It is often very important to see how the result of some analysis changes through time. If that result is a number, you can simply draw changes as function of one variable – time, using the Instrument values log. But, if the result is a "signal", for example, some FFT sequence, you can track its changes through time by creating a 3D graphic or Spectrogram. Each time FFT values change, all its values will be added as one new column in a 3D graphic or Spetrogram. You can perform this on an FFT window but also for any other signal or analysis result window in SIGVIEW.

You can perform this function in SIGVIEW by selecting the “Signal tools/Track changes in 3D graphics” or  Signal tools/Track changes in spectrogram view”  option from the main menu. You will first have to determine the number of columns in the 3D graphic, i.e. how many last signal changes will be stored.

Each time the origin signal changes, one new column containing this new signal will be added to the 3D graphic and the oldest column will be removed.

The X-axis unit will initially be marked as change, i.e. the number of signal changes, and the Y-axis units will be the same as for the signals X-axis. After a few signals are added to the 3D graphic, the X-axis unit and range will be automatically detected by backtracking through the analysis chain to the root signal window. If X values are equidistant (i.e. the difference between two consecutive values is always the same), those will be displayed on the X-axis of the 3D-graphic. If not, the X-axis will switch again to a "change" unit where each new signal will simply be labelled with its index, i.e. 0,1,2,3,4...

If the length of origin signal changes (for example by zooming it in/out), its further changes will not be added to the 3D graphic until you return the signal to the previous (original) length.

For more information see: Track analysis results through time as 3D graphics and Basic 3D operations.