| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical correlator which is easily adaptive to an increase in the number of chips of a modulated code and can obtain a high diffusion gain. SOLUTION: CDM-modulated light is made incident on a beam splitter 2 which is so formed that the transmittance is spatially different and is split into a beam transmitted through the beam splitter 2 and a reflected beam; and the beams having time delay by reflection between the beam splitter and a mirror 3 arranged in parallel to the beam splitter are transmitted, mutually adjacent beams are delayed by one-chip lengths of the modulated code and reach a spatial optical modulation plate 4 at equal intervals, and the individual beams are given differences or an amplitude distribution, reach a lens 5 which performs Fourier transform on a focal plane, and photodetected by a photodetecting element 7 through a mask 6 passing only a main lobe, and correlation is checked as to whether the same phase difference or amplitude distribution as the CDM modulation of the incident light has been given by the spatial optical modulation plate 4 from light signals on the photodetecting element 7. |
