To achieve an extra-high density of the color-trios for an indoor-use JT, a hybrid JT (R & G from LEDs (light-emitting diodes), blue from Trini-Lite, 5.5-mm triopitch) was developed in 1988 on trial. To improve cost, performances and power-efficiency, a CRT (cathode ray tube)-matrix type JT was developed. It uses a single-beam index type CRT including 8*8=64 trios with 7.5 mm triopitch in 60*60 mm.<>

AbstractThe kinetic deuterium isotope effect in the thermal dehydration stages of powdered SrCl2 · 2H2O was examined by means of both isothermal and dynamic gravimetries. These dehydration processes proved to be controlled by a random nucleation and its subsequent growth mechanism. No significant kinetic isotope effect was seen in these dehydration stages. It seems that there exists a kinetic compensation effect between the hydrate and its deuterium analog, if any isotopic differences in activation energy and frequency factor could exist.

Optical-fiber transmission systems application to long-haul optical trunk lines is studied. Development on optical transmission systems is found to be most advanced for short-haul interoffice systems, with many countries in the world already having systems in commercial use. This is largely due to the amount of demand that exists in this field, and that insufficient laser diode reliability does not permit constructing a long-haul optical circuit. However, from an economical viewpoint, optical transmission systems introduction into long-haul trunk lines is quite attractive. This paper reports the results of a survey on some economic and reliability aspects of the system, together with the technology state of the art. Attainable repeater spacings are estimated after detailed consideration of optical-fiber loss and dispersion. Some experimental results are also shown to clarify the transmission characteristics for high-speed signals and long repeater spacing systems. Based on the survey, future developmental targets are discussed.

An allowable transmission-line loss as high as 65.6 dB has been experimentally obtained by using a newly developed high-power 1.32 μm Nd-y.a.g. laser with an average fibre input power of +22.0 dBm at 32 Mbit/s in return-to-zero pulses, which ensures 100 km repeater-spacing transmission with presently available low-loss optical fibres

Newly developed two-cavity ring-type filters for a millmeter-wave communication system are described. They are used in a five-channel transmit and receive multiplexer which operates in the 50-GHz frequency band. The pulse response and interchannel crosstalk characteristics for 250-Mbit PCM-AM or PCM-PSK transmission were calculated and compared with experimental results.