User's Manual

UE910 3G HARDWARE USER GUIDE 1vv0301171 Rev.3 • 2015-04-17 60 of 78
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LINE IN Connection
If the audio source is not a mike but a different device, the following connections can be done.
Place 100nF capacitor in series with both inputs, so the DC current is blocked.
Place the 33pF-100Ohm-33pF RF-filter, in order to prevent some EMI field to get into the high
impedance high gain MIC inputs.
Since the input is differential, the common mode voltage noise between the two (different) ground is
rejected, provided that both MIC+ & MIC- are connected directly onto the source.