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Dran-View 6 User Guide

13.12. DFT Chart Specific Information

Specific

Information

DFT charts display harmonics data, calculated for a specific time range. DFT charts

differ from the general description of charts in the following ways:

• The DFT chart defaults to bar graph.

• The DFT chart has frequency or harmonic index along the X-axis.

• The DFT chart footer contains DFT data as opposed to event data by

default.

• The data displayed in the chart is calculated by Dran-View based on the

measured waveforms.

• The DFT chart does not always contain data.

• The DFT chart, although not a child of any other chart, can be connected to

one as a time-range source.

• Textual DFT data and child-phasors always use the same time-range for

calculations as the DFT chart itself.

• There are additional settings on the Harmonics Page of the properties dialog

box.

For more information about harmonics, see the Harmonics Page.

Time Range

The DFT chart determines the time-range to use for calculations in the following

order:

1. If connected to an Event Details/Waveform Chart which contains an active

Area Marker, the range of the Area Marker is used.

2. If not connected to another chart, the time range of the active event is used

(if this is a full cycle).

3. If the range in 1 or 2 is not a full cycle, the starting-point is maintained and

the end-point is moved to the end of a full cycle after the starting point (if

there are enough waveforms available).

4. If there are any "gaps" and ranges with missing samples having been

determined, the starting-point is maintained and the end-point is moved to

the nearest full cycle ending before this gap.

If the range now determined does not equal at least one cycle, no data is calculated

Settings The settings for the DFT chart are mostly identical to those of other charts. Specific

differences can be found on the Harmonics Page.

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Dranetz Guide Guide de l'utilisateur Page 177