DIGITAL TIMING RECOVERY

摘要

DIGITAL TIMING RECOVERY Sample timing recovery in a differentially coherent phase-shift keyed data transmission system is accomplished through the use of digital techniques. Samples of received phase-modulated signal waves taken at a rate high with respect to the carrier frequency are applied to a delay medium advantageously implemented by a shift register. Stored samples spaced by known carrier phase differences are compared for the purpose of detecting phase changes. Digital indications of such phase changes resulting from differentiation of comparator outputs are then effective to control a phase-locked oscillator and provide a substantially jitter-free timing recovery wave without using excess bandwidth for the transmitted wave.