Since the cable conducts noise, EMI filters are installed in the cable
connections. Generally, the BLM Series (Chip Ferrite Bead), and a capacitor-type
EMI filter such as the NFM21C Series (Chip Solid "EMIFIL®"),
are used together. To get the maximum effects from this capacitor-type
EMI filter, it is important to minimize the high-frequency impedance
between the filter GND and the metal case.
Each filter is placed close to a corresponding connector terminal. This
prevents any noise being conducted to the GND pattern behind the filters
and then radiating from the cable. |
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