Experimental Characterization of IdleTones in Second-Order Bandpass ΣΔ Modulators

This paper analyses the tonal behaviour of the quantization noise in second-order bandpass ΣΔ modulators. The analysis performed for lowpass modulators is extended to the bandpass case. As a result, closed form expressions for the frequency of idle tones are derived for different cases regarding the signal center frequency position. All these results have been validated by measurements from a silicon prototype using fully differential switched-current circuits implemented in a standard 0.8μm CMOS technology.Ministerio de Ciencia e Innovación CICYT TIC 97-058