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Paul J. HURST Bret C. ROTHENBERG
A programmable digital clock generator that produces a wide range of clock frequencies with fine resolution is described. The clock generator consists of a noise-shaping control loop and a number-controlled oscillator. The generated clock has a time-varying period. When this clock is used as the sampling clock in a switched-capacitor filter (SCF) to set its frequency response, the time-varying period causes nonuniform sampling, which is acceptable under certain conditions that are described. Measured performance of a 2-µm CMOS implementation of the clock generator is presented. Also, measured data for the clock generator driving two SCF's are reported.