What is the definition of even mode in a differential pair?

Conditions

• Applies to the two signal lines of a differential pair.
• The driving voltages on the two lines have the same magnitude and polarity.

Reasoning, step by step

1. Observe the two signal lines of the differential pair.
2. Note that both lines experience a positive voltage transition simultaneously.
3. Note that the waveforms change in the same direction.
4. Conclude that this same-phase driving condition defines the even mode.

Example

The video shows a waveform plot for even mode where both lines change in the same direction, appearing as pulses of the same polarity.

Common misconceptions

• Confusing even mode with common mode (one is a line property, the other is an applied signal).
• Believing that even mode means the lines are shorted together.

Watch the explanation

Explore next

• What is the definition of odd mode?
• How is common-mode impedance calculated from even-mode impedance?
• Why are odd and even modes considered intrinsic properties of the transmission line?