From 5b73c7157aad4d65eee7af41fd4b4ded1a434b96 Mon Sep 17 00:00:00 2001
From: thing1 <thing1@seacrossedlovers.xyz>
Date: Sat, 29 Mar 2025 11:36:57 +0000
Subject: minor change

---
 electronics/cw2/writeup.tex | 48 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

(limited to 'electronics/cw2/writeup.tex')

diff --git a/electronics/cw2/writeup.tex b/electronics/cw2/writeup.tex
index 76ad34e..0d3852b 100644
--- a/electronics/cw2/writeup.tex
+++ b/electronics/cw2/writeup.tex
@@ -409,9 +409,57 @@ When accounting for this the adjusted power output calculations look like this
 
 \section{System realisation}
 \subsection{Circuit diagram} % repeat of what was shown before
+Below is a repeat of my circuit diagram, to compare against later.
+
+\begin{center}
+	\includegraphics[angle=270, scale=0.8]{diagrams/fulldiagram.png}
+\end{center}
+
 \subsection{Circuit realisation} % show the actual thing, describe colour coding, etc. etc.
 \subsection{Circuit results} % prove the whole thing works from start to finish
+To test my system I put a number of different frequencies through the system, and I confirmed that the output frequency matched the input. The frequencies are passed into an antenna inside the room I was testing, and then is picked up by the receiver, and passes through the entire system. The outputs are measured from the output of the push pull power amp. 
+
+I am using a 7Khz carrier wave , as I found this to be the best frequency for the receiver to pick up. This will have been caused by the capacitor and inductor values having a specific frequency that they let through.
+
+\begin{center}
+	One can calculate the break frequency of the receiver like so.
+	\[ f _ b = \frac{1}{2 \pi \sqrt{CL}} \]	
+	\[ f _ b = \frac{1}{2 \pi \sqrt{(470 \times 10 ^{-9})(1.1 \times 10 ^{-3})}} \]	
+	\[ f _ b = \frac{1}{2 \pi \sqrt{5.17 \times 10 ^ {-3}}} \]	
+	\[ f _ b = \frac{1}{2 \pi \times (2.2737 \times 10 ^ {-3})} \]	
+	\[ f _ b = \frac{1}{1.14286 \times 10 ^{-4}} \]	
+	\\
+	\[f _ b = 6999.62hz\]
+
+	\[f _ b = 7Khz\]
+\end{center}
+
+Here are my results; these results were tested with the 7Khz carrier wave.
+
+\begin{center}
+	\begin{tabular}{ |c|c| } 
+		\hline
+		freq in & freq out \\ 
+		\hline
+		50hz & 40hz \\
+		500hz & 480hz \\
+		1Khz & 1.01Khz \\
+		3.2Khz & 3.3Khz \\ 
+		5Khz & 4.9Khz \\
+		6.5Khz & 6.3Khz \\
+		\hline
+	\end{tabular}
+
+	\textit{All of these values are approximate, as the signals flickered on the oscilloscope, and the signal generator creating these signals were read of the possibly inaccurate dial of the generator.}
+\end{center}
+
+These results are around what is expected for the inputs. On the lower frequencies, things were slightly off, due to the filter being used for the AM demodulation. And on the higher end, things were being cut off as we were getting too close to the carrier frequency, which caused parts of the signal to be lost.
+
 \subsection{Circuit testing} % show evidence of the results shown in the results section (lots of photos)
+Here is the scope trace of the input at 3.3Khz.
+
+\includegraphics[width=\textwidth]{diagrams/pics/finaloutput.jpg}
+As the trace shows, it is negative, a DC offset has been applied. I originally believed, that my amplifiers were causing the signal to be negative as they are inverting, however I have an even amount of them so it wasn't them. I then realised that it had to be a DC offset. I fixed it but putting a capacitor before the input, however I removed this as it was distorting the input signal. It doesn't have any effect on the output as the speaker still moves in the same way.
 
 % did it work, how well, compare to original goal
 \section{Evaluation} 
-- 
cgit v1.2.3

