A phase-coherent numerically controlled oscillator based on pipeline architecture

Abstract

A design of a pipeline architecture for a phase coherent numerically controlled oscillator (NCO) is presented. The NCO synchronously generates sampled sinusoidal waveforms A cos(2/spl pi/ft+/spl phi/) and A sin(2/spl pi/ft+/spl phi/), as 16-bit signed integer values. The pipeline architecture includes multipliers, adders, and a 64K/spl times/16 embedded ROM. The proposed NCO provides waveform phase coherency relative to the time reference over varying frequencies, which is essential for coherent radar seekers using stepped frequency in Doppler synthesis.