PURPOSE: To provide a signal processor for branching a quantized pulse string signal at a prescribed branch ratio and processing the branched signal and a method for predicting the branched quantized pulse signal.

CONSTITUTION: A branch ratio is determined (S120), a signal pattern expressing a signal formed by quanta discontinuously distributed on a time base is generated (S121), any one of plural branched destinations is allocated to each quantum in the generated signal pattern so that the ratio of the quantum numbers of plural branched destinations becomes a branch ratio (S122), a signal pattern expressing a signal to be inputted to each branched destination is generated so that each quantum is inputted only to the allocated branched destination (S123), and the generated signal is evaluated (S124). Consequently the processing result of the signal processor for processing a signal formed by an extremely small quantum number can be predicted.