Increasing the Efficiency of Projection Models of Strip Lines

Journal of Communications Technology and Electronics - Abstract—The matrix coefficients of projection models of strip lines obtained using the Chebyshev basis are presented as a sum of...     

Correlation functions of complete AltBOC signals with a constant envelope

The structure of the modulating function (MF) of a complete alternative binary offset carrier modulated signal (AltBOC signal) with a constant envelope (eight-component complete AltBOC signal) is considered. Analytical expressions for the correlation functions (CFs) of single elements of the MFs of complete AltBOC signals with a constant envelope are derived at typical values of multiplicity coefficient N _m of meander pulses (N _m = 2 and 3). Plots of the CFs of single elements of the MFs of complete AltBOC signals with a constant envelope are obtained for N _m = 2 and 3. The properties of these CFs are discussed. With the help of the Fourier transform applied to the CFs, the energy spectra (spectral power densities) of single elements of the MFs of complete AltBOC signals with a constant envelope are calculated at N _m = 2 and 3. In illustrating examples, most attention is focused on complete AltBOC signals with a constant envelope at the carrier frequency f _car = 1191.795 MHz for the AltBOC (15, 10) modulation and the repetition rate of the elements of ranging-code pseudorandom sequences f _s = 10f _ref = 10.23 MHz, where the reference (base) frequency is f _ref = 1.023 MHz. These signals are applied in the Galileo European satellite radio navigation system (SRNS) and, as is supposed, in the Chinese BeiDou-2/Compass SRNS.     

The spectral characteristics of navigation alternative binary offset carrier modulated signals (AltBOC signals)

Analytical expressions are obtained for spectral densities and energy spectra of single elements and single periods of modulating functions of alternative binary offset carrier modulated signals (AltBOC signals) for new-generation satellite radio navigation systems (SRNSs) (in particular, the Galileo system). The spectral characteristics are presented and analyzed for an elementary (two-component) AltBOC signal, a complete AltBOC with a time-variable envelope (a four-component complete AltBOC signal), and a complete AltBOC with a constant envelope (an eight-component complete AltBOC signal) in the case when the multiplicity coefficient of meander pulses has an arbitrary value. Plots are depicted, and the properties of energy spectra of single elements of modulating functions of all groups of AltBOC signals are discussed in the cases of the following modulation types: AltBOC(10, 10), AltBOC(15, 10), AltBOC(20, 10), and AltBOC(25, 10).     

Fibrillation in the flow of polyoxymethylene melts

The phenomenon of specific fibrillation from melts of polymer mixtures is considered (using mixtures of polyoxymethylene with copolyamide as an example) when, in contrast to conventional fibre spinning methods, a complex thread consisting of hundreds of thousands of ultrafine fibrils oriented along the extrusion axis is obtained as a result of compressing the melt mixture through a single orifice (or upon extension of one stream of the polymer melt mixture). Here we deal with a radically new process of fibrillation of one of the polymers of the mixture (under the effect of the rheological forces at the capillary inlet) in the matrix of the other, when the number of the filaments in the thread is not determined by the number of the orifices in the die.After solvent extraction (from the solidified extrudate) of the polymer forming the matrix the other component remains as a bundle of fine fibrils less than 1 μm in diameter. The microstructure of mixture extrudates depends on the rheological properties of the melt, the mixture composition, the conditions of mixing and extrusion. Capillary viscometry methods have revealed a drastic difference in the viscoelastic properties of melt mixtures as compared with the separate components.     

Suboptimal Algorithms with Parameter Reassignment for Receiving and Processing BOC Signals in Global Navigation Satellite Systems

Journal of Communications Technology and Electronics - In this paper, we develop suboptimal algorithms for receiving and processing binary offset carrier (BOC) signals for use in global navigation...     

Correlation Functions of Navigational GBOC Signals

The structure of generalized binary offset carrier (GBOC) signals of satellite radio navigation systems, such as global positioning system (GPS) (USA), global navigation satellite system (GLONASS) (Russia), Galileo (European Union), and BeiDou/Compass (China), is examined. Analytical expressions for the correlation functions (CFs) characterizing the single components of the GBOC-signal modulation function (MF) are derived at the typical pulse multiplicity coefficients N_R (N_R = 2 and 4) and different duty cycles. The CFs properties of the components of GBOC-signal MFs are discussed and their graphs are constructed at ρ = 0 (or ρ = 1) corresponding to binary phase-shift keying signals, ρ = 0.1 (or ρ = 0.9), ρ = 0.25 (or ρ = 0.75), ρ = 0.3 (or ρ = 0.7), ρ = 0.45 (or ρ = 0.55), and ρ = 0.5 corresponding to binary offset carrier signals. The energy spectra (power spectral densities) of the single components of GBOC-signal MFs are calculated via the Fourier transform of CFs at the pulse multiplicity coefficients N_R= 2 and 4.     

Navigational GBOC signals and their energy spectra

The modulation functions (MFs) of generalized binary offset carrier (GBOC) signals of promising satellite radio-navigation systems, such as Galileo (European Union), global positioning system (GPS) (USA), and BeiDou/Compass (China), is estimated. Analytical expressions for the spectral density and energy spectrum of the single component of the GBOC-signal MF are obtained at different pulse multiplicity coefficients N _RSO of rectangular subcarrier oscillations and different duty cycles ρ. The spectra characterizing the important particular cases, namely, binary offset carrier and binary phase-shift keying signals are analyzed by means of the derived general formulas for GBOC signals. The Mathcad software package is used to construct graphs and discuss the properties of the energy spectra of single components entering into the GBOC-signal MF for the following types of modulation: GBOC(1, 1, ρ), GBOC(2, 2, ρ), and GBOC(10, 5, ρ).     

Correlation Functions of Navigational cosGBOC Signals as the Inverse Fourier Transform of the Energy Spectra

Journal of Communications Technology and Electronics - Abstract—The modulating functions (MFs) of cosGBOC signals (cosine generalized BOC signals) for new-generation satellite radio...     

Navigational cosGBOC Signals in Promising Satellite Radio-Navigation Systems

The formation and structure of the modulation function (MF) of cosine generalized binary offset carrier (cosGBOC) signals applied in promising satellite radio-navigation systems, such as Galileo (European Union), global positioning system (GPS) (USA), and BeiDou/Compass (China), are discussed. Analytical expressions for the spectral density and energy spectrum characterizing the single components of cosGBOC-signal MFs are derived at the different values of pulse multiplicity coefficients N_R (N_R=2, 4, 6, …) and duty cycles ρ (ρ ∈ [0, 1]). The obtained general formulas for cosGBOC signals are employed to analyze spectra in the important particular cases of cosGBOC and BPSK signals. With the help of the Mathcad software package, the graphs of the energy spectra of the single components entering into the cosGBOC-signal MF are constructed for the following types of modulation: cosGBOC(1, 1, ρ), cosGBOC(2, 2, ρ), and cosGBOC(10, 5, ρ). The properties of the given energy spectra are investigated.