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Method of improving of soft multithreshold decoder's performance for self-orthogonal codes is considered. A modified way of selecting weights coefficients on initial iterations of multithreshold decoding (MTD) at high noise is described. Some simulated results obtained by using these two decoding techniques (the base and modified ways ) are presented as well.Comparison of the results showed that the change in the computing of weights coefficients can significantly improve decoding parameters of a convolutional code with soft MTD. It's shown that MTD is in many cases as effective as an optimum decoder. MTD implementation complexity is also discussed.MTD is characterized with a very small number of operations, soft versions of these decoders can correct in channels with high enough noise level streams of the data in high-speed communication systems

Expressions describing the time of flight of charged particles taking into account time-of-flight chromatic aberrations in electrostatic mirrors of rotational symmetry are presented. The conditions of time-of-flight focusing by particle energy up to the third order inclusively in the three-electrode mirrors, the electrodes of which are coaxial cylinders of equal diameter, were determined by numerical calculations. Various modes of operation of such mirrors are considered: 1) space-time-of-flight focusing in the Gaussian plane of the mirror; 2) space-time-of-flight focusing in the focal plane of the mirror; 3) time-of-flight focusing in telescopic mode; 4) time-of-flight focusing in collimator mode. The results of calculations are presented for two fundamental solutions of the equation of paraxial trajectories. One of these solutions describes trajectories whose direct and reverse branches coincide, and the second solution describes trajectories whose direct and reverse branches are symmetrical with respect to the axis of symmetry of the field. It is shown that the time-of-flight dispersion of the mirror by mass, determined on the basis of the second solution, is several times higher than that obtained on the basis of the first solution for all modes of its operation.

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The article considers an internal boundary value problem of the distribution of an electrostatic field in a lens formed by two identical semi-infinite circular cylinders coaxially located inside an infinite external cylinder. The problem is reduced to solving a system of singular Wiener-Hopf integral equations, which is further solved by the Wiener-Hopf method using factorized Bessel functions. Solutions to the problem for each region inside the infinite outer cylinder are presented as exponentially converging series in terms of eigenfunctions and eigenvalues.