Patent ID: 8115519

Claim:
A direct digital synthesis (DDS) device comprising: a polyphase accumulator configured to generate a plurality of digital phase signals in response to a clock signal and a frequency control word, each of the digital phase signals representing phase data corresponding to phase points on a sinusoidal waveform, the phase data being based on multiples of the frequency control word and an incrementing reference phase such that the digital phase signals remain locked to the incrementing reference phase to provide phase coherency when the frequency control word changes; a plurality of phase-to-amplitude converters coupled to the polyphase accumulator and configured to produce a plurality of digital amplitude signals in response to the digital phase signals, respectively, the digital amplitude signals representing digital amplitude data corresponding to the phase points on the sinusoidal waveform; a multiplexer coupled to the phase-to-amplitude converters and configured to multiplex the digital amplitude signals from the phase-to-amplitude converters to produce a multiplexed digital amplitude signal; and a digital-to-analog converter coupled to the multiplexer and configured to convert the digital amplitude data represented by the multiplexed digital amplitude signal into an analog output to produce an analog sinusoidal signal.