Patent ID: 6021110
Filing Date: 2000-02-01
Classification: H04L

Abstract:
A method of searching for an electromagnetic signal having an initially unknown timing offset between transmitter and receiver, the transmitter having a first reference oscillator, the receiver having a second reference oscillator, the first and second reference oscillators having an initially unknown frequency offset, the method comprising the steps of:(a) providing the receiver with a first initial frequency offset to cause transmitted signals to be received with a changing timing error;(b) searching for a repeatedly transmitted identifiable signal block having a timing error;(c) if the signal block is found, then:(c1) detecting when the timing error of the signal block reaches a pre-determined value;(c2) computing the frequency offset; and(c3) adjusting one of the first and second reference oscillators to account for the frequency offset; andif the signal block is not found, then (d) repeating steps (a)-(c) with a subsequent initial frequency offsets different from the first initial frequency offset until the full range of the reference oscillator has been explored.