Broadcast-Signal Bandwidth Measurements Using Real-Time Data Averaging

The bandwidth of a signal may be analyzed in terms of what is defined as an observable, or detectable, signal level, the frequency range over which this detectable signal occurs, and the percentage of time that the sigal exceeds defined limits. This paper presents a technique for observing and quantitating in real time the frequency excursion of radio signals in the time domain. A scanning spectrum analyzer interfaced to a minicomputer data-acquisition system is used to collect spectral bandwidth data. The concept of percentage band-width occupancy is presented for evaluating the broadcast-signal modulation character and representative data are given for signals in the FM broadcast band.