Changeset 9617

Timestamp:

10/05/09 13:49:45 (4 years ago)

Author:

hvolos

Message:

 

Files:

• ossiedev/branches/hvolos/docs/OSSIETalkWithUSRP/OSSIETalkWithUSRP.tex (modified) (12 diffs)

ossiedev/branches/hvolos/docs/OSSIETalkWithUSRP/OSSIETalkWithUSRP.tex

@@ -54 +54 @@
 
 %opening
-\title{OSSIE Lab \#:The OSSIETalk Waveform}
+\title{OSSIE Lab: The OSSIETalk Waveform}
 \author{Haris I. Volos and Carl B. Dietrich\\
 Virginia Tech, Blacksburg, VA\\
@@ -71 +71 @@
 
 \section{Objective}
-The objective of this lab is to familiarize the user with the OSSIETalkUSRP waveform.
+The objective of this lab is to familiarize the user with digital voice waveforms.
 
 \section{Version}
@@ -117 +117 @@
 \item File $\rightarrow$ New $\rightarrow$ OSSIE Waveform
 \item Project name: ``OSSIETalkStep1''
-\item Add the following components in the waveform panel:OSSIETalk, PacketResizer, Conv\_Enc, DigitalModulator, FrameAssembler, amplifier,Channel, DigitalDemodulator, and Conv\_Dec
-\item Add the default\_GPP\_USRP\_node to the platform panel
-\item Expand the the node, and add all the components, one by one, the the GPP device.
+\item Add the following components to the waveform panel:OSSIETalk, PacketResizer, Conv\_Enc, DigitalModulator, FrameAssembler, amplifier,Channel, DigitalDemodulator, and Conv\_Dec
+\item Add the default\_GPP\_node to the platform panel
+\item Expand the the node, and add all the components, one by one, to the GPP device.
 \item Set the OSSIETalk component as the assembly controler
 \item Make the following connections:
@@ -147 +147 @@
 \end{verbatim} 
 
-\subsubsection{DigitalModulato1}
+\subsubsection{DigitalModulator1}
 \begin{verbatim}
 ModScheme=QPSK
@@ -172 +172 @@
 \subsection{Waveform Testing}
 \begin{enumerate}
- \item Run the waveform and press the ``Push to Talk'' button while talking at the microphone. You should hear your voice from the speakers. Note that the CVSD encoding used has an inherent distortion. At 400000 noise power (20dB SNR) the any channel distortion should be negligible.
+ \item Built and run the waveform using the default\_GPP\_node and press the ``Push to Talk'' button while talking at the microphone. You should hear your voice from the speakers. Note that the CVSD encoding used has an inherent distortion. At 400000 noise power (20dB SNR) the any channel distortion should be negligible.
 \item Change the noise power to 1265000 (approx. 15dB SNR), the voice should be still comprehensible.
 \item Change the noise power to 400000 (approx. 10dB SNR), the voice may not come through.
@@ -190 +190 @@
 
 \subsubsection{FrameSynchronizer1}
-Performs carrier recovery, symbol sychnronization and extracts the frame information added by the FrameAssembler component.
+Performs carrier recovery, symbol sychnronization and extracts the frame information added by the FrameAssembler. The component is using a polyphase synchronizer that requires two samples per symbol.
 
 \subsubsection{Interpolator1}
@@ -205 +205 @@
 \item File $\rightarrow$ New $\rightarrow$ OSSIE Waveform
 \item Project name: ``OSSIETalkStep2''
-\item Add the following components in the waveform panel:OSSIETalk, PacketResizer, Conv\_Enc, DigitalModulator, FrameAssembler, amplifier, Interpolator, Channel, Decimator, AutomaticGainControl, FrameSynchronizer, DigitalDemodulator, and Conv\_Dec
-\item Add the default\_GPP\_USRP\_node to the platform panel
-\item Expand the the node, and add all the components, one by one, the the GPP device.
-\item Set the USRPTalk as the assembly controler
+\item Add the following components to the waveform panel:OSSIETalk, PacketResizer, Conv\_Enc, DigitalModulator, FrameAssembler, amplifier, Interpolator, Channel, Decimator, AutomaticGainControl, FrameSynchronizer, DigitalDemodulator, and Conv\_Dec
+\item Add the default\_GPP\_node to the platform panel
+\item Expand the the node, and add all the components, one by one, to the GPP device.
+\item Set the OSSIETalk as the assembly controler
 \item Make the following connections:
 \begin{enumerate}
@@ -278 +278 @@
 \subsection{Waveform Testing}
 \begin{enumerate}
- \item Run the waveform and press the ``Push to Talk'' button while talking at the microphone. You should hear your voice from the speakers. The SNR should be about 20dB. An increased delay between talking and hearing back your voice is normal and it is due to the long component chain and computer processing limitations.
+ \item Run the waveform with the default\_GPP\_node and press the ``Push to Talk'' button while talking into the microphone. You should hear your voice from the speakers. The SNR should be about 20dB. An increased delay between talking and hearing back your voice is normal and it is due to the long component chain and computer processing limitations.
 \item Change the noise power to 2846250 (approx. 15dB SNR), the voice should be still comprehensible.
 \item Change the noise power to 9000000 (approx. 10dB SNR), the voice should still come through, the matched filtering improves the SNR.
@@ -284 +284 @@
 
 \section{Step 3}
-In this step describes how to build the complete waveform that uses the USRP and the FLEX400 board.
+This step describes how to build the complete waveform that uses the USRP and the FLEX400 board.
 \osfigvs{blockdiagram3}{Block Diagram}{0.6}
 
@@ -369 +369 @@
 rx_decim=256
 tx_interp=512
-tx_freq=462.5625e6
-rx_freq=462.5625e6
+tx_freq=462.5625e6 (3e6 if using BasicTx/Rx)
+rx_freq=462.5625e6 (3e6 if using BasicTx/Rx)
 \end{verbatim}
 
@@ -376 +376 @@
 \begin{verbatim}
 I_gain=1
-Q_gain=-1
+Q_gain=-1 (Only for FLEX400, 1 otherwise)
 \end{verbatim}
 
@@ -417 +417 @@
 \subsection{Waveform Testing}
 
-Run the waveform in two separate PCs and press the ``Push to Talk'' button while talking at the microphone. You should hear your voice from the other computer. The voice delay should be significantly reduced compared to the last steps.
+Run the waveform in two separate PCs and press the ``Push to Talk'' button while talking at the microphone. You should hear your voice from the other computer. The voice delay should be significantly reduced compared to the previous steps.