A method is described for calculating the error response of optical-reticle systems used to convert line-of-sight angle into an electrical signal. The calculation is carried out in the frequency domain and relates optical aberrations as expressed in terms of a spot diagram, and the reticle pattern which is characterized by a reticle phase function, to the amplitudes and phases of the significant harmonics in the output waveform. The procedure is easily programmed for a computer and permits the rapid evaluation of reticle and optical designs and design changes.
PAUL E. MENGERS and KATHRYN B. O’BRIEN, "Analysis of Error Response of Amplitude Modulated Reticles," J. Opt. Soc. Am. 54, 668-668 (1964)