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?
My questions:
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?
My questions:
- 1. 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.
- 2. 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?
- 3.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.