Acoustic emission signals are signals from materials like steel or building materials like cement which are emitted before or at the time of cracking.
the preamp will take the signal in from a sensor the input impedence of the amp is ideally 10kohms 15pf, the signal freq ranges from 20-1200khz freq.
ie the input bandwidth is 1Mhz
Now the main problem ,the input signal is of microvolts so how do
i differentiate between the signal and the noise the good preamps hav a noise level of <2u volts like 1220A by Physical Acoustic corp.