From b10e262690bcd58921ebe548fd61b8f7d08022c0 Mon Sep 17 00:00:00 2001
From: Jan Grewe <jan.grewe@g-node.org>
Date: Thu, 10 Jan 2019 17:39:18 +0100
Subject: [PATCH] [project_eod] textual changes
---
projects/project_eod/eod.tex | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)
diff --git a/projects/project_eod/eod.tex b/projects/project_eod/eod.tex
index 647a756..e225546 100644
--- a/projects/project_eod/eod.tex
+++ b/projects/project_eod/eod.tex
@@ -11,31 +11,38 @@
%%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%%
+Weakly electric fish employ their self-generated electric field for
+prey-capture, navigation and also communication. In many of these fish
+the {\em electric organ discharge} (EOD) is well described by a
+combination of a sine-wave and a few of its harmonics (integer
+multiples of the fundamental frequency).
\begin{questions}
- \question In the data file {\tt EOD\_data.mat} you find a time trace
- and the {\em electric organ discharge (EOD)} of a weakly electric
- fish {\em Apteronotus leptorhynchus}.
+ \question In the data file {\tt EOD\_data.mat} you find two
+ variables. The first contains the time at which the EOD was sampled
+ and the second the acutal EOD recording of a weakly electric fisch
+ of the species {\em Apteronotus leptorhynchus}.
\begin{parts}
- \part Load and plot the data in an appropriate way. Time is in
- seconds and the voltage is in mV/cm.
- \part Fit the following curve to the eod (select a small time
- window, containing only 2 or three electric organ discharges, for
+ \part Load the data and create a plot showing the data. Time is given in
+ seconds and the voltage is given in mV/cm.
+ \part Fit the following curve to the EOD (select a \textbf{small} time
+ window, containing only two or three electric organ discharges, for
fitting, not the entire trace) using least squares:
$$f_{\omega_0,b_0,\varphi_1, ...,\varphi_n}(t) = b_0 +
\sum_{j=1}^n \alpha_j \cdot \sin(2\pi j\omega_0\cdot t + \varphi_j
- ).$$ $\omega_0$ is called {\em fundamental frequency}. The single
+ ).$$ $\omega_0$ is called the {\em fundamental frequency}. The single
terms $\alpha_j \cdot \sin(2\pi j\omega_0\cdot t + \varphi_j )$
- are called {\em harmonic components}. The variables $\varphi_j$
+ are called the {\em harmonic components}. The variables $\varphi_j$
are called {\em phases}, the $\alpha_j$ are the amplitudes. For
the beginning choose $n=3$.
\part Try different choices of $n$ and see how the fit
- changes. Plot the fits and the original curve for different
- choices of $n$. Also plot the fitting error as a function of
- $n$.
+ changes. Plot the fits and the section of the original curve that
+ you used for fitting for different choices of $n$. Also plot the
+ fitting error as a function of $n$.
+ \part Why does the fitting fail when you try to fit the entire recording?
\part (optional) If you want you can also play the different fits
- and the original as sound.
-
+ and the original as sound (check the help).
+
\end{parts}
\end{questions}