Thesis: introduce vim markers into beacon chapter

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Eric Teunis de Boone 2023-04-28 20:12:09 +02:00
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@ -1,5 +1,7 @@
% vim: fdm=marker fmr=<<<,>>>
\documentclass[../thesis.tex]{subfiles}
% Local preamble <<<
\graphicspath{
{.}
{../../figures/}
@ -32,9 +34,10 @@
\newcommand{\pProp}{\pTrue_d}
\newcommand{\pClock}{\pTrue_c}
% >>> Local Preamble
\begin{document}
\chapter{Disciplining by Beacon}
\chapter{Disciplining by Beacon} %<<<
\label{sec:disciplining}
Time synchronisation for autonomous stations is typically performed with a \gls{GNSS} clock in each station.
The time accuracy supplied by the \gls{GNSS} clock ($\sim 10 \ns$) is not enough to do effective interferometry.
@ -58,8 +61,7 @@ This influences the tradeoff between methods.
In the following, the synchronisation scheme for both the continuous and intermittent beacon are elaborated upon.
\Todo{further outline}
\section{Physical Setup}
\section{Physical Setup} %<<<
\begin{figure}
\centering
@ -178,11 +180,10 @@ The nature of the beacon allows for different methods to determine $(\tMeasArriv
In the following, two approaches for measuring $(\tMeasArriv)_i$ are examined.
\Todo{reword towards next sections?}
%%%%
%%%% >>>
%%%% Pulse
%%%%
\section{Intermittent Pulse Beacon}
\section{Intermittent Pulse Beacon}% <<<
\label{sec:beacon:pulse}
If the stability of the clock allows for it, the synchronisation can be performed during a discrete period.
The tradeoff between the gained accuracy and the timescale between synchronisation periods allows for a dead time of the detectors during synchronisation.
@ -293,13 +294,10 @@ Since the filtered signal is sampled discretely, this means the start of the
% dead time
%%%%
%%%% >>>
%%%% Sine
%%%%
\section{Continuous Sine Beacon}
\section{Continuous Sine Beacon}% <<<
\label{sec:beacon:sine}
% continuous -> can be discrete
In the case that the stations need continuous synchronisation, a different route must be taken.
@ -374,7 +372,7 @@ Later, a mechanism to lift the period degeneracy using an airshower as discrete
%%
%% Phase measurement
\subsection{Phase measurement}
\subsection{Phase measurement}% <<<
A continuous beacon can syntonise an array of antennas by correcting for the measured difference in beacon phases $(\Delta \pMeasArriv)_{ij}$.
They are derived by applying a \gls{FT} to the traces of each antenna.
@ -417,9 +415,9 @@ These aspects are examined in the following section.
}
\label{fig:beacon:ttl_sine_beacon}
\end{figure}
% >>>
% DTFT
\subsubsection{Discrete Time Fourier Transform}
\subsubsection{Discrete Time Fourier Transform}% <<<
% FFT common knowledge ..
The typical \gls{FT} to obtain spectral information from periodic data is the \gls{FFT} (a fast implementation of the \gls{DFT} \eqref{eq:fourier:dft}).
Such an algorithm efficiently finds the magnitudes and phases within a trace $x$ at specific frequencies $f = f_s \tfrac{k}{N}$ determined solely by the number of samples $N$ ($0 \leq k < N$) and the sampling frequency $f_s$.
@ -485,9 +483,9 @@ With a constant beacon frequency, the coefficients for evaluating the \gls{DTFT}
% Removing the beacon from the signal trace
% >>>
% Signal to noise
\subsubsection{Signal to Noise}
\subsubsection{Signal to Noise}% <<<
% Gaussian noise
The traces will contain noise from various sources, both internal (e.g. LNA) and external (e.g. radio communications) to the detector.
@ -587,20 +585,22 @@ Phase distribution: gaussian
\label{fig:time_res_vs_snr}
\end{figure}
% Signal to Noise >>>
\subsection{Period degeneracy}
\subsection{Period degeneracy}% <<<
% period multiplicity/degeneracy
% airshower gives t0
% Period Degeneracy >>>
% Continuous Sine Beacon >>>
% >>>
\bigskip
\section{Old work on Sine Beacon}
\chapter{Old work on Sine Beacon}% <<<
\Todo{fully rewrite}
The idea of a sine beacon is semi-analogous to an oscillator in electronic circuits.
A periodic signal is sent out from a transmitter (the oscillator), and captured by an antenna (the chip the oscillator drives).
@ -681,17 +681,14 @@ This slower timescale allows to count the ticks of the quicker signal.\todo{Exte
\end{figure}
\subsection{Beacons in Airshower timing}
\subsection{Beacons in Airshower timing}% <<<
To setup a time synchronising system for airshower measurements, actually only the high frequency part of the beacon must be employed.
The low frequency part, from which the number of oscillations of the high frequency part are counted, is supplied by the very airshower that is measured.
% >>>
\section{Beacon synchronisation}
\section{Beacon synchronisation}% <<<
As outlined in Section~\ref{sec:time:beacon}, a beacon can also be employed to synchronise the stations.
@ -768,7 +765,7 @@ However, while in a static setup the value of $k$ can be estimated from the dist
\\
\subsection{Lifting period degeneracy}
\subsection{Lifting period degeneracy}% <<<
\begin{figure}
\begin{subfigure}[t]{0.5\textwidth}
\includegraphics[width=\textwidth]{radio_interferometry/dc_grid_power_time_fixes.py.X400.no_offset.scale4d.pdf}
@ -795,7 +792,9 @@ However, while in a static setup the value of $k$ can be estimated from the dist
\label{fig:grid_power_time_fixes}
\end{figure}
% >>>
%>>>
\end{document}