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QuintSonic 7
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8 Echo Signal Processing
8.1 Introduction
The QuintSonic 7 sensor integrates a signal processing algorithm consisting of several complex
mathematical procedures. This algorithm uses the ultrasonic receive signal to calculate an echo
signal. In this echo signal, all reflections are present in the form of echo signals of different size
and directions (positive / negative) and of different time offset. This echo-to-echo time offset finally
provides the necessary information for calculating the layer thickness.
Apart from the echoes produced by the reflections at the layer interfaces (and thus marking the
interfaces between layers), the echo signal includes further portions produced from different
sources (see sections below). For that reason, the echo signal calculated from the algorithm has to
be processed in order to sort out echoes required for the calculation of layer thickness. For this
purpose, the QuintSonic 7 sensor disposes of a number of filtering and selection methods. Please
refer to the section to follow for a detailed description of their function, parameter setting and
application.
In many cases a simple parameter setting or the basic settings will be good enough for reliable
measurement (see below). For difficult settings of task, however, it will be necessary to find the
correct parameter setting in order to deal with high levels of interference in the echo signal. In such
cases, an appropriate assessment of the A-scan image of the echo signal will be vital for reliable
measurement.
For a new setting of task you should generally start with a basic setting suitable for your
application. The gauge provides a series of basic settings for typical applications in the form of pre-
defined parameter sets (section
11 “Data Management”). Choose a suitable pre-defined parameter
set before you proceed on trial measurements. Take a few readings and view the A-scan image. In
many cases, you will find valid results at this early stage, i.e. the number and thickness of layers
corresponds to your expectations and measurement is reproducible. In such case you can proceed
on measurement using the selected basic settings.
In other circumstances, the A-scan will provide information why measurement is not reliable.
Change settings accordingly and repeat the processing. With QuintSonic 7, it will not be necessary
to take new readings. After a few trials you will find the appropriate parameter settings. You can
store this parameter set under a new name and use it for further applications of the same kind. It is
recommended to verify the correct function of the parameter set by carrying out further trial
measurements before proceeding on the regular measurements.
The described procedure might seem to be rather complicated at first view. Experience has shown,
however, that most users quickly get familiar with the standard “tools kit” and can take full
advantage of the same. The variety of tools enables you to make the correct parameter choice
adapted to the physical conditions of nearly any kind of application suitable for being measured