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/*
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* analyze_fft2048_iq_F32.cpp Assembled by Bob Larkin 8 Mar 2021 |
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* |
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* This class is Teensy 4.x ONLY. |
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* F32 Bolocks are always 128 floats, and any data rate is OK. |
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*
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* Converted to F32 floating point input and also extended |
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* for complex I and Q inputs |
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* * Adapted all I/O to be F32 floating point for OpenAudio_ArduinoLibrary |
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* * Future: Add outputs for I & Q FFT x2 for overlapped FFT |
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* * Windowing None, Hann, Kaiser and Blackman-Harris. |
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* |
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* Conversion Copyright (c) 2021 Bob Larkin |
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* Same MIT license as PJRC: |
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* |
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* Audio Library for Teensy 3.X |
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* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com |
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* |
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* Development of this audio library was funded by PJRC.COM, LLC by sales of |
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* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop |
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* open source software by purchasing Teensy or other PJRC products. |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this software and associated documentation files (the "Software"), to deal |
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* in the Software without restriction, including without limitation the rights |
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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* copies of the Software, and to permit persons to whom the Software is |
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* furnished to do so, subject to the following conditions: |
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* |
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* The above copyright notice, development funding notice, and this permission |
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* notice shall be included in all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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* THE SOFTWARE. |
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*/ |
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#include <Arduino.h> |
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#include "analyze_fft2048_iq_F32.h" |
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// Note: Suppports block size of 128 only. Very "built in."
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// Move audio data from audio_block_f32_t to the interleaved FFT instance buffer.
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static void copy_to_fft_buffer1(void *destination, const void *sourceI, const void *sourceQ) { |
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const float *srcI = (const float *)sourceI; |
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const float *srcQ = (const float *)sourceQ; |
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float *dst = (float *)destination; // part of fft_buffer array. 256 floats per call
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for (int i=0; i < 128; i++) { |
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*dst++ = *srcI++; // real sample, interleave
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*dst++ = *srcQ++; // imag
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} |
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} |
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static void apply_window_to_fft_buffer1(void *fft_buffer, const void *window) { |
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float *buf = (float *)fft_buffer; // 0th entry is real (do window) 1st is imag
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const float *win = (float *)window; |
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for (int i=0; i < 2048; i++) { |
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buf[2*i] *= *win; // real
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buf[2*i + 1] *= *win++; // imag
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} |
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} |
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void AudioAnalyzeFFT2048_IQ_F32::update(void) { |
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audio_block_f32_t *block_i,*block_q; |
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int ii; |
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uint32_t tt; |
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block_i = receiveReadOnly_f32(0); |
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if (!block_i) return; |
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block_q = receiveReadOnly_f32(1); |
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if (!block_q) { |
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release(block_i); |
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return; |
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} |
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// Here with two new blocks of data
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tt=micros(); |
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switch (state) { |
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case 0: |
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blocklist_i[0] = block_i; blocklist_q[0] = block_q; |
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state = 1; |
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break; |
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case 1: |
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blocklist_i[1] = block_i; blocklist_q[1] = block_q; |
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state = 2; |
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break; |
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case 2: |
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blocklist_i[2] = block_i; blocklist_q[2] = block_q; |
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state = 3; |
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break; |
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case 3: |
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blocklist_i[3] = block_i; blocklist_q[3] = block_q; |
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state = 4; |
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break; |
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case 4: |
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blocklist_i[4] = block_i; blocklist_q[4] = block_q; |
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state = 5; |
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break; |
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case 5: |
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blocklist_i[5] = block_i; blocklist_q[5] = block_q; |
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state = 6; |
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break; |
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case 6: |
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blocklist_i[6] = block_i; blocklist_q[6] = block_q; |
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state = 7; |
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break; |
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case 7: |
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blocklist_i[7] = block_i; blocklist_q[7] = block_q; |
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state = 8; |
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break; |
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case 8: |
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blocklist_i[8] = block_i; blocklist_q[8] = block_q; |
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state = 9; |
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break; |
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case 9: |
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blocklist_i[9] = block_i; blocklist_q[9] = block_q; |
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state = 10; |
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break; |
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case 10: |
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blocklist_i[10] = block_i; blocklist_q[10] = block_q; |
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state = 11; |
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break; |
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case 11: |
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blocklist_i[11] = block_i; blocklist_q[11] = block_q; |
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state = 12; |
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break; |
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case 12: |
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blocklist_i[12] = block_i; blocklist_q[12] = block_q; |
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state = 13; |
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break; |
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case 13: |
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blocklist_i[13] = block_i; blocklist_q[13] = block_q; |
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state = 14; |
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break; |
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case 14: |
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blocklist_i[14] = block_i; blocklist_q[14] = block_q; |
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state = 15; |
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break; |
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case 15: |
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blocklist_i[15] = block_i; blocklist_q[15] = block_q; |
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copy_to_fft_buffer1(fft_buffer+0x000, blocklist_i[0]->data, blocklist_q[0]->data); |
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copy_to_fft_buffer1(fft_buffer+0x100, blocklist_i[1]->data, blocklist_q[1]->data); |
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copy_to_fft_buffer1(fft_buffer+0x200, blocklist_i[2]->data, blocklist_q[2]->data); |
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copy_to_fft_buffer1(fft_buffer+0x300, blocklist_i[3]->data, blocklist_q[3]->data); |
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copy_to_fft_buffer1(fft_buffer+0x400, blocklist_i[4]->data, blocklist_q[4]->data); |
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copy_to_fft_buffer1(fft_buffer+0x500, blocklist_i[5]->data, blocklist_q[5]->data); |
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copy_to_fft_buffer1(fft_buffer+0x600, blocklist_i[6]->data, blocklist_q[6]->data); |
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copy_to_fft_buffer1(fft_buffer+0x700, blocklist_i[7]->data, blocklist_q[7]->data); |
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copy_to_fft_buffer1(fft_buffer+0x800, blocklist_i[8]->data, blocklist_q[8]->data); |
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copy_to_fft_buffer1(fft_buffer+0x900, blocklist_i[9]->data, blocklist_q[9]->data); |
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copy_to_fft_buffer1(fft_buffer+0xA00, blocklist_i[10]->data, blocklist_q[10]->data); |
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copy_to_fft_buffer1(fft_buffer+0xB00, blocklist_i[11]->data, blocklist_q[11]->data); |
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copy_to_fft_buffer1(fft_buffer+0xC00, blocklist_i[12]->data, blocklist_q[12]->data); |
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copy_to_fft_buffer1(fft_buffer+0xD00, blocklist_i[13]->data, blocklist_q[13]->data); |
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copy_to_fft_buffer1(fft_buffer+0xE00, blocklist_i[14]->data, blocklist_q[14]->data); |
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copy_to_fft_buffer1(fft_buffer+0xF00, blocklist_i[15]->data, blocklist_q[15]->data); |
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if (pWin) |
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apply_window_to_fft_buffer1(fft_buffer, window); |
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// Teensyduino core for T4.x supports arm_cfft_f32
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// arm_cfft_f32 (const arm_cfft_instance_f32 *S, float32_t *p1, uint8_t ifftFlag, uint8_t bitReverseFlag)
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arm_cfft_f32(&Sfft, fft_buffer, 0, 1); |
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count++; |
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for (int i = 0; i < 1024; i++) { |
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// From complex FFT the "negative frequencies" are mirrors of the frequencies above fs/2. So, we get
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// frequencies from 0 to fs by re-arranging the coefficients. These are powers (not Volts)
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// See DD4WH SDR
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float ss0 = fft_buffer[2 * i] * fft_buffer[2 * i] + |
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fft_buffer[2 * i + 1] * fft_buffer[2 * i + 1]; |
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float ss1 = fft_buffer[2 * (i + 1024)] * fft_buffer[2 * (i + 1024)] + |
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fft_buffer[2 * (i + 1024) + 1] * fft_buffer[2 * (i + 1024) + 1]; |
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if(count==1) { // Starting new average
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sumsq[i+1024] = ss0; |
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sumsq[i] = ss1; |
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} |
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else if (count <= nAverage) { // Adding on to average
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sumsq[i+1024] += ss0; |
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sumsq[i] += ss1; |
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} |
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} |
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if (count >= nAverage) { // Average is finished
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count = 0; |
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float inAf = 1.0f/(float)nAverage; |
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for (int i=0; i < 2048; i++) { |
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// xAxis, bit 0 left/right; bit 1 low to high
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if(xAxis & 0X02) |
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ii = i; |
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else |
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ii = i^1024; |
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if(xAxis & 0X01) |
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ii = (2047 - ii); |
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if(outputType==FFT_RMS) |
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output[i] = sqrtf(inAf*sumsq[ii]); |
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else if(outputType==FFT_POWER) |
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output[i] = inAf*sumsq[ii]; |
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else if(outputType==FFT_DBFS) |
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output[i] = 10.0f*log10f(inAf*sumsq[ii])-60.21f; // Scaled to FS sine wave
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else |
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output[i] = 0.0f; |
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} |
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} // end of Average is Finished
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outputflag = true; |
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release(blocklist_i[0]); release(blocklist_q[0]); |
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release(blocklist_i[1]); release(blocklist_q[1]); |
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release(blocklist_i[2]); release(blocklist_q[2]); |
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release(blocklist_i[3]); release(blocklist_q[3]); |
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release(blocklist_i[4]); release(blocklist_q[4]); |
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release(blocklist_i[5]); release(blocklist_q[5]); |
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release(blocklist_i[6]); release(blocklist_q[6]); |
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release(blocklist_i[7]); release(blocklist_q[7]); |
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blocklist_i[0] = blocklist_i[8]; |
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blocklist_i[1] = blocklist_i[9]; |
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blocklist_i[2] = blocklist_i[10]; |
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blocklist_i[3] = blocklist_i[11]; |
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blocklist_i[4] = blocklist_i[12]; |
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blocklist_i[5] = blocklist_i[13]; |
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blocklist_i[6] = blocklist_i[14]; |
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blocklist_i[7] = blocklist_i[15]; |
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blocklist_q[0] = blocklist_q[8]; |
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blocklist_q[1] = blocklist_q[9]; |
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blocklist_q[2] = blocklist_q[10]; |
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blocklist_q[3] = blocklist_q[11]; |
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blocklist_q[4] = blocklist_q[12]; |
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blocklist_q[5] = blocklist_q[13]; |
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blocklist_q[6] = blocklist_q[14]; |
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blocklist_q[7] = blocklist_q[15]; |
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state = 8; Serial.println(micros()-tt); |
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break; // From case 15
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} // End of switch & case 15
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} // End update()
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@ -0,0 +1,300 @@ |
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/*
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* Analyze_fft2048_iq_F32.h Assembled by Bob Larkin 8 Mar 2021 |
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* |
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* Note: Teensy 4.x Only, 3.x not supported |
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* |
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* Does Fast Fourier Transform of a 2048 point complex (I-Q) input. |
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* Output is one of three measures of the power in each of the 2048 |
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* output bins, Power, RMS level or dB relative to a full scale |
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* sine wave. Windowing of the input data is provided for to reduce |
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* spreading of the power in the output bins. All inputs are Teensy |
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* floating point extension (_F32) and all outputs are floating point. |
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* |
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* Features include: |
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* * I and Q inputs are OpenAudio_Arduino Library F32 compatible. |
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* * FFT output for every 512 inputs to overlapped FFTs to |
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* compensate for windowing. |
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* * Windowing None, Hann, Kaiser and Blackman-Harris. |
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* * Multiple bin-sum output to simulate wider bins. |
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* * Power averaging of multiple FFT |
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* * Soon: F32 audio outputs for I & Q |
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* |
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* Conversion Copyright (c) 2021 Bob Larkin |
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* Same MIT license as PJRC: |
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* |
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* From original real FFT: |
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* Audio Library for Teensy 3.X |
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* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com |
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* |
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* Development of this audio library was funded by PJRC.COM, LLC by sales of |
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* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop |
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* open source software by purchasing Teensy or other PJRC products. |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this software and associated documentation files (the "Software"), to deal |
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* in the Software without restriction, including without limitation the rights |
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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|
* copies of the Software, and to permit persons to whom the Software is |
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* furnished to do so, subject to the following conditions: |
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* |
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* The above copyright notice, development funding notice, and this permission |
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* notice shall be included in all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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* THE SOFTWARE. |
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*/ |
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/* Does complex input FFT of 2048 points. Multiple non-audio (via functions)
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* output formats of RMS (same as I16 version, and default), |
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* Power or dBFS (full scale). Output can be bin by bin or a pointer to |
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* the output array is available. Several window functions are provided by |
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* in-class design, or a custom window can be provided from the INO. |
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* |
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* Functions (See comments below and #defines above: |
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* bool available() |
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* float read(unsigned int binNumber) |
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* float read(unsigned int binFirst, unsigned int binLast) |
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* int windowFunction(int wNum) |
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* int windowFunction(int wNum, float _kdb) // Kaiser only
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* float* getData(void) |
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* float* getWindow(void) |
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* void putWindow(float *pwin) |
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* void setNAverage(int NAve) // >=1
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* void setOutputType(int _type) |
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* void setXAxis(uint8_t _xAxis) // 0, 1, 2, 3
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* |
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* x-Axis direction and offset per setXAxis(xAxis) for sine to I |
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* and cosine to Q. |
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* If xAxis=0 f=fs/2 in middle, f=0 on right edge |
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* If xAxis=1 f=fs/2 in middle, f=0 on left edge |
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* If xAxis=2 f=fs/2 on left edge, f=0 in middle |
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* If xAxis=3 f=fs/2 on right edgr, f=0 in middle |
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* If there is 180 degree phase shift to I or Q these all get reversed. |
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* |
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* Timing, max is longest update() time: |
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* T4.0 Windowed, dBFS Out, 987 uSec |
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* |
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* Scaling: |
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* Full scale for floating point DSP is a nebulous concept. Normally the |
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* full scale is -1.0 to +1.0. This is an unscaled FFT and for a sine |
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* wave centered in frequency on a bin and of FS amplitude, the power |
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* at that center bin will grow by 2048^2/4 = 1048576 without windowing. |
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* Windowing loss cuts this down. The RMS level can grow to sqrt(1048576) |
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* or 2048. The dBFS has been scaled to make this max value 0 dBFS by |
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* removing 60.2 dB. With floating point, the dynamic range is maintained |
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* no matter how it is scaled, but this factor needs to be considered |
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* when building the INO. |
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*/ |
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#ifndef analyze_fft2048iq_h_ |
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#define analyze_fft2048iq_h_ |
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// *************** TEENSY 4.X ONLY ****************
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#include "Arduino.h" |
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#include "AudioStream_F32.h" |
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#include "arm_math.h" |
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#include "mathDSP_F32.h" |
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#include "arm_const_structs.h" |
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#define FFT_RMS 0 |
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#define FFT_POWER 1 |
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#define FFT_DBFS 2 |
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#define NO_WINDOW 0 |
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#define AudioWindowNone 0 |
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#define AudioWindowHanning2048 1 |
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#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 |
@ -0,0 +1,65 @@ |
|||||||
|
|
||||||
|
// TestFFT2048iq.ino for Teensy 4.x
|
||||||
|
// Bob Larkin 9 March 2021
|
||||||
|
|
||||||
|
// Generate Sin and Cosine pair and input to IQ FFT.
|
||||||
|
// Serial Print out powers of all 2048 bins in
|
||||||
|
// dB relative to Sine Wave Full Scale
|
||||||
|
|
||||||
|
// Public Domain
|
||||||
|
|
||||||
|
#include "OpenAudio_ArduinoLibrary.h" |
||||||
|
#include "AudioStream_F32.h" |
||||||
|
|
||||||
|
// GUItool: begin automatically generated code
|
||||||
|
AudioSynthSineCosine_F32 sine_cos1; //xy=76,532
|
||||||
|
AudioAnalyzeFFT2048_IQ_F32 FFT2048iq1; //xy=243,532
|
||||||
|
AudioOutputI2S_F32 audioOutI2S1; //xy=246,591
|
||||||
|
AudioConnection_F32 patchCord1(sine_cos1, 0, FFT2048iq1, 0); |
||||||
|
AudioConnection_F32 patchCord2(sine_cos1, 1, FFT2048iq1, 1); |
||||||
|
// GUItool: end automatically generated code
|
||||||
|
|
||||||
|
void setup(void) { |
||||||
|
float* pPwr; |
||||||
|
|
||||||
|
Serial.begin(9600); |
||||||
|
delay(1000); |
||||||
|
AudioMemory_F32(50); |
||||||
|
Serial.println("FFT2048IQ Test"); |
||||||
|
|
||||||
|
sine_cos1.amplitude(1.0f); // Initialize Waveform Generator
|
||||||
|
|
||||||
|
// Pick T4.x bin center
|
||||||
|
sine_cos1.frequency(689.0625f); |
||||||
|
|
||||||
|
// or pick any old frequency
|
||||||
|
//sine_cos1.frequency(7100.0);
|
||||||
|
|
||||||
|
// elect the output format
|
||||||
|
FFT2048iq1.setOutputType(FFT_DBFS); |
||||||
|
|
||||||
|
// Select the wndow function
|
||||||
|
//FFT2048iq1.windowFunction(AudioWindowNone);
|
||||||
|
//FFT2048iq1.windowFunction(AudioWindowHanning2048);
|
||||||
|
//FFT2048iq1.windowFunction(AudioWindowKaiser2048, 55.0f);
|
||||||
|
FFT2048iq1.windowFunction(AudioWindowBlackmanHarris2048); |
||||||
|
|
||||||
|
// Uncomment to Serial print window function
|
||||||
|
//float* pw = FFT2048iq1.getWindow(); // Print window
|
||||||
|
//for (int i=0; i<2048; i++) Serial.println(pw[i], 4);
|
||||||
|
|
||||||
|
// xAxis, bit 0 left/right; bit 1 low to high; default 0X03
|
||||||
|
FFT2048iq1.setXAxis(0X03); |
||||||
|
|
||||||
|
delay(1000); |
||||||
|
// Print output, once
|
||||||
|
if( FFT2048iq1.available() ) { |
||||||
|
pPwr = FFT2048iq1.getData(); |
||||||
|
for(int i=0; i<2048; i++) |
||||||
|
Serial.println(*(pPwr + i), 8 ); |
||||||
|
} |
||||||
|
Serial.println(""); |
||||||
|
} |
||||||
|
|
||||||
|
void loop(void) { |
||||||
|
} |
Loading…
Reference in new issue