Kan-sia̍p (interference) sī kóng 2 ê he̍k-chiá í-siōng ê pho (wave) sio-tha̍h (superposition) chò-hoé, chō-chiâⁿ sin ê pho-iūⁿ (wave pattern).

2 ê îⁿ pho ê kan-sia̍p, pho-tn̂g jú téng-koân jú té, pho-sim jú chiàⁿ-pêng jú hng.