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@ -42,14 +42,14 @@
\lipsum[3-4]
\section{Methodology}
\section{Methodology} \label{section:methodology}
To characterize the system, several tests have been performed. The
characteristics of interest are the following:
\begin{enumerate}[nosep]
\item Efficiency
\item Noise
\item Ripple characteristics
\item Transients
\item Start up
\end{enumerate}
In this section a test or measurement will be described for each of the above
characteristics.
@ -60,7 +60,7 @@
were chosen to give characterize the circuit over a broad range of conditions.
\subsection{Efficiency}
\subsection{Efficiency} \label{section:efficiency}
\begin{Figure}
\centering
\includegraphics[scale=0.34]{SCHEMATIC_EFFICIENCY.png}
@ -94,11 +94,11 @@
\subsubsection{Peak to peak}\label{section:peak_to_peak}
Peak to peak is the simplest way to look at noise. The signal has a stationary
mean over the period of 1 millisecond. Thus the highest measured value can be
mean over the period of 1 millisecond. Thus, the highest measured value can be
subtracted from the lowest measured value.
\subsubsection{Standard Deviation}
\subsubsection{Standard Deviation}\label{section:standard_devation}
The second metric used to measure noise was the standard deviation.
Unlike, peak to peak it givesa better impression of the noise over a longer
signal. SD can be calculated using equation \ref{eq:sd}.
@ -111,7 +111,8 @@
Where $x[i]$ is each voltage measurement, $\mu$ is the mean of the signal and
$N$ is the total amount of samples.
\subsection{Ripple characteristics}
\subsection{Ripple characteristics}
\begin{Figure}
\centering
\includegraphics[scale=0.5]{RIPPLE.png}
@ -130,7 +131,7 @@
section \ref{section:peak_to_peak}.
To measure the frequency of the signal using an FFT, it had to be pre-processed
first using a Hamming window this eliminates sharp edges at the edge of the
first using a Hamming window, this eliminates sharp edges at the edge of the
measurement, causing unwanted frequencies to appear in the frequency domain.
\begin{equation}
\label{eq:hamming}
@ -141,12 +142,67 @@
sample in the signal can be multiplied by the corresponding value in the window,
preparing the signal for the FFT.
\subsection{Transients}
The last measurements were hocus pocus
\subsection{Start up}
The last characteristics is the start up, specifically the different rise times
under load. The voltage was measured at the output as the supply was turned on.
Different rise times can be defined. First off, $\tau$ and $2 \tau$ were
defined as $63\%$ and $95\%$ respectively. Further more, 'rise time' was defined
as $90\%$, a metric used often in control theory.
One problem that occured during the measurements, is that the aforementioned
ripples and noise would cause erroneous readings. As such, the signal was
filtered using a low pass filter, reducing the high frequencies from the
measurement.
\section{Results}
\lipsum[1-2]
In this section the results from section \ref{section:methodology} will be
discussed, as well as discuss some probable causes for unknown or unintended
results.
\subsection{Efficiency}
\begin{Figure}
\centering
\includegraphics[scale=0.5]{EFFICIENCY_PERCENTAGE.jpg}
\captionof{figure}{WIP}
\label{fig:efficiency}
\end{Figure}
\noindent The results for the efficiency measurements, as described in section
\ref{section:efficiency} are displayed in figure \ref{fig:efficiency}.
The $7V$ measurements follow a predictable curve, however, the $3.3V$ makes
an unexplained jump back to a higher percentage.
\subsection{Noise}
\begin{Figure}
\centering
\includegraphics[scale=0.5]{SNR_LOADVSPKPK.jpg}
\captionof{figure}{WIP}
\label{fig:noise_pkpk}
\end{Figure}
\noindent The results for the efficiency measurements, as described in section
\ref{section:peak_to_peak} are displayed in figure \ref{fig:noise_pkpk}.
The peak to peak voltage is a significant fraction of the output voltage,
with $3V$ peaking at $33\%$. It seems there is a relation between peak to
peak voltage and the output voltage as well, as $7V$ has more noise than
$3.3V$
\begin{Figure}
\centering
\includegraphics[scale=0.5]{SNR_LOADVSSD.jpg}
\captionof{figure}{WIP}
\label{fig:noise_sd}
\end{Figure}
\noindent The results for the efficiency measurements, as described in section
\ref{section:standard_devation} are displayed in figure \ref{fig:noise_sd}.
Although the voltage peaks are high, the noise's standard deviation is in the
range of millivolts. The trend that a higher output voltage has more noise
is continued in this graph.
\subsection{Ripple}
\section{Conclusion}
\lipsum[3-4]