RU2550358C1 - Method of formation of noiseimmune radio signals - Google Patents

Abstract

FIELD: radio-engineering, communication.

SUBSTANCE: preliminary numerical binary pseudorandom sequence is set, in it values of zeros and units are modulated by the preliminary formed functions. Values of zeros and units in the pseudorandom sequence are modulated by pair of straight and inverse, and respectively inverse and straight form of biorthogonal wavelet-function.

EFFECT: increased noiseimmune of radio signals in the communication systems by increasing of the frequency band width.

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Description

The invention relates to radio engineering and can be used to improve the noise immunity of radio signals (PC) in communication systems.

Various methods are known for generating noise-tolerant PCs. (see RF patents No. 2231924, 2205496). In the proposed methods for the formation of noise-like PCs, modulation of the carrier wave by a pseudo-random sequence (PSP) is used.

A known method of forming noise-like radio pulses for transmitting binary information symbols with complex signals [patent RU 2231924 C1 of 06.27.2004]. The claimed invention relates to information transmission systems and includes a minimum code-frequency modulation of the carrier frequency by summing the amplitude and phase modulated oscillations of the quadrature channels, the modulating code sequences of which are obtained by recoding the code sequence of noise-like radio pulses, gating the resulting amount with a video pulse equal to the length of the code sequence, generating the opposite signal by inversion code modulating code sequence One of the quadrature channels.

The disadvantage of this method is the complexity of its implementation, associated with the need to form quadrature channels. In addition, the specified method employs an energetically non-optimal signal-code design, including amplitude-phase modulation, which reduces the effect of increasing noise immunity.

A known method of forming and processing a complex signal in noise-protected radio systems [patent RU 2205496 C1 from 05.27.2003]. The claimed invention relates to the field of radio engineering and includes phase shift keying (FM) of the carrier oscillation of the SRP and the information signal, on the receiving side, the removal of the SRP with subsequent demodulation in the Costas circuit, and a modified band noise is used as the carrier wave.

The disadvantage of this method is that increasing the stealth of the transmitted PC is achieved by reducing the noise immunity of the radio receiver.

The closest analogue in technical essence to the claimed is a method of generating noise-resistant signals [patent RU 2412551 C2, published on 02.20.2011, Bull. No. 5]. In the analogue method, biorthogonal wavelet functions (BVF) are preliminarily formed, then a numerical PSP is modulated, which is modulated by binary FM, while “0” and “1” are modulated by opposite BVF.

The disadvantage of the closest analogue is the relatively low noise immunity associated with an insufficient increase in the bandwidth of the PC modulated by the BCF compared with the bandwidth of the PC modulated by binary FM.

The purpose of the claimed technical solution is to develop a method of forming noise-resistant PCs, which increases the noise immunity of the PC by increasing the bandwidth occupied by their frequencies.

This goal is achieved by the fact that in the known method of generating noise-resistant PCs, based on the formation of a broadband signal, which uses the spread spectrum method of the SRP, which modulate BVF. To modulate the logical elements “1” and “0”, pairs of the direct and inverse wavelet functions are used, and when modulating the logical element “1”, a pair is formed in which the direct wavelet function is the first in the pair, and the inverse second, or in where the inverse wavelet function is the first, and the line is the second. In this case, when modulating the logical element “0”, the reverse arrangement of the direct and inverse wavelet functions is used in pairs, with respect to their arrangement in the case of modulation of the logical element “1”.

Moreover, when forming a pair of BVF, which modulate the logic elements, use the direct and inverse forms of the function of the derivative of the Gaussian function of arbitrary order.

Thanks to the new combination of essential features in the claimed method provides increased noise immunity of the PC due to the use of each “0” and each “1” PSP when modulating a pair of direct and inverse (inverse and direct) forms of BVF.

The claimed method is illustrated by drawings, which show:

FIG. 1 - numeric binary PSP 1010010100, formed using a random number generator;

FIG. 2 - temporary representation of BVF: a - direct form of BVF; b - inverse form of BVF;

FIG. 3 - a temporary representation of the signal “1” Sl (t), built on the basis of a pair: a - direct and inverse form of the BVF, representing the second derivative of the Gaussian function; b - the inverse and direct form of the BVF, representing the second derivative of the Gauss function;

FIG. 4 is a temporary representation of the signal “0” S0 (t), constructed on the basis of a pair: a - inverse and direct waveform form, representing the second derivative of the Gauss function; b - the direct and inverse form of the BVF, representing the second derivative of the Gauss function;

FIG. 5 shows a PC formed by modulating the numerical binary SRP shown in FIG. 1, by signals based on pairs of direct and inverse forms of BVF for “1” and inverse and direct forms of BVF for “0”;

FIG. 6 shows a PC formed by modulating the numerical binary SRP shown in FIG. 1, by signals based on the direct form of the BVF for “1” and the inverse form of the BVF for “0”;

FIG. 7 is a spectrum (module) of a PC formed by modulating the numerical binary SRP shown in FIG. 1, by signals based on pairs of direct and inverse forms of BVF for “1” and inverse and direct forms of BVF for “0”;

FIG. 8 is a spectrum (module) of a PC formed by modulating the numerical binary SRP shown in FIG. 1 by signals based on the direct form of the BVF for “1” and the inverse form of the BVF for “0”.

The implementation of the claimed method is explained as follows.

p. 1. Preliminarily set a numerical binary SRP.

A numerical binary SRP can be set, for example, using a random signal generator. Random signal generators are known and described, for example, in the patent of the Russian Federation No. 2168260 dated 05/27/2001.

As an example in FIG. 1 shows a numerical binary PSP 1010010100 formed using a random number generator.

p. 2. The values "1" and "0" are modulated with preformed pairs of BVF.

In FIG. Figure 2 shows examples of the direct (see Fig. 2a) and inverse (see Fig. 2b) form of the BVF, from which pairs are formed to modulate the logic elements (in the proposed description of the method, the second derivative function of the Gaussian function is used).

In FIG. 3a shows a temporal representation of the signal S1 (t) generated on the basis of a pair of direct and inverse BVF forms representing the second derivative of the Gaussian function, and in FIG. 3b is a temporal representation of the signal S1 (t) generated on the basis of a pair of inverse and direct waveforms of the BVF, representing the second derivative of the Gaussian function.

In FIG. 4a is a temporal representation of the signal S0 (t) generated on the basis of a pair of inverse and direct waveforms of the BVF representing the second derivative of the Gaussian function, and in FIG. 4b is a temporal representation of the signal S0 (t) generated on the basis of a pair of direct and inverse waveforms representing the second derivative of the Gaussian function.

The function of the second derivative of the Gaussian function is known (figure 2). The principle of its formation is described, see [N.M. Asafiev. Wavelet Analysis: Fundamentals of the Theory and Application Examples // Uspekhi Fizicheskikh Nauk, vol. 166, No. 11, 1996, p. 1152] and [patent RU 2412551 C2, published 02.20.2011, Bull. No. 5].

Using a pair of direct and inverse BVF forms, representing the second derivative of the Gaussian function, to modulate the logical elements of the memory bandwidth leads to an increase in the occupied PC frequency band and thereby allows to increase the signal base. In turn, an increase in the signal base leads to an increase in its noise immunity.

The signal base is the product of the effective value of the signal duration and the effective value of the width of its spectrum [see S.I. Baskakov. Radio circuits and signals. M .: "Higher School", 2nd ed., 1988, 446 p.].

item 3. Modulate the values "0" and "1" in the PSP with a pair of direct and inverse forms of the BVF and a pair of inverse and direct forms of the BVF.

Modulation procedures are known [patent RU 2412551 C2 from 02.20.2011]. In FIG. 5 shows PC Z (t) formed by modulating a numerical binary SRP with signals based on BVF pairs. Units modulate the S1 (t) - signal based on a pair of direct and inverse forms of the BVF, and zeros modulate S0 (t) - a signal based on the pair of inverse and direct forms of the BVF.

The purpose of the claimed technical solution is to develop a method of forming noise-resistant PCs, which increases the noise immunity of the PC by increasing the bandwidth occupied by their frequencies.

The specified increase in the occupied bandwidth is obtained with respect to PC V (t) - formed by modulating the digital binary SRP (see Fig. 1) by the BVF signals and its opposite form used to form noise-resistant PCs in the closest analogue [patent RU 2412551 C2 from 02.20.2011] (see Fig. 6).

7 shows Fz (f) - the spectrum modulus of the PC Z (t), formed by modulating a digital binary SRP signals based on pairs of BVF. And in FIG. 8 shows Fv (f), the modulus of the spectrum of a PC formed by modulating the numerical binary SRP shown in FIG. 1 signals based on BVF and its inverse form.

An analysis of the obtained spectra showed an increase of more than 1.5 times the bandwidth of the PC modulated by signals based on BHF pairs relative to the PC modulated by signals based on single BWFs. Or more than 4.9 times compared with the bandwidth of the signal modulated by binary FM. At the same time, the increase in noise immunity of the obtained PC is proportional to the increase in bandwidth see [patent RU 2412551 C2 of 02.20.2011] (the spectral width was measured at a level of 20 dB relative to the maximum value of the spectrum modulus in accordance with the requirements of calculating statistical estimates [Mathematical Encyclopedic Dictionary. M. : Sov. Encyclopedia, 1988. 847 pp .; G. Korn, T. Korn. A Handbook of Mathematics. Translated from English - M.: Nauka, 1977. pp. 638-643]).

Thus, thanks to a new set of essential features, the claimed method provides increased noise immunity of the PC due to the use of a pair of direct and inverse (inverse and direct) forms of BVF when modulating each “0” and each “1” PSP.

Claims (2)

1. A method of generating noise-tolerant radio signals based on the formation of a broadband signal, for which the spread spectrum is used by the pseudorandom sequence method, which is modulated by biorthogonal wavelet functions, characterized in that pairs of direct and inverse are used to modulate the logic elements “1” and “0” wavelet functions, and when modulating the logic element “1”, a pair is formed in which the direct wavelet function is the first in the pair, and the inverse second, or in which the inverse wave the fly-in function is the first, and the line is the second, while in modulation of the logic element “0” the reverse arrangement of the direct and inverse wavelet functions is used in pairs, with respect to their arrangement in the case of modulation of the logic element “1”. 2. The method of generating a noise-tolerant signal according to claim 1, characterized in that when forming a pair of biorthogonal wavelet functions that modulate logic elements, the direct and inverse forms of the function of the derivative of the Gaussian function of arbitrary order are used.

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