Decoder Spectrum Display

 

General description

All of the SkySweeper decoders have an integrated spectrum display to help the decoder tuning. There are two different types of spectrum displays provided: FFT and waterfall spectrogram. The decoder frequency/frequencies are shown with a bar in the display. The decoder frequency can be changed by a mouse click if the frequency is not fixed (like in ACARS etc.). The decoder frequency can also be set from the keyboard by double clicking the left mouse button over the frequency value (located just below the bar). It then opens a dialog into which the frequency value can be typed.

 

The parameters and the type (FFT/waterfall) of spectrum display can be changed by a right mouse button click over the spectrum display. There is more information about the parameters below.

 

Parameters

Stop / Start

This switch allows the stopping and starting of the spectrum display update

Spectrogram / FFT

The used spectrum display type (spectrogram (waterfall) or FFT)

Autoscale

If this switch is selected the spectrum display is automatically scaled

Zoom Out

If this switch is selected the spectrum view is zoomed out (returned to the original zoom)

Grid

If this switch is selected the grid is shown in the spectrum display. This switch is not active in waterfall mode.

LogX

If this switch is selected the X scale is shown as log (logarithmic) based. This switch is not active in waterfall mode.

Average

If this switch is selected the spectrum calculation will be averaged over the update interval. This switch is not active in waterfall mode.

Maximum

If this switch is selected the spectrum is shown as ‘max and hold’. This switch is not active in waterfall mode.

Update Interval

The interval of spectrum display updates in milliseconds. This parameter is not active in waterfall mode.

Copy To Clipboard

Copies the spectrum picture to the Windows Clipboard.

Help

Activates the HELP file.

Save

Saves the spectrogram picture to a file. This parameter is not active in FFT mode.

Properties

Allows the more detailed configuration of the waterfall/spectrogram display. This parameter is not active in FFT mode.

  • Spectrum resolution

The points used in spectrum calculation (32-4096)

  • Number of lines

The number of lines showed in the spectrum display

  • Input squared

The input signal is squared before spectrum calculation

  • Orientation

The drawing direction (vertical/horizontal) of the display

  • Palette

Used palette (B&W/color) of the display

  • Draw

The used draw method for scrolling or overdrawing