Numerically-controlled oscillator with dithered coarse and fine splitter

Abstract

A numerically-controlled oscillator (NCO) includes a phase accumulator (PA) which has a first input adapted to receive a phase increment, a second input adapted to receive a clock signal, and a third input adapted to receive a reset signal. The PA provides an instantaneous phase at an output. The NCO includes a dithered splitter which has an input coupled to receive the instantaneous phase. The dithered splitter dithers the instantaneous phase using a pseudo-random binary sequence (PRBS) and provides a dithered course phase and a dithered fine phase. The NCO includes a polynomial approximation unit which has a first input coupled to receive the dithered course phase and a second input coupled to receive the dithered fine phase. The polynomial approximation unit provides a sequence of numbers representing a discrete sinusoidal signal.