公开(公告)号：US3816647A

公开(公告)日：1974-06-11

申请号：US24131772

申请日：1972-04-05

Applicant: NORTHROP CORP

Inventor： CHANG M ,  MCCRICKERD J

IPC: G06E3/00 ,  G06K9/74 ,  H04N3/00

CPC classification number: G06E3/003 ,  G06K9/74

Abstract: A light beam is generated by means of a narrow band collimated light source, and this light beam is modulated in accordance with an electrical input signal to be identified. The light beam is then optically scanned at a predetermined scanning rate to produce an optical image of the input signals against a time base. Light from this optical image is passed through a holographic reference transparency, which is a spatial filter corresponding to the Fourier transform of the image of known electrical signals, the light passing through the transparency being fed to a detector. Successive reference transparencies are utilized until correlation between the transparency and the input signal to be identified is indicated by a peaking of the detector output which is sensed by a correlation indicator.