Simulcast same frequency repeater system

摘要

The simulcast communication system includes a transmitting station for transmitting a first signal at a given frequency and a same frequency repeater (SFR) having a receiver for receiving the first signal and a transmitter for retransmitting the received signal at the same given frequency. The SFR rebroadcasts the received signal with a time delay of T. The receiver of the SFR receives the retransmitted signal as a spillover signal. A mechanism is coupled to the transmitting station for generating a second signal which consists of the first signal delayed in time by T1 which is approximately equal to T. Another mechanism coupled to the SFR substantially cancels the spillover signal and the second signal since the second signal is in phase with the spillover signal. Thus, the signal retransmitted by the SFR differs in phase from the second signal transmitted by the transmitting station only by the propagation delay between the SFR and the transmitting station, whereby the likelihood that a mobile unit will experience simulcast distortion due to the reception of the second signal and the retransmitted signal can be minimized. This invention further contemplates that multiple SFR's may be employed wherein each SFR includes a mechanism for cancelling any other retransmitted signals by other SFR's as received at each SFR.