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Diffstat (limited to 'python/dpd/RX_Agc.py')
| -rw-r--r-- | python/dpd/RX_Agc.py | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/python/dpd/RX_Agc.py b/python/dpd/RX_Agc.py new file mode 100644 index 0000000..0cc18b8 --- /dev/null +++ b/python/dpd/RX_Agc.py @@ -0,0 +1,166 @@ +# -*- 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 +import numpy as np +import matplotlib +matplotlib.use('agg') +import matplotlib.pyplot as plt + +import dpd.Adapt as Adapt +import dpd.Measure as Measure + +class Agc: + """The goal of the automatic gain control is to set the + RX gain to a value at which all received amplitudes can + be detected. This means that the maximum possible amplitude + should be quantized at the highest possible digital value. + + A problem we have to face, is that the estimation of the + maximum amplitude by applying the max() function is very + unstable. This is due to the maximum’s rareness. Therefore + we estimate a far more robust value, such as the median, + and then approximate the maximum amplitude from it. + + Given this, we tune the RX gain in such a way, that the + received signal fulfills our desired property, of having + all amplitudes properly quantized.""" + + def __init__(self, measure, adapt, c): + assert isinstance(measure, Measure.Measure) + assert isinstance(adapt, Adapt.Adapt) + self.measure = measure + self.adapt = adapt + self.min_rxgain = c.RAGC_min_rxgain + self.rxgain = self.min_rxgain + self.peak_to_median = 1./c.RAGC_rx_median_target + + def run(self): + self.adapt.set_rxgain(self.rxgain) + + for i in range(2): + # Measure + txframe_aligned, tx_ts, rxframe_aligned, rx_ts, rx_median= \ + self.measure.get_samples() + + # Estimate Maximum + rx_peak = self.peak_to_median * rx_median + correction_factor = 20*np.log10(1/rx_peak) + self.rxgain = self.rxgain + correction_factor + + assert self.min_rxgain <= self.rxgain, ("Desired RX Gain is {} which is smaller than the minimum of {}".format( + self.rxgain, self.min_rxgain)) + + logging.info("RX Median {:1.4f}, estimated peak {:1.4f}, correction factor {:1.4f}, new RX gain {:1.4f}".format( + rx_median, rx_peak, correction_factor, self.rxgain + )) + + self.adapt.set_rxgain(self.rxgain) + time.sleep(0.5) + + def plot_estimates(self): + """Plots the estimate of for Max, Median, Mean for different + number of samples.""" + if self.c.plot_location is None: + return + + self.adapt.set_rxgain(self.min_rxgain) + time.sleep(1) + + dt = datetime.datetime.now().isoformat() + fig_path = self.c.plot_location + "/" + dt + "_agc.png" + fig, axs = plt.subplots(2, 2, figsize=(3*6,1*6)) + axs = axs.ravel() + + for j in range(5): + txframe_aligned, tx_ts, rxframe_aligned, rx_ts, rx_median =\ + self.measure.get_samples() + + rxframe_aligned_abs = np.abs(rxframe_aligned) + + x = np.arange(100, rxframe_aligned_abs.shape[0], dtype=int) + rx_max_until = [] + rx_median_until = [] + rx_mean_until = [] + for i in x: + rx_max_until.append(np.max(rxframe_aligned_abs[:i])) + rx_median_until.append(np.median(rxframe_aligned_abs[:i])) + rx_mean_until.append(np.mean(rxframe_aligned_abs[:i])) + + axs[0].plot(x, + rx_max_until, + label="Run {}".format(j+1), + color=matplotlib.colors.hsv_to_rgb((1./(j+1.),0.8,0.7)), + linestyle="-", linewidth=0.25) + axs[0].set_xlabel("Samples") + axs[0].set_ylabel("Amplitude") + axs[0].set_title("Estimation for Maximum RX Amplitude") + axs[0].legend() + + axs[1].plot(x, + rx_median_until, + label="Run {}".format(j+1), + color=matplotlib.colors.hsv_to_rgb((1./(j+1.),0.9,0.7)), + linestyle="-", linewidth=0.25) + axs[1].set_xlabel("Samples") + axs[1].set_ylabel("Amplitude") + axs[1].set_title("Estimation for Median RX Amplitude") + axs[1].legend() + ylim_1 = axs[1].get_ylim() + + axs[2].plot(x, + rx_mean_until, + label="Run {}".format(j+1), + color=matplotlib.colors.hsv_to_rgb((1./(j+1.),0.9,0.7)), + linestyle="-", linewidth=0.25) + axs[2].set_xlabel("Samples") + axs[2].set_ylabel("Amplitude") + axs[2].set_title("Estimation for Mean RX Amplitude") + ylim_2 = axs[2].get_ylim() + axs[2].legend() + + axs[1].set_ylim(min(ylim_1[0], ylim_2[0]), + max(ylim_1[1], ylim_2[1])) + + fig.tight_layout() + fig.savefig(fig_path) + + axs[3].hist(rxframe_aligned_abs, bins=60) + axs[3].set_xlabel("Amplitude") + axs[3].set_ylabel("Frequency") + axs[3].set_title("Histogram of Amplitudes") + axs[3].legend() + + fig.tight_layout() + fig.savefig(fig_path) + plt.close(fig) + + +# 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. |