Spectral analysis of delta and sigma-delta modulators using linear FM input signals

In this paper we present a simple and intuitive way to analyze different aspects of digital Delta and Sigma- Delta modulators. The analysis is based on studying the spectrum of the signals at different stages of the modulator. Linear FM (LFM) signals are used as test signals for different configurations. The evaluation of systems is simplified to "spectrum matching" between the input signal sequence and the output sequence of the quantizer. "Noise shaping" is also analyzed for the verification of the linear model assumption