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/* AFC (Automatic Gain Control) Implementation */
/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <stdint.h>
#include <stdio.h>
#include <osmocom/gsm/gsm_utils.h>
#include <debug.h>
#include <rffe.h>
#include <layer1/agc.h>
#include <calypso/dsp.h>
/* compute the input level present at the antenna based on a baseband
* power measurement of the DSP at baseband */
int16_t agc_inp_dbm8_by_pm(int16_t pm)
{
/* pm is in 1/8 dBm at baseband */
int16_t total_gain_dbm8;
/* compute total current gain */
total_gain_dbm8 = (system_inherent_gain + rffe_get_gain()) * 8;
/* subtract gain from power measurement at baseband level */
return pm - total_gain_dbm8;
}
uint8_t agc_il_by_dbm8(int16_t dbm8)
{
uint16_t il;
/* convert from 1/8 dBm to l1c format: [220..0] in -1/2dBm unit */
if (dbm8 >= 0)
il = 0;
else
il = -dbm8;
/* saturate */
if (il > 4 * 255)
il = 4 * 255;
return (uint8_t)(il >> 2);
}
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