This refers to a cable for electrical communication or power transmission designed to be laid on the seabed. Only a few are used for power transmission, and most are for undersea communication. To protect against high water pressure on the seabed, corrosion by seawater, and damage caused by fishing, etc., strong structures and materials different from those of land cables are used. It has a history of about 100 years, and the old one was made of a copper core wire surrounded by gutta-percha or polyethylene insulation and an armored iron wire. Most of the current cables are coaxial cables, and the core of the inner conductor is replaced with a strong steel wire, eliminating the armored iron wire. Signal attenuation associated with long-distance communication is a unique problem of undersea cables, and as a solution, loaded and unloaded cables were invented, but today's transoceanic cables have built-in repeater amplifiers every 20 nautical miles, and the power required for them is sent at high voltages of several thousand volts from both ends. The lifespan is about 20 years. They are laid by cable-laying ships. Since the 1970s, low-loss optical fiber cables have become the norm. → Related topics Submarine cable laying ship | Communication cable | Telephone Source : Heibonsha Encyclopedia About MyPedia Information |
海底に敷設するために作られた電気通信用または電力伝送用のケーブルをいう。電力輸送用はわずかでほとんど海底通信用。海底における高水圧,海水による腐食,漁労などによる損傷等の保護のため,陸上ケーブルと異なる強力な構造,材料が用いられている。約100年の歴史があり,旧来のものは,銅心線とそれを囲むグタペルカやポリエチレンの絶縁物と外装鉄線からなる構造。現在はほとんど同軸ケーブルで,内部導体の心の部分を強力な鋼線におきかえ外装鉄線を廃止している。長距離通信に伴う信号の減衰が海底ケーブル固有の難問で,その対策として装荷ケーブル,無装荷ケーブルの発明があったが,今日の大洋横断ケーブルでは20カイリごとに中継増幅器を内蔵させ,それに必要な電力は両端局から数千Vの高圧で送る。寿命は約20年。ケーブル敷設船で布設する。1970年代からは低損失の光ファイバーによるケーブルが主体となった。 →関連項目海底ケーブル敷(布)設船|通信ケーブル|電話 出典 株式会社平凡社百科事典マイペディアについて 情報 |
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