摘要:

A method is described of constructing waveguide phase-shifters well matched over a broad frequency band. The principles of design are discussed, and details are given of the performance of experimental S-band models having bandwidths of 10–25%.

DOI:10.1049/pi-3.1953.0029

出版商:IEE    

年代:1953

数据来源: IET

摘要:

In Sections 1 and 2, after an account of factors influencing the work function of metals, values are quoted and the usefulness of a number of metals as practical thermionic emitters is discussed. The effect of adsorbed films is described in Section 3 and illustrated in connection with emitters with monatomic layers of thorium, caesium and barium.The emission from compounds, and in particular from semiconductors, is considered in Section 4. Sections 5 and 6 deal with the behaviour of certain metallic borides and carbides. Some of these, such as lanthanum boride and thorium carbide, are likely to be valuable as practical emitters. The general properties of oxides are discussed in Sections 8 and 9, where the groups in the periodic table are compared. The barium-strontium-oxide type of cathode is treated in Section 10. This is the most important practical cathode, and the behaviour and limitations are dealt with in some detail. Section 11 describes the performance of thoria as a thermionic emitter.

DOI:10.1049/pi-3.1953.0030

出版商:IEE    

年代:1953

数据来源: IET

摘要:

A new method of solving electrical networks is described which is more rapid than the classical determinant method. The new method is based on the properties of certain sub-networks termed “trees” and “2-trees.”. It is shown that, with suitable algebraic representations, the required sets of trees and 2-trees can be evaluated with the aid of equations in which the terms are networks. Functions known as linkages are defined in terms of sets of trees and 2-trees, and it is shown that these functions obey laws analogous to Kirchhoff's laws for voltages and currents. Hence relations involving voltages and currents can be expressed in terms of linkages. In particular, the transfer admittance of a network can be expressed as the ratio of the set of all trees on the network to an appropriate linkage. Network theorems can be rapidly deduced with the aid of trees and 2-trees. Since the method gives results in terms of admittances, a rule is given whereby admittance functions can be transformed into the corresponding impedance functions.

DOI:10.1049/pi-3.1953.0033

出版商:IEE    

年代:1953

数据来源: IET

摘要:

The requirements for the output amplifier at the repeaters of a frequency-modulated 4.000-Mc/s radio link are discussed, and it is shown that the travelling-wave tube compares favourably with the klystron and disc-seal triode.Details are given of the construction, performance and operating conditions of the type CV2188 travelling-wave tube which is used in the Manchester-to-Edinburgh television relay as an output amplifier, and which delivers a power of about 1.5 watts to the aerial feeder at each repeater.

DOI:10.1049/pi-3.1953.0034

出版商:IEE    

年代:1953

数据来源: IET

摘要:

The conventional analysis of the action of the ring reproducing head is re-examined and experiments are described which demonstrate divergences between the theoretical and practical results. The action of a reproducing head consisting of a single loop of non-magnetic conductor is analysed and experimental results which verify the theory are given. The effects of various common imperfections and maladjustments in all the types of reproducing head are predicted and checked by experiment. The findings are then applied to the problem of frequency-characteristic calibration, and the corrections which are necessary to obtain consistent results with various heads are ascertained. The practical aspects of standardization are discussed, and the possible application of special heads in this and other roles is noted.

DOI:10.1049/pi-3.1953.0035

出版商:IEE    

年代:1953

数据来源: IET

摘要:

With recording heads of conventional design, the distribution of magnetization through the depth of a recorded tape may be markedly non-uniform to an extent depending upon the h.f. bias setting. An analysis of this effect is shown to be of value in explaining several aspects of recording performance, including the anomalous loss of high-frequency response commonly observed when using large values of h.f. bias.An analysis of the self-demagnetizing fields created within a recorded tape is also given, and an attempt is made to relate the losses these introduce into the high-frequency performance of the system to the dimensional and magnetic constants of the tape.

DOI:10.1049/pi-3.1953.0036

出版商:IEE    

年代:1953

数据来源: IET

DOI:10.1049/pi-3.1953.0037

出版商:IEE    

年代:1953

数据来源: IET