Digital High Order Multiplier-free Delta Sigma Modulator for Multistandard Fractional-N Frequency Synthesizer

Abstract

This paper proposes a new stable design strategy for 1-bit high order digital DS modulator for multistandard fractional-N frequency synthesizer. The proposed digital DS modulator presents simplicity, low power consumption and controls a dual-modulus divider instead of multi-modulus one as in existing DS fractional-N frequency synthesizer. Simulation results illustrate the DS modulator good performances in terms of spectrum purity and accuracy. Using this stable 1-bit digital DS modulator output to a fractional-N frequency synthesizer Simulink model verifies the multistandard frequency synthesizer specifications.