The State Unitary Enterprise "RD&P Center "Orion", Moscow, Russia

A system is described for automatic measurements of the light spectral density characteristics of light-emitting structures in 1...2-mkm spectral band, including the case of low emission intensities. Based on widely used monochromators and PCs, the system has relatively low cost and provides both high-accuracy and short time measurements possibilities. The setup includes low-noise programmable-gain preamplifier and 12-bit ADC card with ISA PC interface. Effective algorithms of digital filtration are implemented for signal processing, providing both LF-noises and multiple narrow-band industrial frequencies suppression. Thus signals can be sensed as low as 2 10^–14 Watts/VN^1/2 (N being averaging number preset by user or set by the system adaptively in real-time mode to attain desired signal-to-noise value). Flexible user interface and versatile experiment-control possibilities allow to shorten drastically time one spent to perform experimental procedure.