12-11 The Influence and the Cancellation of Multiple Coupling Multipass for DTTB Relay SFN

Abstract

ISDB-T which uses OFDM as modulation scheme has been adopted for Digital Terrestrial Television Broadcasting (DTTB) system in Japan. It has the advantage against multipass, and Single Frequency Network (SFN) using broadcast signal is considered. But the re-transmitting signal is degraded by the coupling-multipass interference from transmitting antenna to receiving antenna. We have been developing the loop canceller to cancel not only the coupling-multipass but also other multipass interference. This paper describes the result of testing the equipment.