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analyze_fft1024_iq_F32.cpp
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analyze_fft1024_iq_F32.cpp
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/*
* analyze_fft1024_iq_F32.cpp Assembled by Bob Larkin 3 Mar 2021
* Rev 6 Mar 2021 - Added setXAxis()
* Rev 10 Mar 2021 Corrected averaging bracket - Bob L
*
* 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
* * Windowing None, Hann, Kaiser and Blackman-Harris.
*
* 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
*
* 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.
*/
#include <Arduino.h>
#include "analyze_fft1024_iq_F32.h"
// Note: Suppports block size of 128 only. Very "built in."
// Move audio data from audio_block_f32_t to the interleaved FFT instance buffer.
static void copy_to_fft_buffer1(void *destination, const void *sourceI, const void *sourceQ) {
const float *srcI = (const float *)sourceI;
const float *srcQ = (const float *)sourceQ;
float *dst = (float *)destination; // part of fft_buffer array. 256 floats per call
for (int i=0; i < 128; i++) {
*dst++ = *srcI++; // real sample, interleave
*dst++ = *srcQ++; // imag
}
}
static void apply_window_to_fft_buffer1(void *fft_buffer, const void *window) {
float *buf = (float *)fft_buffer; // 0th entry is real (do window) 1st is imag
const float *win = (float *)window;
for (int i=0; i < 1024; i++) {
buf[2*i] *= *win; // real
buf[2*i + 1] *= *win++; // imag
}
}
void AudioAnalyzeFFT1024_IQ_F32::update(void) {
audio_block_f32_t *block_i,*block_q;
int ii;
block_i = receiveReadOnly_f32(0);
if (!block_i) return;
block_q = receiveReadOnly_f32(1);
if (!block_q) {
release(block_i);
return;
}
// Here with two new blocks of data
switch (state) {
case 0:
blocklist_i[0] = block_i; blocklist_q[0] = block_q;
state = 1;
break;
case 1:
blocklist_i[1] = block_i; blocklist_q[1] = block_q;
state = 2;
break;
case 2:
blocklist_i[2] = block_i; blocklist_q[2] = block_q;
state = 3;
break;
case 3:
blocklist_i[3] = block_i; blocklist_q[3] = block_q;
state = 4;
break;
case 4:
blocklist_i[4] = block_i; blocklist_q[4] = block_q;
state = 5;
break;
case 5:
blocklist_i[5] = block_i; blocklist_q[5] = block_q;
state = 6;
break;
case 6:
blocklist_i[6] = block_i; blocklist_q[6] = block_q;
state = 7;
break;
case 7:
blocklist_i[7] = block_i; blocklist_q[7] = block_q;
copy_to_fft_buffer1(fft_buffer+0x000, blocklist_i[0]->data, blocklist_q[0]->data);
copy_to_fft_buffer1(fft_buffer+0x100, blocklist_i[1]->data, blocklist_q[1]->data);
copy_to_fft_buffer1(fft_buffer+0x200, blocklist_i[2]->data, blocklist_q[2]->data);
copy_to_fft_buffer1(fft_buffer+0x300, blocklist_i[3]->data, blocklist_q[3]->data);
copy_to_fft_buffer1(fft_buffer+0x400, blocklist_i[4]->data, blocklist_q[4]->data);
copy_to_fft_buffer1(fft_buffer+0x500, blocklist_i[5]->data, blocklist_q[5]->data);
copy_to_fft_buffer1(fft_buffer+0x600, blocklist_i[6]->data, blocklist_q[6]->data);
copy_to_fft_buffer1(fft_buffer+0x700, blocklist_i[7]->data, blocklist_q[7]->data);
if (pWin)
apply_window_to_fft_buffer1(fft_buffer, window);
#if defined(__IMXRT1062__)
// Teensyduino core for T4.x supports arm_cfft_f32
// arm_cfft_f32 (const arm_cfft_instance_f32 *S, float32_t *p1, uint8_t ifftFlag, uint8_t bitReverseFlag)
arm_cfft_f32(&Sfft, fft_buffer, 0, 1);
#else
// For T3.x go back to old (deprecated) style
arm_cfft_radix4_f32(&fft_inst, fft_buffer);
#endif
count++;
for (int i = 0; i < 512; i++) {
// From complex FFT the "negative frequencies" are mirrors of the frequencies above fs/2. So, we get
// frequencies from 0 to fs by re-arranging the coefficients. These are powers (not Volts)
// See DD4WH SDR
float ss0 = fft_buffer[2 * i] * fft_buffer[2 * i] +
fft_buffer[2 * i + 1] * fft_buffer[2 * i + 1];
float ss1 = fft_buffer[2 * (i + 512)] * fft_buffer[2 * (i + 512)] +
fft_buffer[2 * (i + 512) + 1] * fft_buffer[2 * (i + 512) + 1];
if(count==1) { // Starting new average
sumsq[i+512] = ss0;
sumsq[i] = ss1;
}
else if (count <= nAverage) { // Adding on to average
sumsq[i+512] += ss0;
sumsq[i] += ss1;
}
}
if (count >= nAverage) { // Average is finished
count = 0;
float inAf = 1.0f/(float)nAverage;
for (int i=0; i < 1024; i++) {
// xAxis, bit 0 left/right; bit 1 low to high
if(xAxis & 0X02)
ii = i;
else
ii = i^512;
if(xAxis & 0X01)
ii = (1023 - ii);
if(outputType==FFT_RMS)
output[i] = sqrtf(inAf*sumsq[ii]);
else if(outputType==FFT_POWER)
output[i] = inAf*sumsq[ii];
else if(outputType==FFT_DBFS) {
if(sumsq[i]>0.0f)
output[i] = 10.0f*log10f(inAf*sumsq[ii])-54.1854f; // Scaled to FS sine wave
else
output[i] = -193.0f; // lsb for 23 bit mantissa
}
else
output[i] = 0.0f;
} // End, set output[i] over all 512
outputflag = true; // moved; rev10mar2021
} // End of average is finished
release(blocklist_i[0]); release(blocklist_q[0]);
release(blocklist_i[1]); release(blocklist_q[1]);
release(blocklist_i[2]); release(blocklist_q[2]);
release(blocklist_i[3]); release(blocklist_q[3]);
blocklist_i[0] = blocklist_i[4];
blocklist_i[1] = blocklist_i[5];
blocklist_i[2] = blocklist_i[6];
blocklist_i[3] = blocklist_i[7];
blocklist_q[0] = blocklist_q[4];
blocklist_q[1] = blocklist_q[5];
blocklist_q[2] = blocklist_q[6];
blocklist_q[3] = blocklist_q[7];
state = 4;
break; // From case 7
} // End of switch & case 7
} // End update()