Patent ID: 8542138
Filing Date: 2013-09-24
Classification: H03M

Abstract:
1. A continuous-time delta-sigma modulator for analog-to-digital conversion, comprising: an actual signal path including a converter that drives a ring voltage controlled oscillator, a ring sampler for sampling said voltage controlled oscillator, a phase decoder that maps values from the ring sampler into a phase number, a digital differentiator that differentiates the phase number and a nonlinearity corrector providing a corrected signal path output; and a calibration circuit including a replica signal path, the calibration circuit measuring a voltage controlled oscillator center frequency of said replica signal path, wherein said replica signal path is corrected with calibration sequences of independent, zero-mean, pseudo-random sequences, said calibration circuit using said center frequency to adjust current of said converter in said signal path, said calibration circuit further providing correction data generated from an output of said replica signal path to said nonlinearity corrector.