Integrated Services Digital Broadcasting. Standard for digital broadcasting used in Japan. ISDB has many similarities to DVB including OFDM modulation for transmission and the flexibility to trade signal robustness against delivered data rate. ISDB-T (terrestrial) is applicable to all channel bandwidth systems used worldwide: 6, 7, and 8 MHz. The transmitted signal comprises OFDM blocks (segments) allowing flexible services where the transmission parameters, including modulation and error correction, can be set segment-by-segment for each OFDM segment group of up to three hierarchical layers in a channel. Within one channel, the hierarchical system allows both robust SD reception for mobile and portable use and less robust HD; a form of graceful degradation.