METHOD AND APPARATUS FOR VARIABLE SIGMA-DELTA MODULATION

摘要

A method [100] for modulating a digital input signal [102] is disclosed. The digital input signal [102] is partitioned into a less-significant bit signal [108] and a more-significant bit signal [106]. A lower-order modulation of the less-significant bit signal [108] is performed to generate an intermediate output signal [112]. The intermediate output signal [112] is appended to the more-significant bit signal [106] to form an intermediate input signal [116]. A higher-order modulation of the intermediate input signal [116] is performed to generate a digital output signal [120]. The higher-order modulation is of an order higher than the lower-order modulation. A phase locked loop [400] using the method [300] and apparatus [100] is disclosed.