摘要:

A sensitive correlation detector has been constructed in which the input signal and noise voltages are amplitude-limited. The correlator is described and experimental results are given in support of the theory. A method of analysing the data from the correlator to obtain the maximum output signal/noise ratio is discussed for the case where the signal and noise voltages depend on slowly varying functions of time. Particular reference is made to the analysis of data from observations with the stellar intensity interferometer for which the correlator was specifically designed. It is concluded that the dual-channel amplitude-limited correlator is stable and that it can be used to obtain accurate, meaningful and linear results despite the non-linear operations involved.

DOI:10.1049/ree.1968.0069

出版商:IERE    

年代:1968

数据来源: IET

摘要:

Various interconnection techniques for use in conjunction with thin film planar devices are described. The special character of the substrate imposed a number of limitations on processing and assembly, the most restrictive being that all interconnections should be made at the lowest possible temperature, at the same time being capable of repair. The method of mounting integrated circuit chips directly on the 2 μm thick copper circuitry uses soldering techniques for both chip mounting and the connections from chip to copper circuitry. The connection system used to make ground and signal connections between adjacent planes and the special handling and soldering equipment produced for this work, and the processes used to manufacture connection straps and overlays are described. The metallurgical aspects of soldered interconnections are discussed, particularly with regard to the effects of short range diffusion which greatly influences both the metallurgical structure and the resultant mechanical integrity of joints in the size range covered.

DOI:10.1049/ree.1968.0070

出版商:IERE    

年代:1968

数据来源: IET

摘要:

In spite of the fact that inter-element coupling in a receiving array markedly affects the amplitude of the output signals when the beam is deflected from its normal axis, and also introduces correlation into otherwise-uncorrelated noise outputs from the various elements, yet its effect on signal/noise performance and on the beam-steering itself is small and usually negligible. The correlation introduced by inter-element coupling and the way it adds to correlation already existing in the acoustic field is examined and discussed in more detail. It is shown that it has important implications for a class of sonar systems in which signal and noise are distinguished by their inter-element correlation.

DOI:10.1049/ree.1968.0072

出版商:IERE    

年代:1968

数据来源: IET

摘要:

Existing methods for the theoretical determination of the capture range of selected automatic phase control loops, using a sin (ϕ-phase comparator, are analysed. From the results of this analysis, an equivalent method to the one used by Goldstein in his treatment of loops with sawtooth comparator is developed that can be applied to a wider variety of interesting loop filters. The method is based on the experimentally suggested hypothesis that all non-synchronized states of loops of most interest are asymptotically periodic. A function is derived which allows quick determination of the capture range of most stable a.p.c. loops containing one large integration time-constant in their filter branch. The method is directly applied to a few technically interesting cases, and very good agreement with experimental results is found.

DOI:10.1049/ree.1968.0074

出版商:IERE    

年代:1968

数据来源: IET

摘要:

By applying field theory and transmission line theory, theQ-factor of a surface-wave resonator is derived. A new technique for determining theQ-factor is developed. Attenuation constants of Sommerfeld and Goubau surface-wave lines of different diameters are determined from a large number of measurements ofQ-factor as a function of length of the resonator. The effect of tilt and rotation of one of the end-plates on theQ-factor is also studied. Radiation loss is evaluated. The paper also contains power-flow calculations and experimental verifications of the radial field spread for Sommerfeld and Goubau lines. Physical realizability of the Sommerfeld wave is confirmed.

DOI:10.1049/ree.1968.0075

出版商:IERE    

年代:1968

数据来源: IET