Timing margin

Timing margin[1] is an electronics term that defines the difference between the actual change in a signal and the latest time at which the signal can change in order for an electronic circuit to function correctly.

Data is recognized by the circuit at the positive edge of the clock.

The edges of the signals can shift around in a real-world electronic system for various reasons.

If it is known from experience that the signals can shift relative to each other by as much as 2 microseconds, for instance, designing the system with at least 2 microseconds of timing margin will prevent incorrect interpretation of the data signal by the receiver.

If the signals have been designed with enough timing margin, only the correct data will be received.