How is common mode noise filtered on differential lines that have a noise source that is driving them relative to chassis GND? I drew a picture of what I am imagining below. Imagine a PCB with differential signals that are in a metal enclosure.
I think the common mode noise will drive the entire circuit with a current shown in purple below:
All the documentation I find show single ended examples like the one in reference image 1 below, where a choke is used between the signal line and system GND to reject the common mode. There are also examples like reference image 2 below where a choke is used to reject common mode between two differential lines (say from a skew mismatch of the transmission lines).
To deal with this do I need to use 3 common mode chokes? One between the two differential signals, and then on each differential signal and ground? Advice is appreciated.
Choke 1: N and P signal
Choke 2: N signal and system GND
Choke 3: P signal and system GND
REFERENCE IMAGE 1: Choke on single-ended signal and system GND. Image Source
REFERENCE IMAGE 2: Choke on differential signals.