  Quantization problem in digital control system have attracted more and more
attention in these years. Normally, a quantized variable is regarded as a
perturbed copy of the unquantized variable in the research of quantization
effect, but this model has shown many obvious disadvantages in control system
analysis and design process. In this paper, we give a new model for
quantization based 'cell mapping' concept. This cell model could clearly
describe the global dynamics of quantized digital system. Then some important
characteristics of control system like controllability are analyzed by this
model. The finite precision control design method based on cell concept is also
presented.
