Thankyou, that was very enlighteing, so if live and neutral conducted emissions scans are different, then that means its a mixture of common mode and diff mode emissions?
Presumably, the more different they are, the more it means ....urmm...something (?)
Yeah that's about the gist of it.
You can start looking at RF combiners - very useful if you understand what's going on. Great way to generate confusion if you don't. Keep in mind that subtracting two signals that are in phase is the same as adding two signals that are 180deg out of phase.
0 degree combiner - adds signals A + B
- Any signal only in A or B only will pass through at +0dB.
- Any signal which is common to both A and B will sum together at +6dB (double the magnitude).
- Any signal which is 180deg out of phase will sum to zero.
Any signal that increases when using a 0deg combiner is a good sign it's common mode. Conversely, any signal that reduces is differential mode.
180 degree combiner - subtracts signals A - B (doesn't matter which one is subtracted).
- Any signal only in A or B only will pass through at +0dB.
- Any signal which is common to both A and B will subtract to zero.
- Any signal which is 180deg out of phase will sum together at +6dB (double the magnitude).
Any signal that increases when using a 180deg combiner is a good sign it's differential mode. Conversely, any signal that reduces is common mode.