fft_mt_r2iq.h

/*
 * This file is part of SDDC_Driver.
 *
 * =====================
 *      MIT License
 * =====================
 *
 * Copyright (C) 2020 - Oscar Steila
 * Copyright (C) 2020 - Howard Su
 * Copyright (C) 2021 - Hayati Ayguen
 * Copyright (C) 2021 - Phil Ashby
 * Copyright (C) 2025 - RenardSpark
 *
 * 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 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.
 */
 
#pragma once
 
// --- External dependencies --- //
#include <thread>
#include <mutex>
#include <condition_variable>
#include "fftw3.h"
 
// --- Internal dependencies --- //
#include "../config.h"
#include "../dsp/ringbuffer.h"
 
// use up to this many threads
#define N_MAX_R2IQ_THREADS 1
#define PRINT_INPUT_RANGE  0
#define NDECIDX 7 // Number of decimation steps
 
static const int BASE_FFT_SCRAP_SIZE = 2048;
static const int BASE_FFT_USEFUL_SIZE = FFTN_R_ADC;
static const int BASE_FFT_SIZE = BASE_FFT_USEFUL_SIZE + BASE_FFT_SCRAP_SIZE;
static const int BASE_FFT_HALF_SIZE = BASE_FFT_SIZE / 2;
 
struct r2iqThreadArg;
 
class fft_mt_r2iq
{
public:
    fft_mt_r2iq();
    virtual ~fft_mt_r2iq();
 
    void Init(float gain, ringbuffer<int16_t>* buffers, ringbuffer<float>* obuffers);
 
    void TurnOn();
    void TurnOff(void);
    bool IsOn(void);
 
    // --- Decimation --- //
    int getRatio();
    bool setDecimate(uint8_t dec);
    // --- //
 
    void SetRand(bool v) { this->stateADCRand = v; }
    bool getRand() const { return this->stateADCRand; }
 
    void setSideband(bool lsb) { this->useSidebandLSB = lsb; }
    bool getSideband() const { return this->useSidebandLSB; }
 
    float setFreqOffset(float offset);
 
private:
    // --- Tools --- //
    template<bool rand> void convert_float(const int16_t *input, float* output, int size)
    {
        for(int m = 0; m < size; m++)
        {
            int16_t val;
            if (rand && (input[m] & 1))
            {
                val = input[m] ^ (-2);
            }
            else
            {
                val = input[m];
            }
            output[m] = float(val);
        }
    }
 
    void shift_freq(fftwf_complex* dest, const fftwf_complex* source1, const fftwf_complex* source2, int start, int end)
    {
        for (int m = start; m < end; m++)
        {
            // besides circular shift, do complex multiplication with the lowpass filter's spectrum
            // (a+ib)(c+id) = (ac - bd) + i(ad + bc)
            dest[m][0] = source1[m][0] * source2[m][0] - source1[m][1] * source2[m][1];
            dest[m][1] = source1[m][1] * source2[m][0] + source1[m][0] * source2[m][1];
        }
    }
 
    template<bool flip> void copy(fftwf_complex* dest, const fftwf_complex* source, int count)
    {
        if (flip)
        {
            for (int i = 0; i < count; i++)
            {
                dest[i][0] = source[i][0];
                dest[i][1] = -source[i][1];
            }
        }
        else
        {
            for (int i = 0; i < count; i++)
            {
                dest[i][0] = source[i][0];
                dest[i][1] = source[i][1];
            }
        }
    }
 
    bool r2iqOn;        // r2iq on flag
 
    ringbuffer<int16_t>* inputbuffer;    // pointer to input buffers
    size_t inputbuffer_block_size = 0;
 
    ringbuffer<float>* outputbuffer;    // pointer to output buffers
 
    // --- Decimation --- //
    int decimation = 0;   // selected decimation ratio
      // 64 Msps:               0 => 32Msps, 1=> 16Msps, 2 = 8Msps, 3 = 4Msps, 4 = 2Msps
      // 128 Msps: 0 => 64Msps, 1 => 32Msps, 2=> 16Msps, 3 = 8Msps, 4 = 4Msps, 5 = 2Msps
    int decimation_ratio[NDECIDX];  // ratio
 
    // Lookup table linking the decimation level to the size of the resulting FFT
    // Each step divides the fft size by 2
    // Definition : fft_size_per_decimation[x] = FFT_HALF_SIZE / 2^k
    int fft_size_per_decimation[NDECIDX];
    // --- //
 
    bool stateADCRand;       // randomized ADC output
    bool useSidebandLSB;
 
    // number of ffts needed to process one block of the input buffer
    int ffts_per_blocks = 0;
 
    int bufIdx;         // index to next buffer to be processed
    r2iqThreadArg* lastThread;
 
    float GainScale;
 
    // The bin (the portion of the FFT result) in which
    // the desired center frequency is located
    int center_frequency_bin = 0;
 
    void *r2iqThreadf(r2iqThreadArg *th);   // thread function
 
    void * r2iqThreadf_generic(r2iqThreadArg *th);
    void * r2iqThreadf_avx(r2iqThreadArg *th);
    void * r2iqThreadf_avx2(r2iqThreadArg *th);
    void * r2iqThreadf_avx512(r2iqThreadArg *th);
    void * r2iqThreadf_neon(r2iqThreadArg *th);
 
    fftwf_complex **filterHw;       // Hw complex to each decimation ratio
 
    fftwf_plan  plan_time2freq_r2c;      // fftw plan buffers Freq to Time complex to complex per decimation ratio
    fftwf_plan *plan_freq2time;          // fftw plan buffers Time to Freq real to complex per buffer
    fftwf_plan  plan_freq2time_per_decimation[NDECIDX];
 
    uint32_t processor_count;
    r2iqThreadArg* threadArgs[N_MAX_R2IQ_THREADS];
    std::mutex mutexR2iqControl;                   // r2iq control lock
    std::thread r2iq_thread[N_MAX_R2IQ_THREADS]; // thread pointers
};
 
// assure, that ADC is not oversteered?
struct r2iqThreadArg {
 
    r2iqThreadArg()
    {
#if PRINT_INPUT_RANGE
        MinMaxBlockCount = 0;
        MinValue = 0;
        MaxValue = 0;
#endif
    }
 
    uint8_t thread_id;
    float *ADCinTime;         // point to each threads input buffers [nftt][n]
    fftwf_complex *ADCinFreq; // buffers in frequency
    fftwf_complex *inFreqTmp; // tmp decimation output buffers (after tune shift)
#if PRINT_INPUT_RANGE
    int MinMaxBlockCount;
    int16_t MinValue;
    int16_t MaxValue;
#endif
};