Method and apparatus for generating carriers for phase demodulation having at least two phase states, and a corresponding demodulation stage

摘要

The apparatus and method pertain to generation of two receive carriers which are related to each other in quadrature. The apparatus and method employ a phase-shifter which generates one or more phase-shifted signals from a received signal. A signal selector selects a signal as a function of either a predetermined phase state associated with an initialization symbol during reception of the symbol or an estimated phase state estimated by a demodulation state on the basis of the received signal during reception of the message symbols such that the selected signal constitutes a receive carrier, which is also referred to as a reference carrier. In addition, the selected signal is stored and played back after a symbol duration before delivering the reference carrier. Finally, a second phase-shifter is used to generate a second receive carrier from the reference carrier.