Code word determination

Claim 1

In a method for determining a unique word contained in received signals in a transmission system operating with multiple phase modulation or multiple phase difference modulation at the transmitter and coherent demodulation at the receiver and in which successive signal increments are transmitted and received during successive clock periods, the unique word being transmitted only as signals in two phases which are 180° apart, and the received signals being divided into two orthogonal voltage components during demodulation, the two components representing the amplitude and phase angle of a received signal relative to a selected reference phase, the improvement comprising: forming a single value for the two-phase signal by deriving a quotient signal representing the ratio of the amplitudes of the orthogonal components for each signal increment, integrating the resulting quotient signal over a plurality of clock periods, deriving a product signal representing the product of the integrated quotient signal and one of the orthogonal components for each signal increment, and deriving a sum signal representing the sum of the resulting product signal and the other orthogonal component for each signal increment, the value of which sum signal constitutes the single value; and evaluating the sum signal on the basis of its algebraic sign.