The operating principle of raster and snapshot was reviewed.A circuit for snapshot operation was designed,which enables all pixels simultaneous update,maximizing the time during which the displayed image is stable,even at the highest frame rate,and greatly simplifying the task of synchronizing the scene simulator to the unit-under-test.Spectra simulation with 0.6um standard CMOS process model are made,the chip was produced and tested.Generally,the above research shows that this kind of circuit is feasible,and builds substance foundations for circuit design for large-scale resistor array DIRSP in the future.