Digiscope Display
MFSK modes
This
is what you expect to see for all of the MFSK type modes. This
includes MFSK-8, MFSK-16 and all of the the dominoEX modes. The
number of steps in the slant lines will change with the various modes,
but they will all have the same general appearance. If the signal
is mistuned the sloped lines will become bowed and distorted.
CW mode
The
CW signal will consist of the time domain amplitude detected signal.
The horizontal timing is dependent on CW speed, so that the
display will appear similar independent of CW speed.
RTTY mode
The
signal can be viewed in two different ways on the digiscope. This
is the time domain representation of the detected FSK signal. The
two yellow lines represent the MARK and SPACE frequencies. This
display is for Baudot, 45.45 baud, 182 Hz shift. If the
tranmitting station were transmitting at 200 Hz shift the signal
extremes would lie above and below the yellow lines. Try tuning
across the RTTY signal with the AFC disabled. You will see the
signal move above and below the yellow lines as you tune. Then
enable the AFC and the signal should rapidly move into the center
region of the display. This signal was about 3 - 6 dB above the
noise floor. It looked marginal on the waterfall but still gave
good copy.
This
is the other digiscope display for RTTY. You obtain this view by
left clicking anywhere in the digiscope display window. You can
toggle back and forth between these views. The MARK / SPACE
frequencies are represented by the RED and GREEN lines. When the
RTTY signal is properly tuned in the lines will be in quadrature and
aligned as shown. Tune across the RTTY signal and the MARK/SPACE
lines will rotate around the center.