Vol 64, No 2 (2019)

A numerico–analytical method for calculating the eigenwaves of striplines, making it possible to obtain numerical results with high accuracy at low computational costs, is developed. An algebraic model of a microstrip line in a multilayer dielectric medium is constructed. The elements of the matrix of a system of linear algebraic equations are transformed into rapidly converging series. Asymptotic expressions for the matrix coefficients and an asymptotic solution of an infinite system of linear algebraic equations are obtained. The results of a numerical analysis of the convergence of the method, confirming its efficiency, are presented.

Specific features of the formation of transient electromagnetic pulse emanation fields induced by the pulsed excitation of printed elements are discussed. The field formation affects the electromagnetic compatibility of digital signal processing devices. It is shown that printed conductors in complex-layout boards with a specific geometrical configuration can work as electromagnetic emitters. It has been established that the video pulse length, clock frequency, and code sequence alternation phase determine the spectral behavior of a digital signal, which may coincide with the eigenfrequencies of printed emitters, in particular, forming a mode of excitation on the self-oscillations when decreasing video pulse length or front steepness. The results of investigations of potentially emitting printed element prototypes are reported.

The methods of numerical signal differentiation are discussed. The convergence conditions for numerical differentiation are formulated. The approach to numerical signal differentiation is generalized based on regular local interpolation with generalized polynomials. The coefficients of optimal differentiators are determined using numerical-analytical methods. Various methods of numerical differentiation are subjected to comparative analysis. The results are implemented in practice.

It is shown that the phase–frequency characteristic (PFC) of an analog filter connected to an ADC can be linearized with the aid of a digital filter with a finite impulse response (FIR). Circuit simulation is used to show that an end-to-end PFC becomes more linear and the frequency response function (FRF) is equal to squared FRF of the analog filter. It is also shown that the PFC of bandpass complex analog filters can be linearized. Series-connected real low-pass filter and complex bandpass filter are simulated using low-frequency fifth-order Butterworth prototype with the corresponding linearizing FIR filters. It is shown that the nonuniformity of group delay time in the pass band can be decreased by a factor of greater than 100.

The theory of generation of periodic pseudorandom binary В‑sequences, which is based on the bеnt-function theory, is presented. The algorithm of construction of the generator is detailed, and the results of computer calculations for sequences of certain periods are given.

In this paper, we numerically studied the interaction of signal and noise in a second-order nonlinear active filter. The filtering of the signal against a background of intense noise through a nonlinear filter with a bandpass filter at output is analyzed. The output signal-to-noise ratio is established as more than three times higher than the similar ratio without using a nonlinear filter.

An untraditional approach to solving problems of spatiotemporal processing of signal received on the background of structurally determined interference is presented. It allows one to consider the main processing operations: interference compensation and signal demodulation a single technology of interrelated procedures.

In this paper, we extended the theory of optimal nonlinear filtering of discrete-continuous processes to receiving signals with intersymbol information coupling, i.e., signals with a shape depending on both the current information symbol and the previous symbols at a certain time interval. The general algorithm of receiving these signals and its simplified version that allows practical implementation of a demodulator are considered.

It is shown that the Electronics Workbench (EWB) software can be used to analyze working regimes of a high-power device and minimize switching loss. Problems of measurement of parameters of high-power devices based on FETs from the EWB library needed for development of control circuits are considered.