Patent ID: 8934582
Filing Date: 2015-01-13
Classification: H04L,H04Q

Abstract:
1. A method of detecting a set up signal used for data transmissions over a communication network, the set up signal having a predetermined frequency, comprising: filtering a received signal by a filter having a passband including the predetermined frequency, determining an energy level of the filtered received signal and comparing the determined energy level of the filtered received signal with a first predetermined value and providing a first detect signal when the determined energy level is greater than the first predetermined value; identifying a component of the received signal at the predetermined frequency and determining an energy level of the identified component, comparing the determined energy level of the identified component with a second predetermined value and providing a second detect signal when the determined energy level is greater than the second predetermined value; performing an autocorrelation function on the received signal to discriminate between the set up signal and other signals in the received signal and providing a check signal when the autocorrelation function identifies the set up signal; detecting the set up signal in the received signal in response to the first and the second detect signals and the check signal; and detecting phase reversals in the set up signal when determined energy levels comprising the determined energy level correspond to a predetermined pattern.