\documentclass{../signatures}
\labacronym{LLS}
\labtitle{Low Light Signal Measurements}

\begin{document}

\maketitle

\names

\textbf{Suggested reading to start with (see the end of the manual for more):}
\begin{enumerate}
    \item 111B LLS Manual
    \item About Lock-In Amplifiers: Application Note \# 3” \href{https://drive.google.com/file/d/132FYfGLOt9ue8UWSOA31-Mgl27g-ZSIA/view?usp=drive_link}{\textbf{About Lock-ins}}
    \item R. Ramirez, ``\href{https://drive.google.com/file/d/1ajsiFtRe8k86CYFSN72hqXV7qs8iwC-6/view?usp=drive_link}{\textbf{The FFT: Fundamentals and Concepts}}''; Prentice-Hall, 1985, pp. 3-16 \& 115-123.
    \item 111B LLS Experiment Videos \href{http://youtu.be/X4XQ1jcMuoI}{\textbf{Low Light Signal Measurements}} and the \href{http://youtu.be/lQKLakISoBA}{\textbf{Light Sources and Detectors}}. Note: In order to view the private Youtube videos hosted by the university, you must be signed into your berkeley.edu Google account.
     
\end{enumerate}

\prelab

\begin{enumerate}

    \item What is the purpose of having the SR760 FFT Spectrum Analyzer? What mathematical operation does it perform on an input signal? Give several examples of what goes in and what comes out.
    
    \item Why don’t we just put a filter in front of our photodiode which only passes light at the frequency given off by the LED (e.g. 635 nm)?

    \item Explain how chopping the steady-state signal from the LED helps you to recover the signal from the LED.

    \item Explain the working principle of lock-in amplifiers. You can first assume that the input signal is an arbitrary signal expressed by a Fourier Series, and assume your reference signal is a unit sine wave at targeted frequency. Show how the target frequency component of the input signal is extracted. Consider how the phase difference between the input and reference signal and lock-in settings such as the SLOPE and TIME CONSTANT affect the result. (Hint: Think about the relation between X, Y, and R).
       \\[36pt]
\end{enumerate}

\prelabsignatures

\midlab

\begin{enumerate}

    \item Before beginning Experiment X, you should have produced a plot of the Johnson noise signal using the measurements obtained in Experiment IX.
\\[36pt]
\end{enumerate}

\midlabsignaturesLLS

\checkpointsection 
\\[12pt]
\begin{enumerate}

\item \checkp{Fourier Components}

\item \checkp{Slope/Oct and Time Constant }

\item \checkp{1/f Noise}

\item \checkp{Capacitive Noise}

\item \checkp{Johnson-Noise Measurement}
\end{enumerate}
\end{document}