manuale presto

Emission Profiles and Maps EmiR

PRESTO

Chapter 4 Emission Profiles and Maps 4.

4.1 Introduction 4.2 Emission Profiles in Far Field 4.2.1 Making the Results Available 4.2.2 Viewing the Results 4.2.3Printing a Profile Window on UNIX platforms 4.2.4 Customizing a Print Shell 4.2.5 Printing a Profile Window on NT platforms 4.2.6 Closing the Profiles Window 4.2.7 Selecting a Frequency 4.2.8 Selecting Layers 4.2.9 Selecting Nets 4.2.10 Selecting the Scale Limits 4.2.11 Zooming 4.2.12 View Modes 4.2.13 Setting the Background Color 4.2.14 Selecting the Plot Mode 4.3 Emission Maps in Near Field 4.3.1Simulating the Surface Scanning of a Board

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4.3.2 Viewing the Results 4.3.3 Printing a Maps Window on UNIX platforms 4.3.4 Customizing a Print Shell 4.3.5 Printing a Maps Window on NT platforms

4.3.6 Closing the Maps Window 4.3.7 Selecting a Frequency 4.3.8 Selecting the Scale Limits 4.3.9 Zooming 4.3.10 View Modes 4.3.11 Setting the Background Color 4.3.12 Selecting the Plot Mode

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4.1 Introduction Starting from the results of an EmiR simulation it is possible to visualize in a dedicated window emission profiles and maps. Suppose to obtain the results of a simulation of a board in far field conditions. It is certainly useful being able to know which nets give the most important contribution to the total radiated em field; so one can concentrate his attention on these nets and neglect the not influential ones. The visualization of the emission profiles has been implemented to this end. The nets are displayed in different colors according to the values of the radiation at one frequency, or to the maximum radiated field over the whole range of frequency. Suppose instead to obtain the results of a simulation of a board in near field. It is useful in this case visualizing the distribution of the emissions in the different areas of the board. The visualization of the emission maps has been implemented to this aim. The board is displayed with its zones differently colored according to the values of the radiation at one frequency, or to the maximum radiated field over the whole range of frequency. In this way the user can point his attention on the more critical areas of the board, neglecting the ones not giving an important contribution to the total radiation.

4.2 Emission Profiles in Far Field 4.2.1 Making the Results Available 1. Choose EmiR Analysis from Run menu. The EmiR main window will appear. 2. Choose a simulation condition from Options menu (No floor, Floor without cable, Floor with cable). 3. Set the simulation parameters. 4. Click on Run button. The simulation will start. At the end of the simulation the Emi Profiles button is enabled.

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4.2.2 Viewing the Results 1. Click on Emi Profiles button. The Profiles window will appear; an example is shown below:

The nets are differently colored according to the values of the radiated field. Near the layout display window the scale showing the relation between colors and field values is displayed. The nets not selected for the EmiR simulation and the segments laying between two shields (striplines) are drawn in special colors. It is possible to visualize only the nets corresponding to certain ranges of emission, by clicking on the buttons near each color of the scale.

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4.2.3 4.2.3Printing a Profile Window on UNIX platforms To make a hardcopy of the emission profiles displayed in the graphic window, choose Hardcopy from Control menu. Three different options will be presented: Color: this selection creates a temporary file in the /hardcopy directory that will be processed by the shell printcolor and then sent to the printer. The shell printcolor is present in $HOME/.prestoenv and can be modified by the user as specified in 4.2.4. Black/White: this selection creates a temporary file in the /hardcopy directory that will be processed by the shell printbw and then sent to the printer. The shell printbw is

File:

present in $HOME/.prestoenv and can be modified by the user as specified in 4.2.4. this selection creates a file in the current directory containing a dump of the graphic window in .xwd format. Upon activated the command,

the file manager window will be open, allowing the user to specify the name of the output file. Click on OK to complete the procedure. If using laser printers, the background should be set to BLACK, whereas for postcript printers the background should be set to WHITE.

4.2.4 Customizing a Print Shell The default print shells available in $HOME/.prestoenv can be customized by activating the command Printer Setup from Control menu. Two different options will be presented: Color this selection allows the user to edit the file $HOME/.prestoenv/printcolor and modify the printing statements (for example to specify the device or the print queue) for color printers. Black/White this section allows the user to edit the file $HOME/.prestoenv/printbw and modify the printing statements (for example to specify the device or the print queue) for black/white printers.

This is the script that has to be used for laserjet printers:

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#! /bin/csh set a = "tmpfile" echo "printbw script infile $1" echo "outfile $a" xpr -device ljet -output $a -cutoff 20 $1 lp -o nobanner $a rm -f $a rm -f $1 # for hp platform #xwd2sb < $1 > $a #rm -f $1 #pcltrans -C -r300 -h10 -d7 $a > $1 #rm -f $a #lp -d deskgl2 -oraw $1 #rm -f $1 Note The line “xpr -device ljet -output $a -cutoff 20 $1” is correct for laser printers; for postcript printers the line must be changed into “xpr -device ps -output $a -cutoff 20 $1”.

4.2.5 Printing a Profile Window on NT platforms To print a Profile window: 1. Choose the Options  Background  White menu in the Profile window 2. Choose the Control  Print setup menu The following window will appear:

In this window it is possible to choose the printer and the paper format and size.

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2. Click on OK when done. 3. Click on the Control  Print menu in the Profile window The printing will automatically start.

4.2.6 Closing the Profiles Window To close the Emission Profiles window: 1. Click on the Control menu. The submenu with two options will be presented. 2. Click on Quit. The emission profiles window will be closed.

4.2.7 Selecting a Frequency The default visualization is made at the first frequency of the range established in the Simulation Setup window. By selecting another frequency value from the list below the colors scale, the display of the layout and the corresponding scale is automatically updated.

4.2.8 Selecting Layers 1. Choose Layers from Selection menu. The following window will appear:

The number of layers depends on the crossection of the design under test. By clicking on one or more buttons the user can enable/disable the visualization of the corresponding layer.

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2. Click on OK to confirm the selection. The profiles display window will show the selected layers. The button CANCEL allows the user to close the layer selection window without changes.

4.2.9 Selecting Nets 1. Choose Nets from Selection menu. The following window will appear:

The default plotting mode will display all the nets of the design fitted in the window. The user can select/unselect one or more nets by clicking on them twice. The currently selected nets will be displayed.

4.2.10 Selecting the Scale Limits 1. Choose Set limits from Selection menu. The following window will appear:

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The user can change the maximum and minimum values of the scale of the radiated field, in order to better discriminate the emissions of the nets within a narrow range of values. Before setting the new maximum and minimum values, the user has to click on Default values button. If the user wants to return to the default values, they will be automatically set by clicking on Default values button again.

4.2.11 Zooming This section shows the procedure to enlarge a section of the display window. Point the first corner of the area to enlarge and click the left button of the mouse. Maintain it pressed. Drag the mouse to the second corner of the area to enlarge and release the button. The selected area will be enlarged. It is possible to repeat the procedure. Choose Unzoom to fit the entire layout in the window.

4.2.12 View Modes The board can be displayed in two different ways: top view and bottom view. To switch between the two different views: 1. Select Options->View->top The board geometry is displayed looking the board from the top. 2. Select Options->View->bottom The board geometry is displayed looking the board from the bottom.

4.2.13 Setting the Background Color Usually the board is displayed with the background color black. In any case, it is sometimes useful to invert the background color (for example to make hardcopies). To switch between the two different views: 1. Choose Background from Options menu.

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A submenu with two options will be shown. 2. Choose White The background of the layout window will become white.

4.2.14 Selecting the Plot Mode 1. Choose Plot mode from Options menu. A submenu with two options will be shown: Sel. Freq and By max. The default choice is Sel. Freq.: the emission profiles are displayed at one frequency selected by the user. 2. Click on By max. button. The list of the frequencies disappears: maximum and minimum emissions are the ones on the whole frequency range

4.3 Emission Maps in Near Field 4.3.1 Simulating the Surface Scanning of a Board 1. Choose EmiR Analysis from the Run menu in the main PRESTO window. The main EmiR window appears. 2. Choose No floor from the Options menu. 3. Choose Spectrum from the Analysis menu. 4. Click on Near Field button. 5. Click on Surface scan button. The following window will appear:

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6. Set the simulation parameters.  z is the coordinate of the observation point above (z>0) or under (z