RU2379826C2 - Method of generating composite quasioptimal signals and device for realising said method - Google Patents

Abstract

FIELD: physics; radio.

SUBSTANCE: invention relates to radio engineering and can be used in space command radio links. The technical outcome of the invention is increased noise immunity of signals, simplification and increased reliability of error-correction decoding. The method of generating composite quasioptimal signals involves converting binary information into a series of n steps distinguished by generated signals. Information is propagated in each step for generating pseudonoise codes of the composite quasioptimal signal by synchronously generated clock pulses. The device for generating composite quasioptimal signals includes a series of n steps, each of which is distinguished by generated signals. Each step includes data inputs "1" and "0", an i^th pseudonoise code generator, first, second, third and fourth AND components, as well as first and second OR components connected to each other.

EFFECT: use of composite pseudonoise signals with high noise immunity to transmit information in space radio links, with optimal processing at the receiving side using a cascade of discrete matched filters.

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Description

The proposed invention is intended for use in radio engineering, namely, devices for the formation of complex composite quasi-optimal signals that allow optimal reception to matched filters. Preferred is the use of the proposed invention in space command radio links.

At present, noise-like signals of various types are known (Barker codes, M-sequences, Gold codes, additional codes, etc.) with good autocorrelation and cross-correlation properties, widely described in the technical literature (L.E. Varakin. Theory of complex signals. M .: Soviet Radio, 1970; Alekseev A.I. et al. Theory and Application of Pseudorandom Signals (Moscow: Nauka, 1969). Such signals are widely used in space command and measuring systems with optimal correlation reception, requiring significant time spent on the mandatory stage of the signal entering synchronism.

Also widely known are methods for generating noise-like signals using multi-cycle linear filters (V.D. Kolesnik, E.T. Mironchikov. Decoding of cyclic codes. M: Communication, 1968, Fig. 3.3, p. 64; A.I. Alekseev and Theory and Application of Pseudorandom Signals, Moscow: Nauka, 1969, § 4.3; W. Peterson, E. Weldon, Codes for Correcting Errors, Moscow: Mir, 1976, chapter 7).

When using noise-like signals generated by known methods in space command radio links processed using matched filters and taking into account working conditions at high radial velocities, developers encounter great difficulties associated with a mismatch between the received signal and the impulse response of the matched filter. To reduce losses, it is necessary to expand the uncertainty function along the frequency axis, which leads to a reduction in the duration of the pseudo-noise signal and, as a result, to a reduction in the value of its base. Even with a very accurate prediction of the orbit of the spacecraft, the minimization of hardware during signal addition using matched filters as compared to pseudorandom signals leads to the expediency of forming complex composite quasi-optimal signals. (For identical values of the code distance of the optimal and quasi-optimal signals, assuming that

where N _i ≅B _i and

hardware costs can be represented as

where i is the number of steps of the proposed complex quasi-optimal signal, k is the coefficient of complexity of hardware implementation).

The technical result expected from the use of the proposed technical solution is to create a noise-tolerant signal that allows optimal processing using matched filters, for which it is proposed to form a complex composite quasi-optimal signal, built on the principle of "one in one". Also, the proposed technical solution will ensure the selection of the ACF in a discrete matched filter not only at the stage of processing the signal stage of a complex signal, but also at the stage of processing subsequent stages, thereby increasing simplicity of execution, and therefore, reliability with respect to the usual decoding operation with error correction. In general, the technical solution will ensure the use of complex quasi-optimal signals in space command radio links.

The expected technical result is achieved by the fact that the proposed method and device for the formation of complex quasi-optimal signals.

The method for generating complex quasi-optimal signals involves converting the input binary information in the NRZ-L format in n steps in series that differ in the quality of the generated signal. In each of the stages, the first and second combinations of the pseudo-noise code are generated on channel “0” and on channel “1”. The signals are generated at a rate equal to the period of the i-th stage pseudo-noise sequence generator. Information is promoted at each stage of the formation of realizations of pseudo-noise codes of a complex quasi-optimal signal by synchronously generated clock pulses. The values of the logical “1” and “0” of the input information of the i-th stage of the pseudo-noise code open for the duration of its operation the passage of units and zeros, respectively, of the first and second code combinations of the pseudo-noise code of the i-th stage. The values of the logical “1” and “0” of the output information of the i-th stage of the pseudo-noise code open for the duration of its action the passage of units and zeros, respectively, of the first and second code combinations of the pseudo-noise code of the next (i + 1) or last (signal) stage.

The device for generating complex quasi-optimal signals includes n stages in series, each of which differs in the quality of the generated signal, generates the first and second combinations of i pseudo-noise code, and includes information inputs “1” and “0”, i-th generator of pseudo-noise code, first, second , the third and fourth scheme “AND”, as well as the first and second scheme “OR”. Information input “1” is the first input for the first and second circuits “And”. Information input “0” is the first input for the third and fourth circuits “And”. At the input of the pseudo-noise code generator, clock pulses with frequencies selected for each stage are supplied. The direct and inverse outputs of the first combination of the pseudo-noise code are connected to the second input, respectively, of the first and second "And" circuits. The direct and inverse output of the second combination of the pseudo-noise code are connected to the second input, respectively, of the third and fourth "And" circuits. The outputs of the first and fourth “AND” circuits are connected, respectively, with the first and second inputs of the first “OR” circuit. The outputs of the second and third "AND" circuits are connected, respectively, with the first and second inputs of the second "OR" circuit. The outputs of the first and second circuits "OR" are, respectively, information outputs "1" and "0". In the presence of subsequent stages, the outputs of the first and second OR circuits are also connected, respectively, to the information inputs 1 and 0.

The proposed technical solution is illustrated by drawings:

Figure 1 is a structural diagram of a device for generating complex quasi-optimal signals;

Figure 2 is a timing diagram of the formation of a quasi-optimal pseudo-noise code;

Figure 3 - examples of data formats.

The block diagram of the device for generating complex quasi-optimal signals is shown in Fig. 1, the process of generating a complex quasi-optimal signal is illustrated by the time diagram shown in Fig. 2 and illustrating the type of code combinations at the input of the signal-forming device, as well as at the output of each stage. An M-sequence generator, a Barker code generator, a Gold code generator, and the like can be used as a generator of a code combination of a pseudo-noise code in each stage of the formation of quasi-optimal signals, it is advisable to use those with more uniform spectral characteristics when shifting along the frequency axis M- sequence. To build a device for generating complex signals, any number of steps can be used, each of which can generate pseudo-noise signals using various classes of codes that have optimal autocorrelation and cross-correlation functions.

The first stage of the device for generating complex quasi-optimal signals includes information inputs “1” and “0”. In the PN code generator inlet of the first stage 1 supplies a clock pulse T ₁ and generates the first and second combinations of PN code, and they direct Q _I, Q _II and inverse Q _'I, Q' _II output of the generator 1 are fed to the circuit "I" 2, 3, 4, 5 of the first stage. Information input "1" is connected to the first inputs of the first 2 and second 3 circuits "And". Information input "0" is connected to the first inputs of the third 4 and fourth 5 circuits "And". The direct output of the first combination of the pseudo noise code Q _{I of} generator 1 is connected to the second input of the first AND circuit 2. The inverse output of the first combination of the pseudo noise code Q _{I of} generator 1 is connected to the second input of the second circuit AND 3. Direct output of the second combination of pseudo noise code Q ′ _{II of} generator 1 is connected to the second input of the third AND circuit. The inverse output of the second combination of the pseudo-noise code Q ′ _{II of the} generator 1 is connected to the second input of the fourth “And” circuit. The outputs of the first 2 and fourth 5 circuits “And” are connected, respectively, with the first and second inputs of the first circuit “OR” 6. The outputs of the third 4 and second 3 circuits “And” are connected, respectively, with the first and second inputs of the second circuit “OR” 7. The output of the first “OR" circuit 6 is the output "1" of the first stage of formation of a complex quasi-optimal signal and the input of the second stage of signal formation. The output of the second OR circuit 7 is the output “0” of the first stage of formation of a complex quasi-optimal signal and the input of the second stage of signal formation.

The second and subsequent stages of the device for generating complex quasi-optimal signals are constructed according to a similar scheme. Information inputs "1" and "0" are connected to the corresponding information outputs "1" and "0" of the previous stages. To the input of the generators 8, 15 of the pseudo-noise code of the second and subsequent stages, clock pulses T ₂ , T _n are supplied and the first and second combinations of the pseudo-noise code are generated. The combinations of the pseudo-noise code with direct Q _I , Q _II and inverse Q ′ _I , Q ′ _II outputs of the generators 8, 15 are fed to the “And” circuits of 9, 10, 11, 12 of the second and 16, 17, 18, 19 of the subsequent stages. Information inputs "1" of the second and subsequent stages are connected to the first inputs of the first 9, 16 and second 10, 17 circuits "And". Information inputs "0" of the second and subsequent stages are connected to the first inputs of the third 11, 18 and fourth 12, 19 of the "And" circuits. The direct outputs of the first combination of the pseudo-noise code Q _{I of the} generators 8, 15 are connected to the second inputs of the first “I” circuits 9, 16. The inverse outputs of the first combination of the pseudo-noise code Q _{I of the} generators 8, 15 are connected to the second inputs of the second “I” circuits 10, 17 The direct outputs of the second combination of the pseudo-noise code Q _{II of} generators 8, 15 of the second combination are connected to the second inputs of the third AND circuits 11, 18. The inverse outputs of the second combination of the pseudo-noise code Q _{II of} generators 8, 15 are connected to the second inputs of the quarters of AND circuits 12, 19. In the second and subsequent studies The outputs of the first 9, 16 and fourth 12, 19 “I” circuits are connected, respectively, with the first and second inputs of the first “OR” circuits 13, 20. Also, in the second and subsequent stages, the outputs of the third 11, 18 and second 10, 17 “I” circuits are connected, respectively, with the first and second inputs of the second “OR” circuits 14, 21. The outputs of the first “OR” circuits 13, 20 are outputs “1” for the second and subsequent stages of the formation of a complex quasi-optimal signal. The outputs of the second OR circuits 14, 21 are the outputs “0” for the second and subsequent stages of formation of a complex quasi-optimal signal and the input of the second stage of signal formation. In the presence of subsequent stages, the outputs "1" and "0" are also the inputs of the stages of signal formation. For the last stage, the outputs "1" and "0" are the outputs of the signal conditioning device.

When the device for generating complex quasi-optimal signals is operating, block binary information in the NRZ-L format is received at the input of the device, which is further converted in successive n steps that differ in signal quality. In the first, second and subsequent steps of the device, the first and second combinations of the pseudo-noise code are generated via channels “0” and “1”. The signals are generated at a rate equal to the period set for the pseudo-noise sequence generators 1, 8, 15 of the first, second and subsequent stages. Promotion of information in each stage of the formation of realizations of pseudo-noise codes of a complex quasi-optimal signal is carried out by synchronously generated clock pulses T ₁ , T ₂ , T _n . In each of the device steps “1” and “0”, the input information for the duration of the step opens the passage of units and zeros, respectively, of the first and second code combinations of the pseudo-noise code of the step. In this case, “1” and “0” of the output information of each stage opens for the duration of its operation the passage of units and zeros, respectively, of the first and second code combinations of the pseudo-noise code of the next or last (signal) stage.

Thus, the proposed technical solution will ensure the formation of a noise-tolerant quasi-optimal signal that allows optimal processing using matched filters, and will also ensure the selection of an ACF in a discrete matched filter both at the stage of processing the signal stage of a complex signal and at the stage of decoding subsequent stages. In a preferred implementation of the proposed technical solution, the proposed technical solution will ensure the use of complex pseudo-noise signals for transmitting information in space radio links, including those with delayed OS and without OS, increasing the noise immunity of the system as a whole.

Claims (2)

1. A method of generating complex quasi-optimal signals, according to which the binary information code entering the input in the NRZ-L format is converted into n successively arranged steps differing in the generated signals, in each of which the first and second channels are generated by the “0” and the “1” channels the second combination of the pseudo-noise code, while the signals are generated at a rate equal to the period of the generator of the pseudo-noise sequence of the i-th stage, the promotion of information from the i-th to the (i + 1) stage of the formation of pseudo-noise codes of complex quasi-optical of the input signal is carried out by synchronously generated clock pulses, with “1” and “0” or “0” and “1” of the input information, respectively, on the channel “1” and on the channel “0” of the i-th stage, the passage “ 1 "or" 0 "to the outputs of channel" 1 "and, respectively," 0 "or" 1 "to the outputs of channel" 0 "of the first or second code combination of the pseudo-noise code, pseudo-noise sequence generator of the i-th stage. 2. A device for generating complex quasi-optimal signals, including n stages in series, each of which generates the first and second combinations of a pseudo-noise code, and includes information inputs “1” and “0”, the first pseudo-noise code generator, the first, second, third, and the fourth circuit "And", as well as the first and second circuit "OR", while the information input "1" is the first input for the first and second circuits "And", and the information input "0" is the first input for the third and fourth circuits "And", and the input pseudo generator of the noise code, clock pulses with the frequencies selected for each stage are applied, the direct and inverse outputs of the first combination of the pseudo-noise code are connected to the second input, respectively, of the first and second “I” circuits, and the direct and inverse outputs of the second combination of the pseudo-noise code are connected to the second input, respectively, of the third and the fourth circuit “AND”, the outputs of the first and fourth circuits “AND” are connected respectively to the first and second inputs of the first circuit “OR”, the outputs of the second and third circuits “AND” are connected respectively to the first and second inputs In the case of the second OR circuit, the outputs of the first and second OR circuits are information outputs 1 and 0, respectively, and, if there are subsequent steps, are also connected respectively to information inputs 1 and 0.

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