• 基本性质
性质 公式表示
线性定理 - 齐次性 L[af(t)]=aF(s)L[af(t)]=aF(s)L[af(t)]=aF(s)
线性定理 - 叠加性 L(f1(t)±f2(t))=F1(s)±F2(s)L(f_1(t)\pm f_2(t))=F_1(s)\pm F_2(s)L(f1(t)±f2(t))=F1(s)±F2(s)
微分定理 - 一阶导 L[df(t)dt]=sF(s)−f(0)L[\frac{df(t)}{dt}]=sF(s)-f(0)L[dtdf(t)]=sF(s)f(0)
微分定理 - 二阶导 L[d2f(t)dt2]=s2F(s)−sf(0)−f′(0)L[\frac{d^2f(t)}{dt^2}]=s^2F(s)-sf(0)-f'(0)L[dt2d2f(t)]=s2F(s)sf(0)f(0)
微分定理 - n阶导 L[dnf(t)dtn]=snF(s)−∑k=1nsn−kfk−1(0)L[\frac{d^n f(t)}{dt^n}]=s^nF(s)-\sum_{k=1}^{n}s^{n-k}f^{k-1}(0)L[dtndnf(t)]=snF(s)k=1nsnkfk1(0)
微分定理 L[tf(t)]=−ddsF(s)L[tf(t)]=-\frac{d}{ds}F(s)L[tf(t)]=dsdF(s)
积分定理 - 一阶导 L[∫f(t)dt]=F(s)s+[∫f(t)dt]t=0sL[\int f(t)dt]=\frac{F(s)}{s}+\frac{[\int f(t)dt]_{t=0}}{s}L[f(t)dt]=sF(s)+s[f(t)dt]t=0
积分定理 - 二阶导 L[∬f(t)(dt)2]=F(s)s2+[∫f(t)dt]t=0s2+[∬f(t)(dt)2]t=0sL[\iint f(t)(dt)^2]=\frac{F(s)}{s^2}+\frac{[\int f(t)dt]_{t=0}}{s^2}+\frac{[\iint f(t)(dt)^2]_{t=0}}{s}L[f(t)(dt)2]=s2F(s)+s2[f(t)dt]t=0+s[f(t)(dt)2]t=0
积分定理 - n阶导 L[∫…∫⏞nf(t)(dt)n]=F(s)sn+∑k=1n[∫…∫⏞kf(t)(dt)k]t=0sn−k+1L[\overbrace{\int \dotso \int}^{n}f(t)(dt)^n]=\frac{F(s)}{s^n}+\sum_{k=1}^n\frac{[\overbrace{\int \dotso \int}^{k}f(t)(dt)^k]_{t=0}}{s^{n-k+1}}L[ nf(t)(dt)n]=snF(s)+k=1nsnk+1[ kf(t)(dt)k]t=0
延迟定理 L[f(t−T)1(t−T)]=e−TsF(s)L[f(t-T)1(t-T)]=e^{-Ts}F(s)L[f(tT)1(tT)]=eTsF(s)
衰减定理 L[f(t)e−at]=F(s+a)L[f(t)e^{-at}]=F(s+a)L[f(t)eat]=F(s+a)
终值定理 lim⁡t→∞f(t)=lim⁡s→0sF(s)\lim\limits_{t \to \infty}f(t)=\lim\limits_{s \to 0}sF(s)tlimf(t)=s0limsF(s)
初值定理 lim⁡t→0f(t)=lim⁡s→∞sF(s)\lim\limits_{t \to 0}f(t)=\lim\limits_{s \to \infty}sF(s)t0limf(t)=slimsF(s)
卷积定理 L[∫0tf1(t−τ)f2(τ)dτ]=F1(s)F2(s)L[\int_{0}^{t}f_1(t-\tau)f_2(\tau)d\tau]=F_1(s)F_2(s)L[0tf1(tτ)f2(τ)dτ]=F1(s)F2(s)
尺度定理 L[f(at)]=1∣a∣f(sa)L[f(at)]=\frac{1}{\vert a\vert}f(\frac{s}{a})L[f(at)]=a1f(as)
  • 常用函数的变换
时间函数 变换后 时间函数 变换后
δ(t)\delta(t)δ(t) 1 1−e−at1-e^{-at}1eat as(s+a)\frac{a}{s(s+a)}s(s+a)a
δT(t)=∑n=0∞δ(t−nT)\delta_T(t)=\sum_{n=0}^\infty\delta(t-nT)δT(t)=n=0δ(tnT) 11−e−Ts\frac{1}{1-e^{-Ts}}1eTs1 e−at−e−bte^{-at}-e^{-bt}eatebt b−a(s+a)(s+b)\frac{b-a}{(s+a)(s+b)}(s+a)(s+b)ba
1(t)1(t)1(t) 1s\frac{1}{s}s1 sin⁡ωt\sin \omega tsinωt ωs2+ω2\frac{\omega}{s^2+\omega^2}s2+ω2ω
ttt 1s2\frac{1}{s^2}s21 cos⁡ωt\cos \omega tcosωt ss2+ω2\frac{s}{s^2+\omega^2}s2+ω2s
t22\frac{t^2}{2}2t2 1s3\frac{1}{s^3}s31 e−atsin⁡ωte^{-at}\sin \omega teatsinωt ω(s+a)2+ω2\frac{\omega}{(s+a)^2+\omega^2}(s+a)2+ω2ω
tnn\frac{t^n}{n}ntn 1sn+1\frac{1}{s^{n+1}}sn+11 e−atcos⁡ωte^{-at}\cos \omega teatcosωt s+a(s+a)2+ω2\frac{s+a}{(s+a)^2+\omega^2}(s+a)2+ω2s+a
e−ate^{-at}eat 1s+a\frac{1}{s+a}s+a1 at/Ta^{t/T}at/T 1s−(1/t)ln⁡a\frac{1}{s-(1/t)\ln a}s(1/t)lna1
te−atte^{-at}teat 1(s+a)2\frac{1}{(s+a)^2}(s+a)21
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