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Click on the following bookmarks for further details of a Design Guide for emc:

Shielding, PCB, Signal Integrity and ESD Design Guides.
A flexible Design Review Check List generator, which is fully user-editable.


Shielding Integrity Design Guides

    The diagram below highlights several areas in the design of a shielded enclosure which can affect the emc performance of the equipment as a whole.

Shield Integrity.gif (10324 bytes)

    Clicking on a label such as 'Gasketted Interface' with the left mouse button provides more information on the topic, whilst clicking with the right mouse button launches the relevant analysis tool. In the case of the gasket, the tool which analyses the gasket groove design is provided.

PCB Design Guide

    The PCB Design guide highlights areas of the pcb layout which can affect emc performance. These are highlighted in the diagram shown below, and as with the Shielding Integrity guide, the left mouse button provides further information, and the right mouse button launches the appropriate analysis tool.

PCB Design Guide.gif (9822 bytes)

    In addition, a series of 'Golden Rules' for PCB design are provided, to further highlight some of the design principles.

PCB Loop Area.gif (7480 bytes)

    The Golden Rule for PCB design describing the importance of reducing loop area, formed by a clock signal and its return for instance. This reduces differential mode radiated emissions.

Signal Integrity Design Guides

    The Signal Integrity item in the Design Guides menu summarises the tools which deal with the examination of sinusoidal signals. Thus a trapezoidal waveform can be represented by a series of sinusoidal waveforms at odd harmonics of the fundamental frequency, and a link to the Fourier analysis tool is provided.

    As with the other design Guide items, the left mouse button can be clicked for more information, and the right mouse button can be clicked to jump to the indicated analysis tool. The signal integrity window is shown below.

Signal_Integrity.gif (9755 bytes)

Design Guide: ESD Protection

    The ESD item on the Desgin Guides menu provides a number of tips for dealing with electrostatic discharge. These include the problems of plastic panels with openings for components, of pcbs with ground connections resulting in preferential grounding paths, and the need to maintain continuity across cabinet seams.

Design Review

    A Design Review facility is provided under the Design Guides menu, to enable the emc aspects of a development project to be reviewed for emc considerations in a structured manner.

    A series of check lists is provided, which divide the project into a number of logically separate areas. Each area, or module, contains a number of items which the user can check as 'OK', 'X', 'N/A' or leave blank. OK is used to show that the item requirement is met, X not met, and N/A to mean the item is not applicable.

    The series of checks can be attached to a particular project, and the item checking details saved with the project.

    The user can edit and add to the list of items to check, and can even create entirely new design review check lists, on subjects unrelated to electromagnetic compatibility.

    The Design Review form is shown below.

Desreview CheckList.gif (10206 bytes)

    An item is checked by pointing at it on the check list, and using the Check button to toggle between the four possible check states. The 'More Info' button accesses further details of the check itself.

    Checked lists can be printed from the File Menu, which also allows a Project to be opened or created. This allows a series of checks to become a unique data set. An analysis of the user's checks is available, and is described on the following page.

    The check items themselves are created and edited from the Edit Module form, accessed with the Edit Module button.

The Edit Module form is shown below:

Design Review Modcheck.gif (11487 bytes)

   Each Check List contains a number of modules, created, edited and removed using the New Module, Edit Module and Delete buttons at the top of the form. A description can also be attached to the module, using the text box below the Module title.

    The list of check items for each module is shown in the centre of the form, and the check itself is entered in the box below the list. The item is added to the list using the Add To List button, to add a new item to the end of the list, the Insert button, to put the new item at the highlighted point in the list, or the Edit button, to replace the highlighted item in the list.

    Checks may be deleted using the Delete button. A description can also be added to each check, which is subsequently accessible directly from the Design Review Check List form. A graphic can also be attached to the description, using the Info Picture button, to provide further guidance to the user of the check list.

    A series of checks can be analysed from the Design Review Check List form using the Analysis menu item, which displays the form shown below:


Analyse.gif (6767 bytes)

 

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