path: root/scenarios.tex
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authorMatthias P. Braendli <matthias.braendli@mpb.li>2014-12-11 17:57:48 +0100
committerMatthias P. Braendli <matthias.braendli@mpb.li>2014-12-11 17:57:48 +0100
commit50cc2b0dcceff73b5f86690f0f442e75efaf3d21 (patch)
tree5bb5d4127b8150e4454fa2a66257dba41522a19a /scenarios.tex
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\section{Usage Scenarios}
\subsubsection{Creation of Non-Realtime Multiplex}
+The creation of a ETI file containing two programmes, one DAB and one \dabplus{} is covered in
+section \ref{sec-files}.
\subsubsection{Modulation of ETI for Offline Processing}
+The ETI file generated before can then be used with ODR-DabMod to generate a file containing I/Q
+samples. Here, we must chose between using the command line or the configuration file. For a very
+simple example, using the command line makes sense, but for more advanced features it is preferable
+to use a configuration file. For illustration, we will present both.
+To modulate the file \texttt{myfirst.eti} into \texttt{myfirst.iq}, with the default options, the
+command is simply
+odr-dabmod myfirst.eti -f myfirst.iq
+This will create a file containing 16-bit interleaved I/Q at $2048000$ samples per second. The
+transmission mode is defined by the ETI file.
+The equivalent configuration file would be
+This is a very minimal file that defines only the necessary settings equivalent to the above command
+line options. The configuration file however supports more options that the command line, and
+becomes easier to manager once the set becomes more complex. It is best to use the example
+configuration availble in the \texttt{doc/} folder.
\subsection{Interfacing Hardware Devices}
\subsubsection{Ettus USRP}
+ODR-DabMod integrates support for the UHD library that can interface with all USRP devices from
+Ettus. The following configuration file illustrates how to send the \texttt{myfirst.eti} over a USRP
+B200 on channel 13C:
+This example also shows more options that the example for the file output:
+ \item \texttt{remotecontrol telnet=1} enables the Telnet server that can be used to set
+ parameters while the modulator is running.
+ \item \texttt{loop=1} rewinds the input file when the end is reached. The same ETI file will be
+ transmitted over and over.
+ \item \texttt{gainmode=2} sets the GainMode to VAR, which reduces overshoots in the output.
+ \item \texttt{digital\_gain=0.8} reduces the output sample deviation, to reduce compression in
+ the USRP.
+ \item \texttt{firfilter enabled=1} enables an additional FIR filter to improve the spectrum
+ mask.
+ \item \texttt{master\_clock\_rate=32768000} sets the USRP internal clock to a multiple of
+ $2048000$, which is required if we want to use the native DAB sample rate.
+ \item \texttt{txgain=40} Sets the analog transmit gain of the USRP to 40dB, which is specific to
+ the B200.
+Some of these options are not necessary for the system to work, but they improve the performance.
\subsubsection{Other Hardware}
\subsection{Audio sources}