SeaTTY 2.0 Download

The working area of the program is divided into several windows, the sizes of which can be changed by the user by dragging the borders.

In the top window the current spectrum of a signal (blue line) and a peak detector of spectral components (green line) are shown. Ruler under this window shows frequencies of sound spectrum. The long vertical red lines in this window show the working frequencies of the decoder filters. In FAX mode these lines show “black” and “white” frequencies. To change the center frequency, click on the desired frequency (probably between the peaks).

The bottom window shows an oscillogram of the decoded signal. This window can be hide by the “Setup->View->Show oscillogram window” option
 
The “Setup->View->Logarithmic spectrogram scale” option or Alt-Z hotkey switch spectrogram window between linear or logarithmic scale. Analogously, the “Setup->View->Logarithmic oscillogram scale” option or Ctrl-Z hotkey switch oscillogram scale. Logarithmic scale is more convenient usually, but it needs more computer resources.

The “SQL” button switches squelch on. The number to the left of the “SQL” button determines the squelch threshold. When squelch is switched on, the horizontal red line shows the squelch threshold in spectrogram window.

The “AFC” button (auto frequency control) adjusts the long red lines (working frequencies) to the closest peak frequencies. The numbers to the left of the AFC button determines the limits of AFC. The first number is local deviation in hertzs, i.e. maximal deviation from current frequency. Second number is global deviation in hertzs, i.e. maximal deviation from last user-selected frequency. User-selected frequencies are shown at spectrogram by short red lines .