This page links to a number of translations of seminal papers
in the development of the ICTs. The translator is Chris Bissell, a
member of the ICT Group with a long-standing interest in the history of
the subject.

*These translations are offered as a resource for individuals.
Files may not be redistributed in electronic form or hardcopy. Please
send any comments or corrections to Chris
Bissell.*

- Kotelnikov, V A (1933), On the capacity
of the 'ether' and cables in electrical communication. In:
*Procs. of the first All-Union Conference on the technological reconstruction of the communications sector and low-current engineering,*Moscow.

In 1933 the young Russian communications engineer Vladimir Aleksandrovich Kotelnikov published a paper in which he formulated, for the first time in an engineering context, the sampling theorem for lowpass and bandpass signals. He also considered the bandwidth requirements of discrete signal transmission for telegraphy and images. Although Kotelnikov's name later became known in the West as a result of his subsequent work, particularly that on optimal detection, his pioneering 1933 results received little attention at the time outside Russian-speaking areas.

- K Küpfmüller, On the dynamics
of automatic gain controllers,
*Elektrische Nachrichtentechnik,*Vol. 5, No. 11, pp. 459-467.

Karl Küpfmüller was a German engineer who worked for eight years during the 1920s at Siemens & Halske in Berlin. During that time he carried out fundamental work on telegraphy and telephony, network theory, and the systems theory of electrical signal transmission. Like his contemporary in the US, Harry Nyquist, he derived fundamental results in information transmission and closed-loop modelling. Both derived stability criteria for feedback systems. In contrast to Nyquist, however, little has appeared in English about Küpfmüller or his work, although his pioneering results in systems theory informed later American work, particularly through the contributions of Ernst Guillemin, a prolific writer of highly influential student texts - and a great engineering educator at MIT.

- Wischnegradsky, J [Vyshnegradskii,
I. A.] (1876), On
the General
Theory of Governors,
*Comptes Rendus de l'Académie des Sciences de Paris,*Vol. 83, p.318

In modelling a steam engine with a centrifugal governor, Vyshnegradskii neglected Coulomb friction and linearised the system about an operating point. Unaware of the work of Maxwell and Routh from 1868 onwards, he investigated the conditions for the onset of 'hunting' (instability). Treating the engine as an integrator, and the governor as a second-order system, he made an ingenious change of variables in order to transform the resulting third-order characteristic equation into the form

φ^{3}+ xφ^{2}+ yφ + 1 = 0

the nature of whose roots determines the general form of the system transient response.

The parameters x and y, which depend on such system characteristics as governor restoring-force constant, moment of inertia, and so on, became known in the Russian and German literature as the Vyshnegradskii parameters. The transformed equation lent itself perfectly to a graphical technique of stability analysis, which the Zürich-based engineer A. B. Stodola later used in his work on hydraulic turbine control; as a result he prompted Adolf Hurwitz to develop his celebrated version of a general stability criterion.

- Andronov, A. A, Poincaré limit
cycles and the theory of self-sustaining oscillations,
*Comptes Rendus de l'Académie des Sciences de Paris,*Vol. 189, 1929, 559-561

Aleksandr Aleksandrovich Andronov (1901-1952) was a key figure in the development of control engineering in the former Soviet Union during this period, yet his name, and his contributions to control theory and nonlinear dynamics, are much less well known in the West than they deserve. (For further information about his work, see the full list of Chris Bissell's publications via http://oro.open.ac.uk.) One of Andronov's key achievements was to apply the work of Poincaré and Lyapunov to a range of non-linear dynamic systems, including closed-loop systems. The*Comptes Rendus*article translated here is his first publication in the West in this field, deriving from an earlier conference presentation in the Soviet Union, a brief summary of which is also provided here. Andronov's work was long thought to be the first to generalize Poincaré's limit cycles in this way, but it has recently been discovered that Poincaré himself appreciated such applications in 1908. An interesting paper on this finding is here.