diff options
Diffstat (limited to 'dpd/src')
| -rw-r--r-- | dpd/src/TX_Agc.py | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/dpd/src/TX_Agc.py b/dpd/src/TX_Agc.py new file mode 100644 index 0000000..832c4d4 --- /dev/null +++ b/dpd/src/TX_Agc.py @@ -0,0 +1,111 @@ +# -*- coding: utf-8 -*- +# +# Automatic Gain Control +# +# http://www.opendigitalradio.org +# Licence: The MIT License, see notice at the end of this file + +import datetime +import os +import logging +import time + +logging_path = os.path.dirname(logging.getLoggerClass().root.handlers[0].baseFilename) + +import numpy as np +import matplotlib + +matplotlib.use('agg') +import matplotlib.pyplot as plt + +import src.Adapt as Adapt +import src.Measure as Measure + + +#TODO fix for float tx_gain +class TX_Agc: + def __init__(self, + adapt, + max_txgain=70, + tx_max_target=0.85, + tx_max_threshold_max=0.95, + tx_max_threshold_min=0.65): + """ + In order to avoid digital clipping, this class increases the + TX gain and reduces the digital gain. Digital clipping happens + when the digital analog converter receives values greater than + it's maximal output. This class solves that problem by adapting + the TX gain in a way that the peaks of the TX signal are in a + specified range. The TX gain is adapted accordingly. + + :param adapt: Instance of Adapt Class to update + txgain and coefficients + :param max_txgain: limit for TX gain + :param tx_max_threshold_max: if the maximum of TX is larger + than this value, then the digital gain is reduced + :param tx_max_threshold_min: if the maximum of TX is smaller + than this value, then the digital gain is increased + :param tx_max_target: The digital gain is reduced in a way that + the maximal TX value is expected to be lower than this value. + """ + assert isinstance(adapt, Adapt.Adapt) + self.adapt = adapt + self.max_txgain = max_txgain + self.txgain = self.max_txgain + + assert tx_max_threshold_max > tx_max_target,\ + "The tolerated tx_max has to be larger then the goal tx_max" + self.tx_max_threshold_tolerate_max = tx_max_threshold_max + self.tx_max_threshold_tolerate_min = tx_max_threshold_min + self.tx_max_target = tx_max_target + + def adapt_if_necessary(self, tx): + tx_max = np.max(np.abs(tx)) + if tx_max > self.tx_max_threshold_tolerate_max or\ + tx_max < self.tx_max_threshold_tolerate_min: + delta_db = \ + np.floor(20 * np.log10(self.tx_max_target / tx_max)).astype(int) + new_txgain = self.adapt.get_txgain() - delta_db + assert new_txgain < self.max_txgain,\ + "TX_Agc failed. New TX gain of {} is too large.".format( + new_txgain + ) + self.adapt.set_txgain(new_txgain) + txgain = self.adapt.get_txgain() + + digital_gain_factor = 10 ** (delta_db / 20.) + digital_gain = self.adapt.get_digital_gain() * digital_gain_factor + self.adapt.set_digital_gain(digital_gain) + + logging.info( + "digital_gain = {}, txgain_new = {}, " \ + "delta_db = {}, tx_max {}, " \ + "digital_gain_factor = {}". + format(digital_gain, txgain, delta_db, + tx_max, digital_gain_factor)) + + time.sleep(1) + return True + return False + +# The MIT License (MIT) +# +# Copyright (c) 2017 Andreas Steger +# +# 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. |