Camera exposure control system having digitally controlled timing circuitry including a decimal count storing memory

摘要

This invention provides apparatus for producing a command signal used to control the closing of a camera shutter. Before the shutter opens, a photo-responsive portion of the apparatus generates a number of serially occurring data pulses. After the shutter opens, a timing pulse generator portion produces a number of serially occurring timing pulses. A memory portion, including a plurality of registers, accumulates a decimal count of the serially occurring data pulses with each register storing a respective one of unit and higher decimal place portions of the decimal count. The memory forms part of a comparison circuit arrangement which responds to the data pulses and the timing pulses to produce the command signal.