Mark Nave of EMC Services patented a DMRN based totally on resistors no
transformers - trade-named LISN MATE, back in the late 1980s. If memory
serves, there was a three phase variant as well as the more common
three-port devices that connected to a pair of LISNs and the EMI receiver.
Later on h
Be careful to model right.
In DM mode the parasitic elements in a DM coil are in parallel,
in anti-parallel (CM) configuration they are in series.
The ratio between induction and stray inductance is not more then
100:1 in most CM coil so 100:2 in DM mode This severely limits the usable
freque
Thanks Gert. We were thinking 4-wire LISN (phase A,B,C and Neutral)
Your idea of two sets could work; I'd likely simulate on SPICE, then
arrange a breadboard if those results looked promising.
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Ralph McDiarmid |
Just use 2 sets of 2 anti parallel CM coils and couple the common via
a third to ground (I suppose).
I do not know your specific application, but in general DM signals
come in paired sets of 2..
The only application I know where DM is over 4 wires,
is a phantom signal in phone l
A DMRN (Differential-Mode Reject Network) works well for 2-wires, but has
anyone tried for 4 wires? I suppose a common-mode transformer with a
bandwidth up to 30MHz would do.
Any suggestions from the RF gurus in the group?
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