From 62e4fe1cac74a1055c20212f246d3547e976bd4f Mon Sep 17 00:00:00 2001
From: sara <sara.halter@gmx.ch>
Date: Tue, 12 Oct 2021 16:56:07 +0200
Subject: Simulations Versuch von AM und SSB

---
 doc/thesis/chapters/theory.tex | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'doc/thesis/chapters/theory.tex')

diff --git a/doc/thesis/chapters/theory.tex b/doc/thesis/chapters/theory.tex
index de1524d..67938f1 100644
--- a/doc/thesis/chapters/theory.tex
+++ b/doc/thesis/chapters/theory.tex
@@ -13,14 +13,14 @@
 
 \subsection{Continuous time model}
 
-Continuous time small scale fading channel response.
+Continuous time small scale fading channel response. \cite{Alimohammad2009}
 
 time varying channel impulse response:
 \begin{equation}
 	h(t, \tau) = \sum_k c_k (t) \delta(\tau - \tau_k(t))
 \end{equation}
 
-received signal \(y = h * x\), i.e. convolution with channel model.
+received signal \(y = h * x\), i.e. convolution with channel model. 
 
 \subsection{Time discretization of the model}
 
-- 
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From bbf0196c4f77bc7dbc8a021a09d30b40b2168427 Mon Sep 17 00:00:00 2001
From: Naoki Pross <np@0hm.ch>
Date: Tue, 12 Oct 2021 19:35:21 +0200
Subject: Block diagram of communication and start AM and QAM

---
 doc/thesis/chapters/theory.tex | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

(limited to 'doc/thesis/chapters/theory.tex')

diff --git a/doc/thesis/chapters/theory.tex b/doc/thesis/chapters/theory.tex
index de1524d..4b4f1f7 100644
--- a/doc/thesis/chapters/theory.tex
+++ b/doc/thesis/chapters/theory.tex
@@ -1,14 +1,48 @@
-% vim: set ts=2 sw=2 noet:
+% vim: set ts=2 sw=2 noet spell:
 
 \chapter{Theory}
 
+\section{Review of modulation schemes}
+
+\begin{figure}
+	\centering
+	\input{figures/tikz/overview}
+	\caption{
+		Block diagram for a general wireless communication system with annotated signal names.
+		Frequency domain representations of signals use the uppercase symbol of their respective time domain name.
+		\label{fig:notation}
+	}
+\end{figure}
+
+In this section we will briefly give the mathematical background required by the modulation schemes used in the project. For conciseness encoding schemes and (digital) signal processing calculations are left out and discussed later. Thus in this section is \(m_e = m\).
+
+\paragraph{AM / DSB}
+
+Ordinary amplitude modulation (AM), sometimes also known as double sideband (DSB) modulation in its simplest form is mathematically formulated in time and frequency domain through the following equations\cite{Hsu}:
+\begin{subequations}
+	\begin{align}
+		x(t) &= \big( 1 + \mu m(t) \big) x_c(t), \\
+		X(\omega) &= \pi\delta(-\omega_c)
+			+ \pi\delta(\omega_c)
+			+ \frac{\mu}{2} M(\omega - \omega_c)
+			+ \frac{\mu}{2} M(\omega + \omega_c).
+	\end{align}
+\end{subequations}
+Where \(\mu > 0\) is the so called modulation factor, that can be adjusted to avoid clipping and improve performance.
+
+\subsection{Quadrature amplitude modulation (QAM)}
+
+Quadrature amplitude modulation is a family of modern digital modulation methods, that use an analog carrier signal. In general a QAM signal has the form
+
+\paragraph{QPSK}
+
 \section{Problem description}
 
 \section{Geometric Model}
 
 \section{Statistical Model}
-%% TODO: write about advantage of statistical model instead of geometric
 
+%% TODO: write about advantage of statistical model instead of geometric
 %% TODO: review and rewrite notes
 
 \subsection{Continuous time model}
-- 
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