Digiscope Display
Fldigi provides several different views
of the decoded signal with its waterfall, text and a scope displays. The
scope display is a separate moveable, resizeable dialog that is opened
from the "View/Digiscope" menu item. If you have used a previous
version of fldigi you will know that the digiscope was a part of the
main display and adjacent to the waterfall. You can still have
the digiscope displayed that way by using the command line switch
"--twoscopes". Twoscopes allows you to have two signal scopes
open at one time. For those modes in which more than one type of
scope view is available you can have different views on the independent
digiscopes.
Psk Mode
The digiscope display just to the right of the waterfall displays signal quality in various formats. The display for PSK modes is the vector scope:
The display with no signal or below squelch level. If the SQL is off this display will be random vectors driven by noise.
The display with a normal psk31 signal. The vector flips between 0 and 6 o'clock.
AFC off and receive carrier set below the center of the received signal
AFC off and receive carrier set above the center of the received signal.
You can see the effect of mistuning by slewing the carrier carrier control moving from low to high over the signal . You must do this with AFC off. Engage the AFC and the vectors will immediately snap to vertical positions.
You can alter the appearance of the phase vectors by left clicking on the digiscope display. One click will give you a history of phase vectors that fade with time. A second click will give you a history of phase vectors that both fade with time and are amplitude significant. The third click returns you to the original phase vector display.
The effect is the same with QPSK signals except you will see 4 vectors that are 90 degrees from each other.
Psk Mode
The digiscope display just to the right of the waterfall displays signal quality in various formats. The display for PSK modes is the vector scope:
The display with no signal or below squelch level. If the SQL is off this display will be random vectors driven by noise.The display with a normal psk31 signal. The vector flips between 0 and 6 o'clock. AFC off and receive carrier set below the center of the received signalAFC off and receive carrier set above the center of the received signal.You can see the effect of mistuning by slewing the carrier carrier control moving from low to high over the signal . You must do this with AFC off. Engage the AFC and the vectors will immediately snap to vertical positions.
You can alter the appearance of the phase vectors by left clicking on the digiscope display. One click will give you a history of phase vectors that fade with time. A second click will give you a history of phase vectors that both fade with time and are amplitude significant. The third click returns you to the original phase vector display.
The effect is the same with QPSK signals except you will see 4 vectors that are 90 degrees from each other.
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