RU2577913C2 - Method of amplification and demodulation of frequency-modulated signals and device for its implementation - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method of amplification and demodulation of frequency-modulated signals and the device for the method implementation are offered. The device of amplification and demodulation of frequency-modulated signals is formed by DC power supply, direct transmission circuit in the form of triple-pole nonlinear element, four-pole network, external feedback circuit, low pass filter, separating capacitance and low-frequency load, while the four-pole network is resistive, the external feedback circuit is an arbitrary complex four-pole network connected to triple-pole nonlinear element using parallel-series circuit, the triple-pole nonlinear element and feedback circuit as a single unit are in cascade manner are connected between the frequency-modulated signal source with a complex resistance and input of resistive four-pole network, between output of the resistive four-pole network and the low pass filter the high-frequency load in the form of compound two-pole network with the complex resistance z_l is connected, which is formed by series connected the first resistive two-pole network with the resistance R₁, the capacitor with the capacitance C, arbitrary compound two-pole network with the resistance Z₀ = R₀+jX₀ and parallel connected among themselves the second resistive two-pole network with the resistance R₂ and the coil with the inductance L; R₁, R₂, L, C parameters are selected from the condition of matching by the criterion of simultaneous providing of amplification and frequency demodulation according to the given mathematical expressions.

EFFECT: increase of dynamic range and quasilinear section of the frequency demodulation characteristic due to presence of resistive four-pole network and matching using the compound complex two-pole network used as high-frequency load, by criterion of formation of quasilinear section of the left slope of AFC coinciding with the range of change of frequency of input FMS.

2 cl, 3 dwg

Description

The invention relates to the fields of radio communication, radar, radio navigation and electronic warfare and can be used to create multifunctional devices for amplifying the amplitude and demodulating frequency-modulated signals with an increased quasilinear portion of the frequency demodulation characteristic for arbitrary specified characteristics of a nonlinear element, external feedback circuit, and parameters of a resistive four-terminal .

A known method of amplification and frequency demodulation of a high-frequency signal, based on the use of the energy of a constant voltage source, the organization of internal feedback in a nonlinear element by using a bipolar nonlinear element with negative differential resistance [Radio receivers. Under the general editorship of V.I. Siforova. M .: “Owls. Radio ", 1974, p. 137-150], the fulfillment of the amplification conditions by matching with a given tolerance of negative resistance with the resistance of the rest of the amplifier. The input part is made of a parallel oscillatory circuit. The output part of the amplifier is performed from a low-pass filter (low-pass filter), separation capacitance and low-frequency load [Gonorovsky I.S. Radio circuits and signals. - M .: "Soviet Radio", 1977, p. 190-193, 290-293, 311-316]. If the average frequency of the input frequency-modulated signal (HMS) coincides with the average frequency of the left slope of the amplitude-frequency characteristic (AFC) of the oscillating circuit, then the HMS is converted to an amplitude-modulated ChMS (AHMS). A nonlinear element destroys (splits) the frequency response spectrum into high-frequency and low-frequency components, the low-pass filter selects low-frequency components, and suppresses the rest. The separation capacity eliminates the constant component. A low-frequency signal arrives at a low-frequency load, the amplitude of which changes according to the law of changing the frequency of the input HMS. As a result, amplification and demodulation of ChMS is simultaneously provided.

A device for amplification and frequency modulation, consisting of a constant voltage source that sets the operating point in the middle of the falling section of the current-voltage characteristics of the bipolar nonlinear element with negative differential resistance [Radio receivers. Under the general editorship of V.I. Siforova. M .: “Owls. Radio ", 1974, p. 137-150], an input circuit from a parallel oscillatory circuit and a reactive four-terminal, while the parameters of the circuit, a two-pole nonlinear element and a four-terminal are selected from the condition that the average frequency of the left slope of the frequency response and the average frequency of the input HMS coincide and the amplitude of the HMS is amplified simultaneously. [Honorovsky I.S. Radio circuits and signals. - M .: "Soviet Radio", 1977, p. 190-193, 290-293, 311-316]. The principle of operation of this device is as follows. When you turn on the source of constant voltage (current), the operating point of the nonlinear element is set on the falling section of its volt-ampere characteristic. Due to the presence of internal feedback in a bipolar nonlinear element, a negative differential resistance arises in a section with a falling current-voltage characteristic, which, by matching with a reactive four-terminal device, compensates for losses in the entire circuit with a given tolerance. Due to this, the input HMS with an average frequency equal to the average frequency of the left slope of the oscillating circuit is amplified to a level at which the amplitude goes beyond the falling section of the current-voltage characteristic, and the input HMS is converted to AFM. A nonlinear element splits (destroys) the frequency response spectrum into components, the low-pass filter isolates the low-frequency component, and suppresses the others, and the separation capacitance eliminates the constant component. The low-frequency component, the amplitude of which changes according to the law of changing the frequency of the input HMS, enters the low-frequency load. There is demodulation of the emergency response. The disadvantage of this method and device is the simple summation of the gain and frequency demodulation functions. If the device is effective in gain mode, then it is not effective in frequency modulation mode, and vice versa, if the device is effective in frequency modulation mode, then it is not effective in gain mode. Therefore, in the general case, undesirable frequency or nonlinear distortions occur in one of the modes.

The closest in technical essence and the achieved result (prototype) is a method of amplification and frequency demodulation of a high-frequency signal, based on the use of energy from a constant voltage source, organization of a direct transmission circuit (DPC) and external feedback circuit (OS), the fulfillment of amplification conditions by agreement with the specified tolerance of the OS and the CPU from the rest of the amplifier. If the average frequency of the input HMC coincides with the average frequency of the left slope of the frequency response, and the output of the rest of the amplifier is a low-pass filter and a low-frequency load, then simultaneously with the amplification, the HMS will be converted to AHMS, the amplitude of which will change according to the law of the frequency of the input HMS, as well as the amplitude AFMD demodulation with the formation of a low-frequency load of the LF signal, the amplitude of which varies according to the law of the frequency of the input HMS. [Honorovsky I.S. Radio circuits and signals. - M .: "Soviet Radio", 1977, p. 190-193, 290-293, 311-316].

The closest in technical essence and the achieved result (prototype) is a device for amplification and frequency demodulation of a high-frequency signal, consisting of a constant voltage source that sets an operating point in the middle of the quasilinear section of the transient current-voltage characteristic of the transistor, a direct transmission circuit in the form of a first four-terminal network for matching the output transistor electrode and load, the input circuit in the form of a parallel oscillatory circuit, RC - external positive reverse circuit connection (in general, the second four-terminal network for matching the control electrode of the transistor and the load) between the load and the control electrode of the transistor, the output circuit in the form of a low-pass filter, isolation capacitance and low-frequency load, while the parameters of the circuit, direct transfer circuit, feedback circuit and transistor selected from the condition of coincidence of the average frequency of the left slope of the frequency response of the entire device and the average frequency of the input HMS and the simultaneous amplification of the amplitude of the HMS [Gonorovsky IS Radio circuits and signals. - M .: "Soviet Radio", 1977, p. 190-193, 290-293, 311-316].

The principle of operation of this device is as follows. When a constant voltage (current) source is turned on, the operating point of the nonlinear element is set in the middle of the quasilinear section of its through-current voltage-current characteristic. Due to the presence of external feedback, matching the output electrode with the load and the load with the control electrode using reactive four-terminal devices, the losses in the entire circuit are compensated with a certain tolerance necessary to eliminate the possibility of excitation of the device. Due to this, the input HMS with an average frequency equal to the average frequency of the left slope of the oscillating circuit is amplified to a level at which the amplitude goes beyond the quasilinear portion of the current-voltage characteristic, and the input HMS is converted to AFM. A nonlinear element splits (destroys) the frequency response spectrum into components, the low-pass filter isolates the low-frequency component, and suppresses the others, the separation capacitance eliminates the constant component, the low-frequency component, the amplitude of which changes according to the law of the frequency of the input frequency, is applied to the low-frequency load. There is demodulation of the emergency response. The disadvantage of this method and device is the simple combination of amplification and frequency demodulation. A common disadvantage of all known methods and devices is that there are no technical solutions that contribute to providing a gain mode and a frequency demodulation mode using a single radio device. If a minimum of nonlinear and frequency distortion is achieved in the frequency demodulation mode, then in the amplification mode these distortions will be maximum, and vice versa, if a minimum of nonlinear and frequency distortion is achieved in the amplification mode, then these distortions will be maximum in the frequency demodulation mode 6. This question arises especially sharply when designing amplification and frequency demodulation devices in the HF and UHF bands, on which, in addition, it is necessary to take into account the reactive components of the parameters of nonlinear elements. Currently, the classical theory of radio circuits does not take this into account. In addition, frequency demodulation and amplification can be achieved with resistive quadripoles, the parameters of which are independent of the frequency in a sufficiently large frequency range, which under certain conditions contributes to an increase in the quasilinear portion of the frequency demodulation characteristic, providing a given gain and dynamic range. This ensures a minimum of non-linear and frequency distortion. The basis for this invention is the definition of these conditions.

The technical result of the invention is the amplification and frequency demodulation of a high-frequency signal using a device with an increased dynamic range and a quasilinear portion of the frequency demodulation characteristic due to the presence of a resistive four-terminal and matching using a complex complex two-terminal, used as a high-frequency load, according to the criterion for the formation of a quasilinear portion of the left slope of the frequency response coinciding with the frequency range of the input HMS. The possibility of using various options for including a three-pole nonlinear element with respect to a resistive four-terminal and various types of feedback expands the possibilities of the physical feasibility of this result.

1. The specified result is achieved by the fact that in the known method of amplification and demodulation of frequency-modulated signals, based on the use of energy from a constant voltage source, the interaction of the frequency-modulated signal with a device that is performed from a direct transmission circuit in the form of a three-pole nonlinear element, four-terminal, circuit external feedback, low-pass filter, separation capacitance and low-frequency load, meeting the conditions for matching the forward circuit with the external feedback circuit conditions for matching the external feedback circuit with the control electrode of a three-pole nonlinear element, matching conditions for the direct transmission circuit and the external feedback circuit with the rest of the device with a given tolerance, converting the frequency-modulated signal into an amplitude-frequency-modulated signal on the left slope of the amplitude frequency response, splitting the spectrum of the amplitude-frequency-modulated signal into low-frequency and high-frequency components using a three-pole nonlinear element, isolating the low-frequency component using a low-pass filter, eliminating the constant component using a dividing capacitance, and receiving a low-frequency signal at a low-frequency load, the amplitude of which changes according to the law of frequency change of the frequency-modulated signal, additionally, the four-terminal network is made resistive as an external feedback circuit use an arbitrary complex four-terminal connected to a three-pole nonlinear element in parallel-serial hydrochloric scheme tripolar nonlinear element and a feedback loop as a single node in cascade inserted between the source of the frequency-modulated signal with a complex impedance and the input resistive quadripole, between the output of the resistive quadripole and lowpass filter includes high-frequency load in the form of two-terminal network with a complex impedance z _n, conditions coordination according to the criterion of simultaneously providing gain and frequency demodulation is performed by selecting the frequency dependence of the resistance z _n in accordance with the following mathematical expression:

- заданные отношения соответствующих элементов классической матрицы передачи резистивного четырехполюсника a, b, c, d; z₀ - заданная зависимость комплексного сопротивления источника входного частотно-модулированного сигнала от частоты в заданной полосе частот; f₁₁, f₁₂, f₂₁, f₂₂ - заданные суммарные зависимости комплексных элементов смешанной матрицы F трехполюсного нелинейного элемента от частоты в заданной полосе частот и соответствующих зависимостей комплексных элементов смешанной матрицы F цепи внешней обратной связи от частоты в заданной полосе частот; m, φ - заданные зависимости модуля и фазы передаточной функции устройства от частоты для формирования заданной крутизны левого склона АЧХ устройства в заданной полосе частот, совпадающей с диапазоном изменения частоты частотно-модулированного сигнала; j - мнимая единица.Where

- the given relations of the corresponding elements of the classical transmission matrix of the resistive four-terminal a, b, c, d; z ₀ - a given dependence of the complex resistance of the source of the input frequency-modulated signal on the frequency in a given frequency band; f ₁₁ , f ₁₂ , f ₂₁ , f ₂₂ - the given total dependences of the complex elements of the mixed matrix F of a three-pole nonlinear element on the frequency in the given frequency band and the corresponding dependences of the complex elements of the mixed matrix F of the external feedback circuit on the frequency in the given frequency band; m, φ are the given dependences of the module and phase of the transfer function of the device on the frequency to form the specified slope of the left slope of the frequency response of the device in a given frequency band that matches the frequency range of the frequency-modulated signal; j is the imaginary unit.

2. The specified result is achieved by the fact that in the known device for amplification and demodulation of frequency-modulated signals made from a constant voltage source, a direct transmission circuit in the form of a three-pole nonlinear element, four-terminal, external feedback circuit, low-pass filter, separation capacitance and low-frequency load , additionally the four-terminal is made resistive, as an external feedback circuit an arbitrary complex four-terminal connected to a three-pole circuit is used a linear element in a parallel-serial circuit, a three-pole non-linear element and a feedback circuit as a single node are cascaded between the source of the frequency-modulated signal with complex resistance and the input of the resistive four-terminal, between the output of the resistive four-terminal and the low-pass filter, a high-frequency load in the form of a complex two-terminal complex resistance z _n , which is formed from a series-connected first resistive bipolar with resistance m R ₁ , a capacitor with a capacitance C, an arbitrary complex two-terminal with resistance Z ₀ = R ₀ + jX ₀ and in parallel connected to each other a second resistive two-terminal with resistance R ₂ and a coil with inductance L, parameters R ₁ , R ₂ , L, С are selected from the matching condition according to the criterion of simultaneously providing gain and frequency demodulation in accordance with the following mathematical expressions:

где

Where

-- оптимальные значения действительных и мнимых составляющих сопротивления высокочастотной нагрузки на двух частотах, рассчитанные по формуле

- the optimal values of the real and imaginary components of the resistance of the high-frequency load at two frequencies, calculated by the formula

- заданные отношения соответствующих элементов классической матрицы передачи резистивного четырехполюсника a, b, c, d; R₀₁, R₀₂, X₀₁, X₀₂ -- заданные значения действительных и мнимых составляющих сопротивления Z₀ произвольного комплексного двухполюсника на двух частотах ω_i=2πf_i; i=1, 2 - номер частоты; z_0i - заданные значения комплексных сопротивлений источника входного частотно-модулированного сигнала на двух заданных частотах; f_11i, f_12i, f_21i, f_22i - заданные суммарные значения комплексных элементов смешанной матрицы F трехполюсного нелинейного элемента и соответствующих значений комплексных элементов смешанной матрицы F цепи внешней обратной связи на двух заданных частотах; m_i, φ_i - заданные значения модулей и фаз передаточной функции устройства на двух заданных частотах для формирования заданной крутизны левого склона АЧХ устройства в заданной полосе частот, совпадающей с диапазоном изменения частоты частотно-модулированного сигнала; j - мнимая единица.

  - the given relations of the corresponding elements of the classical transmission matrix of the resistive four-terminal a, b, c, d; R₀₁, R₀₂, X₀₁, X₀₂ - given values of the real and imaginary components of the resistance Z₀ arbitrary complex bipolar at two frequencies ω_i= 2πf_i; i = 1, 2 - frequency number; z_0i - set values of the complex resistances of the source of the input frequency-modulated signal at two predetermined frequencies; f_11if_12if_21if_22i - the set total values of the complex elements of the mixed matrix F of the three-pole nonlinear element and the corresponding values of the complex elements of the mixed matrix F of the external feedback circuit at two given frequencies; m_i, φ_i - the set values of the modules and phases of the transfer function of the device at two predetermined frequencies to form a given slope of the left slope of the frequency response of the device in a given frequency band that matches the frequency range of the frequency-modulated signal; j is the imaginary unit.

In FIG. 1 shows a diagram of a device for amplification and demodulation of frequency-modulated signals (prototype) that implements the prototype method.

In FIG. 2 shows a structural diagram of the proposed device according to claim 2., which implements the proposed method of amplification and demodulation of frequency-modulated signals according to claim 1.

In FIG. 3. The scheme of the matching complex complex two-terminal network that implements the optimal values of the resistance of the high-frequency load of the proposed device is shown (Fig. 2).

The prototype device (Fig. 1), which implements the prototype method, contains a direct transmission circuit in the form of a three-pole non-linear element VT-1 connected to a constant voltage source-2, matching device SU-3 in the form of a reactive four-terminal device. An OS-4 feedback circuit is connected to the direct transmission circuit (DPC). An LPF-5, isolation capacitance C _P -6 and low-frequency load R _n -7 are connected to the node output from the CPU and OS as a whole. A parallel oscillatory circuit KK-9 on elements L, R, C is connected in parallel between the source of the ChMS with resistance z ₀ -8 and the input of the CPU and OS.

The principle of operation of the device for amplification and demodulation of the ChMS (prototype) that implements the prototype method is as follows.

When you turn on the source of constant voltage (current) -2, the operating point of the nonlinear element-1 is set in the middle of the quasilinear section of its passage volt-ampere characteristic. Due to the coordination of the output electrode with OS-4 and OS-4 with the control electrode using SU-3, negative resistance arises in the circuit and losses in the entire circuit are compensated with a certain tolerance necessary to eliminate the possibility of excitation of the device. Due to this, the input HMS with an average frequency equal to the average frequency of the left slope of KK-9 is amplified to a level at which the amplitude goes beyond the quasilinear portion of the current-voltage characteristic, and the input HMS is converted to AFM. Non-linear element-1 splits (destroys) the frequency response spectrum into components, the low-pass filter-5 separates the low-frequency component, and suppresses the rest, the separation capacitance C _P -6 eliminates the constant component, the low-frequency component, the amplitude of which changes according to the law of the frequency of the input HMS, goes to low load-7. There is demodulation of the emergency response.

на заданных частотах, подключенный к источнику постоянного напряжения-2 и соединенный по высокой частоте с цепью внешней ОС по параллельно-последовательной схеме (входы соединены параллельно, а выходы - последовательно), выполненной в виде произвольного четырехполюсника-10, сформированного в общем случае на двухполюсниках с комплексными сопротивлениями. Источник входного ЧМС с сопротивлением z_0i=r_0i+jx_0i-8 на заданных частотах подключен к входу узла из нелинейного элемента-1 и четырехполюсника-10. К выходу этого узла подключен произвольный резистивный четырехполюсник РЧ-11, между выходом РЧ-11 и ФНЧ-5 параллельно включена высокочастотная нагрузка-12 с оптимальными сопротивлениями z_нi=r_нi+jx_нi на заданных частотах. Высокочастотная нагрузка-12 выполнена в виде сложного двухполюсника с комплексным сопротивлением z_нi, который сформирован из последовательно соединенных первого резистивного двухполюсника с сопротивлением R₁-13, конденсатора с емкостью С-14, произвольного комплексного двухполюсника с сопротивлением Z₀=R₀+jX₀-15 и параллельно соединенных между собой второго резистивного двухполюсника с сопротивлением R₂-16 и катушки с индуктивностью L-17. Произвольный четырехполюсник-10 тоже характеризуется известными значениями элементов смешанной матрицы F

на заданных частотах i=1, 2.. - номер частоты). Четырехполюсник-11 может быть выполнен в виде произвольного соединения произвольного количества резистивных двухполюсников. Этот четырехполюсник описывается известными элементами классической матрицы передачи a, b, c, d. Синтез усилителя и частотного демодулятора (выбор оптимальных частотных зависимостей сопротивления высокочастотной нагрузки - сложного согласующего двухполюсника, выбор его параметров R₁, R₂, L, C) осуществлен по критерию обеспечения заданной крутизны левого склона АЧХ в заданной полосе частот, совпадающей с диапазоном изменения частоты частотно-модулированного сигнала, в интересах одновременного обеспечения усиления и частотной демодуляции. В результате реализуется увеличенный квазилинейный участок частотной демодуляционной характеристики и динамический диапазон.The disadvantages of the prototype method and device for its implementation are described above. The proposed device according to p. 2 (Fig. 2), which implements the proposed method according to p. 1, contains a three-pole non-linear element-1 with known elements of a mixed matrix F

at specified frequencies, connected to a constant voltage source-2 and connected at high frequency to an external OS circuit in a parallel-serial circuit (inputs are connected in parallel and outputs are connected in series), made in the form of an arbitrary four-terminal-10, formed generally on two-terminal devices with complex resistances. The source of the input FMC with resistance z _0i = r _0i + jx _0i -8 at given frequencies is connected to the input of the node from non-linear element-1 and four-terminal-10. An arbitrary resistive four-terminal RF-11 is connected to the output of this node, between the RF-11 and LPF-5 output, a high-frequency load-12 with optimal resistances z _ni = r _ni + jx _ni at given frequencies is _connected in _parallel . High-frequency load-12 is made in the form of a complex two-terminal with complex resistance z _ni , which is formed from a series-connected first resistive two-terminal with resistance R ₁ -13, a capacitor with capacitance C-14, an arbitrary complex two-terminal with resistance Z ₀ = R ₀ + jX ₀ -15 and in parallel connected to each other of the second resistive two-terminal with resistance R ₂ -16 and coils with inductance L-17. An arbitrary quadripole-10 is also characterized by the known values of the elements of the mixed matrix F

at given frequencies i = 1, 2 .. is the frequency number). The four-terminal-11 can be made in the form of an arbitrary connection of an arbitrary number of resistive two-terminal devices. This quadrupole is described by the well-known elements of the classical transfer matrix a, b, c, d. The synthesis of the amplifier and the frequency demodulator (the choice of the optimal frequency dependences of the resistance of the high-frequency load - a complex matching two-terminal device, the choice of its parameters R ₁ , R ₂ , L, C) was carried out according to the criterion for ensuring a given slope of the left slope of the frequency response in a given frequency band that matches the frequency range frequency-modulated signal, in the interests of simultaneously providing amplification and frequency demodulation. As a result, an enlarged quasilinear section of the frequency demodulation characteristic and a dynamic range are realized.

The proposed device operates as follows.

When you turn on the source of constant voltage (current) -2, the operating point of the nonlinear element-1 is set at the initial section of its through-current voltage-current characteristic (the mode of operation with cut-off, which allows to destroy the signal spectrum). Due to the coordination of the CPU and the OS as a whole with the help of the high-frequency load-12 with the rest of the device, negative resistance arises in the circuit and losses in the entire circuit are compensated with a certain tolerance necessary to amplify the amplitude and eliminate the possibility of excitation of the device, and the left side slope of the frequency response with given slope in a given frequency band. An increase in the quasilinear portion of the left slope of the frequency response occurs. Due to this, the input HMS with an average frequency equal to the average frequency of the left slope of the frequency response is amplified to a level at which the amplitude goes beyond the quasilinear section of the left slope of the frequency response, and the input HMS is converted to AFM. There is an increase in the amplitude of the AFM in the quasilinear section of the left slope of the frequency response, which is equivalent to an increase in the dynamic range. Non-linear element-1 splits (destroys) the spectrum of the AFMC into components, the low-pass filter-5 separates the low-frequency component, and suppresses the rest, the separation capacitance of the CP-6 eliminates the constant component, the low-frequency component, the amplitude of which changes according to the law of the frequency of the input HMS, goes to the low-frequency load -7. FMD demodulation occurs, frequency and nonlinear distortions are reduced. The detection coefficient increases by a factor equal to the gain — the transfer function module of the high-frequency part (up to the low-pass filter) of the proposed device.

Let us prove the feasibility of implementing these properties.

,

,

,

и элементов смешанной матрицы F цепи внешней обратной связи (ОС)

,

,

,

от частоты. При параллельно-последовательном соединении четырехполюсников элементы их матриц F складываются. Суммарные зависимости элементов смешанной матрицы F от частоты: f₁₁=r₁₁+jx₁₁, f₁₂=r₁₂+jx₁₂, f₂₁=r₂₁+jx₂₁, f₂₂=r₂₂+jx₂₂. Размерности элементов матрицы F: f₁₁ (проводимость), f₁₂(безразмерный), f₂₁(безразмерный), f₂₂ (сопротивление). Параметры нелинейного элемента зависят, кроме того, от амплитуды низкочастотного управляющего сигнала. Для простоты аргументы (амплитуда и частота) опущены. Требуется определить частотную зависимость комплексного сопротивления z_н согласующей высокочастотной нагрузки, оптимальную по критерию обеспечения условий формирования левого склона АЧХ и усиления амплитуды ЧМС в режиме частотной демодуляции и усиления.We introduce the notation of the dependences of the resistance of the signal source z ₀₁ = r ₀ + jx ₀ , the load z _n2 = r _n + jx _n and the dependences of the elements of the mixed matrix F of the nonlinear element (VT)

,

,

,

and elements of the mixed matrix F of the external feedback circuit (OS)

,

,

,

from frequency. With a parallel-serial connection of the four-terminal networks, the elements of their matrices F add up. The total dependences of the elements of the mixed matrix F on the frequency: f ₁₁ = r ₁₁ + jx ₁₁ , f ₁₂ = r ₁₂ + jx ₁₂ , f ₂₁ = r ₂₁ + jx ₂₁ , f ₂₂ = r ₂₂ + jx ₂₂ . Dimensions of matrix elements F: f ₁₁ (conductivity), f ₁₂ (dimensionless), f ₂₁ (dimensionless), f ₂₂ (resistance). The parameters of the nonlinear element also depend on the amplitude of the low-frequency control signal. For simplicity, the arguments (amplitude and frequency) are omitted. It is required to determine the frequency dependence of the complex resistance z _{n of the} matching high-frequency load, which is optimal according to the criterion for ensuring the conditions for the formation of the left slope of the frequency response and amplification of the FMR amplitude in the mode of frequency demodulation and amplification.

The common mixed matrix F of the nonlinear element (VT) and the four-terminal feedback loop (OS) and the corresponding classical transmission matrix:

Резистивный четырехполюсник (РЧ) характеризуется матрицей передачи:Where

Resistive four-terminal (RF) is characterized by a transmission matrix:

a, b, c, d - элементы классической матрицы передачи. Общая нормированная классическая матрица передачи высокочастотной части усилителя и частотного демодулятора получается перемножением матрицы передачи (1) и матрицы (2) и учетом условий нормировки:Where

a, b, c, d - elements of the classical transmission matrix. The general normalized classical transmission matrix of the high-frequency part of the amplifier and the frequency demodulator is obtained by multiplying the transmission matrix (1) and matrix (2) and taking into account normalization conditions:

Using the well-known connection between the elements of the scattering matrix and the elements of the classical transmission matrix (Feldstein A.L., Yavich L.R. Synthesis of four-terminal and eight-terminal devices on a microwave. M: Communication, 1971, p. 34-36) and a transmission matrix (3), we obtain the expression for the transmission coefficient of the high-frequency part of the amplifier and the frequency demodulator:

ПоэтомуIt can be shown that the transmission coefficient (4) is related to a physically realized transfer function by a simple relation

therefore

Let it be required to provide the required dependences of the module m (AFC) and phase φ (PFC) of the transfer function of the amplifier and frequency modulator on frequency:

The transfer function (5) is reduced to a known form for the gain of a feedback amplifier:

- коэффициенты усиления цепи прямой передачи и цепи обратной связи.Where

- gains of the forward link circuit and feedback loop.

Let it be required to provide the required dependences of the module m (AFC) and phase φ (PFC) of the transfer function of the amplifier and frequency modulator on frequency:

Substitute (5) or (6) in (7). We solve the resulting complex equation with respect to the resistance of the high-frequency load:

The optimal load characteristics (8), providing a given slope and linearity of the left slope of the frequency response in the entire frequency range, cannot be realized. Here we propose the implementation of quasi-optimal characteristics that approximately coincide with the optimal characteristics in a certain frequency band. Such an implementation can be carried out in various ways, for example, using the interpolation method. For this, it is necessary to form a two-terminal network with a resistance z _n of at least 2N (N is the number of interpolation frequencies) of reactive and resistive elements, find expressions for its resistance, equate them with the optimal values of two-terminal resistance at given frequencies determined by formulas (8), and solve the thus formed system of 2N equations for 2N selected parameters of reactive and resistive elements. The parameter values of the remaining elements can be chosen arbitrarily or on the basis of any other physical considerations, for example, from the condition of physical realizability.

In accordance with this algorithm, for the case N = 2, mathematical expressions are obtained for determining the parameters of a complex bipolar, forming a high-frequency load with resistance z _n , in the form of a complex bipolar from a series of connected first resistive bipolar with a resistance R ₁ , a capacitor with a capacitance C, an arbitrary complex a two-terminal impedance Z ₀ = R _{0 0} + jX and connected in parallel between a second two-terminal resistive with a resistance R ₂ and coil with inductance L (FIG. 3).

The complex resistance of this bipolar:

We divide in (9) the real and imaginary parts and compose a system of four equations:

Decision:

где

Where

- оптимальные значения действительных и мнимых составляющих сопротивления высокочастотной нагрузки (сложного комплексного двухполюсника) на двух частотах, рассчитанные по формуле (8); R₀₁, R₀₂, X₀₁, X₀₂ - заданные значения действительных и мнимых составляющих сопротивления Z₀ произвольного комплексного двухполюсника на двух частотах ω_i=2πf_i; i - номер частоты. Индекс i можно ввести и для других величин, которые зависят от частоты явным образом.

- the optimal values of the real and imaginary components of the resistance of the high-frequency load (complex complex bipolar) at two frequencies, calculated by the formula (8); R ₀₁ , R ₀₂ , X ₀₁ , X ₀₂ - given values of the real and imaginary components of the resistance Z _{0 of} an arbitrary complex two-terminal network at two frequencies ω _i = 2πf _i ; i is the frequency number. Index i can also be introduced for other quantities that explicitly depend on the frequency.

The implementation of the optimal frequency characteristics r _n , x _n , (8) using characteristics (9), which are quasi-optimal characteristics with parameters (11), provides in the vicinity of these two frequencies the specified slope of the left slope of the frequency response (m) in the interests of amplification and conversion of the FM in frequency response in gain mode and frequency demodulation. If the frequencies f ₁ , f ₂ are arranged in increasing order, then the values of m ₁ , m ₂ must be set increasing and with a given slope. With a reasonable choice of the positions of the set frequencies f ₁ , f ₂ relative to each other, the quasilinear slope of the frequency response in the vicinity of these two frequencies will slightly differ from the linear slope when they completely coincide at two frequencies. If you set the operating point in the middle of the quasilinear section of the through-current volt-ampere characteristic of a nonlinear element, then the described algorithm allows you to synthesize a device that operates only in amplification mode (without demodulation). In this case, the output signal must be removed from the high-frequency load-12, the frequency response (m) must be set flat (values m ₁ = m ₂ ), and the input signal can be arbitrary, not just an FMC.

The proposed technical solutions have an inventive step, since it does not explicitly follow from the published scientific data and known technical solutions that the claimed sequence of operations (using an arbitrary four-terminal device connected to a three-pole nonlinear element in a parallel-serial circuit as an external feedback circuit, including a three-pole nonlinear feedback element and circuit as a single node between the signal source and the input of the resistive quadripole , Inclusion of high load between the output of the resistive quadripole and the low-frequency part made of a low-pass filter, the separation capacity and low-frequency loads (FIG. 2), the choice of optimal frequency dependency of the real r _n and the imaginary x _and high load resistance components forming circuit complex two-terminal network for implementing quasioptimal characteristics of the high-frequency load in the specified form (Fig. 3), the choice of the values of its parameters) provides both amplification, conversion of the emergency AFMC on the left slope of the frequency response, demodulation of the frequency response, which is equivalent to frequency demodulation;

The proposed technical solutions are practically applicable, since for their implementation three-pole non-linear elements (transistors or lamps) commercially available by the industry, reactive and resistive elements formed in the claimed circuit of a complex two-pole can be used (Fig. 3). The values of the parameters of the resistors, inductances and capacitances of this circuit can be uniquely determined using mathematical expressions given in the claims.

The technical and economic efficiency of the proposed device is to provide amplification and frequency demodulation of a high-frequency signal by selecting the circuitry and parameter values of the reactive and resistive elements of a complex matching two-terminal device - a high-frequency load according to the criterion for the formation of the left slope of the frequency response with specified slope and gain, which unifies the device, increases quasilinear portion of the frequency demodulation characteristic and dynamic range in gain mode and hour total demodulation.

Claims (2)

1. The method of amplification and demodulation of frequency-modulated signals, based on the use of energy from a constant voltage source, the interaction of the frequency-modulated signal with a device that is performed from a direct transmission circuit in the form of a three-pole nonlinear element, four-terminal, external feedback circuit, low-pass filter, separation capacitance and low-frequency load, meeting the conditions for matching the forward circuit with the external feedback circuit, matching conditions for the external feedback circuit with a control electrode of a three-pole nonlinear element, matching conditions for the direct transmission circuit, and the external feedback circuit with the rest of the device with a given tolerance, converting the frequency-modulated signal into an amplitude-frequency-modulated signal on the left slope of the amplitude-frequency characteristic, splitting the spectrum -frequency-modulated signal to low-frequency and high-frequency components using a three-pole nonlinear element, the selection of the low-frequency component with using a low-pass filter, eliminating the dc component using a dividing capacitance, and obtaining a low-frequency signal at a low-frequency load, the amplitude of which changes according to the law of frequency change of the frequency-modulated signal, characterized in that the four-terminal is made resistive, an arbitrary complex four-terminal is used as the external feedback circuit connected to a three-pole nonlinear element in parallel-serial circuit, a three-pole nonlinear element and The feedback circuit as a single node is cascaded between the source of the frequency-modulated signal with complex resistance and the input of the resistive four-terminal, between the output of the resistive four-terminal and the low-pass filter, they include a high-frequency load in the form of a two-terminal with complex resistance z _n , matching conditions according to the criterion of simultaneously providing amplification and frequency demodulation is performed by selecting the frequency dependence of the resistance z _n in accordance with the following mathematical by rage:

Where

- the given relations of the corresponding elements of the classical transmission matrix of the resistive four-terminal a, b, c, d; z ₀ - a given dependence of the complex resistance of the source of the input frequency-modulated signal on the frequency in a given frequency band; f ₁₁ , f ₁₂ , f ₂₁ , f ₂₂ - the given total dependences of the complex elements of the mixed matrix F of the three-pole nonlinear element on the frequency in the given frequency band and the corresponding dependences of the complex elements of the mixed matrix of the external feedback circuit on the frequency in the given frequency band; m, φ are the given dependences of the module and phase of the transfer function of the device on the frequency to form the specified slope of the left slope of the frequency response of the device in a given frequency band that matches the frequency range of the frequency-modulated signal; j is the imaginary unit. 2. A device for amplifying and demodulating frequency-modulated signals made from a constant voltage source, a direct transmission circuit in the form of a three-pole nonlinear element, a four-terminal, external feedback circuit, a low-pass filter, a separation capacitance, and a low-frequency load, characterized in that the four-terminal is made resistive , as an external feedback circuit, an arbitrary complex four-terminal network connected to a three-pole nonlinear element via a parallel-serial circuit was used hydrochloric scheme tripolar nonlinear element and a feedback circuit as a unit cascade connected between a source of frequency modulated signal with a complex impedance and the input resistive quadripole, between the output of the resistive quadripole and lowpass filter including high-load in the form of a complex two-terminal network with a complex impedance z _n, which is formed from a series-connected first resistive two-terminal with resistance R ₁ , a capacitor with a capacitance C, arbitrary of a complex two-terminal with resistance Z ₀ = R ₀ + jX ₀ and a second resistive two-terminal with resistance R ₂ and coils with inductance L connected in parallel to each other, parameters R ₁ , R ₂ , L, C are selected from the matching condition according to the criterion of simultaneously providing amplification and frequency demodulation in accordance with the following mathematical expressions:

Where

- the optimal values of the real and imaginary components of the resistance of the high-frequency load at two frequencies, calculated by the formula

- the given relations of the corresponding elements of the classical transmission matrix of the resistive four-terminal a, b, c, d; R ₀₁ , R ₀₂ , X ₀₁ , X ₀₂ - given values of the real and imaginary components of the resistance Z _{0 of} an arbitrary complex two-terminal network at two frequencies ω _i = 2πf _i ; i = 1, 2 - frequency number; z _0i are the set values of the complex resistances of the source of the input frequency-modulated signal at two given frequencies; f _11i , f _12i , f _21i , f _22i are the set total values of the complex elements of the mixed matrix F of the three-pole nonlinear element and the corresponding values of the complex elements of the mixed matrix F of the external feedback circuit at two given frequencies; m _i , φ _I - the set values of the modules and phases of the transfer function of the device at two predetermined frequencies to form a given slope of the left slope of the frequency response of the device in a given frequency band that coincides with the frequency range of the frequency-modulated signal; j is the imaginary unit.

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