Cross correlation (correlating a signal with another) can be used to detect and locate known reference signal in noise.
The diagram shows how the signal can be located within the noise.
- A copy of the known reference signal is correlated with the unknown signal.
- The correlation will be high when the reference is similar to the unknown signal.
- A large value for correlation shows the degree of confidence that the reference signal is detected.
- The large value of the correlation indicates when the reference signal occurs.