Sigma-delta-based frequency synthesis

摘要

The present invention, generally speaking, satisfies the foregoing requirements using in combination within a frequency synthesis loop an SDM-based synthesizer and an SDM-based frequency digitizer. Since both blocks are SDM-based, the resulting signals can be differenced and filtered to produce a control signal for an oscillator. Low noise (and low spurs), fine frequency resolution and fast switching times may all be achieved simultaneously.