CAN interface adopts differential signal transmission mode.
Differential signal transmission is a method of information transmission using two complementary electrical signals. Take high-speed CAN as an example, different logic states are transmitted through two signal lines CANH and CANL, and the receiving circuit only recognizes the signal difference between the two signal lines.
Interference signals generally exist in the form of common mode, when the bus is interfered, the two buses will be affected at the same time, but the differential voltage will not be affected. Compared with single-ended signal transmission, differential signal transmission has better anti-interference ability.
Therefore, for bus applications, we recommend the use of twisted pair.
CAN bus uses twisted pair differential voltage transmission, because in a pair of twisted pair signal current direction is opposite, the generated magnetic field can cancel each other, plus shielding layer and correct grounding can achieve electromagnetic compatibility.
The helical symmetrical structure of the twisted pair can make the twisted pair maintain the force balance in each direction when bending, and also indirectly protect the balance of electrical performance.