System for reception of digitally modulated radio signals to a vehicle, using antenna diversity

Abstract

A reception system for motor vehicles having a diversity antenna system with a plurality of antennas and an antenna switch coupled to a receiver for the reception of digital, MPSK-modulated satellite and terrestrially broadcast radio signals containing phrase reference signals. The antenna diversity system optionally switches through at least one of two available antennas and has a signal level testing device with its input coupled to the receiver and its output coupled to the antenna switch. This is to provide an indication for the need for antenna switching to avoid signal loss by means of a signal at its output, whereby the phase reference signals occur repeatedly in a time sequence. A MPSK demodulator having a computer device and coupled to the receiver evaluates the phase reference signals so that when a phase reference signal occurs that carries the current reference phase related to the reference signal, the reference phase is updated in the receiver, thereby causing the subsequently transmitted useful symbols to be detected with the correct phase.