The blockdiagram of the weak spectral measurement system developed in our group is shown in Fig.1. The luminescence of a sample is excited by a laser

and dispersed through a spectrometer to become spectral signal. The weak

spectral signals are first intensified by an image intensifier and then picked up by a TV camera to convert into video signal. The TV picture of the video signal corresponds to the spectral. The signal of each channal is integrated along the direction of spectrum fringe to increase signal-to-noise ratio. The data converted by A/D converter enter microcomputer system and are processed according to the reguirement of each operational function. Finally a CRT displays the spectral curve as well as the relative character comments. At the same time

a plotter can draw spectral curve and a printer can give all the data required by user. According to a laser power monitor

the microcomputer only collects the spectral data within the range of predetermined power

or classifies the spectral data with laser power. Spectral curves with different excitation density are then displayed.