RU2305876C2 - Miltifrequency signal amplitude-and-phase modulating device - Google Patents

Abstract

FIELD: radio communications; shaping phase-keyed, amplitude-keyed, as well as amplitude-and-phase keyed signals.

SUBSTANCE: proposed multifrequency signal amplitude-and-phase modulating device has multifrequency signal source; circulator whose first and third arms function as superhigh-frequency input and output and whose second arm is connected to input of reactive four-terminal network; semiconductor diode; and low-frequency control voltage source. Four-terminal network is made in the form of arbitrary connection of three reactive two-terminal networks. Semiconductor diode is inserted in longitudinal circuit between carrier signal source and four-terminal network input. Connected in parallel with diode is low-frequency control signal source whose resistance is arbitrarily chosen. Connected to four-terminal network output is feed-through microwave signal load with arbitrary resistances at preset interpolation frequencies of desired frequency responses. Two-terminal networks are made of arbitrarily interconnected reactive components whose number is chosen to be not less than number of preset interpolation frequencies of desired amplitude-frequency and phase-frequency response characteristics; parameters of reactive components are chosen to ensure desired relationships between modules and phase differences of reflectivity and gain factors at given number of frequencies in two states of semiconductor diode depending on two extreme levels of control signal.

EFFECT: ability of ensuring different desired mechanisms of both echo and feed-through signal amplitude and phase variation.

1 cl, 6 dwg

Description

The invention relates to radio communications and can be used to form phase-shifted, amplitude-manipulated, as well as amplitude-phase-shifted signals.

A device for modulating amplitude and phase, consisting of a circulator, the first input of which is connected to the signal source, the third input is connected to the load, and the second is connected to a piece of open transmission line of length λ / 4, at the beginning of which the p-i-n diode is turned on [Radio transmitting devices. / Edited by O.A. Chelnokov. - M.: Radio and Communications, 1982, p. 152-156]. If the diode is closed, then reflection occurs from the cross section in which it is turned on, the reflected wave enters the load with a resistance of 50 Ohms. If the diode is open, then reflection occurs from the end of the line. The phase of the reflected signal in one state of the diode differs from the phase of the reflected signal in the other state of the diode by π. If necessary, change the phase difference, the length of the length of the transmission line is changed accordingly.

The disadvantage of this modulation device is that in the two states of the diode only the phase of the reflected signal changes, and the set values of the phase difference of the reflected signal in the two states of the diode is provided only at one fixed frequency. Another disadvantage is the constancy of the amplitude of the reflected signal in two states of the diode, that is, the absence of amplitude manipulation, which narrows the functionality. For example, this does not allow providing two radio communication channels on one carrier frequency [one channel can be formed using amplitude manipulation, and the other using phase manipulation] or it does not allow encoding of the transmitted information. The third disadvantage should be considered large masses and dimensions associated with the need to use segments of the transmission line. The fourth disadvantage is that the manipulation device, consisting of controlled and uncontrolled parts, is connected between the signal source and the load, which have certain resistance values. The signal source has a purely real resistance (second input). The load for the reflected signal (third input) also has a real resistance. The manipulator is connected to an open (infinite resistance) or to a closed (zero resistance) transmission line. Another important disadvantage is that this device does not provide manipulation of the amplitude and phase of the transmitted signal.

A modulation device is known, consisting of a certain number of reactive elements of type L, C, the parameters of which are selected from the condition for providing the required arbitrary phase difference of the reflection coefficient [V.G. Sokolinsky, V.G. Sheinkman. Frequency and phase modulators and manipulators. - M.: Radio and Communications, 1983, p. 146-158].

Compared with the previous device, this device does not require the use of semiconductor diodes only in the open and only closed states. For any diode states determined by two levels of low-frequency control action, for certain values of parameters of type L, C, a given value of the phase difference of the reflected signal at a fixed frequency can be provided. If the amplitude of the control low-frequency signal between these two levels changes continuously, then modulation is ensured.

The main disadvantages of the device are the lack of the ability to provide the required values of the phase difference and the ratio of the modules of the reflection coefficients in two states of the controlled element at two or more frequencies. Another disadvantage is that, like the first device, the manipulator can only be switched on between certain resistances. Another important disadvantage is that this device does not provide manipulation of the amplitude and phase of the transmitted signal.

A device is known (prototype) [A. Golovkov A device for modulating the reflected signal. Auth. certificate No. 1800579 dated 10/09/1992], containing a circulator, the first and third arms of which are a microwave input and output, and a reactive four-terminal and a semiconductor diode connected to a source of low-frequency control action are included in the second shoulder, while the four-terminal is made in the form of a T-shaped connection of two-terminal devices with reactance values that are selected from the condition for ensuring the required identical laws of two-level changes in the amplitude and phase of the reflected signal at two given frequencies. As in the previous device, phase and amplitude modulation is possible if the control signal changes continuously. In this case, the amplitude and phase of the transmitted signal changes according to an unknown law or does not change at all.

The main disadvantages of this device include the lack of the possibility of implementing different specified laws of changing the amplitude and phase of the reflected signal at two or more specified frequencies, which reduces the functionality and the amount of transmitted information. Another disadvantage is that, as in the first two devices, the manipulator can only be switched on between certain resistances. Another important disadvantage is that this device does not provide the specified laws of manipulation of the amplitude and phase of the transmitted signal.

The examination is considering the claimed modulation devices for the case of the inclusion of a controlled element in the longitudinal circuit between the reactive four-terminal network and the source of the modulating signal. The place where the modulating signal source is turned on does not matter. However, the inclusion of the controlled element is of great importance. In the general case, for a given specific load, there is a very definite place of the included controlled element at which the greatest depth of amplitude modulation, phase deviation and broadband are achieved.

In this application for the invention, the authors show the possibility of achieving ultimate performance when a controlled element is included in a longitudinal circuit between the carrier signal source and the four-terminal network.

The technical result of the invention is the simultaneous provision of the required different laws of changing the amplitude and phase of both the reflected and transmitted signals with limit characteristics at a given number of fixed frequencies when the manipulator is turned on between arbitrary resistances and the controlled element is included in the longitudinal circuit between the carrier signal source and the four-terminal network.

This result is achieved by the fact that in the device for modulating the amplitude and phase of multi-frequency signals containing a carrier signal source, a circulator, the first and third arms of which are a microwave input and output, and a reactive four-port input, a semiconductor diode and a low-frequency control voltage source are connected to the second arm, in addition, the four-terminal is made in the form of an arbitrary connection of three reactive two-terminal, a semiconductor diode is included in the longitudinal circuit between the with a carrier signal and a four-terminal input, a low-frequency control signal source is connected in parallel with the diode, the signal source resistance is chosen arbitrarily, the load for the transmitted microwave signal with arbitrary resistances at a given number of interpolation frequencies of the required frequency characteristics is connected to the output of the four-terminal, two-terminal made of randomly connected between themselves reactive elements, the number of which is chosen not less than the number of specified frequencies of the interpo yatsii required amplitude-frequency and phase-frequency characteristics, and the parameters of the reactive elements are selected from the conditions required to ensure the simultaneous relations modules and phase differences of reflection and transmission coefficients of a predetermined number of frequencies in the two states of a semiconductor diode defined by the two extreme levels of the control signal.

Figure 1 shows a diagram of a device for modulating the amplitude and phase of the signals that implements the prototype method.

Figure 2 shows a diagram of the proposed device.

Figure 3 shows a diagram of a first embodiment of the proposed device for modulating the amplitude and phase of the reflected and transmitted multi-frequency signal for the case n = 1, 2 (n is the number of interpolation frequencies).

Figure 4 shows a diagram of a second embodiment of the proposed device for modulating the amplitude and phase of the reflected and transmitted multi-frequency signal for the case n = 1, 2.

Figure 5 presents a diagram of a third embodiment of the proposed device for modulating the amplitude and phase of the reflected and transmitted multi-frequency signal for the case n = 1, 2, 3.

Figure 6 is a diagram of a fourth embodiment of the proposed device for modulating the amplitude and phase of the reflected and transmitted multi-frequency signal for the case n = 1, 2, 3.

The prototype device contains a circulator 1 with input 2, load 3 and output 4 shoulders, three bipolar 5, 6, 7 with reactances x ₁ , x ₂ , x ₃ , connected by a T-circuit, as well as a semiconductor diode 8, connected in parallel to the source of the modulation signal 9. The two-terminal 7 is connected to the diode 8, the two-terminal 5 to the load arm 3 of the circulator 1.

The principle of operation of the device manipulating the parameters of the signal that implements the prototype method is as follows.

The signal from the master oscillator (not shown in FIG. 1) through the input arm 2 of the circulator 1 enters the load arm 3. As a result of the interaction of the received signal with the reactive elements and the diode and due to the special choice of the values of the reactive elements of the two-terminal devices, the values of the phases and amplitudes of the reflected signals two frequencies turns out to be such that, as a result of their interference, signals are output to the output arm 4 of the circulator 1, the amplitude and phase of which are in the same state of diode 8, determined by one extreme value of the signal modulation source 9 differs from the amplitude and phase of these signals in a different state of the diode 8 at the same predetermined magnitude at the respective two frequencies. The maximum phase deviation can be 360 °, the minimum is zero, and the maximum amplitude ratio is ∞.

The proposed device and four variants of its implementation (Figs. 3-6) contain a circulator with input 2, load 3 and output 4 arms, a four-terminal device and three two-terminal devices 5, 6, 7 with reactances x _1n , x _2n , x _3n connected between by a T or P-circuit, as well as a semiconductor diode 8, connected in a longitudinal circuit between the arm 3 and the four-terminal and connected in parallel to the modulation signal source 9, the two-terminal 5 is connected to the diode 8, the two-terminal 7 is connected to the load 10 for the passage signal. The burden for the reflected signal is the arm 4. The arm 3 is essentially a signal source for the quadrupole. The load may be, for example, an antenna.

These devices operate as follows. Due to the special choice of the number of reactive elements of two-terminal circuits, their connections and the values of their parameters when switching the control (modulating) signal on the diode, the amplitude and phase of both the reflected and transmitted signal will be simultaneously manipulated at a given number of frequencies in the general case with different laws of two-level amplitude change and phases at each of the frequencies. With a continuous change in the amplitude of the control signal, the amplitude and phase of the reflected and transmitted signal will be modulated in amplitude and phase in the general case according to arbitrary given laws.

Let us prove the feasibility of implementing these properties.

Let the resistance of the signal source Z ₀ = r ₀ + jx ₀ , the load Z _n = r _n + jx _n and the controlled element Z _1,2 = r _1,2 + jx _1,2 in two states defined by two levels be known at a fixed frequency control action.

It is required to determine the structure of the matching filtering device (SFU) scheme, the minimum number of elements and the values of their parameters at which a change in the state of a controlled element entails a change in the modules and phases of the transmission and reflection coefficients according to the following laws:

- требуемые отношения модулей и разности фаз коэффициентов передачи

и отражения

амплитудно-фазовых манипуляторов в двух состояниях их управляемого элемента.Where

- the required ratio of the modules and the phase difference of the transmission coefficients

and reflections

amplitude-phase manipulators in two states of their controlled element.

The equivalent circuit of the manipulator, taking into account the signal source and load, is presented in the form of four cascade-connected four-terminal devices.

The first quadrupole is a signal source; the second is a controlled element included in the longitudinal chain; the third - SFU; the fourth is the load (antenna).

Using the approach proposed in [Golovkov A.A., Minakov V.G. The relationship between the elements of the resistance matrix and their use for the synthesis of matching-filtering devices of amplitude-phase manipulators. Telecommunications No. 8, 2004, p.29-32], we find that the normalized classical matrix transfer equivalent circuit has the form:

- это определитель матрицы (4):where X ₁₁ , X ₂₁ , X ₂₂ - elements of the matrix SFU (4), built only using reactive elements of type L, C;

is the determinant of the matrix (4):

Using the known relations between the elements of the transfer matrix and the elements of the scattering matrix [Feldstein A.L., Yavich L.R. Microwave four-terminal and eight-terminal synthesis. M .: Communication, 1971, 388 pp.], We obtain expressions for the transmission and reflection coefficients of the manipulators:

We substitute (5) into (1) and after separating the real and imaginary parts from each other, we obtain a system of two equations:

the solution of which is:

Where

The obtained two relationships (8) between the elements of the SFU resistance matrix are optimal according to the criterion for ensuring the required law of change in the modulus and phase of the transmission coefficient (1). Therefore, SFU must have at least two reactive elements, the parameters of which must satisfy the system of two equations, formed as follows. It is necessary to determine the resistance matrix of the test SFU circuit and find its elements X ₁₁ , X ₂₂ , X ₂₁ , expressed through specific parameters. The parameters of these elements must be substituted in (8) and the system of two equations formed in this way relative to the two selected parameters should be solved. The values of the parameters of the remaining elements can be arbitrarily chosen, since the condition of physical realizability arising from the requirement of positivity of the radical expression in (8) is satisfied for any value of X ₁₁ .

This condition has the form:

From the expression (9) for the same reasons, there follows a restriction on the square of the ratio of the modules of transmission coefficients in two states:

- качество управляемого элемента, последовательно соединенного с источником сигнала.Where

- the quality of the controlled element connected in series with the signal source.

To determine the relationships between the elements of the SFU resistance matrix that are optimal according to the criterion for ensuring the law of reflection coefficient change (2), we use the obtained solution (8) and the auxiliary task of providing the required phase difference φ and the module ratio m of one of the elements (T ₂₁ ) of the wave matrix transmission [Feldstein A.L., Yavich L.R. Microwave four-terminal and eight-terminal synthesis. M .: Communication, 1971, 388 p.]:

Where

In accordance with (12), the following relations hold:

Thus, to ensure the required values of m ₁₁ , φ _11, it is necessary to find the relationship between the elements of the matrix of resistances of SFU that are optimal according to the implementation criterion m and φ.

We substitute (12) into (11), separate the real and imaginary parts from each other, and obtain a system of two equations:

the solution of which is:

Where

To simultaneously provide the required values of m, φ, m ₂₁ , φ ₂₁ , that is, to ensure the values of m ₁₁ , φ ₁₁ (13), it is necessary that the relationships (8) and (15) be performed simultaneously.

Since the elements of the resistance matrix describe the same SFU, then (8) and (15) should be equal in pairs. From these equalities there follows a restriction on the third element of the resistance matrix

Since all three elements X ₁₁ , X ₂₁ , X _{22 are} strictly defined, the SFU must contain at least three reactive elements, the values of the parameters that must be determined from the solution of the system of three equations generated from (8) and (16) or (15) and ( 16) as indicated above. The second equality from (16) is satisfied with the zero radical expression, which imposes restrictions on one of the quantities m ₁₁ , φ ₁₁ .

The radical expression in (15) is positive for any X ₁₁ if D ₂ <0. This inequality implies a restriction on φ, m:

Where

In accordance with the developed algorithms, the simplest schemes were synthesized in the form of a T-shaped and U-shaped connections of three two-terminal devices.

For a T-joint:

For a U-shaped connection:

In expressions (19) and (20), the elements of the matrix X ₁₁ , X ₂₁ , X _{22 are} determined by the relationships (8) and (16) or (15) and (16). These relationships complement the known relationships between the elements of the matrix of parameters arising from the conditions of reciprocity, symmetry, antimetry, non-dissipativity and unitarity, and expand the possibilities of synthesizing SFU amplitude-phase manipulators.

(k - номер двухполюсника).The structure of the schemes is defined as follows. If in formulas (19) - (20) X _kn > 0 (k = 1, 2, 3), then this is the inductance L _kn = X _kn / ω _n , (ω _n = 2пf _n ). If X _kn <0, then this is the capacity

(k is the number of the two-terminal network).

The implementation of the required frequency characteristics in two states can easily be done by interpolation on two, three, etc. frequencies. For this, it is necessary to form each of the two-terminal circuits of the Siberian Federal University (Figs. 3-6) from the elements L, C so that it provides the required resistance values at the given frequencies, calculated according to formulas (19) - (20) for these same frequencies. In this case, the coefficients D, E, F are also calculated for the corresponding frequency, which is taken into account by its number n. Here are two solutions to such problems. For two given frequencies, it is proposed to form two-terminal circuits from parallel and serial oscillatory circuits connected in series between each other. The resistance of such a two-terminal device at two frequencies is determined by the expressions:

The solution of the system of two equations (13) determines the parameters L ₁ , C _{1 of the} parallel circuit:

where k = 1, 2 is the number of the two-terminal network; n = 1, 2 - frequency number.

In expressions (14), the parameters L, C can be chosen arbitrarily, based on any physical considerations, for example, from the condition of ensuring a minimum of deviations of the given characteristics in a given frequency band, or based on the condition of physical realizability of the circuits.

For three given frequencies, it is proposed to form two-terminal circuits from series-connected capacitance C ₀ , a parallel circuit L ₁ , C ₁ and a reactive two-terminal with resistance jx ₀ . In this case, the parameters are determined from the solution of the system of three equations:

The solution has the form:

Where

X _k1 = x _k1 -X ₀ (ω ₁ ); X _k2 = x _k2 -X ₀ (ω ₂ ); X _k3 = x _k3 -X ₀ (ω ₃ ); X _k1 , X _k2 , X _k3 - reactance of a series-connected capacitance C ₀ and a parallel oscillatory circuit with parameters L ₁ , C ₁ ; x _k1 , x _k2 , x _k3 - reactance of a series-connected capacitance C ₀ , a parallel circuit with parameters L ₁ , C ₁ and a two-terminal with reactance x ₀ at three given frequencies, while a two-terminal with reactance x ₀ is formed from an arbitrary number reactive elements connected in any way with arbitrary values of the parameters L, C; ω ₁ , ω ₂ , ω ₃ - given fixed frequencies.

The reactance jx _{0 of the} two-terminal network is formed arbitrarily or on the basis of any physical considerations, for example, on the basis of the conditions for ensuring a minimum of deviations of characteristics in the frequency band.

The obtained solutions (22) and (24) for two and three preset frequencies can be used both in a U-shaped connection scheme of two two-terminal networks and in a T-shaped one. Therefore, the implementation options of the proposed device currently modulating the amplitude and phase of the multi-frequency reflected and transmitted signals can be only four.

The proposed technical solutions are new, since the device for manipulating the parameters of the multi-frequency reflected and transmitted signals at a given number of frequencies, consisting of in a certain way connected a certain number of reactive elements L, C with parameters determined by the corresponding mathematical expressions, is not known from publicly available information.

The proposed technical solutions have an inventive step, since it does not explicitly follow from published scientific data and known technical solutions that the claimed device execution sequences (the formation of an uncontrolled part of a two-terminal network connected in a certain way, from the condition of providing a two-level change in the amplitude and phase of the reflected and transmitted signals at a given the number of frequencies when the state of the controlled element included in the longitudinal circuit changes when values of the resistance of the signal source and loads), as well as implementation options in the form of connection diagrams of the L, C elements forming a two-terminal network, and mathematical expressions to determine their parameters simultaneously ensure the implementation of the required different laws for changing the amplitude and phase of the reflected and transmitted signals for a given number of fixed frequencies when the modulator is turned on between arbitrary resistances.

The proposed technical solutions are practically applicable, since semiconductor diodes, for example p-i-n diodes, varicaps, etc., commercially available inductance and capacitance industry, formed in variants of the implementation of the two-terminal circuit of T, U-shaped connections, can be used for their implementation. The values of the parameters of capacitances and inductances can be uniquely determined using mathematical expressions given in the description of the invention.

The technical and economic efficiency of the proposed device consists in the simultaneous implementation of the required different laws of changing the amplitude and phase of the reflected and transmitted signals at a given number of fixed interpolation frequencies when the modulator is turned on between arbitrary resistances.

Claims (1)

A device for modulating the amplitude and phase of multi-frequency signals, containing a multi-frequency signal source, a circulator, the first and third arms of which are a microwave input and output, a multi-frequency signal source, a reactive four-terminal device consisting of two-terminal devices made on reactive elements, a semiconductor diode and parallel are connected to the first shoulder the source of the low-frequency control signal connected to it, the number of reactive elements is chosen not less than the number of specified frequencies int the polarization of the required amplitude-frequency and phase-frequency characteristics, the parameters of the reactive elements are selected from the condition of simultaneously providing the required ratios of the modules and the phase differences of the transmission and reflection coefficients at a given number of frequencies in two states of the semiconductor diode, determined by the two extreme levels of the control signal, characterized in that the four-terminal in the form of an arbitrary connection of three reactive bipolar, a semiconductor diode is included in the longitudinal circuit between the second m the shoulder of the circulator and the input of the four-terminal, the resistance of the source of multi-frequency signals is chosen arbitrarily, the output of the four-terminal includes a load for loop-through multi-frequency signals with arbitrary resistances at a given number of interpolation frequencies of the required frequency characteristics, the parameters of the reactive elements of the two-terminal are selected from the condition of simultaneously providing the required different ratios of the modules and various phase differences of reflection and transmission coefficients at a given number of frequent t.

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