Digital Alias-free Signal Processing

2

Randomization as a Tool

To achieve flexibility of the digitization techniques essential for matching them to the given signal processing task conditions, these operations should be made variable. The problem was to find out how to achieve this. Techniques existed that were applicable for variations of signal processing procedures. It simply took some time to realize that introducing an element of randomness into signal conversion procedures, an approach initially developed for other purposes, also leads to variations in the basic digitizing functions. Once that was understood, it became clear that randomization might be used as a tool for making signal conversion operations, including sampling and quantizing, more flexible and more adaptable to specific signal processing needs. The application specifics and potential of this instrument are discussed in this chapter.

However, the applicability and efficiency of this tool is arguable. Indeed, introduction of randomness into signal processing operations might also have negative consequences, as it usually leads to increased statistical errors. The end result might therefore not be acceptable. In fact this often happens whenever randomization is carried out in a way that is not sufficiently skilful. The problem of obtaining the targeted positive randomization effect without degradation of the whole signal conversion process is crucial and is not easy to resolve. Work on the development of new alias-free signal processing techniques ...