RU2737005C1 - Method for receiving ultrashort pulse signal in form of gauss monocycle - Google Patents

Abstract

FIELD: radio equipment.SUBSTANCE: invention relates to radio engineering and can be used in ultra-wideband communication systems, radiotelemetry and telecommunications using ultrashort-pulse signals (USP) in the form of a Gaussian monocycle and performing reception of these signals under conditions of narrow-band interference. In the method for receiving a USP signal in the form of a Gauss monocycle under narrow-band interference conditions, which includes input filtering and detection of the signal by exceeding the voltage amplitude of a given threshold, signal obtained after input filtration of the light emitting diode is repeatedly successively differentiated to obtain its derivative in the form of a quasiradiomagnetic pulse whose spectrum is transposed upwards in frequency, quasi-radio pulse is separated from interference by output filtering; envelope is selected by its detection, voltage amplitude of which is compared with preset threshold.EFFECT: technical result is high noise-immunity of receiving a USP signal under conditions of narrow-band interference falling into its spectrum, invariance of the method to the number of these interference, high speed of transmitting information with given reliability of reception.5 cl, 9 dwg

Description

The invention relates to the field of radio engineering and can be used in ultra-wideband (UWB) communication systems, radio telemetry and telecommunications using ultra-short-pulse (SQI) signals in the form of a Gaussian monocycle and receiving these signals under conditions of narrow-band interference.

SQI signals in the form of a Gaussian monocycle (Fig. 1), the spectrum width of which can be up to several hundred MHz with the maximum spectrum at frequencies of ~ 1.5-2 GHz, are widely used in high-speed communication systems, radio telemetry and telecommunications. To use such signals as elementary messages of transmitted messages, it is necessary to create appropriate UWB receivers with a bandwidth from ~ 0.5 GHz to ~ 3 GHz. However, this frequency range is distinguished by the largest number of constantly functioning emitting radio electronic devices capable of creating sufficiently powerful narrow-band interference for the receiving devices of the SQI signal, which can lead to a decrease in the reliability of the received information. Such means include transmitters of digital television broadcasting, cellular communications, satellite navigation systems GLONASS and GPS, radio relay stations, etc. [Table of distribution of radio frequency bands between the radio services of the Russian Federation, approved by the Government of the Russian Federation of December 21, 2011 No. 1049-34].

Known methods for dealing with such interference are based on adaptive and rejection techniques.

A known method of receiving signals in conditions of narrow-band interference [Patent 2269201 RF. IPC Н04В 1/10. Method for compensating narrowband interference / Pakhonin V.A .; applicant and patentee Pakhonin VA; declared 02.12.2004; published on January 27, 2006], selected for the analogue.

The analogous method is based on the formation of a complex Fourier spectrum obtained as a result of sampling the input process, as well as the formation of a complex spectrum of time samples from the complex Fourier spectrum of the useful signal with respect to the frequency of the carrier oscillation, and the subsequent formation of the sum and difference of these spectra. After the formation of the modulus of the difference spectrum, dividing it by two, multiplying by the generated phase factor and inverse Fourier transform of the resulting product, a copy of the useful signal is restored.

The disadvantages of this method, which prevent its use for receiving the SKI signal, are:

- the complexity of sampling the input SQI signal with interference in real time;

- the need to reduce the repetition rate of SQI signals due to the use of direct and inverse Fourier transforms;

- the need for significant computing and time resources;

- the complexity of practical implementation;

- low noise immunity in the presence of other types of interference.

A known method of receiving signals under the influence of narrow-band interference [Patent 2456743 RF. IPC Н04В 1/10. Method of adaptive noise suppression / Matyushin O.T., Varivoda S.E., Gustilyov A.A., Koltsov A.V., Stelin A.V., Chernoplekov A.N .; applicant and patentee of OKB MEI JSC, FGBOU VPO NRU MEI; declared 02.21.2011; published on 20.07.2012], selected for the analogue.

The essence of this analogue method is that an interference-adaptive transfer function is automatically generated, which effectively suppresses arbitrary interference with an unknown spectrum. To form such a transfer function, the input mixture of signal and noise is discretized, the sequence of samples is divided into two streams, in each of which the sequence of samples is multiplied by the weight function, discrete Fourier transforms are calculated, the spectra are averaged, and a discrete suppression function is formed. Then this function is multiplied with the spectra, the inverse discrete Fourier transforms are calculated, and the results are divided by the weight function. The output signal is generated by alternately selecting half of the samples of each stream.

The disadvantages of this analogue method, which prevent its use for receiving the SKI signal, are:

- the complexity of sampling the input SQI signal with interference in real time;

- the need to reduce the repetition rate of SQI signals due to the use of direct and inverse Fourier transforms;

- the need for significant computing and time resources;

- the complexity of practical implementation.

All the analogous methods considered above, which are based on adaptive noise suppression methods, do not allow for noise-immune reception of the SQI signal with a high repetition rate; their algorithms require digitizing the SQI signal and noise to carry out computational operations.

For narrow-band noises, the type and parameters of which are a priori known or can be determined at the place of receiving messages, the input rejection method is used using notch filters tuned to the frequencies of these noises.

A known method of receiving SQI signals with input rejection of narrowband interference, using the correlation principle [Processing of ultra-wideband signals and interference / V.G. Radzievsky, P.A. Trifonov. - M .: Radiotekhnika, 2009.S. 261, fig. 6.1.8], selected for the analogue.

This method is carried out as follows.

Spectral components of these noises are removed from the spectrum of the received SQI signal with narrow-band interference. Next, the input SQI signal is convolved with a reference signal, the result of which is compared with a given threshold.

The disadvantages of the analogue method are:

- the need to generate a reference SKI signal;

- energy loss of the received SQI signal during rejection of spectral components of interference;

- distortion of the form of the SKI signal, leading to errors in the received messages;

- the need for quadrature processing of the received SQI signal;

- the need for information on narrow-band interference falling into the spectrum of the received SQI signal.

The first drawback is associated with the correlation principle of reception, which requires a copy of the emitted SQI signal. The formation of the reference signal required for receiving the SQI signals is a rather difficult task.

The second drawback is associated with the need to reject several narrowband interference signals, in which a significant part of the spectrum of the SQI signal is excluded from its structure.

The third drawback is associated with changes in the duration of the SCI signal and its front, associated with a change in the spectrum due to the rejection of narrow-band interference, which at high data transmission rates can lead to errors in received messages.

The fourth drawback is related to the need to eliminate the dependence of the amplitude of the correlator output voltage on the phase relationships of the SQI signal and the reference signal.

The fifth drawback is associated with the need for information about narrow-band interference a priori or obtained directly from the analysis of the interference situation at the place of receiving messages.

There is a method of receiving SKI signals with input rejection of narrowband interference [Processing of ultra-wideband signals and interference / V.G. Radzievsky, P.A. Trifonov. - M .: Radiotekhnika, 2009.S. 259, fig. 6.1.4], chosen as a prototype.

The prototype method is carried out as follows.

The received SQI signal (Fig. 2a) with a narrow-band interference (Fig. 2b), the spectrum of which is in the spectrum of the SQI signal, is pre-filtered using the input filter 1 (Fig. 3). Further, from the spectrum of the SQI signal using a notch filter 2 (Fig. 3), the spectral components of the interference are cut out (Fig. 2b). The received signal, in the spectrum of which there are no spectral components of the interference (Fig. 4), is compared with a predetermined threshold of the threshold device 3 (Fig. 3).

The disadvantages of the prototype method are:

- low repetition rate of SQI signals in a message, leading to a decrease in the information transfer rate;

- decrease in the energy potential of the radio link;

- the need for information on the parameters of the interference that falls into the spectrum of received SQI signals.

The first drawback is associated with an increase in the duration of the SQI signal and its edges, caused by a change in the spectrum due to interference rejection, which at high data transmission rates can lead to errors in received messages.

The second disadvantage is associated with the energy loss of the received SQI signals during rejection of the spectral components of the interference.

The third drawback is associated with the need to provide rejection at the interference frequency.

With an increase in the number of active narrowband interference in the spectrum of the received SQI signal, the conditions for receiving this signal will worsen.

The technical result of the proposed invention is the noise immunity of receiving the SQI signal under the influence of narrow-band interference falling into its spectrum, the invariance of the method to the amount of these interference, and an increase in the speed of information transmission at a given reliability of its reception.

The technical result is achieved by the fact that in the method of receiving an ultra-short-pulse signal in the form of a Gaussian monocycle under the influence of narrow-band interference, which includes input filtering and detection of a signal when the voltage amplitude exceeds a given threshold, obtained after input filtering, the ultra-short-pulse signal is repeatedly sequentially differentiated until its derivative in in the form of a quasi-radio pulse, the spectrum of which is transposed upward in frequency, the output filtering separates the quasi-radio pulse from the noise, detecting its envelope, the voltage amplitude of which is compared with a given threshold.

In addition, the input filtering is carried out in a frequency band that overlaps the spectra of the received ultrashort pulse signal and its derivative.

In addition, the output filtering is carried out in a frequency band equal to the spectrum width of the derivative of the received ultrashort pulse signal.

In addition, the order of the derivative in differentiating the received ultrashort pulse signal is determined by the relative position of the maximum of its spectrum and the maximum of the spectrum of the most high-frequency interference located in the spectrum of the received ultrashort pulse signal.

In addition, in the absence of a priori information about the interference in the spectrum of an ultrashort pulse signal, the order of the derivative during its differentiation is determined by a given level of overlap of the high frequency slope of the ultrashort pulse signal spectrum by the low frequency slope of its derivative.

The temporal and spectral forms of the SQI signal and narrowband interference are explained in Figure 1 and Figure 2.

FIG. 1 shows the time and spectral forms of the Gaussian monocycle and its derivatives, where: a - stress diagrams, b - spectra (for n = 1,2,3,4 in formulas (1) and (2) of the appendix).

FIG. 2 shows the spectra of the received SQI signal and the interference signal, where: a - SQI signal; b - narrow-band interference.

Method - a prototype of receiving an SKI signal is illustrated by figure 3 and figure 4.

FIG. 3 is a functional diagram explaining the method-prototype of receiving the SKI signal. It shows: 1 - input filter (WF); 2 - notch noise filter (RFP); 3 - threshold device (PU) .-

FIG. 4 shows the spectral form of the SQI signal at the output of the noise notch filter.

The proposed method for receiving an SCI signal is illustrated in FIG. 5-9.

FIG. 5 is a functional diagram explaining the proposed method for receiving an SCI signal. It shows: 1 - input filter (WF); 4 - differentiator; 5 - optimal output filter (OVF); 6 - amplitude detector (AD); 3 threshold device (PU).

FIG. 6 shows the spectra of the SCI signal and narrowband interference after repeated differentiation, explaining the proposed method for receiving the SCI signal, where: a - the derivative of the SCI signal, b - the derivative of the narrowband interference.

FIG. 7 shows the spectral shape of the SCI signal after optimal filtering.

FIG. 8 shows a diagram of the voltage of the SKI signal after optimal filtering.

FIG. 9 shows the diagram of the voltage of the envelope of the SCI signal after detection.

The proposed method for receiving the SCI signal is carried out as follows.

As shown in FIG. 5, the spectrum of the input SQI signal in the form of a Gaussian monocycle with a narrow-band interference, the spectrum of which is in the spectrum of the SQI signal, after passing through the input filter 1 is repeatedly differentiated by the differentiator 4. The input filtering is carried out in a frequency band that overlaps the spectra of the received SQI signal and its derivative ... The spectrum of the SCI signal during differentiation is transposed upward in frequency while maintaining its width, and the spectrum of the narrow-band interference remains at the same place, while the duration of the SCI signal is preserved (see Appendix). The optimal output filter 5 with a bandwidth equal to the width of the spectrum of the derivative of the received SQI signal, the useful signal is separated from the spectral components of the derivative of the narrow-band interference. The result of this filtering in the form of a quasi-radio pulse is detected by the amplitude detector 6 and the resulting envelope is compared with the threshold of the threshold device 3.

With an increase in the amount of narrowband interference in the spectrum of the SQI signal, its transposition upward in frequency is preserved.

The order of the derivative when differentiating the received SQI signal is determined by the relative position of the maximum of its spectrum and the maximum of the spectrum of the most high-frequency interference located in the spectrum of the received SQI signal. In the absence of a priori information about the noise in the spectrum of the SQI signal, the order of the derivative during its differentiation is determined by a given level of overlap of the high-frequency slope of the spectrum of the SQI signal by the low-frequency slope of its derivative.

As proof of the feasibility of the proposed method, FIG. 6 shows the spectral form of the received signal obtained by means of mathematical modeling (Fig. 2), which is the sum of the SQI signal in the form of a Gaussian monocycle with a duration of ~ 1 ns and a narrow-band interference with a carrier frequency of ~ 2 GHz, after 10-fold differentiation. FIG. 2, it can be seen that the SRS signal and the interference are in the same frequency range, while in FIG. 6 shows the separation in the frequency range of the useful SRS signal and interference. The time and spectral waveforms shown in FIG. 6 after optimum output filtering are shown in FIG. 7 and FIG. 8, which shows a significant reduction in the level of interference. FIG. 9 shows the envelope of the quasi-radio pulse (FIG. 8), extracted by amplitude detection, it can be seen that the duration of the useful signal is preserved.

Thus, the transposition of the spectrum of the SRS signal upward in frequency with multiple differentiation while maintaining the spectrum width and duration of the derivative of the SRS signal and its subsequent optimal filtering make it possible to separate the received SRS signal from in-band narrowband interference.

The use of the method for receiving an SKI signal in the form of a Gaussian monocycle with a spectrum transposition upward in frequency allows, in comparison with analogues and the prototype:

- to reduce the likelihood of blocking the receiving device by powerful active intentional and unintentional narrow-band interference, the frequencies of which are in the spectrum of the SKI signal;

- to increase the reliability of the received information;

- to ensure the reception of the SKI signal in real time;

- to exclude the loss of energy of the SQI signal caused by interference rejection;

- save the duration of the SKI signal when receiving;

- to increase the speed of information transfer;

- to provide invariance to the amount of narrow-band interference.

Thus, the proposed method for receiving an SKI signal in the form of a Gaussian monocycle has significant advantages over analogues and the prototype.

Claims (5)

1. A method for receiving an ultra-short-pulse signal in the form of a Gaussian monocycle under conditions of narrow-band interference, which includes input filtering and signal detection when the voltage amplitude exceeds a given threshold, characterized in that the ultra-short-pulse signal obtained after input filtering is repeatedly sequentially differentiated until its derivative is obtained in the form A quasi-radio pulse, the spectrum of which is transposed upward in frequency, separates the quasi-radio pulse from interference by output filtering, and detects its envelope, the voltage amplitude of which is compared with a predetermined threshold. 2. The method according to claim 1, characterized in that the input filtering is performed in a frequency band that overlaps the spectra of the received ultrashort pulse signal and its derivative. 3. The method according to claim 1, characterized in that the output filtering is performed in a frequency band equal to the width of the spectrum of the derivative of the received ultrashort pulse signal. 4. The method according to claim 1, characterized in that the order of the derivative when differentiating the received ultrashort pulse signal is determined by the relative position of the maximum of its spectrum and the maximum of the spectrum of the most high-frequency interference located in the spectrum of the received ultrashort pulse signal. 5. The method according to claim 1, characterized in that in the absence of a priori information about the interference in the spectrum of the ultrashort pulse signal, the derivative order during its differentiation is determined by a given level of overlap of the high-frequency slope of the ultrashort pulse signal spectrum by the low-frequency slope of its derivative.

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