3.4.3 Responses of measuring system to typical excitations 1. Unit impulse response For a unit impulse function d(t,its Fourier transform AGj@)=I and the laplace transform of S(: 4(s=LS(/1. The output of a measuring instrument with d(t) as its excitation: Y(S=H(SX(S=H(S)4(S)=H(S) Making inverse Laplace transform of Y(s) en y()=L[Y(s)]=h(t (3.44) h(t is referred to as the impulse response function or weighting function of a measuring system1. Unit impulse response For a unit impulse function δ(t), its Fourier transform Δ(jω)=1 and the Laplace transform of δ(t): Δ(s)=L[δ(t)]=1. The output of a measuring instrument with δ(t) as its excitation: Y(s)=H(s)X(s)=H(s)Δ(s)=H(s). Making inverse Laplace transform of Y(s), then h(t) is referred to as the impulse response function or weighting function of a measuring system. 3.4.3 Responses of measuring system to typical excitations y(t) = L Y (s) = h(t) −1 (3.44)