Much has been said about the transition to a wireless world, with mobile networks usually cited as the defining example. But wireless telephony is only the first large step among many We are seeing wireless technologies displacing older wired and even infrared architectures just about anywhere people need to communicate with one another or with electronic systems. Inevitably, this has had an impact on the characteristics of wireless signals, requiring them to support more applications and services. Today's RF signals carrying digital content are far more complex than their predecessors, with many of them featuring time varying modulation schemes, appearing only in short, non-repeating bursts. The basic amplitude- and frequency-modulated signal formats of the past simply cannot deliver the required information-rich data streams that may carry digitised voice, text, pictures and even video. It all adds up to a challenging environment for the designer who just wants to get a new product to market on time. Today's complex signal formats contain details that can only be understood by reliably capturing brief, momentary events and analysing changes over time. The article looks at the advantages of real-time spectrum analysis over conventional swept spectrum techniques.