2014-07-21 08:54:25 -07:00
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/**
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*
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* \section COPYRIGHT
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*
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* Copyright 2013-2014 The libLTE Developers. See the
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* COPYRIGHT file at the top-level directory of this distribution.
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*
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* \section LICENSE
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*
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* This file is part of the libLTE library.
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*
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* libLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* libLTE is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* A copy of the GNU Lesser General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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#include <string.h>
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#include <strings.h>
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#include <stdlib.h>
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#include <math.h>
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#include <complex.h>
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#include "liblte/phy/utils/debug.h"
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#include "liblte/phy/agc/agc.h"
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#include "liblte/phy/utils/vector.h"
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#include "liblte/phy/utils/debug.h"
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int agc_init (agc_t *q) {
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bzero(q, sizeof(agc_t));
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2014-07-22 07:56:56 -07:00
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agc_reset(q);
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2014-07-21 08:54:25 -07:00
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return LIBLTE_SUCCESS;
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}
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void agc_free(agc_t *q) {
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bzero(q, sizeof(agc_t));
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}
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2014-07-22 07:56:56 -07:00
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void agc_reset(agc_t *q) {
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q->bandwidth = AGC_DEFAULT_BW;
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q->lock = false;
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q->gain = 1.0;
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q->y_out = 1.0;
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q->isfirst = true;
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}
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2014-07-21 08:54:25 -07:00
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void agc_set_bandwidth(agc_t *q, float bandwidth) {
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q->bandwidth = bandwidth;
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}
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float agc_get_rssi(agc_t *q) {
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return 1.0/q->gain;
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}
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2014-07-22 07:56:56 -07:00
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float agc_get_output_level(agc_t *q) {
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return q->y_out;
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}
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float agc_get_gain(agc_t *q) {
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return q->gain;
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}
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2014-07-21 08:54:25 -07:00
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void agc_lock(agc_t *q, bool enable) {
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q->lock = enable;
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}
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2014-07-22 07:56:56 -07:00
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void agc_process(agc_t *q, cf_t *input, cf_t *output, uint32_t len) {
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// Apply current gain to input signal
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vec_sc_prod_cfc(input, q->gain, output, len);
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// compute output energy estimate
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float y = sqrtf(crealf(vec_dot_prod_conj_ccc(output, output, len))/len);
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2014-07-22 07:56:56 -07:00
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if (q->isfirst) {
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q->y_out = y;
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q->gain = 1/y;
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q->isfirst = false;
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} else {
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q->y_out = (1-q->bandwidth) * q->y_out + q->bandwidth * y;
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if (!q->lock) {
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q->gain *= expf(-0.5*q->bandwidth*logf(q->y_out));
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}
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2014-07-21 08:54:25 -07:00
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}
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2014-07-22 07:56:56 -07:00
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DEBUG("AGC gain: %.3f y_out=%.3f, y=%.3f\n", q->gain, q->y_out, y);
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2014-07-21 08:54:25 -07:00
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}
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