Frequency correction at the receiver end in a packet transmission system

摘要

The invention relates to a system for transmitting packets from interactive terminals to a head station. The terminals intended for consumers are provided with local oscillators which are not very accurate and use carriers having frequency errors which are relatively large with respect to the theoretical reference value (Fp). The invention provides an improvement of the reception of signals having such a frequency shift at the receiver end. To this end, the invention provides a method of estimating the frequency error DELTA f, which consists of rapidly obtaining the maximum value of a discrete error function denoted Z(DELTA f) for a given accuracy (Acc) by computing the function Z(DELTA f) for a minimal number of points.