A low-power analog CMOS vector quantizer

Abstract

The authors describe the implementation and performance of what might be termed a 'Vector A/D Converter'. The IC stores a codebook of vectors on-chip, accepts a 16-element analog vector at the input, calculates the Euclidean distance between the input and all codevectors (referred to as global search), and outputs an 8-bit code to index the codevector closest to the input prompt. At a 5 MHz clock rate it dissipates less than 50 mW to quantize 16 element analog vectors once every 10 clock periods, giving a 30 Hz frame rate for a 512*512 pixel gray scale image.<>