Includes PSDPDF analysis by storing all PSD calculations in a database for later retrieval to plot PSDPDF plots and traditional spectrograms. Additional display of time-domain data by station up to 60 days on a single line. PSD data can be graphically queried to answer questions such as: What is the overall quality of the data? What noise levels can I expect to normally see over all time for a particular station? How often does a particular signal occur?