摘要:

When the first transatlantic telephone cable was planned in 1953 there were two possible systems available: one American, using small-diameter flexible repeaters in two uni-directional cables, and the other British, using much larger, rigid repeaters in a single cable. The former was the more advanced, particularly with respect to laying methods in ocean depths, and was adopted for the main Atlantic crossing, the British system being used between Newfoundland and Nova Scotia. As early as 1951, the British Post Office had started development of a revolutionary type of coaxial cable for use in deep water. This had its strength member in the centre, torsionally balanced, and an external sheath of polythene; its non-twisting characteristics under tension promised major improvements in laying and recovery techniques. When, in 1957, the British and Canadian Governments agreed to provide a new submarine telephone cable between the two countries, British rigid repeaters with the new British Lightweight cable in deep water were envisaged. This cable system, known as CANTAT, was developed, manufactured and completed within a period of four years. In addition to overland connections in Great Britain and Canada to London and Montreal, respectively, there are two submarine cable links, one between Scotland and Newfoundland, providing 240 kc/s bandwidth in each direction (initially 60 telephone circuits recently increased to 80), and one in the Gulf of St. Lawrence providing 480kc/s bandwidth in each direction (initially 120 telephone circuits capable of increase to 160). The system was opened for service by Her Majesty The Queen in December 1961, and is, for the present, the most advanced installation of its kind.

DOI:10.1049/piee.1963.0155

出版商:IEE    

年代:1963

数据来源: IET

摘要:

In 1951, the British Post Office evolved an entirely new type of deep-sea submarine telephone cable which was intended to overcome many of the serious disadvantages inherent in conventional wire-armoured cable. This new cable, known as the Lightweight cable because of its very light weight in water, was under exhaustive development for seven years before it could be accepted with confidence for a trans-ocean system. 1600 miles of this cable have now been laid on the Anglo-Canadian (CANTAT) system, and in all respects it has met the highest performance expectations. It has also proved to be much cheaper than a comparable conventional cable. Its electrical stability is noteworthy as it has exhibited a much smaller attenuation laying change than that experienced with previous cables, and, during the first year, there has been no significant indication of ageing. This type of cable is expected to be employed on all new deep-sea systems.

DOI:10.1049/piee.1963.0156

出版商:IEE    

年代:1963

数据来源: IET

摘要:

The paper describes the repeaters and equalization methods used on the CANTAT submarine telephone system between Oban (Scotland) and Corner Brook (Newfoundland). In contrast to previous submerged repeaters, a new valve was used in the amplifiers and the voltage drop across a repeater was about 70V—a reduction of some 40% despite this, the greater number of repeaters in the cable increased the line voltage supply considerably, and the repeaters were designed to withstand a higher voltage between the inner unit and its housing. Because of the larger number of repeaters and greater difficulty in locating faults, a new supervisory method was adopted which could also locate noise faults. The equalizers, besides having basic networks, allow mop-up equalization to be performed on board ship during the lay.

DOI:10.1049/piee.1963.0157

出版商:IEE    

年代:1963

数据来源: IET

摘要:

On a long, repeatered, submarine-cable link, it is essential that facilities are provided for the terminal-station staff to be able to monitor the performance of each repeater in the link. The paper describes the two types of monitoring equipment that have been designed and installed at the British and Canadian terminal stations of the CANTAT 90-repeater submarine link. One type of equipment uses a radar-type technique, and relies on the natural non-linearity of the repeaters for the return signals; it provides, in effect, a means for monitoring the non-linearity of the repeaters. The other equipment uses a selective frequency-changing device in each repeater for measuring from one terminal station the loop gain to, and the noise—or intermodulation-generated by, any selected repeater.

DOI:10.1049/piee.1963.0158

出版商:IEE    

年代:1963

数据来源: IET

摘要:

A constant-current power system using permanent-magnet reference standards and magnetic-amplifier control circuits has been developed for energizing the Anglo-Canadian link (CANTAT). This system provides the necessary high degree of regulation of cable current, continuity of feed and protection for the submarine system. The protection circuits can be tested whilst the system is energized. The design is sufficiently flexible to make the equipment suitable for powering the majority of existing or planned systems using thermionic valve repeaters.

DOI:10.1049/piee.1963.0159

出版商:IEE    

年代:1963

数据来源: IET

摘要:

The paper describes the stern cable-laying gear and associated equipment developed for cable and repeater stowage, handling and laying on H.M.T.S.Monarch.The techniques and equipment described were used throughout the laying of the CANTAT cable and operated very satisfactorily under widely differing operational conditions.

DOI:10.1049/piee.1963.0160

出版商:IEE    

年代:1963

数据来源: IET

摘要:

CANTAT was the third telephone system to be laid across the Atlantic, but it was of a very different type from its predecessors and was unique in many ways. It was the first system to use the new Lightweight cable. A new equalization technique had to be introduced whereby system transmission misalignments encountered during the lay were corrected by suitable networks built and housed on the ship, without stopping the laying operation. Every effort was made to anticipate all possible eventualities, since the laying of any long ocean system is hazardous. The complete laying operation was spread over seven months, and although many incidents occurred none was abnormal, and no weaknesses were apparent in the equipment or the techniques.

DOI:10.1049/piee.1963.0161

出版商:IEE    

年代:1963

数据来源: IET

摘要:

The inherent accuracy of the simple two-element interferometer of several wavelengths, spacing can be utilized if resolution of the phase ambiguity is obtained. The statistical probability of this in the presence of wave interference is estimated from observations on a narrow-aperture pair of elements. The design problems and system errors are discussed for a five-element direction-finding array.

DOI:10.1049/piee.1963.0162

出版商:IEE    

年代:1963

数据来源: IET

摘要:

A technique of high absolute accuracy for measuring low-loss symmetrical linear passive 4-terminal networks is described. The method is well suited for the v.h.f. and u.h.f. ranges. The unknown network is inserted in turn near a high- and a low-impedance point along a low-loss uniform line short-circuited at each end. From measurement of the two resonant frequencies (coincident, or nearly so, by adjustment of line lengths) and knowledge of the line dimensions, the characteristic impedance Z0xand electrical lengthlxof the equivalent uniform line are computed. Errors are discussed and means suggested for reducing them. The technique has been explored in the frequency range 300–2800 Mc/s, using precise 50Ω coaxial lines. Connectors, adaptors and small-range adjustable stubs, with reflections mostly less than 10%, have been measured. The r.m.s. scatter in the measured results is of the order of 0.1% inZ0xand 0.01 cm inlx. The absolute errors are estimated to be only a little greater. The method should apply over wider ranges of frequency and to a greater variety of unknowns, including waveguide two-ports.

DOI:10.1049/piee.1963.0163

出版商:IEE    

年代:1963

数据来源: IET

摘要:

The effect of the variation of electrical properties at the surface on the propagation of a microwave signal through a semiconductor placed in a guide are analysed by a perturbation method. General expressions are obtained for the reflection and transmission coefficients of the semiconductor sample. The results of the analysis are discussed with reference to microwave measurement of the bulk and surface properties of semiconductors.

DOI:10.1049/piee.1963.0164

出版商:IEE    

年代:1963

数据来源: IET