Cognitive radios (CRs) observe their environment, learn from it and take their findings into account when dealing with signal reception or transmission. Until now, essentially spectral observations are under discussion in the CR context. Smart spectrum sensing may allow secondary or opportunistic use of spectrum and lead to dynamic spectrum access. In this paper we investigate a CR that also employs spectrum sensing but additionally may take results of modulation recognition as well as bit stream recognition into account when tuning its receiver. Bit stream analysis as an essential prerequisite to bit stream recognition is introduced as well. In data communications, bit streams play a prominent role in burst and frame structures, scrambling, synchronization, error correction coding or ciphering. Since modulation recognition found reasonable attention in recent publications, we here concentrate on bit stream recognition and analysis in a CR.