  Discrete Fourier Transform Test (DFTT), which is a randomness test included
in NIST SP800-22, has a problem. It is that theoretical reference distribution
of the test statistic has not been derived. In this paper, we propose a new
test using variance of power spectrum as the test statistic, whose reference
distribution can be theoretically derived. The purpose of DFTT is to detect
periodic features and that of the proposed test is the same. We make some
experiments and show that the proposed test has stronger detection power than
DFTT.
