RU2342780C1 - Generator of broadband frequency-modulated signal - Google Patents

Abstract

FIELD: physics, radio.

SUBSTANCE: invention concerns radio engineering and application as shapers of noises in transmitters of noises of different function, and also in radio communication resorts can find. Generator of the broadband frequency-modulated signal contains the shaper modulating oscillations and the self-oscillator, the generator of a signal with a continuous spectrum, the multiplication block, a loading, thus the shaper modulating oscillations are contained by the shaper of the normalised noise, the shaper of sawtooth impulses, the shaper of a white noise and the adder, and the self-oscillator contains the tunable shaper of a constant voltage and the generator controllabled a voltage.

EFFECT: expansion of instantaneous spectrum of signal, decrease in level of autocorrelation noises.

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Description

The device relates to radio engineering and can find application as signal conditioners in interference transmitters for various purposes, as well as in radio communications.

Known noise generators for AS 1817634, H03B 5/12, US Pat. RF 2042260, Н03В 5/12, their disadvantage is the narrow frequency band of the emitted signal. Known noise generator according to US Pat. RF 25251, Н03В 29/00, chaotic oscillator according to US Pat. RF 2058660, Н03В 29/00, the disadvantage of which is the limited frequency band, as well as the inability to control a parameter such as spectral noise density.

Also known is a system of coupled generators in the presence of inertia described in the article by Kalyanov E.V., Lebedeva M.N. “Stochastic oscillations in a system of coupled generators in the presence of inertia,” published in the journal Radio Engineering and Electronics. Volume XXX, issue 8, August 1985, p. 1574, its drawback is the significant unevenness of the spectral density of the generated noise and the inability to control the parameters of stochastic oscillations.

The closest in technical essence to the proposed one is a noise generator with the adjustment of the spectrum parameters according to the patent for a utility model of the Russian Federation 54277, Н03В 29/00, adopted as a prototype.

Figure 1 presents the functional diagram of the device of the prototype, where indicated:

1 - a generator based on a voltage controlled oscillator (VCO);

1.1 - voltage-controlled generator (VCO);

1.2 - tunable DC voltage driver;

2 - shaper relaxation oscillations;

2.1 - shaper normalized noise;

2.2 - shaper sawtooth pulses;

2.3 - adder;

4 - load.

The prototype device contains a serially connected shaper of modulating relaxation oscillation 2, a self-oscillator based on the VCO 1 and load 4. Moreover, the shaper of modulating relaxation vibration 2 contains a serially connected shaper of normalized noise 2.1, a shaper of sawtooth pulses 2.2 and adder 2.3, the output of which is the output of the shaper modulating relaxation oscillation 2. In addition, the second output of the normalized noise former 2.1 is connected to the second input of the adder 2.3. The oscillator 1 contains a tunable dc voltage generator 1.2 and a VCO 1.1 connected in series, the input of which is the input of the oscillator 1. The VCO 1.1 output is the output of the oscillator 1. The input of the tunable dc voltage generator 1.2 is an input for the control voltage.

The prototype device operates as follows. When the supply voltage is turned on, a constant voltage is generated in block 1.2 and a modulating relaxation oscillation in block 2, which are fed to the VCO 1.1 input. The amplitude of the constant voltage sets the frequency of harmonic oscillations ω ₀ VCO 1.1, which is the average frequency of the spectrum of the noise signal. The amplitude of the DC voltage can be changed under the influence of U _UPR supplied to the input of block 1.2. The operating frequency band of the prototype generator is determined by the amplitude of the modulating relaxation oscillation. The modulating relaxation oscillation is an additive mixture of normalized noise and a sequence of sawtooth pulses modulated by the same noise. The pulses in the sequence differ in duration, and hence in the steepness of the “saw” and “normalize” the relaxation oscillation at the VCO 1.1 input. The average duration of the sawtooth pulses is chosen such that, at certain ratios with the reaction time of the VCO 1.1 on the disturbing effect, the spectrum of noise oscillations expands. Under the influence of variable amplitudes of constant voltage and relaxation oscillations in the load 4, a noise signal is formed with the given parameters.

The disadvantage of the prototype device is that the sequence of sawtooth pulses is modulated by normalized noise, this leads to the formation of correlation between the components of the interference and, accordingly, allows to reduce the effect of such interference. Another disadvantage of the prototype generator is that the instantaneous noise spectrum is a narrow-band frequency-modulated noise interference, the frequency of which varies in accordance with the change in the modulating voltage. In the case where the range of the interference frequency exceeds the receiver bandwidth, the interference becomes pulsed.

To compensate for this type of interference, a large number of effective protection schemes against radio interference have been developed, for example, such as broadband amplification, limiting, amplification (SHO), broadband amplification, interruption, amplification (SHPU), etc. (see for example: Maksimov M.V., Bobnev M.P., Krivitsky B.Kh. et al. “Protection against radio interference”, ed. “Sov. Radio”, 1976, pp. 382 ... 400 )

To eliminate these shortcomings, a broadband frequency-modulated signal generator contains a serially connected modulating oscillator and a self-oscillator, as well as a load, and the modulating oscillator includes serially connected normalized noise shaper, a sawtooth pulse shaper and an adder, the adder output is the output of the modulating oscillator , the oscillator consists of series connected trans spent voltage generator and voltage-controlled generator (VCO), the output of which is the output of the oscillator, and the input of the oscillator is the input of the VCO, the second input of the tunable DC voltage generator is an input for the control voltage, according to the invention, a signal generator and a multiplication unit are introduced, the output of which is connected with the load input, its first input is connected to the output of the oscillator, and the second input to the output of the signal generator, as well as a white noise shaper, the output to orogo connected to the second input of the adder.

The structural diagram of the inventive device is shown in figure 2, where it is indicated:

1 - a generator based on a voltage controlled oscillator (VCO);

1.1 - voltage-controlled generator (VCO);

1.2 - tunable DC voltage driver;

2 - shaper modulating oscillations;

2.1 - shaper normalized noise;

2.2 - shaper sawtooth pulses;

2.3 - adder;

2.4 - shaper white noise;

3 - multiplication block;

4 - load;

5 - signal generator.

The proposed device contains a serially connected modulating oscillation generator 2, an oscillator based on the VCO 1, a multiplication unit 3 and a load 4, as well as a signal generator 5, the output of which is connected to the second input of the multiplication unit 3.

In this case, the modulating oscillator 2 contains a serially connected normalized noise generator 2.1, a sawtooth pulse generator 2.2 and an adder 2.3, the output of which is the output of the modulating oscillator 2, and a white noise generator 2.4, the output of which is connected to the second input of the adder 2.3.

The oscillator 1 consists of a series-connected tunable DC-voltage driver 1.2 and VCO 1.1, the output of the VCO 1.1 is the output of the oscillator 1, and the input of the VCO 1.1 is the input of the oscillator 1. The input of the tunable DC-voltage generator 1.2 is the input for the control voltage.

The proposed device operates as follows.

Modulating oscillation is an additive mixture of white noise and a sequence of sawtooth pulses modulated by normalized noise. The frequency-modulated oscillation from the output of the oscillator 1 is fed to the first input of the multiplication unit 3, the second input of which is supplied with a signal from the output of the signal generator 5. At the output of the signal generator 5, a signal with a continuous spectrum in a certain frequency band is formed.

At the output of the multiplication unit 3, the difference and total combination components are formed between the frequency-modulated noise oscillation coming from the output of the oscillator 1 and the signal coming from the output of the signal generator 5. The signal spectrum at the output of the multiplication unit 3 is continuous, and the signal is frequency-modulated .

For example, one of the frequency components of the resulting signal (total component) can be written as

where U is the amplitude of the resulting signal;

_r ω, φ _d - the frequency and phase of a component of the signal generator 5,

ω _ш , φ _ш (t) - frequency and phase of the frequency-modulated noise vibration coming from the output of the oscillator 1.

As the signal generator 5 can be used, for example, a white noise shaper or a signal generator with a continuous spectrum, according to the scheme in figure 3.

The structural diagram of the signal generator with a continuous spectrum is shown in figure 3, where indicated:

5.1.1-5.1.n - from the first to the n-th tunable dc voltage drivers;

5.2.1-5.2.n - from the first to the nth voltage-controlled oscillators (VCOs);

5.3 - non-linear element;

5.4, 5.5 - the first and second band-pass filters.

The signal generator with a continuous spectrum of 5 contains n tunable DC-shapers 5.1.1-5-1.n, the outputs of which are connected to the inputs of the corresponding n VCOs 5.2.1-5.2.n, the outputs of which are combined and connected to the input of the nonlinear element 5.3, the output which through the first band-pass filter 5.4 is connected to the input of the second band-pass filter 5.5, the output of which is the output of the device. In addition, the output of the first band-pass filter 5.4 is connected to the input of the nonlinear element 5.3. In this case, the inputs of tunable direct-current formers 5.1.1-5.1.n are inputs for the control voltages U _UPR .

As a result of the operation of signal generator 5, due to the formation of combinational components between VCO signals 5.1.1-5.1.n and the signal from the output of the first bandpass filter 5.4, a signal with a spectrum is formed at the output of the second bandpass filter 5.5, the band of which is determined by the value of the band transmittance of the second band-pass filter 5.5. In this case, the distance between the spectral components is regulated by selecting the amplitudes of the control voltages U _UPR , which determine the values of the frequencies of harmonic oscillations at the outputs of the VCO 5.1.1-5.1.n. With certain ratios between the frequencies of harmonic oscillations, for example, when the difference between them tends to an irrational number, the spectrum of the generated signal tends to a continuous spectrum. As a non-linear element 5.3, for example, a non-linear diode bridge type diode bridge can be used, and the diodes used have a quadratic characteristic.

Thus, compared with the prototype, the proposed device provides the formation in the load of a frequency-modulated noise signal with a broadband instantaneous spectrum, which leads to an increase in the time of exposure to interference and thereby increases the efficiency of interference, when using a number of amplitude-frequency selection schemes, such as for example, like SHOW, SHPU schemes, etc. In addition, the proposed device provides a reduction in the level of autocorrelation of interference.

Claims (1)

A broadband frequency-modulated signal generator containing a serially connected modulating oscillator and an oscillator, as well as a load, the modulating oscillator comprising serially connected a normalized noise generator, a sawtooth pulse train and an adder, the output of the adder is the output of the modulating oscillator, the oscillator consists of a series connected tunable constant shaper voltage and voltage-controlled oscillator (VCO), the output of which is the output of the oscillator, and the input of the oscillator is the VCO input, the input of the tunable DC-voltage driver is an input for the control voltage, characterized in that a signal generator with a continuous spectrum and a multiplication unit are introduced, the output of which connected to the load input, its first input is connected to the output of the oscillator, and the second input to the output of the signal generator, as well as a white noise shaper, the output of which is connected to the second input adder.

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