A new broadcast format and receiver architecture for radio controlled clocks

Abstract

A new broadcast format is presented for the atomic-clock time-code signal broadcast by the National Institute of Standards of Technology (NIST) from station WWVB in Fort Collins, Colorado. The new broadcast format, based on BPSK modulation that is added to the existing amplitude-modulation (AM), offers many new features and provides several orders of magnitude of improvement in reception robustness, without impacting existing AM receivers that are based on envelope-detection. Additionally, a digital receiver architecture, amenable to integration in a CMOS system-on-chip (SoC), is proposed, which relies on digital signal processing, thereby eliminating the need for the crystal filter and other passive components found in existing receivers.