This paper is devoted to optimization of surface acoustic wave bandpass filters with apodized interdigital transducers (IDT). Iterative Parks-McClellan algorithm is applied to estimate the apodization coefficients of the IDT fingers. A family of corresponding subroutines is developed in the Matlab mathematical package. The simulation results of the SAW filter optimized design are illustrated. For the refined estimation of the filter frequency response COM-based P-Matrices are employed. The results obtained in this study constitute a set of tools for the practical calculation of apodized IDTs and filters according to a given specification. Subroutines implementing COM-based P-Matrices can be utilized as part of programs for frequency-selective SAW devices design.

Keywords: acoustoelectronics, apodization, approximation, interdigitated transducer, impulse response, surface acoustic wave, optimization, piezoelectricity, filter, frequency response

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

The system is intended to automate the procedure of 3D-models calculation and formation for cooling heatsink of electronic components. Based on user input, the system calculates the design parameters of the heatsink in the mathematical core, then data enters the geometric kernel, where the construction and rendering of 3D-model takes place. The system allows to choose the type of heatsink being constructed, the method by calculations will occur, dimensions and material properties. The result is a 3D-model of the heatsink suitable for use in the design process.

Keywords: heatsink, computer-aided design, automation system, radioelectronic equipment, parameterization, geometric modeling, API

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