Spectrograms: Turning Signals into Pictures

Spectrograms, representing data in both the time and frequency domain, provide a means of easily discerning important details about an event. This paper describes a technique of visual data interpretation that works well when changes in signal frequency are evident over time. The body of the paper includes a section on the theoretical basis for the technique, with relevant time-frequency distributions, and a section on plot interpretation strategies. Further, several practical examples of field applications are brought forth to demonstrate its usefulness. The paper concludes with a summary that includes mention of future research efforts in this area.