ABSTRACT
This chapter discusses issues related to the asynchronous data acquisition and processing of nonstationary signals that result from practical applications. It considers the asynchronous processing of nonstationary signals that typically occur in practical applications. The asynchronous procedures considered and contrasted are based on the level-crossing approach and the asynchronous sigma delta modulator (ASDM). Sampling and reconstruction of nonstationary signals are also possible using the asynchronous sigma delta modulator. Asynchronous analysis using filter banks exhibit similar characteristics as wavelets. Representation and processing of nonstationary signals, from practical applications, are complicated by their time-varying statistics. Sampling and reconstruction of nonstationary signals require a signal-dependent approach. Sampling and reconstruction of nonstationary signals is then shown to be more efficiently done by using an ASDM, which provides a binary representation of a bandlimited and bounded analog signal by means of zero-crossing times that are related to the signal amplitude.
