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C

/**
* Copyright 2013-2021 Software Radio Systems Limited
*
* This file is part of srsLTE.
*
* srsLTE 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.
*
* srsLTE 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: resample_arb.h
*
* Description: Arbitrary rate resampler using a polyphase filter bank
* implementation.
*
* Reference: Multirate Signal Processing for Communication Systems
* fredric j. harris
*****************************************************************************/
#ifndef SRSLTE_RESAMPLE_ARB_H
#define SRSLTE_RESAMPLE_ARB_H
#include <complex.h>
#include <stdbool.h>
#include <stdint.h>
#include "srslte/config.h"
#define SRSLTE_RESAMPLE_ARB_N_35 35
#define SRSLTE_RESAMPLE_ARB_N 32 // Polyphase filter rows
#define SRSLTE_RESAMPLE_ARB_M 8 // Polyphase filter columns
typedef struct SRSLTE_API {
float rate; // Resample rate
float step; // Step increment through filter
float acc; // Index into filter
bool interpolate;
cf_t reg[SRSLTE_RESAMPLE_ARB_M]; // Our window of samples
} srslte_resample_arb_t;
SRSLTE_API void srslte_resample_arb_init(srslte_resample_arb_t* q, float rate, bool interpolate);
SRSLTE_API int srslte_resample_arb_compute(srslte_resample_arb_t* q, cf_t* input, cf_t* output, int n_in);
#endif // SRSLTE_RESAMPLE_ARB_