Patent ID: 8565136
Filing Date: 2013-10-22
Classification: H04H

Abstract:
1. A digital broadcasting system in which a broadcasting network is constructed using a plurality of broadcasting transmitters which receive digital broadcast signals distributed via a cable or a wireless network to transmit the digital broadcast signals through identical frequencies toward areas, a part of which is made to be common, through the identical frequencies by using wireless waves, comprising: a monitoring unit to receive the wireless waves transmitted from the plurality of broadcasting transmitters, respectively, at arbitrary spots to monitor reception states, wherein the monitoring unit comprises a first measuring unit configured to measure a delay of the received wireless waves, and a second measuring unit configured to measure a ratio of reception levels of the received wireless waves; and an output controller to control outputs of the wireless waves of arbitrary broadcasting transmitters on the basis of the delay and the ratio measured by the monitoring unit; wherein the plurality of broadcasting transmitters vary carrier phases of the wireless waves by carrier variation patterns differing from one another, the monitoring unit identifies transmission origins by performing synchronous detection of the carrier variation patterns for reception signals of the wireless waves and by extracting carrier vibration patterns corresponding to the carrier phases of the wireless waves, and notifies the reception states to the transmission origins.