RU2631668C1 - Device for measuring phase difference of radio signals - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: invention can be used in radio direction finders, radio monitoring equipment, phase-locked loop systems, synchronization systems for various purposes and similar facilities and systems, in which the phase difference between the radio signals of radio sources is measured under noise of unknown intensity. The device contains two bandpass filters, three multipliers, three low-pass filters, two subtractors connected in a certain way.

EFFECT: increasing the accuracy of measuring the phase difference of radio signals by increasing the signal-to-noise ratio by noise compensation.

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Description

The invention relates to radio engineering and can be used in direction finders, radio monitoring tools, phase locked loop systems (PLL), synchronization systems for various purposes and similar tools and systems in which the phase difference of radio signals from radio sources (IRI) is measured.

A known method of measuring the phase difference of radio signals [see, for example, Vinokurov V.I., Kaplin S.I., Petelin I.G. Electroradio-measurements: Textbook. allowance for radio special. Universities / Ed. IN AND. Vinokurova. - 2nd ed., Revised. and add. - M .: Higher. school, 1986. - 351 pp., ill., Fig. 8.6., P. 166], based on the conversion of the phase shift between the radio signals in the time interval and measuring its duration.

The disadvantage of this method is the low accuracy of measuring the phase difference in the frequency range above 200 kHz.

The closest in technical essence to the claimed is a method of measuring the phase difference of radio signals, based on the multiplication of the input signals, followed by filtering the low-frequency component of their product, which has a functional dependence on the phase difference of the signals at the input [see, for example, Measurements in electronics: Reference / V .BUT. Kuznetsov, V.A. Dolgov, V.M. Konevskikh et al. Ed. V.A. Kuznetsova. - M.: Energoatomizdat, 1987 .-- 512 p.: Ill., P. 307].

The disadvantage of this prototype is the low accuracy of measuring the phase difference of the radio signals at low signal-to-noise ratios.

The technical result of the invention is to improve the accuracy of measuring the phase difference of radio signals by increasing the signal-to-noise ratio by compensating for noise.

The technical result is achieved by the fact that in the known method for measuring the phase difference of radio signals based on multiplying radio signals, extracting the low-frequency component of the spectrum of the resulting signal and determining the phase difference, according to the invention, the average power of the noise component of the additive mixture of one of the input radio signals is additionally determined and subtracted from the low-frequency component spectrum of the resulting signal.

The invention consists in the following.

According to the invention, the average power of the noise component of the additive mixture of one of the input radio signals is determined, which is subtracted from the average power of the low-frequency component of the spectrum of the received signal, i.e. compensate for the noise component of the resulting signal. This leads to an increase in the signal-to-noise ratio, which is achieved by the technical result indicated in the invention.

The determination of the average power of the noise component of the additive mixture can be performed, for example, according to the method described in [see, for example, Simultaneous measurement of signal power and noise power (noise) in the passband of the main channel of the radio reception. Bubenshchikov A.A., Vladimirov V.I., Bubenshchikov A.V., Sidenko S.V. Information-measuring and control systems (journal), No. 7, 2012, p. 67-73].

The claimed method can be implemented, for example, using a device whose structural diagram is shown in the figure, where it is indicated:

1.1, 1.2 - the first and second band-pass filters;

2.1, 2.2, 2.3 - the first, second and third multipliers;

3.1, 3.2, 3.3 - the first, second and third low-pass filters (low-pass filters);

4.1, 4.2 - the first and second subtractive devices.

The figure shows a diagram of a device in which the compensation of the noise component of the resulting signal is carried out by determining the average power of the noise component of the additive mixture of the first radio signal.

The purpose of the elements of the device is clear from their name, and all elements can be made on the basis of well-known commercially available radio engineering elements.

The device operates as follows.

The input of the first 1.1 and second 1.2 bandpass filters receives an additive mixture of noise and the first radio signal and an additive mixture of noise and the second radio signal, respectively. The passbands of both filters are the same and consistent with the spectrum of the received signal. The signal from the output of the first band-pass filter 1.1 is fed to the first and second inputs of the first multiplier 2.1 and to the first inputs of the second 2.2 and third 2.3 multipliers. The signal from the output of the second band-pass filter 1.2 is fed to the second input of the third multiplier 2.3. The second input of the second multiplier 2.2 receives a reference signal, the amplitude and frequency of which is equal to the amplitude and frequency of the first radio signal. The signals from the output of the multipliers 2.1, 2.2 and 2.3 are fed to the inputs of the first 3.1, second 3.2 and third 3.3 low-pass filters, respectively.

At the outputs of the low-pass filter 3.1-3.3 we obtain signals with a frequency equal to the frequency difference of the input signals of the respective multipliers. In this case, the average signal power output:

the first low-pass filter 3.1 will be equal to the sum of the power of the first radio signal and the noise power (see, for example, Levin B.R. Theoretical foundations of statistical radio engineering. - 3rd ed., revised and additional - M: Radio and communications, 1989 . - p. 484);

the second low-pass filter 3.2 - the power of the first radio signal, because noise is uncorrelated when multiplied with a reference signal (see, for example, Levin B.R. Theoretical foundations of statistical radio engineering. - 3rd ed., revised and additional - M .: Radio and communications, 1989, p. 502 );

third low-pass filter 3.3 - power product of the first and second radio signals and noise power.

At the output of the first subtractor 4.1 we get a signal with a power equal to the power of only noise, because the component of the signal from the output of the first multiplier 2.1 is compensated by the signal from the output of the second multiplier 2.2.

At the output of the second subtracting device 4.2 we get a signal with a power equal to the power of the signal only, because the noise power component from the output of the third low-pass filter 3.3 is compensated by the noise power from the output of the first subtracting device 4.1.

Thus, at the output of the device that implements the claimed method, we obtain a signal with a compensated noise component. Therefore, the signal-to-noise ratio will be higher than in the prototype, which increases the accuracy of the measurement.

Claims (1)

A device for measuring the phase difference of radio signals, containing the first and second band-pass filters, the inputs of which respectively receive an additive mixture of noise and the first radio signal and an additive mixture of noise and the second radio signal, while the pass bands of both filters are the same and are consistent with the spectrum of the received radio signal, the outputs of the first and the second bandpass filters are connected to the inputs of the third multiplier, characterized in that two multipliers, three low-pass filters, two subtracting devices are introduced, the output of the first bandpass filter is also connected to the first and second inputs of the first multiplier and to the first input of the second multiplier, the second input of which is the input of the reference signal, the outputs of the first, second, and third multipliers are connected respectively to the inputs of the first, second, and third low-pass filters, the outputs of the first and a second low-pass filter connected to the inputs of the first subtractor, the output of which is the output of a noise signal, the output of the first subtractor is connected to the first input torogo subtractor, a second input coupled to an output of the third low-pass filter, the output of the second subtractor is an output signal from the compensated noise component, wherein the output of the second subtractor a signal functionally depends on the difference in phases of the signals at the input, that provides a measurement of the phase difference.

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