Abstract: An FM signal or protocol analyzer (PA) system: The PA system is capable of analyzing the broadcast signal at many levels, from analysis of the physical RF link to comprehensive analysis of the subcarrier messaging. The PA system is built on a computer including special hardware and software. The custom hardware comprises at least one precision RF receiver and signal processing circuitry. The custom software includes data acquisition, data analysis and data presentation software. As a feature of the present invention, a PA system is designed to be "user friendly." As such, it operates in a windowing environment and makes extensive use of graphical displays. The PA system can operate in a networking environment so the receiver and signal processing circuitry can be physically distant from the user's display and keyboard, in another computer connected to the network.