RU2284657C1 - Device for suppressing a complex of interferences - Google Patents

Abstract

FIELD: radio engineering, possible use in composition of radio-receiving devices for various purposes.

SUBSTANCE: device contains broadband duct, controlling element and interference selection block. Device additionally contains wavelet transformer, reverse wavelet transformer and clock impulse generator, while controlling element is made multi-channeled and provided therein are first and second groups of inputs and a group of outputs, block for selecting interference is also made multi-channeled and inserted into it are a group of inputs and a group of outputs.

EFFECT: possible analysis of mixture of useful signal with interferences simultaneously in temporal and frequency area, making it possible to substantially reduce the amount of blocks of the same type.

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Description

The invention relates to the field of radio engineering and can be used as part of radio receivers for various purposes.

A device for protection against interference, for example, as 1084995, comprising a broadband filter, an amplifier, a limiter, a narrowband filter, an additional limiter, an odd harmonic filter, a minimum cut-off filter, and a recorder.

It is also known a device for suppressing narrowband and pulsed interference in AS 1243134, comprising an input band-pass filter, a delay element, three subtractors, a phase correlator, a narrow-band filter, and a non-linear signal converter.

A significant drawback of these devices is the inadequate suppression of interference.

The closest in technical essence to the claimed device is a noise suppression device listed in the journal "Radio Engineering", 1978, t.33, No. 6, p. 4, Fig. 2, adopted as a prototype.

The functional diagram of the prototype device is shown in figure 1, where the following notation is introduced:

1 - broadband path;

2, 6 and 8 - the first, second and third control elements (limiters or keys);

3, 9 and 10 - the first, second and third blocks of the allocation of interference (threshold devices);

4 - narrowband path;

5 - block direct Fourier transform;

7 - block inverse Fourier transform.

The prototype device contains a serially connected broadband path 1, the input of which is the input of the device, the first control element 2, the direct Fourier transform unit 5, the second control element 6, the inverse Fourier transform unit 7, the third control element 8 and the narrow-band path 4, the output of which is device output. In addition, the output of the broadband path 1 through the first interference isolation unit 3 is connected to the second input of the first control element 2, the output of the direct Fourier transform unit 5 through the second interference isolation unit 9 is connected to the second input of the second control element 6, and the output of the inverse Fourier transform unit 7 through the third block selection interference 10 is connected to the second input of the third control element 8.

The prototype device operates as follows.

A mixture of the useful signal, white noise, as well as narrow-band and pulsed interference arrives at the input of the device.

The input signal enters the broadband path 1 associated with the impulse noise, from the output of which the signal simultaneously enters the first input of the first control element 2 and the input of the first interference isolation unit 3. From the output of the first interference isolation unit 3, the control signal enters the second input of the first control element 2 , the output of which a signal with suppressed impulse noise is fed to the input of the direct Fourier transform unit 5, where the signal is converted from the time domain to the frequency domain. From the output of the direct Fourier transform unit 5, the signal simultaneously enters the first input of the second control element 6 and the input of the second interference isolation unit 9, from the output of which the control signal enters the second input of the second control element 6, from the output of which the signal with suppressed narrow-band interference enters the input the inverse Fourier transform block 7, where the signal is converted from the frequency domain to the time domain. From the output of block 7, the signal is supplied to the first input of the third control element 8 and the input of the third block of interference isolation 10, from the output of which a signal with suppressed impulse noise (arising after suppressing narrow-band interference as a side effect), through narrow-band path 4, matched with the useful signal, goes to the output of the device.

The prototype device has a significant drawback. The fact is that narrowband and pulsed interference are dual with respect to the Fourier transform. Narrow-band interference is described in the frequency domain, and impulse noise in the time domain. Therefore, when suppressing impulse noise in the time domain, narrow-band interference occurs, and when suppressing narrow-band interference, additional impulse noise occurs. The optimal in this case is the multiple sequential suppression of narrowband and impulse noise, for which several series-connected links are installed to suppress the SST (time-focused noise) and the FH (concentrated on the noise frequency), which greatly complicates the implementation of the prototype device.

To eliminate this drawback, a wavelet converter, an inverse wavelet converter and a clock pulse generator are introduced in a device for suppressing a complex of interference containing a broadband path, the input of which is the input of the device, a control element and an interference isolation unit, according to the invention, the control element being multi-channel and the first and second groups of inputs and the group of outputs are introduced in it, the interference isolation unit is also multi-channel, and the group of inputs and the group of outputs are introduced in it; the output of the broadband path is connected to the first signal input of the wavelet converter, the second, synchronizing input of which is connected to the output of the clock generator; the group of outputs of the wavelet converter is connected by a bus to the first group of inputs of the control element and the group of inputs of the interference isolation unit, the group of outputs of which is connected by a bus to the second group of inputs of the control element, the group of outputs of which is connected by a bus to the group of inputs of the inverse wavelet, the output of which is the output of the device .

In figure 2. the functional diagram of the proposed device, where the notation is introduced:

1 - broadband path;

2 - control element;

3 - block separation interference;

4 - wavelet converter;

5 - reverse wavelet converter;

6 - clock generator.

The proposed device contains a serially connected broadband path 1, the input of which is the input of the device, and a wavelet converter 4, the group of outputs of which is connected by a bus to the first group of inputs of the control element 2, the group of outputs of which is connected by a bus to the group of inputs of the inverse wavelet converter 5, the output of which is the output of the device. In addition, the group of outputs of the wavelet converter 4 is connected via a bus to the group of inputs of the interference isolation unit 3, the group of outputs of which is connected by a bus to the second group of inputs of the control element 2. The output of the clock pulse generator 6 is connected to the second, synchronizing input of the wavelet converter 4.

The proposed device operates as follows.

To analyze signals of various nature in the proposed device, the wavelet transform is used (see Astafieva N.M. Wavelet analysis: the fundamentals of the theory and application examples. - Moscow, "Uspekhi Fizicheskikh Nauk", Volume 166, No. 11, November 1996). ) The wavelet transform, which has a moving time-frequency window, identifies both low-frequency and high-frequency characteristics of signals equally well.

The input signal with noise, pulsed and narrowband interference is fed to the input of the broadband path 1, coupled (matched) with the impulse noise.

From the output of the broadband path 1, a signal with band-limited noise is fed to the first signal input of the wavelet converter 4, and to the second, synchronizing input of which pulses are received from the output of the clock 6. In wavelet converter 4, the time signal is converted into a two-dimensional wavelet spectrum , (n · m) components of which from the group of outputs the bus is fed simultaneously to the first group of inputs of the control element 2 and the group of inputs of the interference isolation unit 3. The interference isolation unit 3, made in the form of multi-channel ceiling elements threshold device with a common threshold, generates control signals for the components of the wavelet spectrum. If the total voltage of the signal and interference exceeds the threshold level, then a log signal is generated at the corresponding output of block 3. "1", and if it does not exceed, then the level is the log. "0". Binary signals from the group of outputs of the block 3 (n · m) -discharge bus are fed to the second group of inputs of the control element 2, which can be made in the form of a controlled key. Each of the (n · m) control signals corresponds to a component of the wavelet spectrum. If the control signal level log. "0", then the corresponding component of the wavelet spectrum passes to the corresponding output of the control element without change. And if the control signal level log. "1", then the corresponding component of the wavelet spectrum is rejected.

Thus, a converted signal spectrum with cut out spectral components is formed on the group of outputs of the control element 2 and fed to the group of inputs of the inverse wavelet converter 5, where the wavelet spectrum is converted into a temporary signal. From the output of the inverse wavelet converter 5, a signal with suppressed pulsed pulsed and narrowband interference is supplied to the output of the device.

Wavelet converter 4 can be implemented according to the functional diagram presented in figure 3, where the following notation is introduced:

41 ₁ ... 41 _n - from the first to the n-th band filters;

42 _1.1 ... 42 _nm - from the first by (nm) th time selectors;

43 - decoder;

44 is a counter.

Wavelet converter 4 contains n bandpass filters 41 ₁ -41 _n , the combined inputs of which are connected to the first, signal input of wavelet converter 4. In addition, it contains (n · m) time selectors 42 _1.1 -42 _nm , forming n groups of m temporary selectors in each. The output of each of n bandpass filters 41 ₁ -41 _{n is} connected to the combined signal inputs of m time selectors of the corresponding group. The synchronizing input of the wavelet converter 4 is the input of the counter 44, the group of outputs of which is connected via a bus to the group of inputs of the decoder 43. The control inputs of each of the temporary selectors of one group are combined with the control inputs of the corresponding temporary selectors of other groups. The outputs (n · m) of the temporary selectors 42 _1.1 -42 _nm form a group of outputs, which is a group of outputs of the wavelet converter 4.

Wavelet Converter 4 operates as follows.

From block 1, the input signal with a frequency band ΔF is supplied to the inputs of n bandpass filters 41 ₁ -41 _n , the frequency band of each of which is ΔF / n. From the output of each of n bandpass filters 41 ₁ -41 _{n, the} filtered signal arrives at m time selectors of the corresponding group. Each of the (n · m) time selectors 42 _1.1 -42 _nm is a controlled "key", which, under the action of the control signal, opens and passes the signal during the time interval from t _i to (t _i + Δt), where i = 1, ..., m. Moreover, the number m - the number of time intervals in one frequency band, is equal to the number of outputs of the decoder 43, the states of which are formed as follows. From block 6, the clock pulses are fed to the input of the counter 44, tuned to the number x = log ₂ m. From the group of outputs of the counter 44, the number x in binary code is fed by a bus to the group of inputs of the decoder 43.

For example, the correspondence between the inputs (x = 3) and outputs (m = 8) of the decoder 43 can be represented in the form of a table:

Inputs Outputs X1 X2 X3 U1 U2 U3 U4 U5 U6 U7 U8 0 0 0 one 0 0 0 0 0 0 0 0 0 one 0 one 0 0 0 0 0 0 0 one 0 0 0 one 0 0 0 0 0 0 one one 0 0 0 one 0 0 0 0 one 0 0 0 0 0 0 one 0 0 0 one 0 one 0 0 0 0 0 one 0 0 one one 0 0 0 0 0 0 0 one 0 one one one 0 0 0 0 0 0 0 one

Therefore, the output signals (n · m) of the time selectors 42 _1.1 -42 _nm are (n · m) samples of the two-dimensional wavelet spectrum, which are sent to block 2 from the group of outputs of block 4.

As an inverse wavelet converter, you can use an adder.

The implementation of the remaining blocks of the claimed device also does not cause any difficulties, since their descriptions are widely published in the technical literature.

Thus, in the proposed device for the analysis of the received signal, a wavelet converter and a reverse wavelet converter are used, which allows us to analyze a mixture of a useful signal with noise simultaneously in the time and frequency domains and, therefore, can significantly reduce the number of blocks of the same type.

Claims (1)

A device for suppressing an interference complex containing a broadband path, the input of which is the input of the device, a control element and an interference isolation unit, characterized in that a wavelet converter, an inverse wavelet converter and a clock pulse generator are introduced, wherein the control element is multi-channel and introduced the first and second groups of inputs and the group of outputs, the interference isolation unit is also multi-channel, and a group of inputs and a group of outputs are introduced into it, while the output of the broadband path with it is single with the first, signal, input of the wavelet converter, the second, synchronizing, whose input is connected to the output of the clock generator, the group of outputs of the wavelet converter is connected via a bus to the first group of inputs of the control element and the group of inputs of the interference isolation unit, the group of outputs of which is connected to the bus with the second group of inputs of the control element, the group of outputs of which is connected via a bus to the group of inputs of the inverse wavelet converter, the output of which is the output of the device.

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