The Japanese digital terrestrial broadcasting (ISDB-T) has special carriers called Auxiliary Channel (AC) in addition to the main signals for video and audio. The AC have beneficial features to transmit an Earthquake Early Warning (EEW). AC can be transmitted in a short delay time because the source coding for video and audio information compression and the channel coding such as time interleaving are not used. The transmission of AC is strong against the interference such as noise and fading because DBPSK modulation is used. This paper describes the results of examination about reducing transmission delay time and power consumption of a receiver on standby for EEW broadcast system using AC.
