A Reconfigurable TAF-DPS Frequency Synthesizer on FPGA Achieving 2 ppb Frequency Granularity and Two-Cycle Switching Speed

Frequency synthesizer is a key component used in electronic systems. Two important features for judging its performance are frequency granularity and frequency switching speed. In this paper, a synthesizer built on the principle of time-average-frequency (TAF) is implemented on an FPGA system. The synthesizer is constructed entirely on the FPGA's configurable elements. The granularity is measured as 2 ppb; the frequency switching speed is experimentally illustrated as two cycles. The configuration of the synthesizer can be adjusted in the field for accommodating various performance versus cost scenarios. The aim of this paper is to provide a field-programmable frequency generator as a handy tool to FPGA users, to enable user create innovations at application level. The key contributions are the 2 ppb frequency granularity and the reconfigurable implementation of the time-average-frequency direct period synthesis (TAF-DPS) synthesizer on FPGA.