Patent ID: 6658042
Filing Date: 2003-12-02
Classification: H04B

Abstract:
In a communication device, a method of providing time tracking between a first signal and a second signal, comprising:a) generating the first signal by the communication device; b) receiving the second signal at the communication device from an outside source; c) generating correlation data between the first signal, at a plurality of timing conditions, and the second signal, the correlation data generated by hardware; d) filtering the correlation data, to remove noise, at the plurality of timing conditions, the filtering step performed using at least a first-order filter implemented in software or firmware; e) comparing the correlation data to a threshold value to evaluate accuracy of a system timing for the first signal, and thereby obtain a result; f) correcting the system timing for the first signal based upon the result of the comparing step; wherein the plurality of timing conditions for the first signal include an one-time condition, a late condition, and an early condition; wherein step (c) comprises: c1) determining an on-time energy value between the first signal, at the on-time condition, and the second signal; c2) determining a late energy value between the first signal, retarded to the late condition, and the second signal; and c3) determining an early energy value between the first signal, advanced to the early condition, and the second signal; g) calculating a late-early energy value, the late-early energy value equal to a difference between the late energy value and the early energy value; h) receiving the threshold value; i) determining a normalized threshold value; and j) comparing the late-early energy value with the normalized threshold value to obtain the result.