Patent ID: 6049720
Filing Date: 2000-04-11
Classification: H04H,H04L

Abstract:
A method for measuring delay, comprising the steps of:receiving a signal at a remote site;processing the signal using Fourier transforms to determine a time delay using an external timing reference;transmitting a gated signal from a central site, the gated signal having a first periodic component which is substantially less than a link time delay between repeaters of the repeater system and a second periodic component which is substantially greater than the link time delay, wherein the first periodic component and the second periodic component are aligned in phase to a reference timing signal;receiving the gated signal at a remote site;analog to digital converting the gated signal to create a sequence of digitized samples, wherein the analog to digital converting is performed in phase with the reference timing signal;locating transition pairs in the sequence of digitized samples;predicting zero crossings associated with each of the transition pairs;averaging the zero crossings and using the averaged value to predict a starting point of the gated signal; andintroducing a delay to compensate for a link delay calculated from the starting point of the gated signal.