Digital video quantizer

摘要

A digital video quantizer for use in TCAS and ATCRBS/SIF systems. A digital delay receives a digitized video signal and produces a plurality of delayed digital signals which are used throughout the quantizer. A threshold generator then produces a predetermined threshold and a dynamic threshold, and a quantized video generator compares one of the delayed digitized signals to a threshold to produce a quantized video signal. A slope quantizer detects a slope of the digitized signal which exceeds either a positive or negative threshold. In addition, a rise time detector detects an excessive rise time in the digitized video signal, and a chip amplitude comparator provides a signal which is used in detecting Mode S data bit values. The digital video quantizer's use of digital references rather than analog references, eliminates the inaccuracies caused by a reference voltage varying over time or temperature. The digital references also facilitate modification of the reference values at a later time.