RU2047942C1 - Adaptive device for separating nonorthogonal binary phase keyed signals - Google Patents

Abstract

FIELD: radio engineering. SUBSTANCE: adaptive device has three multiplies 1, 2, 3, two reference-oscillation shaping units 4, 5, three low-frequency filters 6, 7, 8, two amplifier-limiters 9, 10, two subtracting units 11, 12, two computing units 13, 14, amplitude detector 15, comparator 16, switch 17. EFFECT: improved design. 6 dwg, 1 tbl

Description

 The invention relates to radio engineering and can be used in radio communications and in other industries where it is necessary to provide noise-stable reception of interfering binary phase-shift (FM) signals characterized by intermittent radiation, i.e. conflicting.

 Known devices designed to increase the noise immunity of receiving signals of amplitude and (or) phase manipulation. The disadvantage of these devices is that their use does not allow for noise-tolerant reception of two interfering FM signals characterized by intermittent radiation.

 It is also known a device designed to protect when receiving amplitude-manipulated signals from powerful pulsed and narrowband interference. However, this device also does not allow for the simultaneous reception of two phase-shift keying signals characterized by intermittent radiation.

 The closest in technical essence to the proposed device is an adaptive device for separating non-orthogonal signals of binary phase manipulation, which contains the first, second and third multipliers, the first and second blocks for the formation of reference oscillations; first, second and third low-pass filters, first and second limiting amplifiers, first and second subtracting blocks, first and second decision blocks.

 The device is based on the compensation principle.

The disadvantage of the prototype is the following. An adaptive device for separating non-orthogonal signals of binary phase shift keying allows you to effectively separate the interfering FM signals, significantly increasing the noise immunity of the reception. However, when one of the received FM signals temporarily disappears, the probability of an error when receiving the remaining signal significantly (by several orders of magnitude) increases. The latter is explained by the fact that the compensating voltage U _k1 (U _k2 ) in the device is formed continuously under the assumption of the constant presence of both binary FM signals. This leads to errors in the reception of one signal (for example, the first) with the temporary loss of another (for example, the second).

 The aim of the invention is to increase the noise immunity of the reception of two interfering signals of binary phase manipulation with the intermittent nature of their radiation.

 This goal is achieved by the fact that in an adaptive device for separating non-orthogonal signals of binary phase manipulation, containing the first 1, second 2 and third 3 multipliers, the first 4 and second 5 blocks of the formation of reference oscillations, the first 6, second 7 and third 8 low-pass filters, the first 9 and second 10 limiting amplifiers, the first 11 and second 12 subtracting blocks, the first 13 and second 14 decision blocks, the first inputs of the first and second multipliers combined with the inputs of the first and second blocks for the formation of reference oscillations and are I by the input of the deconflicter, the outputs of the first and second blocks of the formation of reference oscillations are connected to the second inputs of the first and second multipliers, respectively, and also connected to the first and second inputs of the third multiplier, respectively, the outputs of the first and second multipliers are connected to the inputs of the first and second low-pass filters, respectively, the output of the third multiplier is connected to the input of the third low-pass filter, the output of which is simultaneously connected to the second inputs of the first and second amplifiers-limit fels, respectively, the outputs of the first and second low-pass filters are connected to the first inputs of the first and second amplifier-limiters, respectively, as well as the first inputs of the first and second subtracting units, respectively, the second input of the second subtracting unit is connected to the input of the first amplifier-limiter, the outputs of the first and the second subtracting blocks are connected to the inputs of the first and second decision devices, respectively, the outputs of the decision devices are also the outputs of the deconflicter, an amplitude tector 15, comparator 16, key 17. Moreover, the input of the amplitude detector is connected to the output of the first low-pass filter, and the output is from the first input of the comparator, the output of the comparator is connected to the second input of the key and the second input of the second deciding device, the first input of the key is connected to the output of the second amplifier -limiter, and the output with the second input of the first subtracting block.

Figure 1 presents the structural diagram of the proposed device separation of signals of binary phase manipulation with the intermittent nature of their radiation; figure 2 the amplitude characteristics of the amplifier-limiter for different values of the control voltage 2R ₁₂ proportional to the coefficient of mutual difference of the shared signals; figure 3 the amplitude characteristic of the amplifier-limiter for one fixed value 2R ₁₂ .

 The device operates as follows.

 The device is based on the principle of detecting a binary FM signal, characterized by an intermittent nature of the radiation, with its subsequent compensation at the output only upon detection.

 The proposed device in the current clock interval generates not only a compensating voltage, but also makes a decision on the presence or absence of an FM signal. At the end of each clock interval, a decision is made on the need for compensation and compensation is made for the interfering influence of the FM signal.

и r₂

их дискретные информационные параметры;
Q(r) функция дискретного информационного параметра, введенная для описания закона манипуляции
Q(r)

-

Математическая модель передаточной функции фильтров нижних частот 6,7,8 описывается интегратором со сбросом в моменты времени t_k, k= 1,2,3, и с коэффициентом передачи, равным 2/N_o, где N_o односторонняя спектральная плотность мощности белого шума h(t). Тогда на выходе первого фильтра нижних частот 6 в конце К-го интервала будет присутствовать напряжение, пропорциональное величине
b₁ Q(r₁)h² ₁ + Q(r₂) 2R₁₂ + n₁ (2)
Соответственно на выходе второго фильтра нижних частот 7 напряжение, пропорциональное величине
b₂ Q(r₂)h² ₂ + Q(r₁)2R₁₂ + n₂ (3)
В выражениях (2) и (3) приняты обозначения
h $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$

S $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$ (t)dt h $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$

S $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$ (t)dt (4)
где h² ₁ и h² ₂ отношения энергий сигналов S₁(t) и S₂(t) на длительности тактового интервала Т t_k-t_k-1 к спектральной плотности мощности N_oбелого гауссовского шума n(t);
2R₁₂=

S₁(t) S₂(t)dt

(5)
отношение взаимной энергии разделяемых сигналов на длительности тактового интервала Tt₁- t_k-1 к спектральной плотности мощности N_oбелого гауссовского шума n(t);
ρ нормированный к единице коэффициент взаимного различия между сигналами;
n₁=

n(t) S₁(t)dt n₂=

n(t) S₂(t)dt (6)
шумовые случайные составляющие на выходах первого и второго фильтров нижних частот.Let on the current clock interval of duration T (T t _k -t _k-1 , where k 1,2,3. The number of the current clock interval), at the output of the device there is an additive mixture of two binary FM signals Q (r ₁ ) xx S ₁ (t) and Q (r ₂ ) ^. S ₂ (t) and white Gaussian noise n (t)
y (t) Q (r ₁ ) ^. S ₁ (t) + Q (r ₂ ) ^. S ₂ (t) + n (t), (1a) where S ₁ (t) and S ₂ (t) are the carrier oscillations of the first and second digital signals, respectively;
r ₁

and r ₂

their discrete information parameters;
Q (r) is a function of a discrete information parameter introduced to describe the law of manipulation
Q (r)

-

The mathematical model of the transfer function of low-pass filters 6,7,8 is described by an integrator with a reset at time t _k , k = 1,2,3, and with a transmission coefficient equal to 2 / N _o , where N _{o is the} one-sided spectral power density of white noise h (t). Then at the output of the first low-pass filter 6 at the end of the Kth interval there will be a voltage proportional to
b ₁ Q (r ₁ ) h ² ₁ + Q (r ₂ ) 2R ₁₂ + n ₁ (2)
Accordingly, at the output of the second low-pass filter 7, a voltage proportional to
b ₂ Q (r ₂ ) h ² ₂ + Q (r ₁ ) 2R ₁₂ + n ₂ (3)
In the expressions (2) and (3), the notation
h $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$

S $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$ (t) dt h $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$

S $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$ (t) dt (4)
where h ² ₁ and h ² _{2 are the} ratios of the signal energies S ₁ (t) and S ₂ (t) over the duration of the clock interval T t _k -t _k-1 to the power spectral density N _{o of} white Gaussian noise n (t);
2R ₁₂ =

S ₁ (t) S ₂ (t) dt

(5)
the ratio of the mutual energy of the shared signals over the duration of the clock interval Tt ₁ - t _k-1 to the spectral power density N _{o of the} white Gaussian noise n (t);
ρ normalized to unity coefficient of mutual difference between the signals;
n ₁ =

n (t) S ₁ (t) dt n ₂ =

n (t) S ₂ (t) dt (6)
noise random components at the outputs of the first and second low-pass filters.

Regardless of the correlators performed on the first 1 and second 2 multipliers and the first 6 and second 7 low-pass filters, the value 2R ₁₂ is also formed at the output of the third low-pass filter 8, assuming that its transmission coefficient is 2 / N _o (similar to the coefficient transmission of the first 6 and second 7 low-pass filters).

и r₂

. Все возможные комбинации величин на входах и выходах блоков устройства (фиг.4) представлены в таблице. Здесь приняты следующие обозначения: y(t) аддитивная смесь двух двоичных ФМ-сигналов Q(r₁)S₁(t) и Q(r₂)S₂(t) и белого гауссовского шума h(t), столбец 3; b₁ и b₂ величины напряжения на выходах первого 6 и второго 7 фильтров нижних частот, столбцы 4 и 5 соответственно; U_k1 и U_k2 величины компенсирующего напряжения на выходах второго 10 и первого 9 усилителей ограничителей, столбцы 6 и 7 соответственно; B*₁ и B*₂ величины напряжения на входах первого 13 и второго 14 решающих блоков в устройстве прототипа, столбцы 8 и 9 соответственно; r*₁ и r*₂ решения, принимаемые устройством-прототипом на основании анализа первым 13 и вторым 14 решающими блоками величин напряжений B*₁ и B*₂ на их входах, представлены в столбцах 10 и 11 соответственно; величина напряжения с выхода амплитудного детектора 15 в сравнении с напряжением R₁₂ представлена в столбце 12; решение компаратора 16 Х по результатам сравнения U_ад| и R₁₂ представлено в столбце 13; состояние ключа 17 (3 "замкнут" и Р "разомкнут") представлено в столбце 14, В₁** и В₂** величины напряжения на входах первого 13 и второго 14 решающих блоков в предлагаемом устройстве представлены в столбцах 15 и 16 соответственно; r₁** и r₂** решения о дискретных параметрах r₁

и r₂

, передаваемых сигналов S₁(t) и S₂(t), принимаемые предлагаемым устройством на основании анализа первым 13 и вторым 14 решающими блоками величин напряжений В₁** и B₂** на их входах представлены в столбцах 17 и 18 соответственно.At the outputs of the first 11 and second 12 subtracting blocks, at the outputs and inputs of the first 13 and second 14 decision blocks there will be voltage values determined by the specific possible combinations of transmitted discrete messages r ₁

and r ₂

. All possible combinations of values at the inputs and outputs of the device blocks (Fig. 4) are presented in the table. The following notation is used here: y (t) is an additive mixture of two binary FM signals Q (r ₁ ) S ₁ (t) and Q (r ₂ ) S ₂ (t) and white Gaussian noise h (t), column 3; b ₁ and b _{2 the} voltage values at the outputs of the first 6 and second 7 low-pass filters, columns 4 and 5, respectively; U _k1 and U _k2 values of the compensating voltage at the outputs of the second 10 and first 9 amplifiers limiters, columns 6 and 7, respectively; B * ₁ and B * ₂ are the voltage values at the inputs of the first 13 and second 14 decision blocks in the prototype device, columns 8 and 9, respectively; r * ₁ and r * ₂ decisions made by the prototype device on the basis of analysis by the first 13 and second 14 crucial blocks of the voltage values B * ₁ and B * ₂ at their inputs are presented in columns 10 and 11, respectively; the voltage value from the output of the amplitude detector 15 in comparison with the voltage R ₁₂ is presented in column 12; the decision of the comparator 16 X according to the results of comparison U _hell | and R ₁₂ is presented in column 13; the state of the key 17 (3 “closed” and P “open”) is presented in column 14, B ₁ ** and B ₂ ** the voltage values at the inputs of the first 13 and second 14 decision blocks in the proposed device are presented in columns 15 and 16, respectively; r ₁ ** and r ₂ ** decisions on discrete parameters r ₁

and r ₂

of the transmitted signals S ₁ (t) and S ₂ (t), received by the proposed device based on the analysis of the first 13 and second 14 crucial blocks of the voltage values B ₁ ** and B ₂ ** at their inputs are presented in columns 17 and 18, respectively.

Consider the characteristic case when one of the signals, for example, S ₂ (t), will be absent in a given clock interval T t _k -t _k-1 . In the proposed device, it is assumed that the instantaneous power of the second signal exceeds the instantaneous power of the first, and the signals S ₁ (t) and S ₂ (t) are close in structure (ρ ≃ 1) so that
h ² ₂ > 4R ₁₂ and 2R ₁₂ > 2h ² ₁ (7)
In the case under consideration, a signal defined by the expression will be observed at the input of the device (see the 3rd row of Table 1):
y (t) S ₁ (t) + n (t), (8) which is equivalent to transmitting discrete messages r ₁ and r ₂ with values r ₁ = 0, r ₂ 2. Then, at the output of the first low-pass filter 6, based on the expression (2) voltage b ₁ h ² ₁ + + n ₁ will be generated, and at the output of the second low-pass filter 7, according to expression (3) b ₂ 2R ₁₂ + n ₂ .

i

(9)
Из условия (7) в данном случае на выходах усилителей-ограничителей будут соответственно величины напряжения, определяемые выражениями
U_k1 2R₁₂ + n₂; U_k2 h² ₁ + n₁
На выходе первого решающего блока 13 напряжение будет определяться выражением
B₁ b₁ U_k1 h² ₁ 2R₁₂ + n₁ n₂ < 0,
(10а) если ключ 17 будет замкнут, или выражением
B₁ b₁ h² ₁ + n₁ > 0, (10б) если ключ 17 будет разомкнут.From the consideration of the amplitude characteristics of the amplifier-limiters 9, 10 follows the expression for determining the compensation voltage
U _ki =

i

(nine)
From condition (7) in this case, the outputs of the amplifier-limiters will be respectively the voltage values determined by the expressions
U _k1 2R ₁₂ + n ₂ ; U _k2 h ² ₁ + n ₁
The output of the first decision block 13, the voltage will be determined by the expression
B ₁ b ₁ U _k1 h ² ₁ 2R ₁₂ + n ₁ n ₂ <0,
(10a) if the key 17 is closed, or by the expression
B ₁ b ₁ h ² ₁ + n ₁ > 0, (10b) if key 17 is open.

When determining the signs in inequalities (10a) and (10b), it is assumed that the random noise components n ₁ , n ₂ at the outputs of the low-pass filters 6, 7 are small enough to be neglected with great confidence, in addition, condition (7) is taken into account.

Амплитудная характеристика первого решающего устройства 13 представлена на фиг. 4. Иными словами, первое решающее устройство имеет амплитудную характеристику усилителя-ограничителя с зоной нечувствительности.The operation algorithm of the first decision block 13 is described by the relation
r $\genfrac{}{}{0ex}{}{\text{*}}{\text{1}}$

The amplitude response of the first solver 13 is shown in FIG. 4. In other words, the first solver has an amplitude response of the limiter amplifier with a deadband.

If the key 17 in the case under consideration is closed, i.e. Since the device works as a prototype, the decision r * ₁ made by the device will be erroneous (see columns 1 and 10 of the table).

However, in the proposed device for the case under consideration, the voltage from the output of the amplitude detector 15 U _hell turns out to be less than the voltage R ₁₂ at the second input of the comparator 16. The comparator 16 works according to the rule: the logic level is set at its output if the voltage R _{12 is} less than the voltage at the output of the amplitude detector , and logical zero if the voltage R ₁₂ is large. In this case, the output of the comparator is set to "0". The output signal of the comparator is the control signal for the key 17. When the signal “0” arrives at the control input of the key 17, it opens, and the solution r ₁ ** is correct.

The second solving device 14 has a second priority input connected to the output of the comparator 16. When a logical “0” signal is received at this input, the decision device 14 makes a decision r ₂ ** 2, while in the prototype device in this case an erroneous decision is made (see . table). The logical part of the circuit of the resolver 14 is presented in figure 5. When the signal "1" is present at the priority input, the resolver 14 operates according to the prototype solver algorithm.

Consider another characteristic case when the signal of lower power S ₁ (t) will be absent. In the proposed device, as in the prototype, the absence of a "weak" signal does not affect the reception of a "strong" signal. However, in the prototype device, in this case, an unstable decision is made about the transmitted value of r ₁ , since the voltage at the input of the first deciding device is at the noise level n ₁ n ₂ and "1" or "0" can be adopted under the conditions of the operating algorithm used. In the proposed device, this disadvantage is eliminated by using a limiter amplifier with a dead zone as a decisive device. When the input voltage is small at the noise level n ₁ -n ₂ a decision is made r ₁ ** 2.

 The proposed device has new useful features, because, unlike a device for separating non-orthogonal signals of binary phase shift keying, capable of separating only binary signals constantly present at the input of the device, which differ in power, it is able to efficiently receive binary phase shift keying signals characterized by an intermittent pattern of radiation.

Claims (1)

 ADAPTIVE DEVICE FOR SEPARATION OF NON-ORTHOGONAL BINARY PHASE MANIPULATION SIGNALS, comprising a first multiplier, a first low-pass filter, a first subtracting unit and a first decision block, the output of which is the first output of the adaptive device, a second multiplier, a second low-pass filter and a second subtracting the second crucial unit, the output of which is the second output of the adaptive device, the first block of the formation of reference oscillations, the output of which connected to the first inputs of the first and third multipliers, the second input of which and the first input of the second multiplier are connected to the output of the second block of the formation of the reference oscillations, whose input, the input of the first block of the formation of the reference oscillations, the second inputs of the first and second multipliers are connected and are the input of the adaptive device, the output the first low-pass filter is connected to the first input of the first amplifier-limiter, the output of which is connected to the second input of the second subtracting unit, the output of the second lower filter frequency is connected to the first input of the second amplifier-limiter, the output of the third multiplier through the third low-pass filter is connected to the second inputs of the first and second amplifier-limiters, characterized in that, in order to improve the noise immunity of the reception of two mutually interfering signals with an intermittent nature of radiation, are introduced sequentially connected amplitude detector, comparator and key, and the input of the amplitude detector is connected to the output of the first low-pass filter, the output of the second amplifier-limiter is connected inen with the second input of the key, the output of which is connected to the second input of the first subtracting block, the output of the comparator is connected to the second input of the second decision block.

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