Patent ID: 8081939
Filing Date: 2011-12-20
Classification: H04B,H04L

Abstract:
1. A frequency-control unit for use in controlling a reference frequency of an external controllable reference-frequency source, the frequency-control unit comprising: a filter unit with a controllable filter parameter, which filter unit is configured to derive, using the controllable filter parameter, from a frequency-error signal, which is receivable via an input terminal of the frequency-control unit and indicative of a frequency error of the reference frequency with respect to a signal frequency of an external radio-frequency signal, a frequency-control signal for minimizing the frequency error of the reference frequency, and to provide the frequency-control signal at its output for use in controlling the reference frequency of the external controllable reference-frequency source; and a correlation unit, which is configured to determine from frequency errors of the reference frequency at different points in time a correlation measure indicative of a correlation between the frequency errors at the different points in time, wherein the frequency-control unit is configured to adapt the controllable filter parameter of the filter unit in dependence on the determined correlation measure.