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3. Convention of Terms
Some terms that are present this text are listed below, since they have different
interpretations in various literature sources.
1. Sample: Unit value comprising reflected signal amplitude at a definite time.
2. Trace: A set of samples comprising one-dimensional information about reflected signals.
Examples of traces are shown in Figs. 2.3 and 4.1.
3. Profile: A set of samples comprising two-dimensional information about reflected signals
generated while passing a survey line. A profile may contain any quantity of traces. Profile
examples in various types of display are shown in Figs. 4.2 and 4.3. The final result of
sounding shall be a profile (or a certain number of profiles) as a file (or files). Subsequent
steps will be data processing (if required), printout (if required) and interpretation.
4. Zero point: Trace sample corresponding the time of transmitter’s maximum emission. It is
this very sample that has zero number on the scale along the traces, i.e. reflected signal’s
delay time should be counted from this sample. As mentioned above, the transmitter’s pulse
is approximately a one-and-half-period (i.e. three-lobe) signal. Therefore, zero point should
be set to the second lobe of the transmitter’s pulse. The Zero point setting procedure is
described in Section 10 of the present User’s Manual. It is a rather important parameter
which must be considered when measuring the time delays of signals to determine target’s
depth in the sounding medium. Zero point location examples are shown in Figs. 4.1, 4.2, 4.3.
5. Wiggle plot: Way of profile display where traces are running vertically with some spacing
between them. Drawing of each trace is made by a curve deviating to the right or to the left
from the trace centerline, depending on the sample value in each point of the trace. Here,
positive half-waves are painted in the color corresponding to the maximum positive level of
the color scale selected. Examples of wave profile are shown in Fig. 4.2.
6. Line scan: Way of profile display where traces are running vertically close to each other
and are drawn by vertical lines. Color in each point of a line shall depend on the amplitude
of a respective trace sample conforming to the color scale selected. Examples of density
profile are shown in Fig. 4.3.
7. Mark: Distinctive feature of any profile’s trace, designating certain uniqueness of a given
trace and therefore of a given point of the survey line. Marks are used to bind a profile to the
terrain. In the course of sounding, you may press a button to enter marks when passing
certain landmarks on terrain or pre-located stations. Further on, when the profile is
visualized on a display, these marks will be shown together with the profile. Mark display
examples are shown in Fig. 4.3.
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