[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

View full abstract

The synchronized carrier television system utilizes television channels effectively. However, phase fluctuation in the vision carrier reduces the protection ratio against co-channel interference.
This paper investigates the phase fluctuation of a vision carrier. Experiments analyze two elements ; transmitter fluctuation and added fluctuation from radio propagation. It is shown that this additional fluctuation over long distances is very small whenever the path is in the line-of-sight.
This paper also discusses the visibility of phase fluctuations in television ghost images, and points out that these measured fluctuations do not create problems for the planning of a synchronized carrier television system.

View full abstract

Pupil size changes as a function of the processing load or human activity level required to perform a cognitive task. It may also reflect the situation of retentive processes. This study aims to relate the pupil size to retention by examining the reproduction of 8-digit number patterns. The results show that in the case of a complete correct answer, pupil size gradually increases with the presentation of each digit, and decreases monotonically during reporting. However, if the subject cannot answer at all, it does not change and stays large. Blink time, which can be measured by a sharp drop in pupil size, is very short during presenting and reporting, but many subjects blink after reporting the final digit. However, if the subject forgot the digit presented, blink time is longer.

View full abstract

This paper presents a 10-channel HDTV digital transmission system using wavelength-division multiplexing. We have developed an external-grating-cavity laser diode, made up into a compact module for a holographic diffraction grating and an aspherical lens, that operates at high speed. The optical multiplexer and demultiplexer have a narrow channel spacing of 1.9 nm, low polarization-sensitivity, and low optical crosstalk. We have also developed a new method of digital frequency-division multiplexing that transmits one HDTV signal at 668.25 Mb/s per optic channel. Transmission experiments through 3 km of GI fiber demonstrate its high performance.

View full abstract

[in Japanese]

View full abstract