A comparison of noise-shaping clock generators for switched-capacitor filters

A programmable clock generator for switched-capacitor filters (SCFs) that uses noise shaping to generate a wide range of sampling frequencies with fine resolution was described by Hurst and Rothenberg (see IEEE J. Solid-State Circuits, vol. 30, no. 4, p. 403-411, 1995). In this paper, alternative noise-shaping transfer functions are evaluated for the clock generator. Simulated and measured results are presented. Finally, a tone detector that uses a bandpass SCF driven by the clock generator with first-order noise shaping is described.