We developed a new transmission system for 8K Super Hi-Vision satellite broadcasting in Japan. This system has a transmission capacity of over 100 Mbps in a single 34.5MHz satellite transponder. The key technical feature of the new system are lowering roll-off factor to 0.03 and using 16APSK and LDPC code with a coding rate of 7/9. To confirm the transmission performance in a satellite channel, we conducted indoor transmission tests and transmission tests using Japanese communication and broadcasting satellites. This paper shows the transmission performance of this system and similar performance was obtained in indoor-transmission and satellite-transmission tests.

Mobile reception of digital terrestrial broadcasting carrying an 18-Mb/s digital HDTV signals is achieved. The effect of diversity reception in moving automobiles for a 64 quadrature amplitude modulation-orthogonal frequency division multiplexing (QAM-OFDM) signal is investigated by prototype hardware. There are two methods for diversity reception of OFDM signals. The first is the Doppler compensation directivity control system. For this method, high-performance on-glass antennas and new diversity reception systems for OFDM reception have been developed to verify HDTV service availability in mobile reception environments. Novel horizontally polarized on-glass antennas suitable for DTV were developed. The antenna elements were printed on the inside surface of the rear window glass of a passenger van. OFDM signals received by the four antenna elements were weighted and combined using maximal ratio combining (MRC). The experiments were conducted in urban areas and they showed that employing diversity techniques would make HDTV mobile reception possible in many areas. The other method is post-FFT diversity. In the receiver, MRC is performed after an FFT operation on each branch signal. Experimental results show that accurate HDTV mobile reception can be achieved by using a four-branch MRC system. Also, the minimum usable electric field strength could be reduced compared with that of a single dipole antenna.