commfunc.htm

数字通信第四版原书的例程

<TITLE>Communications Toolbox Graphical User Interface Example </TITLE>
<p><h2>Communications Toolbox Graphical User Interface Example </h1>
<hr><br>

You can type <b><a run="commgui">commgui</a></b> to open the graphical user
interface (GUI) example. This example provides a simple tool for you to 
compute bit-error-rates using different combinations of different
methods. This help file briefly describes how to use the tool.

<dl>
<dd><A HREF="#general">General Information</A>
<dd><A HREF="#loadsave">Load/Save Window Parameter Setting</A>
<dd><A HREF="#parameter">Define Computation Parameters</A>
<dd><A HREF="#computation">Start Computation</A>
<dd><A HREF="#data">Manage of Computed Data</A>
</dl>

<p>
<p>
<dd><a href="commhelp.html">Go to the tutorial for Communications Toolbox</a>
<p>
<p>
<dl>
<tt><dd>This is commfunc.html file</bl></tt>
</dl>

<HR><br>
<TITLE>Communication Toolbox GUI Example General Information</TITLE>
<A NAME="general">
<p><h2>General Information</h2>
The graphical user interface (GUI) example illustrates how to
use the Communications Toolbox to compute the bit-error-rate.
The example uses MATLAB functions in sources and sinks,
error-control coding, modulation, and channel categories.

The computation is based on the parameters provided in the data
entry slot. In the GUI window, all white areas are designed for
data input.

<p>You can define your own computation in choosing <b>my own</b> in the 
GUI window. To be able to run your algorithm, you need to
edit the file <b>commod.m</b>.

<p>
<p>
<p>
<HR><br>
<TITLE>Load/Save Window Parameter Setting for Comm Toolbox GUI Example </TITLE>
<A NAME="loadsave">
<p><H2>Load/Save Window Parameter Setting</h2>
The file pull-down menu at the top of the GUI window enables
you to load and save the parameters defined in this example. There is
a <b>commfoo.mat</b> file in the <b>comm</b> directory in the Communications 
Toolbox.
The file is an example of the saved data. The saved data includes the
parameters of the computation methods, the resulting
computation data, and the curve fitting order. <p>

The <b>load</b> and <b>save</b> selection in the <b>file</b> pull-down
menu uses a browser file system to help 
you access your directory (folder) and files.

<p>
<p>
<p>
<HR><br>
<TITLE>Define Computation Parameters in the Communications Toolbox GUI Example</TITLE>
<A NAME="parameter">
<p><H2>Define Computation Parameters</h2>
The GUI window is divided into two sections: the upper section
for parameter entries and the lower section for displaying the computed data.
The computation goes through the stages of 

<dl>
<dd>Source Data
<dd>Error Control Coding
<dd>Modulation
<dd>Channel
<dd>Demodulation
<dd>Error Control Decoding
<dd>Save Data
</dl>

The first parameter in the channel category can be a vector. The vector 
length determines the computed data length. When you use the 
random integers in the Source category, the data length can be a 
scalar or a vector. The vector length must match the length of the
first parameter in the channel. When you use a
workspace variable as an input source, the workspace variable
can be a column vector, or a matrix with its column number the same
length as the first parameter in the Channel category.

<p>You can view the help for the functions <b><A HREF="encode.m">encode</A></b>
and <b><A HREF="decode.m">decode</A></b> to find the definition of the
error-control coding parameters.

<p>You can view the help for the functions <b><A HREF="amod.m">dmod</A></b>
and <b><A HREF="ademod.m">ddemod</A></b> for the passband modulation/demodulation
simulation parameters.
You can view the help for the functions <b><A HREF="amodce.m">dmodce</A></b>
and <b><A HREF="ademodce.m">ddmodce</A></b> for the baseband modulation/demodulation
simulation parameters.<p>

If you don't know how to choose a parameter, leave the parameter entry
empty. The example will fill in a default parameter for you.

<p>
<p>
<p>
<HR><br>
<TITLE>Start Computation in the Communications Toolbox GUI Example</TITLE>
<A NAME="computation">
<p><H2>Start Computation</h2>
After defining the parameters, you can click the button RUN
to start the simulation. There are two indicators showing the
computation stages. A indicator shows 
which computation category is processing. The computation 
categories are:

<dl>
<dd>Source Data
<dd>Error Control Coding
<dd>Modulation
<dd>Channel
<dd>Demodulation
<dd>Error Control Decoding
<dd>Save Data
</dl>

There is also an indication bar that shows the percentage of the
computation completed. The percentage shows the ratio of
the completed computation stages to the total computation stages.

<p> The computed data is stored in the Current Data storage area. The data
comtains SNR, the signal to noise ratio, and bit_err_ratio, the
bit error ratio.

<p>
<p>
<p>
<HR><br>
<TITLE>Manage Computation Data in the Communications Toolbox GUI Example</TITLE>
<A NAME="data">
<p><H2>Manage Computation Data</h2>
The GUI window provides three storage slot for your
data comparison. You can import the data from workspace variables.
You can also export the data to workspace variables. Use your
mouse to drag data from one location and drop the
data in another location.

<p>Note that after you have dropped the data into the trash can,
the data will be deleted from the window. There is no
undo.