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Radio and Electronic Engineer

Issue 1 • Date July 1965

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Displaying Results 1 - 7 of 7
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  • Distributed CR cross-coupling circuits for multivibrators

    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1436 KB)  

    The use of uniformly distributed capacitance-resistance lines as cross-coupling circuits for transistor multivibrators is considered. The differential equation which governs the voltage across the line at any point is set up; this equation is the one-dimensional heat conduction equation. Boundary conditions are derived corresponding to the different parts of the multivibrator cycle. A numerical method of solving the equation for the base and collector waveforms is given. An approximation is introduced to deal with the effects of stored base charge on the multivibrator waveforms. The results of specimen calculations are discussed. Some details of the numerical analysis technique, and of the programming details, are presented in an appendix. View full abstract»

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  • The application of eigen theory to filter networks

    Page(s): 19 - 20
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (166 KB)  

    This note develops the concepts of characteristic impedance and propagation constant using matrix methods. It shows that they can be interpreted in terms of the eigen roots and vectors of the transfer and impedance matrices. It is not suggested that the methods are quicker than the normal ones, but that this approach provides an alternative interpretation of the filter parameters. View full abstract»

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  • The dynamic capacitor electrometer

    Page(s): 37 - 45
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    The theory, historical development, design and construction of the dynamic capacitor electrometer are discussed. Both reed and diaphragm types are considered. Circuits are given and techniques of pH measurement described briefly. View full abstract»

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  • The analysis and demonstration of a method of generating v.l.f. noise

    Page(s): 46 - 52
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (636 KB)  

    The paper describes the analysis of a method of generating v.l.f. white noise based on the sampling principle. A wide-band source of noise is used and a narrow band at fairly high frequency over which the power spectrum is flat is extracted using a band-pass filter. The power spectral densities that result from sampling this band for different sampling frequencies are derived. The case of practical importance resulting in a flat spectral density around zero frequency is demonstrated experimentally for different sampling rates and the resultant maximum r.m.s. noise voltage compared with the theoretical values. View full abstract»

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  • Z-transforms and their applications in control engineering

    Page(s): 53 - 67
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1235 KB)  

    The paper describes the z-transform theory and its application. The background theory is built up in four stages from the continuous convolution integral, through the real-time impulse theory, to the z-transform. It is stressed that, unlike the Laplace transform, the z-transform is only an approximation. Engineering units are used throughout and emphasis is given to the correct representation of the sampler. The finite time of sampling is taken into account and it is shown how to make practical use of it. Illustrations of practical systems show good agreement with the calculations and attention is called to some common errors in the literature. The stability criteria are stated and methods of stability investigations are described. It is shown that for systems with zero-order hold circuits, the continuous Laplace transform is a more useful tool than the z-transform. The paper concludes with a practical approach to the design of discrete controllers. View full abstract»

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