High voltage multichannel wave form generator for liquid crystal research

The article describes a wave form generator designed primarily for experime nts on addressing all kinds of liquid crystal displays. It can also be used in any application requiring several simultaneous sources of high-voltage arbitrary pulse trains. The instrument has eight channels capable of pulse amplitudes of +/- 100 V at a slew rate better than 300 V/mu s. Its design d iffers significantly from a typical arbitrary wave form generator. First an d foremost the wave forms are directly constructed from pulses with variabl e width as well as amplitude. Two interchangeable memory banks guarantee tr ansient-free adjustments of generated wave forms. The generator is computer controlled with well integrated software and provides all functionality to assist in the creation of wave forms and experiments with liquid crystal a ddressing schemes in a straightforward and intuitive way. To point out its versatility we discuss a new mode of operation intended primarily for gener ation of analogue gray shades on a surface-stabilized ferroelectric liquid crystal display. The instrument creates conditions corresponding to driving a display of virtually any size with image frames changing at video rate. (C) 2000 American Institute of Physics. [S0034-6748(00)01502-1].