Time Frequency Pairs Option
The time/frequency pair option within Tsunami allows the user to improve the performance of PSTM without reducing the frequency content of the output. The user specifies the expected output frequency as a function of time and internally the program performs optimizations that will allow the job to run much faster. A similar option is available in PSDM with the function being a depth/frequency function.

In the example the following time/frequency function was used:

Time ms Frequency

2000 80

3000 70

4000 50

This function will use a frequency of 80 for the range of 0-2000 ms, and a frequency of 50 from 4000 ms to the end of the trace. No filtering is applied to the input traces.

The two stacked sections are identical. However the runtime using the time/frequency pairs was 40% faster than the runtime where this option was not used. This example used a relatively short trace, only 4.5 seconds, longer traces will show a greater performance improvement.

It is strongly suggested that target lines be run before running large full volume jobs. The user should compare output using this option with output without the option to double check that the desired frequency content is being preserved.

This option has been used in production for over two years, and its benefits have been proven by many of our customers.