High-performance glitch-free digital frequency synthesiser

Based on modulo-N arithmetic, a new architecture for high-performance digital frequency synthesisers is devised. A set of square waves with the same frequency but different phases is passed through a Gray-encoded multiplexer to generate pulses with a highest frequency. The multiplexer output is used as the reference input for the modulo-N counter. The architecture is realised using the TSMC 0.18 m cell-based process, and its performance is summarised and compared to that of the flying-adder synthesiser.