抄録
Abstract
This paper presents a new method for implementing an All-Digital Phase-Locked Loop (ADPLL) using rapid single flux quantum (RSFQ) circuit technology. The ADPLL consists of a digitally controlled oscillator (DCO), a time-to-digital converter (TDC), a proportional-differential (PD) controller, a DCO controller, and a frequency divider. The DCO is based on a ring oscillator with newly designed tunable delay Josephson transmission line (TDJTL) cells in series. Verilog simulations of the ADPLL demonstrate improved performance with the integration of the TDC and PD controller. In comparison with the configuration without the TDC, the new ADPLL configuration realizes a 54% reduction in the variation of the DCO oscillation period. This reduction in frequency variation makes the ADPLL particularly well-suited for applications requiring highly accurate frequency sources, such as transmon qubit control.