Spectral‐based signal‐processing techniques for characterizing fluctuation data from plasma discharges in the Advanced Toroidal Facility fusion experiment are described. The analysis process moves from wave form display and spectral analysis of single discharges to coherence filtering and database techniques for identifying coherent fluctuations. These analysis techniques are used to distill large volumes of spectral data from many signals per discharge (for many discharges) into simple forms suitable for comparison with the global variation of plasma parameters.