Frequency Response graph
The Frequency Response graph is context sensitive to input data from the active echogram. The graph displays the NASC of a selection/region for a set of Sv variables that have been recorded in parallel on differing frequencies.
NASC is normalized against a reference value (the reference value is the NASC at one of the displayed frequencies).
To display the Frequency Response graph from an Sv echogram:
- On the View menu, point to Graph, then click Frequency Response.
- The Frequency Response graph properties dialog box will allow you to configure the graph, and select displayed variables and the reference variable.
- Make a selection, or click on a region (on an echogram you selected in step 2).
- Use Graph menu > Linking to select the linking to the graph.
Notes:
- It is only possible to view one of this type of Frequency Response graph per EV file.
- Listed Sv variables have a frequency that is either read from file or in the ECS file. Sv variables with a default frequency won't appear in the Sv variables list. Such Sv variables arise from file formats that do not contain frequency information.
Reference
Korneliussen, R. and Ona, E (2003). Synthetic echograms generated from relative frequency response. ICES Journal of Marine Science, 60:636-640.
See also
About graphs
About Linking Graphs
Frequency Response graph properties dialog box
Relative Mean dB graph