A new 32-inch HDTV monitor has been developed. High resolution, color reproduction, and picture fidelity have been acquired. An automatic convergence system has been adopted. This monitor imploys a double dynamic focus system with two individually driven focus electrodes, a feedback control system with video output level controlling reference pulses, a landing correction system with four corner independently conpensated terrestrial magnets, and an automatic convergence circuit. The center and corner visual area horizontal resolutions are 1000 and 950TV lines, respectively, when white luminance is 150cd/m^2. The change of white chromaticity is within ±0.003 on a CIE color chart. The convergence time and precision are within 3minutes and 0.5mm, respectively, under any display condition, such as scan size.
We propose a new scrambling method, which is conrollable of concealed level, for MPEG video data. This method can conceal the video at several levels ranging from barely visible to nonvisible by randomizing specific parameters in video codes, and we can reduce a displeasure level of scrambled image without losing security of deciphering by inserting quantiser matrix codes in MPEG video data. An efficiency of this method is showed by a result of a subjective estimation experiment.
OFDM(Orthogonal Frequency Division Multiplexing) is a useful digital modulation method for terrestrial digital broadcasting systems and shows excellent performance especially in a multipath environment. To apply OFDM to digital TV or ISDB(Integrated Services Digital Broadcasting), it is desirable to increase the bit rate in the same bandwidth without seriously impairing transmission quality. For this purpose, multi-level OFDM systems are suitable. This paper describes a multi-level OFDM system and presents the basic concept of the design of the system and the related simulation results. Preliminary experimental results are also shown and the transmission characteristics of multi-level OFDM are discussed.
The optimal display condition of closed captions on the HDTV monitor is described. The character sizes of the captions in usual HDTV programs are almost over 48×48 dots. This is adapted for the previous subjective assessment tests. We had another test on the character length of captions using two subjective assessment scales. The 24 or more characters' length is desirable for making program enjoyable and easily understandable. A subjective assessment test on time differences between captions and pictures was also conducted using a drama program. Values of the time difference to be allowable deeply depend on contents of pictures. On the most severe condition, the value was within 1 second. In another case, 3 seconds caption delay was allowable.
The 12th ASIAN GAME was held in Biroshima from October 2 to 16,1994. NHK and TBS jointly organized the host broadcaster for the Hirosima Asian Game 1994,titled HARTO'94 (Hiroshima Asian Game Radio and Television Organization '94). This report describes the activities by the HARTO'94 at the International Broadcasting Center (IBC).
NHK Hiroshima Regional Headquarters has contributed to the regional life and culture for 30 years above with various topics and news sent out. However, it has been difficult to comply with recent requirements of the audience by use of the old system. Therefore, we reconstructed New NHK Hiroshima Broadcasting Center Building which had new technologies and systems, with broadcasting programs continued at a part of old one. This method of rebuilding was attempted for the first time as a broadcasting center. This paper above the process of rebuilding and its main functions.