RU2446437C1 - Generator of discrete orthogonal signals - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: generator of discrete orthogonal signals comprises a driving oscillator, a unit of Walsh functions generation, an element of single-sided conductivity, a four-digit cyclic shift register, a double-input commutator, a controller inverter and 2ⁿ group multipliers.

EFFECT: increased energetic security of signals generated by a generator.

8 dwg, 3 tbl

Description

The invention relates to the field of telecommunications, in particular to orthogonal signal generators, and can be used to create generator equipment for multichannel communication systems and networks.

A well-known generator of discrete orthogonal signals, containing a clock generator, a Walsh function generation unit, a pulse shaper, a trigger, two keys, an adder, 2 ⁿ multipliers of the first group, 2 ⁿ multipliers of the second group, 2 ⁿ inverters, 2 ^n-1 -bit cyclic shift register and a controlled inverter (patent No. 2022332 for the invention "Discrete orthogonal signal generator" dated 08/08/1991, published in bulletin No. 20 dated 10/30/1994).

However, the signals generated by this generator, described by sequences of the modified Reed-Muller code, have large amplitude-frequency emission spectra, which indicates poor uniformity of the spectral density, leading to low energy secrecy of the generated signals.

- порядковые номера умножителей, подключены к 1-м выходам блока формирования функций Уолша, а выходы умножителей группы являются выходами генератора (патент №2277718 на изобретение «Генератор функций» от 25.11.2004, опубликован в бюллетене №16 от 10.06.2006).The closest in technical essence to the present invention is a function generator containing a master oscillator, a Walsh function generation unit, a one-way conduction element, a two-bit shift register, a two-input switch, a multiplier, 2 ⁿ group multipliers, where 2 ⁿ is the number of outputs of the Walsh function formation unit, moreover, the output of the master oscillator is connected to the clock input of the unit for generating Walsh functions, the output of the master oscillator is connected to the clock input of a two-bit shift register, the second output Lok forming Walsh functions is connected to the input of one-way conduction element, unilateral conduction element output coupled to an information input of two-bit shift register whose output is connected to the control input of the two-input switch having a first information input coupled to (2 ^n-1 -2) th output block Walsh functions generation, the second information input of the two-input switch is connected to the (2 ^n-1 +1) -th output of the Walsh functions formation unit, the output of the two-input switch is connected to the first input an ode of the multiplier, the second input of which is connected to the second output of the Walsh function generation unit, the output of the multiplier is connected to the first inputs of all the group multipliers, the second inputs ix of the group multipliers, where

- serial numbers of the multipliers are connected to the 1st outputs of the Walsh function generation unit, and the outputs of the group multipliers are the outputs of the generator (patent No. 2277718 for the invention “Function Generator” dated November 25, 2004, published in Bulletin No. 16 of June 10, 2006).

However, the signals generated by this generator have large emission of amplitude-frequency spectra, which indicates a poor uniformity of spectral density, leading to low energy secrecy of the generated signals.

The aim of the invention is to increase the energy secrecy of the signals generated by the generator.

- порядковые номера умножителей, подключены к i-м выходам блока формирования функций Уолша, а выходы умножителей группы являются выходами генератора, введены четырехразрядный циклический регистр сдвига и управляемый инвертор, причем 2^n-l выход блока формирования функций Уолша подключен к входу элемента односторонней проводимости, выход элемента односторонней проводимости соединен с тактовым входом четырехразрядного циклического регистра сдвига и управляющим входом двухвходового коммутатора, первый информационный вход двухвходового коммутатора соединен с 2^n-l-м выходом блока формирования функций Уолша, второй информационный вход двухвходового коммутатора соединен с (2^n-1+n)-м выходом блока формирования функций Уолша, выход двухвходового коммутатора подключен к информационному входу управляемого инвертора, управляющий вход которого подключен к выходу старшего разряда четырехразрядного циклического регистра сдвига, выход управляемого инвертора соединен с первыми входами всех умножителей группы.This goal is achieved by the fact that in a known generator containing a master oscillator, a unit for generating Walsh functions, a one-way conduction element, a two-input switch, 2 ⁿ group multipliers, where 2 ⁿ is the number of outputs of the unit for generating Walsh functions, and the output of the master generator is connected to a clock input unit of the formation of Walsh functions, the second inputs ix of the group multipliers, where

- the serial numbers of the multipliers are connected to the ith outputs of the Walsh function generation unit, and the outputs of the group multipliers are the generator outputs, a four-digit cyclic shift register and a controlled inverter are introduced, the 2 ^nl output of the Walsh function formation unit is connected to the input of the one-way conduction element, the output of the element single-sided conductivity is connected to the clock input of a four-bit cyclic shift register and the control input of a two-input switch, the first information input of a two-input a switch coupled to 2 ^nl-th output block formation of Walsh functions, a second data input of the two-input switch is connected to (2 ^n-1 + n) -th unit output forming Walsh functions, two-input switch output is connected to the information input of a controlled inverter, the control input of which is connected to the high-order output of the four-bit cyclic shift register, the output of the controlled inverter is connected to the first inputs of all the group multipliers.

Figure 1 presents a structural diagram of a generator of discrete orthogonal signals, figure 2 is a timing diagram illustrating the process of generating a discrete orthogonal signal A (12, θ) in the proposed generator, figure 3 is a view of discrete orthogonal signals at the outputs of the analog, figure 4 is a view of discrete orthogonal signals at the outputs of the prototype, figure 5 is a view of discrete orthogonal signals at the outputs of the proposed generator, figure 6 is the amplitude-frequency spectra of the signals generated by the analogue, figure 7 is the amplitude-frequency Fig. 8 shows the amplitude-frequency spectra of signals generated by the proposed discrete orthogonal signal generator.

The function generator comprises a master generator 1, a Walsh function generation unit 2, a one-way conduction element 3, a four-digit cyclic shift register 4, a two-input switch 5, a controlled inverter 6, and multipliers of the 7th group.

Function generator works as follows.

Before the start of operation of the generator, a unit is recorded in the fourth category (high order) of the four-bit cyclic shift register 4.

With the beginning of the arrival of pulses from the output of the master oscillator 1 to the clock input of the Walsh function generation unit 2 (Fig. 2, a), Walsh functions are generated at its outputs, arriving at the second inputs of the corresponding group 7 multipliers. The Walsh function Wal (2 ^n-1 -1, θ) generated at the 2 ^n-1- th output of block 2 (for case 2 ⁿ = 16 this will be the function Wal (7, θ)), (Fig.2, b ) is fed to the input of a single-sided conduction element 3, which can be used as a conventional diode, from the output of which only the positive part of the Walsh function Wal (2 ^n-1 -1, θ) comes to the clock input of a four-digit cyclic shift register 4 (Fig. 2, at).

Due to the fact that in the fourth category of the four-bit shift register 4 (which is cyclic, that is, closed in a ring by a feedback circuit, as in the analogue - patent No. 2022332 for the invention "Discrete orthogonal signal generator" dated 08.07.1991, published in Bulletin No. 20 of October 30, 1994) a unit was recorded in the initial state, with the arrival of the first pulse from the output of the 3-sided element 3 to the clock input of a four-bit shift register 4, it moves to the first bit of the shift register 4. With the arrival of the second impulse, the unit shifts to the second discharge, with the arrival of the third impulse - into the third discharge, with the arrival of the fourth impulse - into the fourth discharge.

The output state of the high-order four-bit shift register 4 is shown in figure 2,

A sequence of ones and zeros from the output of the shift register 4 is fed to the control input of the controlled inverter 6.

The sequence of ones and zeros from the output of the element of one-sided conductivity also goes to the control input of the two-input switch 5, arranged in such a way that when it arrives at the control input "1", the information coming to its first input appears at the output of the switch 5, and when it goes to the control input "0" at the output of the switch 5, information arriving at its second input appears.

The Walsh signal Wal (7, θ) is supplied to the first input of the switch 5, and the Walsh signal Wal (11, θ) is supplied to the second input.

Thus, the type of signal at the output of the switch 5 (Fig.2, e) is determined by the type of Walsh signal Wal (7, θ) (Fig.2, b) and the type of Walsh signal Wal (11, θ) (Fig.2, d) , as well as the value of the control signal from the output of element 3 of one-sided conductivity (Fig.2, c).

The signal from the output of the switch 5 (Fig. 2, e) is fed to the information input of the controlled inverter 6, to the control input of which a signal is output from the shift register 4 (Fig. 2, d), as a result of which a signal appears at the output of the controlled inverter 6 (Fig. .2, g) entering the first inputs of all multipliers of group 7.

Since the corresponding Walsh signals Wal (i, θ) are supplied to the second inputs of the group 7 multipliers, discrete orthogonal signals A (i, θ) are formed at their outputs, having a structure different from the structure of the Walsh functions Wal (i, θ), from the signal structure R (i, θ) generated by the analogue, and from the structure of the signals V (i, θ) generated by the prototype.

Figure 2 shows the timing diagrams illustrating the process of generating the output signal A (12, θ) in the proposed generator for the case 2 ⁿ = 16.

The diagrams show the temporary state:

a) the output of the master oscillator 1;

b) the eighth output of block 2 of the formation of Walsh functions, on which the function Wal (7, θ) is generated;

C) the output element 3 of one-sided conductivity;

d) the output of a four-digit cyclic register 4 shift;

d) the twelfth output of the block 2 of the formation of Walsh functions, on which the function Wal (11, θ) is generated;

e) the output of the switch 5;

g) the output of the controlled inverter 6;

h) the thirteenth output of the block 2 of Walsh functions, on which the function Wal (12, θ) is formed;

i) the output of the thirteenth multiplier of group 7, on which a discrete orthogonal signal A (12, θ) is generated.

Figure 3 shows the timing diagrams of the sequences of the Reed-Muller code R (i, θ) formed by the analogue. Figure 4 shows the timing diagrams of discrete orthogonal functions V (i, θ) formed by the prototype. Figure 5 shows the time diagrams of discrete orthogonal functions A (i, θ) generated by the proposed generator.

The orthogonality of the signals generated by the proposed generator can be verified by multiplying any generated discrete orthogonal signals and integrating the result in a time equal to the period of the functions.

As you know, the energy secrecy of signals characterizes the ability to withstand measures aimed at detecting output signals by a reconnaissance receiving device (see Tuzov G.I., Sivov V.A. Interference immunity of radio systems with complex signals / Edited by G. Tuzov - M. : Radio and communications, 1985, p. 9).

To increase energy secrecy, it is necessary to strive to ensure that the output signals generated by the generator used in the communication system have a uniform spectral density (see Tuzov G.I., Sivov V.A. Interference immunity of radio systems with complex signals / Ed. G. I. Tuzova. - M.: Radio and Communications, 1985, p.21, Fig.2.2).

Spectral density is the most important characteristic of a signal and represents the Fourier transform of its temporal representation S (t):

In the general case, G _(f) is a complex quantity and can be written as:

Where

- the real and imaginary parts of the spectral density G _(f) ,

is the modulus and spectral density argument G _(f) .

называют амплитудно-частотным спектром сигнала S(t) и по его виду определяют равномерность спектральной плотности (см. Смирнов Н.И., Горгадзе С.Ф. Проектирование микроэлектронных устройств обработки шумоподобных сигналов. Часть 2. Спектральные свойства ШПС. - М.: Министерство связи СССР, 1989, с.4-5).Usually

called the amplitude-frequency spectrum of the signal S (t) and by its type determine the uniformity of the spectral density (see Smirnov NI, Gorgadze SF Design of microelectronic devices for processing noise-like signals. Part 2. Spectral properties of ShPS. - M .: The Ministry of communications of the USSR, 1989, p. 4-5).

The gain in the energy secrecy of the signals is conveniently determined by the ratio of the values of the largest emissions of the amplitude-frequency spectra of the compared signals:

- значение наибольшего выброса амплитудно-частотного спектра сигнала A(t),

- значение наибольшего выброса амплитудно-частотного спектра сигнала B(t) (см. Смирнов Н.И., Горгадзе С.Ф. Проектирование микроэлектронных устройств обработки шумоподобных сигналов. Часть 2. Спектральные свойства ШПС. - М.: Министерство связи СССР, 1989, с.13).Where

- the value of the largest outlier of the amplitude-frequency spectrum of the signal A (t),

- the value of the largest emission of the amplitude-frequency spectrum of the signal B (t) (see Smirnov NI, Gorgadze SF Design of microelectronic devices for processing noise-like signals. Part 2. Spectral properties of SHPS. - M.: Ministry of Communications of the USSR, 1989 , p.13).

Using an electronic computer, signals A (i, θ) were synthesized, which have significant energy secrecy in comparison with Walsh signals Wal (i, θ), signals R (i, θ), described by sequences of the modified Reed-Muller code generated by an analog, and discrete orthogonal signals V (i, θ) generated by the prototype, with equal durations and energies.

For the output signals generated by the analog, prototype and the proposed generator, the largest emissions of the amplitude-frequency spectra were calculated in accordance with the relation (5).

The calculation results for option 2 ⁿ = 16 are presented in tables 1, 2 and 3.

Table 1
The largest outliers of the amplitude-frequency spectra of the signals R (i, θ) described by sequences of the modified Reed-Muller code generated by the analog Signal number, K 0 one 2 3 four 5 6 7

The largest outlier value

0.38 0.35 0.32 0.41 0.32 0.50 0.45 0.48 Signal number, K 8 9 10 eleven 12 13 fourteen fifteen The largest outlier value

0.46 0.38 0.44 0.46 0.43 0.48 0.46 0.42

table 2
The largest emissions of the amplitude-frequency spectra of discrete orthogonal signals V (i, θ) generated by the prototype Signal number, K 0 one 2 3 four 5 6 7

The largest outlier value

0.31 0.35 0.38 0.36 0.50 0.44 0.39 0.42 Signal number, K 8 9 10 eleven 12 13 fourteen fifteen The largest outlier value

0.33 0.5 0.41 0.33 0.39 0.39 0.39 0.36

Table 3
The largest emissions of the amplitude-frequency spectra of discrete orthogonal signals A (i, θ) generated by the proposed generator Signal number, K 0 one 2 3 four 5 6 7

The largest outlier value

0.32 0.31 0.32 0.33 0.32 0.31 0.33 0.31 Signal number, K 8 9 10 eleven 12 13 fourteen fifteen The largest outlier value

0.33 0.34 0.32 0.34 0.32 0.34 0.32 0.32

For clarity, Fig. 6 shows graphs of the amplitude-frequency spectra of the output signals R (0, θ), R (3, θ), R (5, θ), R (9, θ), R (13, θ) formed analogue. Figure 7 presents graphs of the amplitude-frequency spectra of the output signals V (0, θ), V (3, θ), V (9, θ), V (12, θ), V (15, θ) formed by the prototype. On Fig presents graphs of the amplitude-frequency spectra of the output signals A (6, θ), A (7, θ), A (11, θ), A (13, θ), A (14, θ) formed by the proposed generator . Moreover, ω = 2πf.

From tables 1, 2 and 3, as well as FIGS. 6, 7 and 8, it can be seen that the signals generated by the proposed generator have better spectral density uniformity than the output signals generated by the analogue and prototype, which provides increased energy stealth.

, наибольший выброс амплитудно-частотных спектров сигналов, формируемых прототипом

, а наибольший выброс амплитудно-частотных спектров сигналов, формируемых предлагаемым генератором

, то в соответствии с соотношением (7) выигрыш в энергетической скрытности составляет:Since the largest surge in the amplitude-frequency spectra of signals generated by an analog

, the largest surge of amplitude-frequency spectra of signals generated by the prototype

, and the largest surge in the amplitude-frequency spectra of the signals generated by the proposed generator

, then in accordance with relation (7), the gain in energy stealth is:

As calculations show, for 2 ⁿ ≥16, the gain in energy stealth is at least 1.47.

Using the invention allows you to create discrete orthogonal signal generators, providing a significant increase in the energy secrecy of the generated signals.

Claims (1)

A discrete orthogonal signal generator comprising a master oscillator, a Walsh function generation unit, a one-way conduction element, a two-input switch, 2 ⁿ group multipliers, where 2 ⁿ is the number of outputs of the Walsh function formation unit, the output of the master generator being connected to the clock input of the Walsh function generation unit, the second inputs ix of the group multipliers, where

- the serial numbers of the multipliers are connected to the ith outputs of the Walsh function generation unit, and the outputs of the group multipliers are the outputs of the generator, characterized in that, in order to increase the energy secrecy of the signals generated by the generator, a four-digit cyclic shift register and a controlled inverter are introduced into it, 2 and ^n-1 output unit for generating the Walsh functions is connected to the input-sided conduction element, unilateral conduction element output coupled to a clock input of four bit cyclical a shift register and a control input of the two-input switch, the first information input of the two-input switch is connected to the 2 ^n-1 -th unit output forming Walsh functions, a second data input of the two-input switch is connected to (2 ^n-1 + n) -th unit output forming Walsh functions , the output of the two-input switch is connected to the information input of the controlled inverter, the control input of which is connected to the high-order output of the four-digit cyclic shift register, the output of the controlled inverter is connected to The first inputs of all multipliers of the group.

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