著者

小妻 勝 梅園 茂

出版者

長崎大学水産学部

雑誌

長崎大学水産学部研究報告 (ISSN:05471427)

巻号頁・発行日

no.47, pp.p75-81, 1979-08

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The training vessels Kakuyo-maru and Nagasaki-maru of the Faculty of Fisheries, Nagasaki University make training trips mainly to the East China Sea and the equatorial waters of the Pacific and Indian Oceans. It often occurred that the vessel could not keep in communication by wireless with home or with other vessels for scores of minutes to several hours because of rain noises, radio interference caused by rain drops. Expecially in the equatorial waters, communication by wireless frequently became completely impossible whenever a squall passed over or near the vessel. The present authors carried out a joint-study on the methods of eliminating rain noises aboard Kakuyo-maru and Nagasaki-maru during the past three years starting from 1976, and almost succeded in it. Rain noises could be eliminated, or reduced to a level at which no incovenience was caused, by blanking the signal flow line at the anterior part of the narrow band pass filter of the intermediate frequency amplifier of the receiver for a short time while pulses of rain noises were being emitted. Heretofore, vessels sailing or operating in the equatorial waters suffered without fail from radio interference. From the results of the present experiments, it is suggested that the attachment of a noise blanker circuit to a commercial radio receiver will ensure a smooth communication and the safety of navigation.これまで赤道周辺を航行する船舶は,必ず雨雑により受信障害を受けた。この雨雑除去法については,まだ改善の余地は残されているものの,受信機の中間周波増幅段の狭帯域フィルターの前の部分で,雨雑パルスの出ている短い時間だけ信号経路をブランキングすることにより,実用通信に支障ないまでに軽減または除去された。すなわち,今回の実験により商用受信機にNoise Blanker Circuitを附加することで,充分雨雑を除去することができ,その結果,常時円滑な通信が可能となった。