Figure 11-30 Update Rate Less Than 60 Hz; Back Wall Echo Attenuator - Olympus EPOCH 650 User Manual

DMTA-10055-01EN, Rev. A, February 2015

11.7 Back Wall Echo Attenuator

The back wall echo attenuator (BEA) option allows you to apply an independent gain
level to the A-scan defined by the gate 2 start position and width. Using the BEA, you
can reduce the amplitude of the back wall echo when high gain levels are used to find
small flaws.
NOTE
The BEA feature is not compatible with the interface gate or DGS.
This option is commonly used with two specific forms of inspections:
• The first is an inspection where potential defects may not be oriented parallel to
the direction of sound from the transducer. Sound will still reflect from these
defects, but the reflection may be directed away from the transducer. In this
situation, little or no signal is returned to the instrument for direct measurement.
Generally, these defects are instead detected by monitoring for back wall signal
loss or attenuation. This back wall amplitude change can be missed entirely if the
back wall signal is saturated. The BEA allows you to monitor the back wall at a
268 Chapter 11

Figure 11-30 Update rate less than 60 Hz

Flag indicating
screen update
rate is less than
60 Hz