Noise realizations stay fixed; only the scaling changes with SNR.
Positive values delay Y₂(t) relative to Y₁(t).
Signal variance
Noise variance
Delay [ms]

Observation Y₁(t) = X(t) + N₁(t)

Observation Y₂(t) = X(t−τ₀) + N₂(t)

Cross-correlation RY₁Y₂(τ)