Together with the millimeter wave propagation experiment, the measurement of one minute rain rates has been continued in Nagoya since December 1974. In this paper, the accumulated time distribution of rain rates has been obtained from the rain rate data observed for 18 years from January 1975 through December 1992. The result shows that the accumulated time distribution of one minute rain rates can be represented approximately by the logarithmic normal distribution. Moreover, the study includes the characteristics of annual changes of the accumulated time distribution, the accumulated time distributions between two observation points, the accumulated time distributions for the worst month as well as for the worst year and others.
The 4-Terminal Inductor that made combines two electric wires and wound to bobbin was developed. It was accomplished the Series Resonance Circuit which features low loss by the way of connecting a capacitance between one edge and the another one. The loss of all filters can be reduced by adopting this method.
This paper explains a filter that ellminates intermodulation that are generated in two radio transmitting stations where having neighboring antenna each other. The STV Hakodate station changed its transmitting frequency when power up from 1kW to 5kW. AS a result, frequency difference is 36 kHz from the first radio channel of NHK. Such a narrow frequency difference is seldom found, if ever, anywhere else in transmitting stations operating at a kilowatt level. The intermodulation anticipated to be generated between these two stations were examined and tested, and goods results were obtained with a filter fabricated for this purpose. The radio transmitting station with this filter is operating in good condition.
Experiment of 64QAM signal transmission by tentative specifications of Ministry of Posts and Telecommunications at Advanced Cable Technology Center and LCV Co. by Cable Television Association was described. Adjacent channel interference between QAM and NTSC-AM indicated that QAM signal level is desired to be lower than NTSC-AM signal level by about 5 dB. At this signal level, bit error rate versus Composite Triple Beat (CTB) showed that CTB is required to be less than-53 dB. An equalizer eliminated effectively reflection of cables (ex.0.3μs, -20dB). The results indicated practicability of Japanese proposal to ITU-T.
A digital broadcasting system for satellites operating in the 12.5 GHz band has been standardized by the Japanese Telecommunication Technology Council. For the maximum commonality and interoperability of the system with other delivery media, the digital broadcasting system uses technologies based on the internationl standards or recommendation for source and channel coding systems. While for the conditional access system. an original system is adopted to meet service requirements in Japan. This paper introduces outlines of the system, as well as remaining issues to be solved.
The Preliminary technical standard of CS digital television broadcasting system was approved in the TTC (Telecommunications Technology Council) this March. The standard which was made in the ARIB (Association of Radio Industries & Business), former BTA (Broadcasting Technology Association)) consists of source coding, multiplexing, channel coding and conditional access subsystems. The test of the digital television broadcasting system complied with this standard was conducted by ARIB. The test results satisfied required functions and performances specified in the standard and was submitted to the TTC. The standardization was completed in the TTC this July. This paper presents this test results.