User`s guide

Role of the Vector Header
The Vector Header record contains the information you need to link a trace to the appropriate correction
factors. First, it tells you which channels were used to gather raw data for the trace. It is the correction
factor for these channels that you will apply to the trace. Second, it tells you how the raw channel data
was processed to create the trace data. The correction factors must be processed in the same way before
they are applied to the trace data. An example will help to illustrate this point.
A frequency response trace is created by processing the data from two channels in the following way:
frequency response =
response channel spectrum
excitation channel spectrum
This formula can also be written as:
freq resp =(resp ch spec)
1
×(exci ch spec)
−1
A similar formula must be used to derive the correction factor for the frequency
response trace:
freq resp correction =(resp ch correction)
1
×(exci ch correction)
−1
Standard Data Format (SDF)
B-31