Dakota Ultrasonics PVX - Manual (Page 74)

Dakota Ultrasonics
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Notice that the amplitude of the cycle just to the left of (C). The amplitude of the
cycle, a t (C), is less than the amplitude of the cycle at (B), in terms of overall height.
If we decreased our gain, we would lose the first cycle (C) long before losing the
second cycle (B). Therefore, adjusting the gain or threshold levels will not help us
in this example. Our final option is adjusting the GATE2 hold-off, shown at point (C)
in the incorrect diagram, to point (B) in the correct diagram. If we adjust the GATE2
hold-off further to the right of the first reflection, the ring down noise from the first
back wall echo no longer interferes with the true detection (D), shown in the correct
diagram.
The adjustment considerations in the example above will typically be used for all thru
paint applications respectively. These examples are true of all potential echo-echo
setups with the PVX. In some applications the hold-off may be sufficient, while a
gain or threshold adjustment will solve the problem. A similar process of elimination
should be considered for all thru paint and general echo-echo applications.