From ede606e746e26ffb49ddd30b1a9638127367bcc5 Mon Sep 17 00:00:00 2001 From: Steven Franke Date: Sun, 10 Jan 2016 01:20:03 +0000 Subject: [PATCH] More thoughts for section 7. git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6378 ab8295b8-cf94-4d9e-aec4-7959e3be5d79 --- lib/ftrsd/ftrsd_paper/ftrsd.lyx | 201 ++++++++++++++++++++++++++++++-- 1 file changed, 192 insertions(+), 9 deletions(-) diff --git a/lib/ftrsd/ftrsd_paper/ftrsd.lyx b/lib/ftrsd/ftrsd_paper/ftrsd.lyx index 1011a986e..75c17a1b4 100644 --- a/lib/ftrsd/ftrsd_paper/ftrsd.lyx +++ b/lib/ftrsd/ftrsd_paper/ftrsd.lyx @@ -2242,7 +2242,169 @@ MAP65 \end_layout \begin_layout Standard -Mention two-pass decoding. +Mention two-pass decoding - could use Fig +\begin_inset CommandInset ref +LatexCommand ref +reference "fig:spectrogram" + +\end_inset + + as a case study. + The table below is for the data shown in Fig +\begin_inset CommandInset ref +LatexCommand ref +reference "fig:spectrogram" + +\end_inset + +. + Maybe less confusing if the third row was deleted. +\begin_inset Float table +wide false +sideways false +status open + +\begin_layout Plain Layout +\align center +\begin_inset Tabular + + + + + + +\begin_inset Text + +\begin_layout Plain Layout +Case +\end_layout + +\end_inset + + +\begin_inset Text + +\begin_layout Plain Layout +# decodes +\end_layout + +\end_inset + + + + +\begin_inset Text + +\begin_layout Plain Layout +one-pass, BM +\end_layout + +\end_inset + + +\begin_inset Text + +\begin_layout Plain Layout +9 +\end_layout + +\end_inset + + + + +\begin_inset Text + +\begin_layout Plain Layout +one-pass, FT +\end_layout + +\end_inset + + +\begin_inset Text + +\begin_layout Plain Layout +12 +\end_layout + +\end_inset + + + + +\begin_inset Text + +\begin_layout Plain Layout +two-pass, BM +\end_layout + +\end_inset + + +\begin_inset Text + +\begin_layout Plain Layout +12 +\end_layout + +\end_inset + + + + +\begin_inset Text + +\begin_layout Plain Layout +two-pass, FT +\end_layout + +\end_inset + + +\begin_inset Text + +\begin_layout Plain Layout +21 +\end_layout + +\end_inset + + + + +\end_inset + + +\end_layout + +\begin_layout Plain Layout +\begin_inset Caption Standard + +\begin_layout Plain Layout +The effect of soft-symbol decoding combined with signal subtraction on the + data shown in Figure +\begin_inset CommandInset ref +LatexCommand ref +reference "fig:spectrogram" + +\end_inset + +. +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Plain Layout + +\end_layout + +\end_inset + + \end_layout \begin_layout Subsubsection* @@ -2250,8 +2412,14 @@ Experience with FT on crowded HF bands: \end_layout \begin_layout Standard -(Re the following paragraph and Figure 5 - just playing around with ideas - - feel free to change, delete, etc.) +(Re the following paragraph and Figure +\begin_inset CommandInset ref +LatexCommand ref +reference "fig:spectrogram" + +\end_inset + + - just playing around with ideas - feel free to change, delete, etc.) \end_layout \begin_layout Standard @@ -2269,19 +2437,28 @@ moonbounce reflection paths at HF. Use on HF was not originally an intended application for the mode, but at present HF use accounts for the largest number of 2-way contacts. - Figure 5 is a spectrogram with frequency in Hz on the horizontal axis showing - JT65 activity during a one-minute time-segment (JT65 transmissions start - at the beginning of a minute and last for approximately 47 s). + Figure +\begin_inset CommandInset ref +LatexCommand ref +reference "fig:spectrogram" + +\end_inset + + is a spectrogram with frequency in Hz on the horizontal axis showing JT65 + activity during a one-minute time-segment (JT65 transmissions start at + the beginning of a minute and last for approximately 47 s). The data was collected in the 20m amateur band during daytime under crowded band conditions. With some straightforward signal processing to demodulate the signals and produce soft-symbol data for the FT decoder it is possible to extract and - decode 21 messages from the data summarized in Figure 5, and this is achieved - with a relatively small timeout parameter + decode 21 messages from the data summarized in Figure 5. + This is achieved with a relatively small timeout parameter \begin_inset Formula $T=1000$ \end_inset -. + and in spite of the fact that the 200 Hz-wide 65-FSK (sync plut 64-FSK) + signals overlap, with as many as 4 signals superposed in some parts of + the spectrum. Using exactly the same pre-processing, but without soft-symbol information the errors-only BM decoder is able to decode only 12 messages. @@ -2310,6 +2487,12 @@ status open \begin_inset Caption Standard \begin_layout Plain Layout +\begin_inset CommandInset label +LatexCommand label +name "fig:spectrogram" + +\end_inset + A spectrogram showing one minute of data collected under crowded band conditions on 20m during daytime hours. WSJT-X extracted 21 JT65 messages in approximately the same bandwidth required