Colloq Abstract - Carlson
Oct 12, 2018
11:00am Mountain
Brent Carlson (NRC, Penticton)
Incoherent Clocking
Abstract
Radio interferometers require synchronization of all signal processing to a coherent timing reference prior to correlation and (optionally) tied-array beamforming. Ideally, digitization occurs as close to the feed as possible for maximum stability and signal fidelity. In this talk, a method of “incoherent clocking” is described whereby a) each receiver operates using its own free-running clock not locked to a central reference clock, b) the phase and frequency of each antenna clock is measured at the central site relative to a common reference using COTS digital fiber connections and all-digital methods, and c) the digitized science data is digitally-corrected at the central site, by applying knowledge of the antenna clock’s behavior before correlation and beamforming. The current state of research into this method, including initial computer modelling results and notional plans for development of a laboratory demonstrator, is discussed.
