Triple Video Multimode Filter

Voltage-controlled filtering, edge and outline extraction, image softening and blur, 2-dimensional filtering

Triple Video Multimode Filter is a high bandwidth analogue signal processing module including three independent voltage-controlled filters and three control voltage processors. Additionally, switchable rectifier circuits allows further processing of the high-pass outputs when extracting different types of edges from an image. This module adds a whole new set of analogue image processing tools to the LZX Visionary system by allowing the manipulation of texture, blurring and sharpening.

Voltage Controlled Filter
The VCF in this module is similar to classic VCFs in audio synthesizer design, except the cutoff range has been extended to a 4MHZ upper limit. This allows the filtering of high frequency video signals. The first two ranges on the range selection switch cover the full audio frequency range (20Hz to 20KHz), and the second two cover the full video frequency range (greater than 15KHz.)

Control Source
Control voltage (CV) inputs are processed by level and inversion controls and then summed with a variable 0 to 1 Volt bias. This sum serves as the frequency modulation amount for the voltage-controlled filter.