1 · Source, wavefronts and path difference
2 · Received signals (wave trains)
antenna 1 (left)antenna 2 (right), after τ_iantenna 2 before τ_i
3–4 · Correlator: multiply and average
product s₁·s₂running meanright: complex visibility (cos and sin channel)
5 · Fringe pattern over the direction
correlator outputenvelope: band × beam × source sizecurrent direction
6 · Fringes over time (Earth rotation)
real part (cos channel)imaginary part (sin channel)amplitude