Patent ID: 6934559
Filing Date: 2005-08-23
Classification: H04B

Abstract:
1. A method of estimating the relative frequency uncertainty between a part of a mobile radio system able to communicate via a first mobile radio network at a first particular frequency and another part of the same mobile radio system able to communicate via a second mobile radio network at a second particular frequency, in which method each part of said mobile radio system has a clock from which said particular frequency is derived and said uncertainty is estimated by measuring the number of pulses of each of said clocks during a time window of duration T starting at a time t, and which method includes the following steps: a) measuring the number of pulses of each of said clocks at n intermediate times t+(T/n), t+(2T/n), . . . , t+(nT/n), where n is a positive integer, b) storing the numbers of clock pulses thereby obtained in memory, c) calculating the relative frequency uncertainty at time t+T from said numbers of clock pulses stored in memory, and d) iterating steps a) and b) at times t′, where the difference between two consecutive times t′ is less than T, and with said time window of duration T sliding to obtain said uncertainty at any time t′.