This paper describes an AE system, which measures four parameters of AE phenomena, namely, amplitude, risetime, ringdown count and event duration for each event.
The system is composed of a piezoelectric sensor, low-noise wideband preamplifier, signal processing unit, threshold level generation module, amplitude-risetime module, ringdown-event duration module, high speed ADC, single board μ-computer, display interface module, and TV CRT.
Measured results are displayed on the CRT of TV in four patterns :
(1) log of amplitude versus number of events
(2) log $Vi^2$ versus log $NiVi^2$
(3) time versus total number of events
(4) event versus ringdown count number
Each of these gives important informations in the study of AE phenomena.
