This report aims to modulate the passage probability of a pulse by the instantaneous value of an analogue input signal. Up to now, some circuits where the status probabilities may be controlled by input from the outside have been found. However, it is considered that in order to freely vary the probability distribution by the instantaneous values of input signals, a still more complicated circuit construction is necessary. This paper describes that such circuits can be realized simply by using shiftregisters, random pulses, and analogue operation circuits.