Spectrum interpolation method, spectrum interpolation apparatus, and spectrum interpolation program storage medium

摘要

A spectrum interpolation method obtains a spectrum value at an arbitrary frequency by interpolating discrete spectra obtained through sampling one period or a periodic function at N sampling points to perform a Fourier transform. The spectrum value Fp(ω) at the arbitrary frequency f = ω/2π is obtained in accordance with the following formula or any of formulae equivalent to the following formula Fpω=∑k=0N-1Fp⁢ω0+k⋅Δ⁢ω⋅Ψ⁢ω-ω0+k⋅Δ⁢ω
where Ψω=1N⋅exp-j⁢N-1⁢π⋅ωN⁢⁢Δ⁢⁢ω⋅sinπ⋅ωΔ⁢ωsinπ⋅ωN⋅Δ⁢ω
(where ω is an angular frequency of interest, Fp(ω) is the spectrum value at the angular frequency ω, Δω is the distance between discrete spectra, ω0 is an arbitrary reference angular frequency, including ω0 = 0, and ψ(ω) is an interpolation function).