This shows how common mode noise creeps into differential lines. What I understand is that the orange region is the top copper and it has many tracks.The green is the ground. Now, when they say stray capacitance, what they mean is the capacitance buid up between the tracks and the ground with the FR4 acting as the di-electric.
So, anywhere on those lines the noise can be dissipated or can enter the ground thereby corrupting it as the copper and ground acts as a giant capacitor(not in capacitance value,rather in the dimension).
Now, my doubt being, how is the common mode noise generated ? What components generate common mode noise ?
Now, in the link1 document it says power sources generate common mode noise. Is this applicable to both ac and dc power ? I thought noise on dc lines contributed to the differential noise which can be eased out using ferrite beads and such.
Now, in one of the sections of the Link1 pdf it states that it is used at the dc power supply input section.
This means We connect one end to Vcc and gnd and then the other side to a dc rail and GND ? Is that it ? So that choke will have a current rating sufficing enough fopr the load ?
Are my assumptions correct ?