Digital Alias-free Signal Processing

13

Estimation of Correlation Functions

Continuing the discussion on the specifics of processing nonuniformly quantized signals, started in the previous chapter, the issues of quantized signal multiplication are studied and put into focus here. They are of special interest in many cases where two or more pseudo-randomly digitized signals are to be processed together. An estimation of correlation functions represents the most typical case. As a rule, numerous multiplications of the quantized signal sample values need to be executed in order to perform signal correlation analysis. As these operations are relatively time consuming, it is essential to rationalize them. That is especially important in cases of special hardware development for correlation analysis. The most suitable quantization method has to be selected first. Referring back to Chapter 5, it is clear that application of pseudo-randomized quantizing should be considered. However, it seems that multiplication of two pseudo-randomly quantized signals is more complicated than multiplication of randomly or deterministically quantized signals. On the other hand, the properties of pseudo-randomized quantizing are superior to the analogous properties of other quantizing techniques.

Application of pseudo-randomized sampling for signal correlation analysis is also discussed. It is shown that signal digitizing strongly impacts on the conditions for the correlation analysis and that applying pseudo-randomized digitizing techniques, ...