| A notebook PC has a limited space for
components. Therefore, it is important to first make a good shield, and
then install EMI filters. Conductive plating is applied to the plastic
case, and a metal plate is installed above and below the PCB. To
suppress noise on the interface cable, the metal plate and GND are
connected around the end of the cable with installed EMI filters.
High noise levels also radiate from the LCD unit due to
the many bus lines connecting the graphic controller and LCD driver.
Therefore, EMI filters such as Chip Ferrite Bead are installed on the
bus lines. The cable connecting the LCD and main board also emits high
noise levels, so also must be shielded.
In the external slot used for PCMCIA cards, the GND for
the card and the main board GND need to be connected with low impedance
at high frequency. The card slot is also shielded with a metal plate.
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