Method and circuit arrangement for determining the frequency of a received signal for demodulation of received signals

摘要

The invention relates to a method and a circuit arrangement for determining the carrier frequency difference during the demodulating of received symbols (P1, P2) in the complex phase space (I, Q; R, α) of a quadrature modulation method (QAM), wherein to determine the frequency the received symbols are compared with symbols (S1, S2) at nominal positions in the complex signal space. In order to make the determination independent of a rotation of the coordinate system of the received signals with respect to the coordinate system of the symbols, it is proposed to determine the angle (∠(P1, P2)) between two received signal values (P1, P2) and compare it to possible nominal angles of the quadrature modulation method. An angle deviation between the determined angle of the received signal values and the nominal angle can be used as a direct measure of a frequency deviation (Δf).