NHK STRL R&D No.48(February, 1998)
This Paper reports frequency domain sub-band space diversity (SB-SD) combination technique for wide-band mobile radio reception which can be applied to severe frequency selective fading environment. In this diversity system, wide band signals from several branches are divided int subband signals, and selected or combined with linear or square method. NHK Scinece and Technical Recearch Laboratories carried out simulation in with SB-SD is applied to OFDM (Orthogonal Frequency Division Multiplexing) reception i multipath environment. The diversity gain at BER = 1 x 10 -2 in Rayleigh fading channel is about 9dB (2branches), 12dB (3branches) and 14dB (4branches), respectively. These results show that SB-SD can improve the performance in mobile reception of wide band radio transmission.
In principle, perpendicular magnetic recording media are able to realize high-density recording. It is expected that these media will be used for high-definition television (HDTV) and high-quality video multimedia. A Co-Cr-Ta tape with a smooth base sheet was prepared by facing-targets sputtering (FSC) in order to study the possibility of high-density recording. The base sheet surface was observed by atomic force microscopy (AFM). The recording characteristics of Co-Cr-Ta tapes with smooth and standard base sheets were investigated at short wavelenghts by using a drum tester (a system that evaluates the head and medium). The output with the smooth version was 3.2 dB higher at 170 kFRPI than with the standard one. The magnetization recorded on the smooth version at 250 kFRPI was clearly observed as a magnetic force microscopy (MFM) image.
In order to clarify system requirements for spatial representation in stereoscopic displays, we studied the characteristics of the wide-field effect through the influence of spatial vision on the human postural control system. Body sway, as induced in subjects by oscillating frontal-plane rotation of random dot visual stimuli, was measured. The stimuli ci=onsisted of 2-D random dot patterns on a flat plane and random dot stereograms containing a squarewave depth grating in the horizontal direction. Therefore, in the case of the 3-D stimuli, subjects can percept important vertical edges with vertical depth discontinuities for their postural control. The results showed a characteristic component of sagittal body sway at the frequency of oscillation of the visual stimulus. The effect increased with the visual angle subtended by the visual stimulus, and moreover was stronger for the 3-D stimuli, suggesting that the binocular disparities affected the formation of subjects' spatial maps in their brain.
The shooting technique of cameramen was analyzed in relayed soccer telecast which is difficult to predict subject's movement. Cameramen's confirmation method of the subjects and control technique of the camera were measured by detecting their eye mocement and velocity of the camera.
Outcomes therefrom:
- Cameramen shoot by repeatedly paying attention of approximately 50 msec at a time to the surroundings.
- They always leave space in front of a moving subject, and the quantity of the space depends on the subject's size in the image and its velocity.
-At an abrupt change in the subject's movement, sense it and perform the optimal correction in a very short time of about 300 msec.
- The maximum acceleration produced during panning was some 200 deg/sec2 while seaching.
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