RU2484577C2 - Noise jamming device - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: result is achieved by using a second parallel nonlinear oscillatory circuit connected to a first. By using new components, the device has a wider range of irreversible nonlinear transformations of the initial signal. The capacitive and inductive coupling between the two circuits enables to control the level of distortion of the initial signal.

EFFECT: wider band of generated frequencies of a noise jamming transmitter, possibility of controlling the noise spectrum and level of irreversible distortions of the signal with a relatively simple design.

14 dwg

Description

The invention relates to radio engineering and can be used for the on-line formation of noise interference generated from an external control signal, for example, to create test noise signals in order to evaluate the noise immunity of radio receivers for various purposes.

It is known "Device for generating response interference to radar stations" (patent RU 2237372, 2004). The effect of a significant increase in the density of the interference spectrum is achieved using N receivers and M transmitters controlled by a specialized computer. A clear drawback of this device is its exceptional complexity and narrow specialization, as well as knowledge of the exact time parameters of pulse signals.

The well-known "Generator of chaotic oscillations" (patent RU 2246790, 2005). It is distinguished by its exceptional simplicity of design (it contains only two resistors, two capacitors, a device with negative conductivity and an RC circuit with negative conductivity), a wide band of generated noise, however, the generator can create interference only in an autonomous self-excitation mode.

Known "jamming Station" (patent US 3896439, 1955). The station is intended for radio suppression of pulse-Doppler radar systems for early detection of air and ballistic targets, by re-reflection, with a certain time delay, of received radar pulses. The disadvantage of this device is the design complexity due to the presence of a large number of measurement channels for time intervals.

The closest in technical essence is a device that implements the "Method for the formation of noise interference" (patent RU 2220508, 2003). The functioning of the device consists in the fact that a periodic signal is amplified to the required power level by an amplifier loaded on a non-autonomous non-linear dynamic system and operating in a non-linear mode with a high efficiency, is converted into noise stochastic noise with the required energy spectrum and high quality coefficient using the appropriate the choice of parameters of a non-autonomous non-linear dynamic system and the frequency of the generating effect based on the phenomenon of statistical ski irreversible changes in the non-autonomous nonlinear dynamical systems. The disadvantage of this device is the relatively narrow band of generated frequencies and the inability to control the interference spectrum.

The aim of the invention is to expand the frequency band of the transmitter of noise interference, the ability to control the interference spectrum, as well as the level of irreversible signal distortion with relative simplicity of design.

This goal is achieved by introducing a second parallel nonlinear oscillatory circuit associated with the first. Due to the introduction of new elements, the device receives a wider range of irreversible nonlinear transformations of the original signal. Capacitive and inductive coupling between the two circuits allows you to control the level of distortion of the original signal.

The invention is illustrated by drawings:

Figure 1. Schematic diagram of a single parallel resonant circuit.

Figure 2. Frequency response of a single resonant circuit.

Figure 3. Phase-frequency characteristic of a single resonant circuit.

Figure 4. Schematic diagram of two single parallel resonant circuits with external capacitive coupling.

Figure 5. Schematic diagram of two single parallel resonant circuits with external mutual inductive coupling to each other.

6. Frequency response of the first (input) of two mutually connected single parallel resonant circuits.

7. Frequency response of the second (output) of two mutually connected single parallel resonant circuits.

FIG. 8. Phase-frequency characteristic of the first (input) of two mutually connected single parallel resonant circuits.

Fig.9. Phase-frequency characteristic of the second (output) of two mutually connected single parallel resonant circuits.

Figure 10. Schematic diagram of two single parallel resonant circuits containing non-linear capacitances C1 and C2 and having an external mutual capacitive coupling C3.

11. Schematic diagram of two single parallel resonant circuits containing non-linear capacitances C1 and C2 and having an external mutual inductive coupling M to each other.

Fig. 12. Schematic diagram of a device for generating noise interference with one parallel nonlinear resonant circuit.

Fig.13. Schematic diagram of a device for generating noise interference with two mutually connected single parallel nonlinear circuits.

Fig.14. Schematic diagram of the claimed device for the formation of noise interference.

As follows from the description of the theory of the formation of noise interference of a bifurcation type (spasmodic) (Kopytov V.V. Synthesis of stochastic interference based on the phenomenon of statistical irreversibility in nonlinear dynamical systems. - M .: MO RF, 2003. - 91 p., P. 75- 86, paragraph 4.2. Experimental determination of the region of occurrence of stochastic oscillations in a non-autonomous non-linear dynamic system) by choosing the level of restriction and the parameters of the system itself, the remainder of the undistorted part of the signal at the output of the noise shaper can be adjusted, thereby changing the noise correlation function even with a relatively simple nonlinear parametric system in the form of a single parallel resonant circuit, the circuit diagram of which is shown in Fig. 1 and consisting of an inductor L1, resistance R1 and an electric capacitor C1, the capacitance of which is determined by the sum of the direct and high-frequency voltage applied to him.

Figure 2 and figure 3 shows the amplitude-frequency and phase-frequency characteristics of a single resonant circuit, where ω is the current angular frequency of the signal, ω ₀ is the resonant frequency of the circuit (Gomerovsky I.S. Theoretical foundations of radio engineering. - M .: Soviet radio. 1963. - 684 pp. See pages 124-130. Fig. 4.7 a, b.).

As can be seen from figure 2, the bandwidth of the circuit at the level of 0.5 from the maximum is 0.02ω / ω ₀ , which corresponds to the quality factor Q = 100. The phase-frequency characteristic of the circuit is a smooth fuzzy function passing through zero and asymptotically approaching the limits of ± 90. Obviously, controlling the capacitance of capacitor C1 according to some random law, it is possible to shift both the amplitude-frequency (Fig. 2) and phase-frequency (Fig. 3) characteristics of the circuit along the frequency axis ω / ω ₀ and thereby create a nonlinear dynamic system driven by the signal. Unfortunately, due to the exceptional simplicity of the circuit in the diagram of Fig. 1, as well as the smoothness of the characteristics in Fig. 2 and Fig. 3, it is difficult to carry out deep nonlinear irreversible transformations of the original signal, which is a feature of the device closest in technical essence and its drawback.

Significantly increase the depth of nonlinear changes in the parameters of the resonant system, if you replace a single circuit with two connected by an external capacitive or inductive coupling, as shown in Fig. 4 and Fig. 5, respectively (Gomerovsky I.S. Radio circuits and signals. - M .: Soviet radio, 1963 - 684 pp. See 157-162, Fig. 5.1, 5.8.) Figures 6 and 7 respectively show graphs of the amplitude-frequency characteristics of two connected parallel loops depending on the coupling coefficient, defined as the product

$$K_{\mathrm{from}\mathrm{at}}=kQ,(\mathrm{one})$$

Where

$$k=\frac{M}{L};(2)$$

M is the coupling inductance;

L = L1 = L2 - intrinsic inductance of each circuit;

Q is the quality factor of the circuit;

$$Q=\frac{{\omega }_{0}L}{r};(3)$$

ω ₀ is the resonant frequency of the circuit;

r is the resistance of the active losses of the circuit.

As follows from Fig.6, the amplitude-frequency characteristics of the first (input circuit) changes its shape from a narrow one-humped with a very weak connection (kQ = 0.1) and retains it until a critical connection is reached (kQ = 0.49), after which it takes a two-humped shape with a deep dip at kQ = 3.0. The amplitude-frequency characteristic of the second (output) circuit behaves similarly, as shown in Fig. 7. The difference between the characteristics of FIG. 6 and FIG. 7 is that as the coupling coefficient decreases, the maximum of the first circuit grows and the second decreases. In Fig.6 and Fig.7 parameter a denotes the relative detuning with respect to the resonant frequency of the circuit ω ₀ :

$$a=\frac{{\omega }_0-\omega }{{\omega }_0}Q.(\mathrm{four})$$

According to the data from the source indicated above (see p. 178, Fig. 5.15 and Fig. 5.16), the phase-frequency characteristics of the double-circuit resonant circuit have much greater non-linearity and curvature compared to single-circuit ones. As follows from Fig. 8, the corresponding phase-frequency characteristic of the first (input) circuit, in the case of a large coupling (kQ≥1), there is an odd symmetry near the resonant frequency and the appearance of two humps with the opposite phase. Figure 9 shows data on the change in the slope of the phase-frequency characteristic of the second (output) circuit with increasing coupling coefficient kQ≥1).

It is obvious that in the case of the use of nonlinear reactive elements of coupled circuits, as shown in FIG. 10 and 11, similar to FIGS. 4 and 5, respectively, the range of deep amplitude-frequency and phase-frequency characteristics of the resonance system will be significantly expanded, This will create more favorable conditions for irreversible non-linear transformations of the signal into noise interference.

Based on the description of the device that implements the method of generating noise interference (patent RU 2220508, 2003), a schematic diagram of a device with one parallel nonlinear oscillatory circuit can be depicted in the form of Fig. 12, where it is conventionally indicated:

E - power source;

VT1 - transistor;

VD1 - varicap;

R1 and R2 - voltage divider in the base-emitter circuit with two resistors to ensure the operation mode of the transistor with collector current cutoff;

C1 is a transition capacitor;

C2 - additional capacitor to establish the required resonant frequency;

L1 - inductor with a ferrite tuning core;

I _K0 - DC collector current.

Figure 13 shows a schematic diagram of a similar amplifier, but having a dual-circuit resonant system as a load, consisting of a primary circuit L1C2 D1, a secondary circuit L2C4VD2 and an element for inter-circuit external communication - capacitive (C3) or inductive (M). The main difference between the device is the presence of a second output circuit L2C4VD2 and a communication element C3 or M. Due to the introduction of new elements, the device receives a wider range of irreversible nonlinear transformations of the original signal. That is, if in the first case of the original prototype according to the scheme in Fig. 12, the process of such transformations is possible under conditions of a relatively small range of changes in the input signal level, abruptly, then for the device according to the scheme in Fig. 13, the required level of distortion of the original signal can be adjusted from an undistorted linear amplification to its almost complete distortion.

To fully realize the potential of the proposed device according to the scheme in Fig. 13, it is necessary to select the capacitance of the capacitor C3 (or the connection M) to achieve the required depth of the frequency response of the amplifier. Additionally, to directly connect the input of the interference generator to the source of the external source signal, an RF connector XA1 is introduced, connected to the base of transistor VT1 through a transistor C1. The output voltage of the device is supplied to the output socket of the high-frequency connector connected to part of the turns of the second inductor.

On Fig presents a schematic diagram of the inventive device for the formation of noise interference, where the following conventions are used:

1 - power source - DC voltage;

2 - bipolar n-p-n transistor operating according to the scheme with a common emitter and zero initial collector current in the absence of a signal;

3 - “Input” jack for connecting a signal source that is converted to noise interference;

4 - a transition capacitor for transmitting a microwave signal for further transformations;

5-6 - resistors of a constant voltage divider of the initial bias in the base-emitter circuit of transistor 2;

7 - inductance coil of the primary circuit;

8 - capacitor of constant capacity of the primary circuit;

9 - the first varicap with an initial zero bias voltage;

10 - inductance coil of the second circuit;

11 - capacitor of constant capacity of the second circuit;

12 - second varicap with an initial zero bias voltage;

13 - capacitor of the external connection of the resonant circuits;

14 - socket "Output" of the device;

15 - transition capacitor in the output circuit of the device.

The operation of the device in Fig.14 is as follows. When the output of the external source of the initial signal is connected to socket 3, its power is amplified in the amplifier on transistor 2. By selecting the values of the resistors 5 and 6 of the initial-voltage DC divider based on the emitter, the operation mode with the collector current cutoff angle Q = 90 ° is set at which the amplitude of the current of the first harmonic is maximum. When operating in the small signal mode, when the distortion of the signal in the amplifier on transistor 2 can be neglected, the first resonant circuit is tuned to the resonant frequency determined by the inductance 7 and the sum of the capacitor 8 and the initial capacitance of the varicap 9, when the bias voltage on it is zero.

As the voltage of the input signal increases, the amplifier on the transistor 2 enters a nonlinear operation mode, and with it the first resonant circuit. So, when a microwave voltage of positive polarity acts on the varicap 9 anode, it behaves like an ordinary diode, biased in the forward direction, that is, as a nonlinear active resistance. When changing the polarity of the voltage, the varicap operates in reverse bias mode, as a capacitor of nonlinear capacitance. As a result of the joint interaction of the nonlinearity of the amplifier and the resonant circuit, the latter causes irreversible bifurcation changes in the signal structure, which make noise noise from it.

The presence of a second resonant circuit tuned in resonance with the first, and a coupling capacitor 13 connected between both circuits, radically changes the picture of the occurrence and maintenance of irreversible bifurcation changes in the signal structure. Due to the connection 13, the second circuit takes on part of the current of the first harmonic of the collector of transistor 2 and makes its own irreversible changes in the signal structure. The result of the interaction of two connected equally tuned resonant circuits are irreversible nonlinear signal transformations, which are supported in a wider range of changes in the input signal level than is the case in the device claimed as a prototype.

Thus, as was presented above, the introduction of an additional resonant circuit identical to the first and a capacitor 12 that provides external communication between them into the prototype device for generating noise interference is a new distinguishing feature of the claimed device, providing the requirements for it.

Claims (1)

A device for generating noise interference, which includes a DC voltage power source, one bipolar pnp transistor, one inductor, one varicap, two constant resistors, three constant capacitors and two high-frequency connectors, interconnected so that the source DC voltage supply is connected with its “minus” to the common wire, and “plus” - with the power bus, the emitter of the transistor is connected to the common wire, its base is connected to the input socket of the first high-frequency by connecting through the first capacitor, both constant resistors are connected in series with each other, with their common point connected to the base of the transistor, one free output connected to a common wire, and the other to the power bus, the first parallel resonant circuit is included in the collector circuit of the transistor, consisting of inductors, second capacitor and varicap, which is connected to the collector of the transistor by its anode and to the power bus by the cathode, the output socket of the second high-frequency connector is connected through the third condensate p, characterized in that it additionally introduced a second parallel resonant circuit, consisting of a second inductor, a fourth capacitor and a second varicap, which is connected by its cathode to the power bus, the anode through the fifth capacitor with the collector of the transistor, and the output voltage of the device is supplied to an output socket of a high-frequency connector connected to a part of the turns of a second inductor.

Images