The theoretical values of rain attenuation coefficients have been reported based on various raindrop size distributions In the range of millimeter waves In this paper, rain attenuation coefficients have been evaluated from the 10 second rain rates in heavy rain. The experiment at 100G Hz band has been carried out along the 390m propagation path In Nagoya. As a result, measured values of rain attenuation coefficients are in satisfactory agreement with the theoretical calculation of I hara and Furuhama.
This paper describes a study of the modulation method and the data transmission capacity for the digital terrestrial TV broadcasting (DTTB). The modulation of the DTTB is the orthogonal frequency division multiplex (OFDM) in Europe, and single carrier QAM in America. We discuss the OFDM for the DTTB , and mention the effect of the ghost and analog TV radio wave. We also describe the error correction code and the relation between the output power and the data transmission capacity.
NHK has been developing ISDB (Integrated Services Digital Broadcasting) which enables to transmit various kinds of services through different types of channels with maximum commonalty. In this paper, basic requirements for ISDB are mentioned, and necessary functions of ISDB transport system are considered to comply the requirements referring to a layered model for ISDB. Then, methods to apply the ISDB transport system to various types of channels, such as satellite, terrestrial and cable, are discussed.
MUSE system has so strong protection on usability to keep its decoded picture that it receives under five dB on carrier to noise ratio. However, when a uplinking site is changed, its protection also causes long recovery time to take over new MUSE signal. This paper describes a proposed protocol on acquisition and release for MUSE signal. Using adaptive for receiving condition, this protocol achieves minimum time to take over new MUSE signal.
This report describes the frame pulse protection system. In the present MUSE decorder, the number of frame pulse protection is 8. This is one of the reasons that the picture is damaged when up-link stations are switched. According to the results of experiments studying the relationship between the reception CN ratio and the frame pulse not possible to be detected, it has been proved that in a normal Situation (CN ratio is more than 15 dB), the sufficient protection number is just 1. Consequently, if the protection is controlled so that it will match the reception CN ratio, the picture damage when switching can be reduced.
Scanning conversions from the double-rate scanning systems of Hi-Vision, as 1125/60/1:1(progressive), 1125/120/2:1, or etc., to 1125/60/2:1 Hi-Vision are investigated. Motion-adaptive conversion methods for each systems and spatio-temporal frequency spectra of the converted pictures from those systems are considered. From the spectra, quality of those pictures are estimated, subjective tests for the converted pictures on artifacts by scanning lines, resolution and picture quality are performed.