A method of generating random numbers comprises: generating a first noise
and passing the first noise through a first high pass filter which removes
a periodic component contained in the first noise to produce a first noise
signal having 1/f characteristic; generating a second noise and passing
the second noise through a second high pass filter which removes a
periodic component contained in the second noise to produce a second noise
signal having 1/f characteristic; supplying the first and second noise
signals to a differential circuit to derive a different signal between the
first noise signal and said second noise signal; and generating, from the
different signal, random numbers which do not have a periodicity due to
1/f characteristics of the first and second noise signals.
