In Japan, the Digital Terrestrial Television Broadcasting (DTTB) scheme should have mobile reception capability. It is well known that the effect of multipath fading in fixed condition can be reduced by Orthogonal Frequency Division Multiplex (OFDM) method. However, the signal quality degrades serially by frequency selecting fading and Doppler shift of the mobile environment. This is because the orthogonality between the inter-carriers will be last due to interference In this paper, we discuss about the effect of multipath fading for OFDM system, and shown the results of influence of Rayleigh model and multipath model.
In this paper, a pilot symbol assisted equaliser that directly estimates complex attenation factor and delay time of multipath is proposed. It is bit error rate characteristics under various multipath environments are analized by computer simulations. As the results, better performance of the proposed equaliser is confirmed.
Transmission characteristic of OFDM signal through cascaded re-broadcasting relay stations in a SFN are studied. In each relay station, the signal is degraded due to a coupling from transmitting antenna to receiving antenna. To keep a bit error rate 10^<-3> or less at the reception in the fifth relay's area for example, the coupling signal ratio at each relay station should be suppressed less than -18dB for C/N=30dB. In a particular case that coupling delay signals of each relay station is very closed, transmission characteristics of OFDM signal vary drastically depending on coupling phase ; BER varies better the order 10^<-4> to 10^<-2>.
This paper introduce a technical outline of the newly designed High Definition Switcher and DME (Digital Multi Effects). Especially 1.5Gbps SDI (Serial Disital Interface), high speed digital signal transmission and processing by new ICs and 64bit RISC CPU board using a Real Time OS have been developed. It allowed same functionality and operation style as Standard Definition's and showed reality of huge sized (3M/E) product.
In the recent syudio systems, various video signal formats have been used in complicated condition. In addition to the conventional formats for SDTV, the advent of new formats for high-quality ATV and HDTV have made the stodio systems far more complicated than before. In such a situation of a video signal format is becoming more and more important for configurating the production system. This paper explainns a newly developed digtal production switcher able to correspond to various types video signal formats, and common systems for component and HDTV.
We have newly developed DVCPRO50/Progressive for professional use VTR (AJ-PD950) into the same 4U size as DVCPRO. It can record up to 93 minutes of high-quality 4 : 2 : 2 or 4 : 2 : 0P digital component video signals, together with four channels of digital sound, onto a compact 1/4 "cassette. And it is able to edit seamlessly different 3 formata (4 : 1 : 1-interlace. 422-interlace, 420P・progressive) on the same tape with frame accuracy.
The five choruses from various parts via satellites of world and an orchestra "Ode to Joy" were synchronized in Opening Ceremony of Nagano Olympic. NHK Engineering Services davaioped the Time-Lag Adjuster (TLA) to conduct this. TLAs overcame time and distance lags, and this technology brought their voices and images together at precisaly the same moment at Minami Stadium in Nagano on huge screens, united in a simultaneous live performance successfully. We also developed "Audio and Video delay time measurement device". which allowed easy and stable operation for the opening ceremony.
We Fuji Television produced 2 Outside Broadcast Trucks. One is designed as production truck. It is a festure for this truck to be able to broaden the width. so we can secure large production room inside this truck. From the Sony DVS-7000 switcher to the Sony DVS-6464 and DVS-3232 Digital video routing systems, the entire signal path is D1. To audio system, we adopted an analog signal path from the TAMURA ADX-5000 audio console to the Sony BVS-A3232 Analog audio routing system. And the other is designed for producing HDTV programs. But with format concerter, we can also make NTSC programs. From the Sony HDS-7000 switcher to the HDW-500 and DVR-28 videotape recorders, to the Sony Routing systems, the system of this truck is composed with HD-SDI and D1. Of course, with special optical fiber cable, we can couple two OB trucks and cover various big event programs.