DOI:10.1049/ree.1979.0056

出版商:IERE    

年代:1979

数据来源: IET

DOI:10.1049/ree.1979.0057

出版商:IERE    

年代:1979

数据来源: IET

DOI:10.1049/ree.1979.0058

出版商:IERE    

年代:1979

数据来源: IET

摘要:

The paper begins with an historical review of radar for ice detection. The most up-to-date estimates of radar cross section of ice in various forms are presented and discussed. Comments are made on recent sea clutter measurements and the influence of scanner height on marine radar.

DOI:10.1049/ree.1979.0059

出版商:IERE    

年代:1979

数据来源: IET

DOI:10.1049/ree.1979.0060

出版商:IERE    

年代:1979

数据来源: IET

摘要:

The increased complexity of modern aircraft has resulted in a proliferation of aerials sited in close proximity to one another, a trend more marked in military types, which makes it even more necessary to ensure compatibility of working in a crowded r.f. spectrum.The paper presents the investigations that have been made to determine the degree of isolation between transmitting and receiving aerials in aircraft within the frequency range 30 to 1250 MHz. From measurements using cylinders, ground planes, helicopters and fixed wing aircraft, empirical formulae for the calculation of aerial-to-aerial isolation have been derived.Investigations have also been carried out to determine the amplitude of the harmonics generated by airborne transmitters. The results obtained from both these aspects of the work are discussed.

DOI:10.1049/ree.1979.0061

出版商:IERE    

年代:1979

数据来源: IET

摘要:

A new procedure for the synthesis of low-pass active RC ladder networks by the recurrent-continuant transformation has been proposed. The transformation scheme consists of simple determinant operations which are carried out subsequent to a frequency transformation and addition of certain parameters to the prescribed all-pole transfer function. The proposed method is more general than those described earlier, and simple as compared with the synthesis procedures based on coefficient matching methods. The method has been illustrated by realizing a number of 3rd and 4th-order characteristic functions. The proposed scheme, with slight modification, is also capable of realizing double ladder networks. The modified scheme has been described with an appropriate example in the third order. The capacitors in all the realized networks have been constrained to be unity. The methods yield multiple sets of values of the network elements and may be used with advantage to obtain optimized networks.

DOI:10.1049/ree.1979.0062

出版商:IERE    

年代:1979

数据来源: IET

摘要:

The use of a microprocessor to control the synchronization of a low-data-rate spread-spectrum system is described. The microprocessor controls a voltage-controlled oscillator and sequence-generator, and carries out the correlation processes needed for the acquisition and tracking modes. Switching between modes is achieved by changing an interrupt vector.

DOI:10.1049/ree.1979.0063

出版商:IERE    

年代:1979

数据来源: IET

摘要:

Secondary Surveillance Radar in Air Traffic Control has evolved from a mere labelling device in support primary radar to a high integrity plotting system inits own right with primary radar relegated to the support role. This change in concept has placed increased demands on the system and there is a greater awareness of the shortcomings and idiosyncrasies which previously were unnoticed or accepted, among which is the problem of reflections causing false target reports. This paper outlines the nature of the difficulty and some of the principal methods for reducing it to an acceptable level.

DOI:10.1049/ree.1979.0064

出版商:IERE    

年代:1979

数据来源: IET