I was reading about the common mode noise and differential mode noise.
I don't understand how a differential mode noise gets coupled and how adding a capacitor across the line will help.
I understand about common mode noise. Like, if we have a noisy source, it might equally couple on both lines and we can use a common mode choke to reflect back the common mode noise back to the upstream source.
But how is a differential noise generated on the lines? Is it generated by places the lines close to differential signals?
In general, does the noise affect only power lines or signal lines as well? I am asking because, I have seen app notes and other illustration depicting these concepts only in the context of Power supplies.
Is differential mode noise, generated on the lines, by placing the differential mode signals near them? Or how else, will the line and neutral wires have noise voltage of opposite polarity? I assume that differential mode noise is obtained only by placing the circuit near differential mode signals. Am I correct in this understanding?
And I understand how a common mode choke attenuates the common mode signal. But how does adding a capacitor between the lines, attenuate the differential mode noise? Can someone provide some help on this.