QuakeManager allows the spectral matching to be performed in multiple passes or steps, which is an optional strategy that can be used be the user in order to improve the convergence of the spectral matching process. Number of steps is the number of passes used to match the records. Each step is a full run of spectral matching. Typically, the user will choose a different matching frequency range for each step, starting with a relatively narrow range for the first step and gradually widening it to reach the full desired frequency range in the final step. This is generally useful in case single step does not yield in the expected match. QuakeManager provides a default of 4 steps with pre-calculated frequency ranges, but the user can vary the number of steps and the frequency ranges to try to achieve a better final match.
Within each step, QuakeManager divides the matching frequencies into groups, each having the defined "group size". This allows the optimization problem to be solved more effectively, where the algorithm breaks the matching frequencies/periods into multiple groups that are solved individually, instead of optimizing the whole period/frequency range at once.
There is no direct relationship between the number of iterations and the period range. With each step and each group, QuakeManager performs many iterations of spectral matching until convergences, which is achieved when the difference between the matched spectrum and target spectrum is less than the tolerance at all periods, or when the maximum number of iterations is exceeded. For more information, please visit the "Matching Criteria" page in the QuakeManager User Manual:
https://quakemanager.eqsols.com/index.htm?context=1550
Regards
