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C

/**
* Copyright 2013-2021 Software Radio Systems Limited
*
* This file is part of srsRAN.
*
* srsRAN is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsRAN is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
/**********************************************************************************************
* File: agc.h
*
* Description: Automatic gain control
* This module is not currently used
*
* Reference:
*********************************************************************************************/
#ifndef SRSRAN_AGC_H
#define SRSRAN_AGC_H
#include <complex.h>
#include <stdbool.h>
#include <stdint.h>
#include "srsran/config.h"
#define SRSRAN_AGC_CALLBACK(NAME) void(NAME)(void* h, float gain_db)
#define SRSRAN_AGC_DEFAULT_TARGET (0.3f) /* Average RMS target or maximum peak target*/
#define SRSRAN_AGC_DEFAULT_BW (0.3f) /* Moving average coefficient */
#define SRSRAN_AGC_HOLD_COUNT (20) /* Number of frames to wait after setting the gain before start measuring */
#define SRSRAN_AGC_MIN_MEASUREMENTS (10) /* Minimum number of measurements */
#define SRSRAN_AGC_MIN_GAIN_OFFSET (2.0f) /* Mimum of gain offset to set the radio gain */
typedef enum SRSRAN_API { SRSRAN_AGC_MODE_ENERGY = 0, SRSRAN_AGC_MODE_PEAK_AMPLITUDE } srsran_agc_mode_t;
/*
* The AGC has been implemented using 3 states:
* - init: it simply starts the process of measuring
* - measure: performs a minimum of SRSRAN_AGC_MIN_MEASUREMENTS and does not set the gain until it needs
* SRSRAN_AGC_MIN_GAIN_OFFSET dB more of gain. The gain is set in the enter hold transition.
* - hold: waits for SRSRAN_AGC_HOLD_COUNT frames as a Rx gain transition period. After this period, it enters measure
* state.
*
* FSM abstraction:
*
* +------+ Enter measure +---------+ Enter hold +------+
* | init | ---------------->| Measure |--------------->| Hold |
* +------+ +---------+ +------+
* ^ Enter measure |
* +-------------------------+
*/
typedef enum { SRSRAN_AGC_STATE_INIT = 0, SRSRAN_AGC_STATE_MEASURE, SRSRAN_AGC_STATE_HOLD } srsran_agc_state_t;
typedef struct SRSRAN_API {
float bandwidth;
float gain_db;
float gain_offset_db;
float min_gain_db;
float max_gain_db;
float default_gain_db;
float y_out;
bool isfirst;
void* uhd_handler;
SRSRAN_AGC_CALLBACK(*set_gain_callback);
srsran_agc_mode_t mode;
float target;
uint32_t nof_frames;
uint32_t frame_cnt;
uint32_t hold_cnt;
float* y_tmp;
srsran_agc_state_t state;
} srsran_agc_t;
SRSRAN_API int srsran_agc_init_acc(srsran_agc_t* q, srsran_agc_mode_t mode, uint32_t nof_frames);
SRSRAN_API int srsran_agc_init_uhd(srsran_agc_t* q,
srsran_agc_mode_t mode,
uint32_t nof_frames,
SRSRAN_AGC_CALLBACK(set_gain_callback),
void* uhd_handler);
SRSRAN_API void srsran_agc_free(srsran_agc_t* q);
SRSRAN_API void srsran_agc_reset(srsran_agc_t* q);
SRSRAN_API void srsran_agc_set_gain_range(srsran_agc_t* q, float min_gain_db, float max_gain_db);
SRSRAN_API float srsran_agc_get_gain(srsran_agc_t* q);
SRSRAN_API void srsran_agc_set_gain(srsran_agc_t* q, float init_gain_value_db);
SRSRAN_API void srsran_agc_process(srsran_agc_t* q, cf_t* signal, uint32_t len);
#endif // SRSRAN_AGC_H