Patent ID: 7506014

Claim:
A direct digital synthesizer (DDS) comprising: an accumulator, the accumulator receiving a phase increment signal and generating a frequency signal having frequency information, the signal varying in accordance with the phase increment signal, the frequency signal being split into a plurality of frequency signals; a plurality of adders, each adder receiving a respective one of the split frequency signals, each adder also receiving a respective phase offset signal, the phase offset signal defining a phase shift for the frequency signal input to the respective adder, wherein each adder of plurality of adders output a phase shifted frequency signal; a plurality of lookup tables corresponding to the plurality of adders, the lookup tables receiving a respective phase shifted frequency signal and generating a magnitude signal in accordance with the respective phase shifted frequency signal; a plurality digital-to-analog converters (DACs), each DAC corresponding to a respective one of the lookup tables and receiving a respective phase shifted frequency signal, each DAC generating a generally periodic analog signal corresponding to the respective phase shifted frequency signal; a plurality low pass filters (LPFs), each LPF corresponding to a respective one of the DACs and receiving a respective periodic analog signal, each LPF filtering the periodic analog output signal from the respective DAC to generate a sinusoidal signal; and a plurality of conversion circuits each corresponding to a respective LPF for converting the respective sinusoidal signal to a respective square wave signal.