -1,15 +1,27 @@
/* analyze_fft256_iq_F32.h
/* analyze_fft256_iq_F32.h Assembled by Bob Larkin 6 Mar 2021
*
* Converted to F32 floating point input and also extended
* for complex I and Q inputs
* * Adapted all I / O to be F32 floating point for OpenAudio_ArduinoLibrary
* * Future : Add outputs for I & Q FFT x2 for overlapped FFT
* Rev 6 Mar 2021 - Added setXAxis ( )
* Rev 7 Mar 2021 - Corrected bug in applying windowing
*
* Does Fast Fourier Transform of a 256 point complex ( I - Q ) input .
* Output is one of three measures of the power in each of the 256
* 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 128 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 :
*
*
* Audio Library for Teensy 3. X
* Copyright ( c ) 2014 , Paul Stoffregen , paul @ pjrc . com
*
@ -36,8 +48,8 @@
* THE SOFTWARE .
*/
/* Does complex input FFT of 1024 points. Output is not audio, and is magnitude
* only . Multiple o utput formats of RMS ( same as I16 version , and default ) ,
/* Does complex input FFT of 256 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 .
@ -51,7 +63,17 @@
* 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 :
* T3 .6 Windowed , RMS out , - uSec max
@ -75,13 +97,13 @@
# ifndef analyze_fft256iq_h_
# define analyze_fft256iq_h_
//#include "AudioStream.h"
//#include "arm_math.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
@ -97,10 +119,21 @@ class AudioAnalyzeFFT256_IQ_F32 : public AudioStream_F32 {
//GUI: inputs:2, outputs:4 //this line used for automatic generation of GUI node
//GUI: shortName:AnalyzeFFT256IQ
public :
AudioAnalyzeFFT256_IQ_F32 ( ) : AudioStream_F32 ( 2 , inputQueueArray ) { // NEEDS SETTINGS etc <<<<<<<<
arm_cfft_radix4_init_f32 ( & fft_inst , 256 , 0 , 1 ) ;
AudioAnalyzeFFT256_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
# 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_len256 ; // This is one of the structures
# else
arm_cfft_radix4_init_f32 ( & fft_inst , 256 , 0 , 1 ) ; // for T3.x
# endif
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.
bool available ( ) {
if ( outputflag = = true ) {
@ -181,6 +214,17 @@ public:
outputType = _type ;
}
// Output power (non-coherent) averaging
// i.e., the number of FFT powers averaged in the output
void setNAverage ( int _nAverage ) {
nAverage = _nAverage ;
}
// xAxis, bit 0 left/right; bit 1 low to high; default 0X03
void setXAxis ( uint8_t _xAxis ) {
xAxis = _xAxis ;
}
virtual void update ( void ) ;
private :
@ -193,10 +237,17 @@ private:
bool outputflag = false ;
audio_block_f32_t * inputQueueArray [ 2 ] ;
audio_block_f32_t * prevblock_i , * prevblock_q ;
# if defined(__IMXRT1062__)
// For T4.x
// const static arm_cfft_instance_f32 arm_cfft_sR_f32_len256;
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 count = 0 ;
int nAverage = 1 ;
uint8_t xAxis = 3 ;
// The Hann window is a good all-around window
void useHanningWindow ( void ) {
@ -238,8 +289,6 @@ private:
kbes = 1.0f / mathEqualizer . i0f ( beta ) ; // An additional derived parameter used in loop
for ( int n = 0 ; n < 128 ; n + + ) {
xn2 = 0.5f + ( float32_t ) n ;
// 4/(1023^2)=0.00000382215877f
// xn2 = 0.00000382215877f*xn2*xn2;
// 4/(255^2)=0.000061514802f
xn2 = 0.000061514802f * xn2 * xn2 ;
window [ 127 - n ] = kbes * ( mathEqualizer . i0f ( beta * sqrtf ( 1.0 - xn2 ) ) ) ;
boblark
4 years ago