With intended application to the theory of current noise in semiconductors, the spectrum is calculated of a random signal which may be in one of two states (YES‐NO: random telegraph signal), where the mean lives &sgr; and &tgr; of the two states may be different. The form of the spectrum is the same as for the case with equal lives, the single parameter &tgr; for that (classical) case now being replaced by 2[(1/&sgr;)+(1/&tgr;)]−1; i.e., the rates of transition are additive.