910-269-EN, Rev. B, June 2011
248 Chapter 13
13.2.1 Pulse Repetition Frequency (PRF)
Pulse repetition frequency (PRF) is a measurement of how often the transducer is
being pulsed by the electronic circuitry in the EPOCH
1000 Series. PRF is typically
adjusted based on the test method or test-piece geometry. For parts with long sound
paths, it is necessary to lower the PRF to avoid wrap-around interference that results
in spurious signals on the display. For applications with rapid scanning, it is often
necessary to use a high PRF rate in order to assure that small defects are detected as
the probe moves past the part.
The EPOCH 1000 Series phased array mode automatically defines the PRF value
based on phased array probe specifications. The PRF value can be reviewed in the
1/5
> PA P/R > PRF parameter.
The EPOCH 1000 Series phased array mode is limited to 1360 Hz.
13.2.2 Pulser Frequency Selection (Pulse Width)
Pulser frequency selection sets the pulse width applied to the phased array
transducer. This frequency selection allows you to tune the shape and duration of
each pulse to obtain the best performance from the transducer being used. In general,
the best performance is achieved by tuning the pulser frequency as close to the center
frequency of the transducer being used as possible.
The EPOCH 1000 Series automatically sets the pulser frequency to match the defined
frequency of the phased array probe selected using the Beam setup page.
To manually adjust the pulser frequency
1. Choose 1/5 > PA P/R > Freq.
2. Use the [UP] and [DOWN] arrow keys or the adjustment knob to vary the Freq
value. In the Freq adjustment, coarse and fine steps are equal.
13.2.3 Pulse Energy (Voltage)
The EPOCH 1000 Series phased array mode allows two pulser voltage values:
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