Abstract: Analog memories such as CCD, which are advantageous in less power consumption and higher integration density, are used to configure a system for highly accurately executing digital/analog processing. A digital to analog converter according to the invention has at least one first analog memory having an input port for receiving input signal packets and a partial output drive port for driving the i-th output signal packet; at least one second analog memory having a function to integrate input signal packets applied thereto; and at least one signal packet routing mechanism for selectively routing output signal packets from the first analog memory according to an input digital signal bit. The extremely simple configuration of the present invention may be effectively utilized for realizing an ultra-parallel analog processor as well as applied to other fields such as video processing by combining a function of an input means for optical signals, which has been a main application of the CCD.