Chapter 8 Plots
3. Smith Overlay Plots
Smith Overlay plots are just a variation on cartesian plots. Instead of a rectangular overlay, a smith overlay is used. Typically, smith overlay plots are used for the x vs. y plotting of scalar channels. Data that is appropriate for Cartesian coordinates is also appropriate for Smith Overlay plots. Smith Overlay plots, unlike cartesian plots, can only have one y channel and must always specify an x channel in the 'x data channel' property.
The 'data color' property in a smith overlay plot's property sheet has no significance. The actual values of the channel are plotted in the foreground color. In addition, the plot's title and the titles of the axes are in the foreground color. All other information is in the colors of the impedance and admittance grids.
The properties unique to Smith Overlay plots are the 'impedance grid,' 'admittance grid,' the 'impedance grid color,' and the 'admittance grid color' properties. The 'impedance grid' and 'admittance grid' properties are choice buttons that allow you to turn the impedance and admittance grids on or off so that they will appear or not appear at run-time. However, you cannot turn both grids off. You can only turn off only one of the two grids because DM must display at least one grid. If you do turn both off, DM will still display the admittance grid. The 'impedance grid color' and 'admittance grid color' properties determine the color of each grid.
Figure 8-3 shows a smith overlay plot that displays both its impedance and admittance grids.
Cartesian Plot of Waveform Channels
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Smith Overlay Plot with Both Grids.
EDD/DM User's Manual, 2.4 - 27 MARCH 1997 [Next] [Previous] [Up] [Top] [Contents] [Index]