General

EMIX VLF is a presentation and processing package for VLF data. VLF field data can be presented as profiles and contour maps. Data can be filtered using either the FRASER or HJELT filters. Results are displayed as either contour maps, profiles, or contoured profile sections.

Apart from displaying VLF data EMIX VLF provides the user with two data filters. The FRASER filter converts crossovers of the correct polarity into peak responses by differencing successive values of the tilt-angle along the survey profile.

The HJELT filter profiles are obtained by using the linear fit theory to solve the integral equation for the current distribution, assumed to be located in a thin horizontal sheet of varying current density, situated everywhere at a depth equal to the distance between measurement stations.

EMIX VLF was designed to read inphase and queadreature VLF data from instruments and files into a grid based data set. Easy to use editors allows for keyboard entry of data collected on a non digital instruent or for the editing of recorded data. Data sets are then saved in a binaryfile for quick and easy retrieval.

The main feature of EMIX VLF is the interactive graphics viewing screens. The first optio is the single map view that allos the user to view a contour map of any of the following datasets: Inphase data Quadrature data, Amplitude, Phase, Fraser inphase, Fraser quadrature, Fraser amplitude, and Hjelt inphase.

The second interactive graphics screen allows users to display two maps side by side with interactive profile selection from the map displays. Any of the datasets available for viewing in the single map mode are available for either of the maps in the dual maps display mode.

Features available in both of the interactive graphics screens include:

• Full Zoom and Replot capabilities
• Direct haedcopy ouput of displayed screen
• Contour line on/off toggle
• Data posting on/off toggle
• Contour color and value editing

Besides the interactive graphics screens EMIX VLF produces plate style graphics output.

Standard Components

EMIX VLF software and manual.