Automatized system of optical measurements of liquid crystal elements with improved output signal characteristics

• Published in: Vestnik Rossiĭskogo universiteta druzhby narodov. Serii͡a︡ Inzhenernye issledovanii͡a Vol. 23; no. 2; pp. 117 - 123
• Main Authors: Vladimir V. Usachev, Victor V. Belyaev, Denis N. Chausov, Sergey V. Moyseenko
• Format: Journal Article
• Language: English
• Published: Peoples’ Friendship University of Russia (RUDN University) 01.08.2022
• Subjects: automated systems; integral optics; liquid crystal; signal generation
• ISSN: 2312-8143; 2312-8151
• DOI: 10.22363/2312-8143-2022-23-2-117-123

The article discusses the developed automated system for the research of a liquid crystal cell, which consists of hardware and software parts. Unlike previously developed devices for optical measurements of liquid crystal elements, the automated system under consideration provides signal generation accuracy within 0.5% and SFDR noise immunity of at least 80 dB. The hardware part of the system includes the development of a circuit for generating a voltage signal of a certain amplitude and frequency, the formation of signals for controlling the movement of a stepper motor and controlling the intensity of the luminous flux of four laser LEDs, the development and tracing of a printed circuit board. The software part consists in the development of an applied executive algorithm that builds a sinusoidal signal at the output of a digital-to-analog converter of a microcontroller. This example uses the STM32F746IGT6 microcontroller based on the ARM Cortex-M7 core, which has a superscalar architecture with dynamic prediction, a memory protection module, a floating-point computing unit, as well as a direct memory access controller DMA (direct memory access), which is used for accelerated data exchange between memory and peripherals. The DMA is used to quickly control the digital-to-analog converter.