To receive an input signal to drive a Bragg cell illuminated by a collimated light beam, in an optical/analog/digital pulse detector.

The Bragg cell spatially modulates the collimated light beam, and an image is formed on a face of an opaque plate by a lens of an optical network after outgoing the Bragg cell. A binary optical plate repeats the image of the Bragg cell on the opaque plate. The opaque plate has slits of various lengths arranged in a place repeated with the images of the Bragg cell. An anamorphic lens is positioned in a route of light passed through the opaque plate, in order to obtain each power spectrum of the each image on the opaque plate. The light passed through the anamorphic lens is detected by a detector array having an output coupled with a focal plane processor for processing an analog output from the detector array into an initial tuning command for detecting and characterizing a pulse in the input signal.