A Diophantine Frequency Synthesizer for the Examination of High Spectral Purity

Diophantine frequency synthesis (DFS), a number theoretic approach to the design of very high resolution and agile frequency synthesizers was introduced at the IEEE frequency control symposium of 2006, [1]. Since DFS uses frequency addition (and/or subtraction), concerns for the impact of mixing spurs in the spectral purity was raised. Further work has been performed to address this issue and is reported in this paper. The focus has been on basic DFS architecture targeting micro-phase type applications. The design goal has been to achieve 100 dB spurious free dynamic range (SPFD) with minimal circuit complexity. The results of the examination demonstrate that the use of DFS does not impart any extraordinary design constraints to spectral purity from that of other topology choices. In fact, the flexibility of the design technique from its applied math basis allows this demonstration synthesizer to be realized with simple and expedient construction.