Levels, frequencies or orders can be represented over time in NoiseImage in the classical way. If, besides acoustical data, additional data such as revolutions per minute (RPM) or temperature, have been acquired during measurement, this data can be used as reference values instead of time.
To start with, activate the option to represent data over Reference ralues in the Axis Properties dialog of the X axis (fig. 1). This enables the Axis unit list of reference channels available (fig. 2).
Alternatively, change the axis unit by double-clicking the unit of the X axis.
Changing the reference value results in the change of the representation of data in the diagram and the unit of the X axis. The level-over-time diagram, for example, will become the level-over-RPM diagram.
If you mark an area in such diagram, the time periods which include the reference value are transferred to all plugins (Photo 2D) connected at this point of time. See fig. 3 and 4. This enables, for example, the calculation of an acoustic photo for the area of 2400-2500 RPM.