The Fast Fourier Transform treats the input signal as if it was a periodical signal. In other words, it assumes the signal is an infinitely long series of repetitions of the record. In practice, mostly the record does not contain an integer number of cycles of the signal. Therefore, if the end of the record is connected to the beginning, a discontinuity will arise, which results in extra frequency components in the resulting spectrum. This effect is called spectral leakage.

To minimize the effect of spectral leakage, the input record of the FFT can be multiplied with a Window. This is called windowing. Several windows can be chosen in the menu of the FFT I/O, which all basically perform the same action: they make the edges of the record smoother to make the discontinuities smaller. In most cases, the Blackman-Harris window will give the best results. However, if your data contains an integer number of cycles, the rectangle (no windowing) window will give the best result. The following window functions are available for the FFT-block:

• Rectangle
• Hanning
• Hamming
• Bartlett
• Parzen
• Welch
• Blackman
• Blackman-Harris

You can change the displayed name of an object by giving it an Alias. This can be handy when you are dealing with a lot of objects and have problems keeping them apart. You can for example give channel one of your instrument the alias "Battery", when it is measuring a battery voltage. To give an object an alias, use the item Alias ... in its menu. To remove an alias and revert to the original name of the object, set the alias to an empty string.

When multiple sources or I/O's are displayed in a graph or a meter, they can be distinguished from each other by their Color. Three different color settings are available for a source or an I/O.

• Automatic
  A color is selected from a group of colors. There are separate groups for channel colors and source colors. The groups can be configured in the program settings. Each new channel or source uses the next available color in the group. When the last color in the group is used and another channel or source is added, picking will start at the top of the group again.
• As source
  This setting is only available for I/O's. The I/O will use the same color as its source. When multiple sources are connected to the I/O, the color of the first connected source is used.
• User defined...
  The color of the source or I/O is user selected, using a color picker dialog. Any color can be used.

To disconnect all sources from an I/O or Sink at once, use the Disconnect all sources action.

To disconnect one or more sinks from an I/O or Source, use the Disconnect sink(s) action. This will show a dialog that lists all connected sinks. Individual sinks can then be selected and disconnected from the object.

To disconnect all sinks from an I/O or source at once, use the Disconnect all sinks action.

When a new object is to be created, similar to an already existing object, with the same properties, the Clone action can be used. This will create an identical copy of the original object, with the exact same properties. Source(s) and sink(s) of the new object are not yet connected.

The Delete action deletes a source, I/O or sink. All connections of the object will be disconnected and then the object will be removed from the object tree. The source property of the objects that used this object as source will be cleared. The sink property of the objects that used this object as sink will be cleared. An axis in a graph that was connected to this object will be also deleted.

The Export data action allows to export the data of an object to a file. This is detailed described on the page about Exporting data.

The Load action allows to load the settings and data for an object from a TPS or TPO file. This is detailed described on the page about Loading into selected objects.

The Save as action allows to save the settings and data of one or more objects to a TPO file. When multiple objects are selected, the connections between the objects are saved as well. This is detailed described on the page about Saving objects to a TPO file.