kopia lustrzana https://github.com/jamescoxon/dl-fldigi
253 wiersze
8.3 KiB
Plaintext
253 wiersze
8.3 KiB
Plaintext
/**
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\page digiscope_display_page Digiscope Display
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\tableofcontents
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Fldigi provides several different views
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of the decoded signal with its waterfall, text and a scope displays. The
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scope display is either a separate moveable, resizable dialog that is opened
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from the "View/Digiscope" menu item or a docked scope.
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<br>
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\section cw_scope CW
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<br>
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\image html digiscope-cw.png "Digiscope CW"
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\image latex digiscope-cw.png "Digiscope CW" width=1.0in
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<br>
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The CW signal will consist of the time domain amplitude detected signal. The
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horizontal timing is dependent on CW speed, so that the display will appear
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similar independent of CW speed.
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<br>
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\image html digiscope-cw.png "Digiscope CW"
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\image latex digiscope-cw.png "Digiscope CW" width=1.0in
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<br>
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\section domino_ex_scope DominoEX / Thor
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\image html digiscope-domexA.png "Digiscope DominoEX \& Thor"
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\image latex digiscope-domexA.png "Digiscope DominoEX \& Thor" width=1.0in
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<br>
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DominoEX and Thor have two alternate views available on the digiscope
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display. You can toggle between the views by left clicking on the
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digiscope display area. The triangular view shows data propogation
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through the interleave filter. As signal s/n degrades this display
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will become more wavy.
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<br>
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\image html digiscope-domexB.png "Digiscope DominoEX \& Thor"
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\image latex digiscope-domexB.png "Digiscope DominoEX \& Thor" width=1.0in
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<br>
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The second view is the decoded data stream viewed in the frequency
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domain. The dots will be very distinct when the signal is fully
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acquired and decoding properly. It will be fuzzy when the decoder is
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not locked or there is interference present.
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<br>
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\section mfsk_scope MFSK
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\image html digiscope-mfsk.png "Digiscope MSFK"
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\image latex digiscope-mfsk.png "Digiscope MSFK" width=1.0in
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<br>
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This is what you expect to see for all of the MFSK type modes. The
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number of steps in the slant lines will change with the various modes,
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but they will all have the same general appearance. If the signal
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is mistuned the sloped lines will become bowed and distorted.
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<br>
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\section psk_scope PSK
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The digiscope display just to the right of the waterfall displays
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signal quality in various formats. The display for PSK modes is
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the vector scope:
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<br>
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<center>
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\htmlonly
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<table style="text-align: left; width: 100%;" border="0" cellpadding="2" cellspacing="2">
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<tr>
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<td style="width: 5%;">
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<br>
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</td>
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<td style="text-align: center;">
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<div style="text-align: center;">
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<img style="width: 102px; height: 100px;" alt="" src="digiscope-psk-nosig.png" hspace="5">
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<br>
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</div>
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<br>
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<div style="text-align: left;">The
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display with no signal or below squelch level. If the SQL is off
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this display will be random vectors driven by noise.</div>
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</td>
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<td style="text-align: center; vertical-align: top;">
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<img style="width: 103px; height: 99px;" alt="" src="digiscope-psk.png" hspace="5">
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<br>
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<br>
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<div style="text-align: left;">The display with a normal psk31 signal. The vector flips between 0 and 6 o'clock</div>
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</td>
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<td style="text-align: center; vertical-align: top;">
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<img style="width: 101px; height: 96px;" alt="" src="digiscope-psk-low.png" hspace="5">
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<br>
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<br>
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<div style="text-align: left;">AFC off and receive carrier set below the center of the received signal</div>
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</td>
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<td style="width: 5%;">
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<br>
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</td>
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</tr>
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<tr>
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<td>
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<br>
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</td>
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<td style="text-align: center; vertical-align: top;">
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<img style="width: 98px; height: 99px;" alt="" src="digiscope-psk-high.png" hspace="5">
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<br>
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<br>
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<div style="text-align: left;">
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AFC off and receive carrier set above the center of the received signal.</div>
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</td>
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<td style="text-align: center; vertical-align: top;">
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<img style="width: 99px; height: 102px;" alt="" src="digiscope-psk-history.png">
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<br>
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<br>
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<div style="text-align: left;">AFC enabled, Fading History Display Mode Selected (left click on scope)</div>
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</td>
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<td style="text-align: center; vertical-align: top;">
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<img style="width: 101px; height: 99px;" alt="" src="digiscope-psk-history-amplitude.png">
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<br>
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<br>
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<div style="text-align: left;">AFC enabled, Fading History / Amplitude Display Mode Selected (2nd left click on scope)</div>
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</td>
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<td>
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<br>
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</td>
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</tr>
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</table>
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\endhtmlonly
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</center>
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\latexonly
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\begin{figure}[H]
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\centering
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\begin{subfigure}[t]{0.3\textwidth}
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\centering
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\includegraphics[width=1.0in]{digiscope-psk-nosig.png}
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\caption{The display with no signal or below squelch level. If the
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SQL is off this display will be random vectors driven by noise. }
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\label{fig:digiscope_psk_nosig}
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\end{subfigure} ~
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\begin{subfigure}[t]{0.3\textwidth}
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\centering
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\includegraphics[width=1.0in]{digiscope-psk.png}
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\caption{The display with a normal psk31 signal. The vector flips between 0 and 6 o'clock}
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\label{fig:digiscope_psk}
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\end{subfigure} ~
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\begin{subfigure}[t]{0.3\textwidth}
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\centering
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\includegraphics[width=1.0in]{digiscope-psk-low.png}
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\caption{AFC off and receive carrier set below the center of the received signal}
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\label{fig:digiscope_psk_low}
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\end{subfigure}
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\begin{subfigure}[t]{0.3\textwidth}
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\centering
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\includegraphics[width=1.0in]{digiscope-psk-high.png}
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\caption{AFC off and receive carrier set above the center of the received signal.}
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\label{fig:digiscope_psk_high}
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\end{subfigure} ~
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\begin{subfigure}[t]{0.3\textwidth}
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\centering
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\includegraphics[width=1.0in]{digiscope-psk-history.png}
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\caption{AFC enabled, Fading History Display Mode Selected (left click on scope)}
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\label{fig:digiscope_psk_history}
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\end{subfigure} ~
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\begin{subfigure}[t]{0.3\textwidth}
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\centering
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\includegraphics[width=1.0in]{digiscope-psk-history-amplitude.png}
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\caption{AFC enabled, Fading History / Amplitude Display Mode Selected (2nd left click on scope)}
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\label{fig:digiscope_psk_history_amp}
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\end{subfigure}
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\caption{PSK Digiscopes}
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\label{fig:psk_digiscopes}
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\end{figure}
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\endlatexonly
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<br>
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You can see the effect of mistuning by slewing the carrier carrier
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control moving from low to high over the signal . You must do
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this with AFC off. Engage the AFC and the vectors will
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immediately snap to vertical positions.
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<br>
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You can alter the appearance of the phase vectors by left clicking on
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the digiscope display. One click will give you a history of phase
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vectors that fade with time. A second click will give you a
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history of phase vectors that both fade with time and are amplitude
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significant. The third click returns you to the original phase
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vector display.
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<br>
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The effect is the same with QPSK signals except you will see 4 vectors that
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are 90 degrees from each other.
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<br>
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\section sec_rtty RTTY
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<br>
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\image html digiscope-rtty.png "Digiscope RTTY"
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\image latex digiscope-rtty.png "Digiscope RTTY" width=1.0in
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<br>
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The signal can be viewed in two different ways on the digiscope. This
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is the time domain representation of the detected FSK signal. The
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two yellow lines represent the MARK and SPACE frequencies. This
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display is for Baudot, 45.45 baud, 182 Hz shift. If the
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transmitting station were transmitting at 200 Hz shift the signal
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extremes would lie above and below the yellow lines. Try tuning
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across the RTTY signal with the AFC disabled. You will see the
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signal move above and below the yellow lines as you tune. Then
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enable the AFC and the signal should rapidly move into the center
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region of the display. This signal was about 3 - 6 dB above the
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noise floor. It looked marginal on the waterfall but still gave
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good copy.
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\image html digiscope-rtty-2.png "Digiscope RTTY"
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\image latex digiscope-rtty-2.png "Digiscope RTTY" width=1.0in
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<br>
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This is the other digiscope display for RTTY. You obtain this view by
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left clicking anywhere in the digiscope display window. You can
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toggle back and forth between these views. The MARK / SPACE
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frequencies are represented by the quadrature ellipses. When the
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RTTY signal is properly tuned in the lines will be in quadrature and
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aligned as shown. Tune across the RTTY signal and the MARK/SPACE
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lines will rotate around the center. If the sending station is
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using a shift that is smaller than you have the decoder setting then
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the two lines will close toward the NW/SE quadrants. If the
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sending station is using a shift that is greater than the decoder
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setting then the two lines will close toward the NE/SW quadrants.
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<br>
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\ref digiscope_display_page "Return to Top of Page"
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<br>
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\ref main_page "Return to Main Page"
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*/
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