Development of CS-36M Submarine Coaxial Cable System

CS-36M system design objectives

Fig.1 CS-36M system design objectives

CS-36M submarine coaxial cable system construction

Fig.2 CS-36M submarine coaxial cable system construction

CS-36M ocean-block equalizer control facility block diagram

Fig.3 CS-36M ocean-block equalizer control facility block diagram

Cross section of 38mm ocean cable

Fig.4 Cross section of 38mm ocean cable

Measured cable attenuation

Fig.5 Measured cable attenuation

Repeater unit block diagram

Fig.6 Repeater unit block diagram

Repeater housing design objectives

Fig.7 Repeater housing design objectives

External view of repeater housing

Fig.8 External view of repeater housing

Total reliability assurance scheme

Fig.9 Total reliability assurance scheme

Photograph showing the packaging of circuits units in under-sea repeater

Fig.10 Photograph showing the packaging of circuits units in under-sea repeater

Power supply block diagram

Fig.11 Power supply block diagram

    The trunk lines of NTT nationwide network were operated mostly by wideband transmission systems via land coaxial cable or microwave. However, there were strong needs of submarine coaxial cable systems to connect the mainland and numerous scattered islands, particularly for transmission of wideband signals including TV.

    To meet this demand, the CS-36M Submarine Coaxial Cable System had been developed that transmits the 4-36 MHz wideband signals on a single 38 mm armorless coaxial cable or 25 mm armored coaxial cable, each for use in deep or shallow sea areas respectively. We had two systems in practice, System D1 and System D2. System D1 can relay 2,700 telephone channels with the quality defined by the noise performance of 1 pW/km, for the total path length up to 6,700 km. System D2 assures the simultaneous transmission of 2 channels of broadcasting TV (one-way) and 900 telephone channels with the noise performance of 1 pW/km, for the total path length up to 500 km.

    The research of CS-36M system was started by the Electrical Communication Laboratory (ECL), NTT Public Corporation in 1968, and it took about 10 years until the development of the system was completed by the cooperative works with the pertinent manufacturing companies. The final field experiment on a test transmission path of 450 km total length (81 repeaters) was started in 1973, between Nakaminato (Ibaraki Prefecture) and Yokosuka (Kanagawa Pref.). The obtained field test data showed that this system was well qualified for all the required design objectives.

    Fumio Ikegami, Haruo Tabata and Ryosuke Kaizu were in charge of the R&D of this syteme at ECL, Yokosuka. They worked on their specific fields of technology and also worked to adjust the output from many related research groups of ECL and to integrate them into the complete total system.

    There were many technical problems to be solved for the development of this system, and various new technologies were explored and developed. They were, establishment of the extremely high reliability design technology of repeater to attain the failure rate lower than 25 FIT, realization of the common amplifiers having sufficient allowance against harmful singing due to overloading of the amplifiers on a long multi-relay transmission line, development of the repeater housing durable for the high water pressure at the sea depth of 8,000 m, a new method of highly precise equalization controlled by magnetic fields through the repeater housing wall, and so on.

    The CS-36M system was the long-distance submarine coaxial cable system that had the broadest bandwidth among those systems put in practice at that time. And also, this was the first submarine cable system that could carry TV signals or the combination of TV and telephone signals. The development of this system contributed a great deal to the further progress of the succeeding submarine cable systems.

    1977, the Institute of Electronics and Communication Engineering of Japan gave the Achievement Award for Fumio Ikegami, Haruo Tabata and Ryosuke Kaizu who contributed to the above advanced technologies.



Publications

[1] Fumio Ikegami、Deep Sea Submarine Coaxial Cable System Development、1974、Review of Electrical Communication Laboratory, Vol.22, No.5-6. 1974
[2] Haruo Tabata et al.、CS-36M Submarine Coaxial Cable System、1974、Review of Electrical Communication Laboratory, Vol.22, No.5-6. 1974
[3] Yukiyasu Negishi et al.、38 mm Submarine Coaxial Cable Transmission Characteristics、1974、Review of Electrical Communication Laboratory, Vol.22, No.5-6. 1974
[4] Ryosuke Kaizu et al.、CS-36M Submarine Coaxial Cable Repeater、1974、Review of Electrical Communication Laboratory, Vol.22, No.5-6. 1974
[5] Hidekichi Satoh et al.、Reliability Assurance of Semiconductor Devices for CS-36M Submarine Cable Repeaters、1974、Review of Electrical Communication Laboratory, Vol.22, No.5-6. 1974
[6] Ryoichi Kaneoya et al.、Development of High Reliability Components for Submarine Cable Repeaters、1974、Review of Electrical Communication Laboratory, Vol.22, No.5-6. 1974
[7] Hiroshi Tanaka et al.、CS-36M Power-Feed Equipment、1974、Review of Electrical Communication Laboratory, Vol.22, No.5-6. 1974

Related Researches

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Communication
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