transform summary
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A summary table dated 3.26.05, noted as added to the spectral document as Appendix E. It lists transform and inverse pairs for the Fourier integral, generalized Fourier, cosine, sine, Fourier series, Laplace, digital Fourier, Z, discrete Fourier and Hilbert transforms, with equation numbers cross-referencing the main text. Integral and sum symbols are garbled in the extraction, so the formulas are only partly legible.
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This is the Title PhL 3.26.05
This has been added as Appendix E to spectral doc.
Appendix E: Table of Transforms
Fourier Integral Transform: x(t) aperiodic and continuous, X(ω) continuous, no image spectra
X(ω) = !Syntax Error, Idt x(t) e-iωt projection = transform (1.1)
x(t) = (1/2π)!Syntax Error, Idω X(ω) e+iωt expansion = inverse transform (1.2)
Generalized Fourier Integral Transform: recovery contour passes below all singularities of X(ω)
X(ω) = !Syntax Error, Idt x(t) e-iωt projection = transform (6.4)
x(t) = (1/2π) !Syntax Error, Idω X(ω) e+iωt expansion = inverse transform (6.5)
Fourier Cosine Transform
Xc(ω) = 2 !Syntax Error, Idt x(t) cos(ωt) projection = transform
x(t) = (1/π)!Syntax Error, Idω Xc(ω) cos(ωt) expansion = inverse transform (1.7)
Fourier Sine Transform
Xs(ω) = 2 !Syntax Error, Idt x(t) sin(ωt) projection = transform
x(t) = (1/π)!Syntax Error, Idω Xs(ω) sin(ωt) expansion = inverse transform (1.8)
Fourier Integral Transform in Appendix C notation: k is an arbitrary convention constant
x^(ω) = k!Syntax Error, Idt x(t) e-iωt projection = transform
x(t) = (1/2πk) !Syntax Error, Idω x^(ω) e+iωt expansion = inverse transform
f^(ω) = k!Syntax Error, Idu f(u) e-iωu Fourier transform of f(u)
f^-1(t) = (1/2πk) !Syntax Error, Idu f(u) e+iut inverse Fourier transform of f(u) (C.1)
Fourier Series Transform: x(t) periodic and continuous with period T1, spectrum is discrete
x(t) = !Syntax Error, I xpulse(t - nT1) (14.1)
Complex form:
cm ≡ (1/T1) !Syntax Error, I dt xpulse(t) e-imωt = (1/T1) !Syntax Error, I dt x(t) e-imωt (14.16)
x(t) =!Syntax Error, Icm e+imωt (15.1)
cm = c(mω1) = (1/T1)Xpulse(mω1) (14.8) and (14.10)
Real form:
am ≡(2/T1) !Syntax Error, Idt xpulse(t) cos(mω1t) = (2/T1) !Syntax Error, I dt x(t) cos(mω1t) (15.6)
bm ≡ (2/T1) !Syntax Error, Idt xpulse(t) sin(mω1t) = (2/T1) !Syntax Error, I dt x(t) sin(mω1t) (15.7)
x(t) = a0/2 + !Syntax Error, I am cos(mω1t) + !Syntax Error, I bm sin(mω1t) (15.9)
Laplace Transform: Right-sided (causal) x(t) vanishes for t < 0, x(t) and X(s) are continuous
X(s) = !Syntax Error, Idt x(t) e-st projection = transform (6.9)
x(t) = (1/2πi) !Syntax Error, Ids X(s) e+is expansion = inverse transform (6.10)
Relation to the Fourier Integral Transform:
X(s) = X(s/i) X(ω) = X(iω) (6.8)
Digital Fourier Transform: x(tn) aperiodic, spectrum X'(ω) is continuous and contains image spectra
X'(ω) ≡ !Syntax Error, I∆t x(tn) e-iωt projection = transform (22.2)
x(tn) = !Syntax Error, Idω X'(ω) e+iωt expansion = inversion (22.4)
or
X'(ω) ≡ T1!Syntax Error, Ixn e-iωnT projection = transform xn = x(tn).
xn = !Syntax Error, Idω X'(ω) e+iωnT expansion = inversion
where: T1 = ∆t ω1 = 2π/T1 = 2π/∆t tn = n ∆t = n T1 .
Relation to the Fourier Integral Transform:
X'(ω) = !Syntax Error, IX(ω - mω1) = [ X(ω) + !Syntax Error, IX(ω - mω1) ] // image spectra (23.1)
Z Transform: x(tn) is aperiodic, spectrum X"(z) is continuous and contains image spectra
X"(z) = !Syntax Error, Ixn z-n projection = transform (24.3)
xn = !Syntax Error, Idz X"(z) zn-1 expansion = inversion (24.4)
where contour C goes once counterclockwise around the unit circle in the z-plane.
Relation to the Digital Fourier Transform and the Fourier Integral Transform:
X"(z) ≡ X'(ω) = !Syntax Error, IX(ω - mω1) z = eiωT
Discrete Fourier Transform of a Pulse Train : x(tn) periodic, spectrum discrete, m integer
x(tm) = !Syntax Error, I xpulse(tm - nT1) sampled pulse train, tm = (m/N)T1
c'm ≡ (1/N) !Syntax Error, Ixpulse(tn) e-imn(2π/N) projection = transform (27.9)
x(tn) = !Syntax Error, Ic'm e+imn(2π/N) expansion = inverse transform (27.11), (27.12)
Discrete Fourier Transform : A is an arbitrary convention constant
c'm ≡ (A/N) !Syntax Error, Ixn e-imn(2π/N) m = 0,1...N-1 projection = transform
xn = (1/A) !Syntax Error, Ic'm e+imn(2π/N) n = 0,1,...N-1 expansion = inverse transform (27.22)
Hilbert Transform:
Xh(ω) = (1/π) dω' projection = transform
X(ω) = - (1/π) dω' expansion = inverse transform (C.41)