The paper is devoted to the problems of the aerodrome automatic direction finders accuracy characteristics checking. Disadvantages of the existing methods are shown. Recommendations to eliminate shortcomings are given, in particular it is proposed to take into account the orthodromic corrections to the measured values of the bearings during the flight tests.

Keywords: radio direction finder, flight tests, orthodromic correction, instrumental error

An analysis of micromovements causing a turboprop effect or a micro-Doppler was carried out, analysis of model input data for building a function bank was performed, an algorithm for reducing the effect of a turboprop effect was considered, the expediency of forming a similarity function for the subsequent reduction of the effect of micromotion on an object

Keywords: spectrum; radar; echo signal; turboprop effect; gliding component, micro-Doppler, radar

The article illustrates the problem of measuring the speed glider component targets in the presence of a turboprop effect of the reflected signal in a pulse-Doppler radar, proposed a model turboprop signal component and an algorithm for its suppression

Keywords: spectrum; radar; echo signal; turboprop effect; gliding component, micro-Doppler, radar

This article describes electronic design software tools OrCAD implementation for the quadrature MSK-signals (minimum shift keying) modulator creation. Emulation results are presented: digital and analog signals, the output spectrum. The model is designed to generate MSK-signal and study their changes in various RF paths, using all possible analog-digital circuit simulation of OrCAD. The presented model is parametrized. The determinative model parameters are MSK-signal central frequency and pulse duration of modulation sequence. The input sequence - unipolar digital signal is read from an external text file. Realization of a parametric model of the MSK-signal modulator in OrCAD allows the researcher to quickly and easily change the parameters of the signal and to carry out research directly into the package without resorting to third-party software tools, thereby reducing the complexity and development time. The model can also be used in the study subjects issues concerning digital data transmission.

Keywords: circuit simulation, OrCAD, minimum-shift keying, quadrature modulator, parametric model

This article describes the model of the pseudorandom sequences (PRS) generator developed in OrCAD program suite.The described model is applicable for radio systems modules circuits simulation that are using in the operation a PRS. The PRS generator implementation in OrCAD make possible to change PRS parametres immediately in the program, without using other software. A model specificity is that it is parametrised. Parametrization facilitates model control and that is reduce to a minimum necessary manipulations for changing of PRS type. The model is constructed on the basis of circuitry implementation of the linear feedback shift register (LFSR). For adjustment of model it is enough to instal code words setting starting state a LFSR, parametres of a signal of a clock source and to specify register tap output. As an example, used a 16-bit LFSR to create maximum length PRS, tap sequence {0, 5, 9, 13}. Emulation results are presented.

Keywords: pseudorandom sequence, PRS generator, LFSR, OrCAD, circuit simulation