%0 Journal Article %T A Biproportional Construction Algorithm for Correctly Calculating Fourier Series of Aperiodic Non-Sinusoidal Signal %A Zicheng Li %A Mingwei Ren %A Zhaoling Chen %A Guohai Liu %J Engineering %P 503-525 %@ 1947-394X %D 2021 %I Scientific Research Publishing %R 10.4236/eng.2021.1310036 %X The Fourier series (FS) applies to a periodic non-sinusoidal function satisfying the Dirichlet conditions, whereas the being-processed function \"\" in practical applications is usually an aperiodic non-sinusoidal signal. When \"\" is aperiodic, its calculated FS is not correct, which is still a challenging problem. To overcome the problem, we derive a direct calculation algorithm, a constant iteration algorithm, and an optimal iteration algorithm. The direct calculation algorithm correctly calculates its Fourier coefficients (FCs) when \"\" is periodic and satisfies the Dirichlet conditions