RU2656840C1 - Broadband signal generator - Google Patents

Abstract

FIELD: radio engineering and communications.

SUBSTANCE: invention relates to radio engineering and can be used as signal formers in transmitters of communication devices for various purposes. For this purpose, a generator containing n renovate formers of constant voltage (1.1–1.n), outputs of which are connected to inputs of corresponding n voltage-controlled generators (VCG) (2.1–2.n), series-connected bandpass filter (5) and load (6), output of which is an output of the device, in this case, inputs of renovate formers of constant voltage (1.1–1.n) are inputs for control voltages, n electronic keys (3.1–3.n), inputs of which are connected to outputs of corresponding n VCGs (2.1-2.n), multiplier (4) whose output is connected to input of bandpass filter (5), and outputs of electronic keys (3.1–3.n) from 1 to k-th are combined and connected to the first input of multiplier (4), and outputs of electronic keys from k+1^st to n-th are combined and connected to the second input of multiplier (4); also, control device (7) is connected, output of which is connected to the second inputs of electronic keys (3.1–3.n).

EFFECT: technical result is to ensure the formation of a broadband signal with common-mode frequency components with uniform frequency response over time, commensurate with the period corresponding to the lower frequency of the signal.

1 cl, 3 dwg, 3 tbl

Description

The invention relates to radio engineering and can be used as signal conditioners in transmitters of communication devices for various purposes.

A generator with electronic frequency tuning is known (copyright certificate No. 1817634 dated 04/04/1989), in which, using the voltages generated by the voltage source, the oscillatory system is controlled in such a way that the stability of the output power during frequency tuning in a wide range with a frequency overlap coefficient is increased K _f = 2.5. The disadvantage of this generator is the narrow frequency band of the emitted signal.

A known generator with electronic frequency tuning (RF patent No. 2042260 from 07.26.1989), designed to generate microwave oscillations with smooth frequency tuning, the disadvantage of which is a narrow frequency band of the emitted signal.

The closest analogue in technical essence to the proposed one is a generator of quasi-chaotic oscillations with variable spectrum parameters according to the patent of the Russian Federation No. 2330375 of 05.16.2007, adopted as a prototype.

In FIG. 1 shows a functional diagram of a prototype device, where it is indicated:

1.1-1.n - from the first to the n-th tunable dc voltage drivers;

2.1-2.n - from the first to the n-th voltage controlled oscillators (VCO);

5 - the first band-pass filter;

6 - load.

8 - non-linear element;

9 - second band-pass filter.

The prototype device contains n tunable dc drivers 1.1-1.n, the outputs of which are connected to the inputs of the corresponding n VCO 2.1-2.n, the outputs of which are combined and connected to the input of the nonlinear element 8, the output of which is through the second 9 and the first 5 connected in series bandpass filters are connected to the input of the load 6, the output of which is the output of the device. Moreover, the output of the second bandpass filter 9 is connected to the input of the nonlinear element 8. This input DC voltage tunable formers 1.1-1.n are inputs for the control voltages U _Ex.

The prototype device operates as follows.

By choosing the values of the amplitudes of the control voltages U _CPr , which are fed to the inputs of n tunable constant-voltage drivers 1.1-1.n, constant voltages are formed at their outputs, whose amplitudes determine the frequency of harmonic oscillations ω ₁ , ω ₂ , ... ω _n for n VCO 2.1-2.n respectively.

Harmonic oscillations from the outputs of the VCO 2.1-2.n are fed to the input of the non-linear element 8. At the output of the non-linear element 8, the combination components of harmonic oscillations ω ₁ , ω ₂ , ... ω _n (total and difference) are formed, which, after passing through the second band-pass filter 9, are together with harmonic oscillations coming from the outputs of the VCO 2.1-2.n are fed to the input of the nonlinear element 8. After the device starts to work, for some time, harmonic oscillations are formed, gradually filling the frequency band, fissioning stripe second bandpass filter 9, the filling density baseband frequency determined by the values of harmonic oscillations ω _1, ω _2, ... ω _n VCO 2.1-2.n respectively.

The band of the first band-pass filter 5 is selected on the basis of the conditions for providing a given value of the signal band.

The distance between the spectral components is regulated by choosing the amplitudes of the control voltages U _CPR , which determine the values of the frequencies of harmonic oscillations at the output of the VCO 2.1-2.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.

The generated signal is fed to the load 6, for example, a broadband amplifier or antenna.

The prototype device provides the formation of a signal, the band of which is limited only by the frequency characteristics of the elements used, and the "occupancy" of the spectrum by harmonic oscillations is controlled by choosing the values of the amplitudes of the control voltages.

The disadvantage of the prototype device is the significant non-uniformity of the amplitude-frequency characteristics of the signal, the large time of signal formation and, accordingly, the presence of restrictions on the speed of data exchange when it is used in communications.

The objective of the invention is to ensure the formation of short powerful pulses in a wide frequency band without a carrier.

Achievable technical result - ensuring the formation of a broadband signal with in-phase frequency components with a uniform amplitude-frequency characteristic (AFC) for a time comparable with the value of the period corresponding to the lower frequency of the signal.

To eliminate these drawbacks, a generator containing n tunable dc voltage drivers 1.1-1.n, the outputs of which are connected to the inputs of the corresponding n voltage-controlled oscillators (VCOs) 2.1-2.n, are connected in series with a band-pass filter (5) and a load (6 ), the output of which is the output of the device, while the inputs of tunable direct-current drivers 1.1-1.n are inputs for control voltages; according to the invention, n electronic keys 3.1-3.n are introduced, the inputs of which are connected to the outputs corresponding n VCO 2.1-2.n, a multiplication device 4, the output of which is connected to the input of the bandpass filter 5, and the outputs of the electronic keys 3.1-3.n from 1 to k are combined and connected to the first input of the multiplication device 4, and the outputs of electronic keys k + 1 through n are combined and connected to the second input of the multiplication device 4; also introduced a control device 7, the output of which is connected to the second inputs of electronic keys 3.1-3.n.

Functional diagram of the proposed device is shown in FIG. 2, where indicated:

1.1-1.n - from the first to the n-th tunable dc voltage drivers;

2.1-2.n - from the first to the n-th VCO;

3.1-3.n - from the first to the n-th electronic keys;

4 - multiplication device;

5 - band-pass filter;

6 - load;

7 - control device.

The proposed device contains n tunable dc drivers 1.1-1.n, the outputs of which are connected to the inputs of the corresponding n VCO 2.1-2.n, n electronic keys 3.1-3.n, the inputs of which are connected to the outputs of the corresponding n VCO 2.1-2.n. n, series-connected device of multiplication 4, a band-pass filter 5 and load 6, the output of which is the output of the device, the outputs of the electronic keys from 3.1 to 3.k are combined and connected to the first input of the device of multiplication 4, and the outputs of the electronic keys from 3. (k +1) by 3.n are combined and connected to the second input of the multiplication device 4; as well as a control device 7, the output of which is connected to the second (control) inputs of electronic keys 3.1-3.n, while the inputs of tunable direct-current drivers 1.1-1.n are inputs for control voltages U _control .

The proposed device operates as follows.

The total number of tunable n dc drivers 1.1-1.n, VCO 2.1-2.n, electronic keys 3.1-3.n and the number of devices k responsible for the formation of the first frequency grid is determined depending on the requirements for the generator by the size of the strip generator frequencies, the density spectrum of the signal and the power of the output signal at the stage of development of the device.

The first group of VCOs 1.1-1.k are the generators of the first frequency grid and form a frequency grid in a given frequency range.

The second group of VCOs 1. (k + 1) -1.n are the generators of the second frequency grid and form a frequency grid in a given frequency range.

The first group 1.1-1.k VCO generates the frequency components in the frequency band of the generator F _n - F _in wherein F _n, F _a - values of the upper and lower oscillator frequencies.

The distance between the spectral components is set and adjusted by selecting the amplitudes of the control voltages U _CPR , which determine the values of the voltages at the output of the tunable direct-current formers from the 1st to the nth.

The number of frequencies of the first frequency grid is calculated by the formula

- целая часть числа.where F _p1 is the frequency change step,

- the integer part of number.

The frequency values of the first frequency grid are determined as follows:

where i is the frequency number, while F ₁ (1) = F _n .

The values of the frequencies of the frequency grid of the second group are determined as follows:

where i is the frequency number, F _p2 is the distance between the spectral components, while F ₂ (1) = F _p2 .

The distance between the spectral components of the second frequency grid is determined by the formula

where N ₂ is the number of frequencies of the second frequency grid.

The number of frequencies of the second grid is set based on the required density of the signal spectrum.

The distance between the spectral components of the second frequency grid is controlled by selecting the amplitudes of the control voltages U _CPR , which determine the voltage values of the tunable direct-current formers 1. (k + 1) -1.n.

The phases of harmonic oscillations are the same. The phase value is selected based on the type of manipulation used.

In the control device 7, pulses are generated that arrive at the second (control) inputs of electronic keys 3.1-3.n and open them for the duration of the existence of these pulses. The duration of the pulses and their repetition period are selected based on the need to ensure a given information exchange rate when using a generator in transmitters of communication equipment and the type of signal manipulation used.

Harmonic oscillations of the first frequency grid from the outputs of the VCO 2.1-2.k through the public electronic keys 3.1-3.k arrive at the first input of the multiplication device 4. Harmonic oscillations of the second frequency grid from the outputs of the VCO 1. (k + 1) -1.n through open electronic keys 3. (k + 1) -3.n are fed to the second input of the multiplication device 4. In the multiplication device 4, the combination components of harmonic oscillations ω ₁ , ω ₂ , ... ω _n (total and difference) are formed, which after passing through the strip filter 5 arrive at load 6. The frequency band of the resulting signal op divided by a band pass filter 5.

The generated signal is fed to the load 6, for example, a broadband amplifier or antenna. Below is an example of the formation of a broadband signal for the following values of harmonic oscillations:

- values of the lower and upper frequencies of the first frequency grid - 10-30 MHz;

- the distance between the spectral components of the first frequency grid is 5 MHz;

- values of the lower and upper frequencies of the second frequency grid - 1-5 MHz;

- the distance between the spectral components of the second frequency grid is 1 MHz.

The values of the frequencies and amplitudes of harmonic oscillations are shown in table 1.

Table 2 shows the result of signal formation for one multiplication cycle.

Based on the analysis of the data given in table 2, it was found that when using the proposed device for one multiplication of harmonics using 10 harmonic oscillations, the amplitudes of which are set to 1, a signal with a band of 5-35 MHz with a non-uniform frequency response of the signal equal to 2 (ratio maximum and minimum signal amplitudes). When choosing a bandpass filter bandwidth of 5 - 11-29 MHz - the frequency response of the signal is uniform.

Table 3 shows the result of signal generation by the prototype device for one signal generation cycle for the case of using 6 harmonic oscillations, the amplitudes of which are set to 1:

- values of the lower and upper frequencies of the first frequency grid - 10-16 MHz;

- the distance between the spectral components is 3 MHz;

- values of the lower and upper frequencies of the second frequency grid - 1-3 MHz;

- the distance between the spectral components is 1 MHz.

It was believed that as a non-linear element 8, a squaring device is used.

Based on the analysis of the data given in table 3, it was found that when using the prototype device for one harmonic multiplication, when using 6 harmonic oscillations, a signal with a band of 1-19 MHz with a signal frequency unevenness equal to 2.5 was obtained.

Moreover, a signal with a uniform characteristic can be obtained only in a narrow frequency range of 16-19 MHz.

In FIG. Figure 3 shows the result of modeling signal formation using the MATLAB system in one multiplication cycle for two periods. The period value corresponds to the lower frequency of the first frequency grid of 100 MHz. Modeling is carried out for the following initial data:

- values of the lower and upper frequencies of the first frequency grid - 100-200 MHz;

- the distance between the spectral components is 10 MHz;

- values of the lower and upper frequencies of the second frequency grid - 1-10 MHz;

- the distance between the spectral components is 1 MHz.

Based on the waveform analysis of FIG. 3, it was found that for one multiplication of harmonics using 20 harmonic oscillations, the amplitudes of which are 1, a signal with a duration of about 0.7 T can be obtained, where T is the period corresponding to the lower frequency of the first frequency grid of 100 MHz.

That is, in this case, a signal with a duration of about 0.7 × 10 ^-8 s can be used.

Moreover, the amplitude of the positive half-wave is about 94% of the maximum possible, and the amplitude of the negative half-wave is about 60% of the maximum.

Thus, the proposed device provides the formation of a broadband signal with uniform frequency response in a time comparable with the value of the signal period corresponding to the lower frequency of the signal.

Note: the first column shows the frequency values of the first frequency grid, by which the frequencies of the second frequency grid are multiplied. The corresponding line shows the result of the multiplication — the amplitudes of the combination components.

Note: the first column shows the values of the frequencies of harmonic oscillations, which are multiplied by themselves. The corresponding line shows the result of multiplication - the amplitudes of the combination components

Claims (1)

A broadband signal generator containing n tunable dc voltage drivers, the outputs of which are connected to the inputs of the corresponding n voltage controlled oscillators (VCOs), a series-pass filter and a load whose output is the output of the device, while the inputs of the tunable dc voltage drivers are inputs for control voltage, characterized in that n electronic keys are inserted, the inputs of which are connected to the outputs of the corresponding n VCOs, the device mind The output of which is connected to the input of the bandpass filter, and the outputs of the electronic keys 1 through k are combined and connected to the first input of the multiplication device, and the outputs of the electronic keys from k + 1 through n are combined and connected to the second input of the device multiplication; and also introduced a control device, the output of which is connected to the second inputs of electronic keys.

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