29407Re: [softrock40] Re: V9 output to audio card?
- Jan 1, 2009
----- Original Message -----
> OK, I see that would isolate and prevent any DC ground loops, but can
> the ground loop not be in the AC region? OR maybe it's only the DC
> ground loops that give a problem?
Well, the current through ground loops is basically at mains frequency and
its lower harmonics. A lowish value capacitor will have a highish impedance
at these frequencies so little current will flow.
The capacitor offers a relatively low impedance at the higher frequencies so
passing the spiky USB signal. In my case the impedance of the ground
connection must have been high enough to suppress this signal.
73 Alan G4ZFQ
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