Understanding Acoustic Emission Testing- Reading 1 Part B-A

Ideally, the AE signal that reaches the mainframe will be free of background
noise and electromagnetic interference. Unfortunately, this is not realistic.
However, sensors and preamplifiers are designed to help eliminate unwanted
signals. First, the preamplifier boosts the voltage to provide gain and cable
drive capability. To minimize interference, a preamplifier is placed close to the
transducer; in fact, many transducers today are equipped with integrated
preamplifiers. Next, the signal is relayed to a bandpass filter for elimination of
low frequencies (common to background noise) and high frequencies.
Following completion of this process, the signal travels to the acoustic system
mainframe and eventually to a computer or similar device for analysis and
storage. Depending on noise conditions, further filtering or amplification at the
mainframe may still be necessary.