What is the meaning of flux cancellation (EMC in PCB)?

[hellen10]

flux cancellation

hi all
I just read an article about the EMC in PCB, there is a phase "flux cancellation", I don't know what meant it is? could you tell me? thanks.
else, what's meaning the "chassis ground "

best regards!

 

[tanuki]

Re: flux cancellation

flux cancellation: a circuit geometry that reduces the magnetic field energy around a set of conductors ....

papers:
http://www.radioing.com/eengineer/pcb-tips.html
**broken link removed**
**broken link removed**

more info... search google using combinations of these keywords and phrases: "PCB" "magnetic flux cancellation" "low inductance""flux cancellation" "zero inductance" "technique" "method" "device"

Chassis Ground is a connection to the cabinet, enclosure or housing of the electronic assembly. Generally used as a current path for electro-static discharge and other hazardous currents that might enter the PCB via it's interface circuits. Common pratice is to connect the signal ground to the chassis grounds with a parallel combination of a 1 M-ohm resistor and 4700 pF ESD rated capacitor. Also, it is normal for the chassis ground to be bonded (single point connection) to the power system earth ground.