RU2583848C2 - Radio receiver - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to radio engineering and can be used to receive randomly distributed frequency-modulated signals in conditions of mobile objects and multi-beam signal propagation. Radio receiver includes two antenna inputs, each of which consists of series-connected filter preselector first amplifier, mixer, intermediate frequency filter, second intermediate frequency amplifier, an analogue-digital converter, a complex mixer and a local oscillator, which outputs are connected to second inputs of mixers each antenna input block with software analysis and output data generating unit. Outputs of mixers are connected to integrated analysis unit for signal/noise ratio via respective delay units forming block output data, which is connected to output of analysis unit for signal/noise ratio. Second inputs of complex mixer are connected to digital local oscillator.

EFFECT: technical result is increasing noise immunity of receiving messages and determining quality of communication channel by adding channel or connecting with best signal/noise ratio.

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Description

The invention relates to radio engineering, namely to a heterodyne receiver with a single frequency conversion, and can be used to receive randomly distributed frequency-modulated signals in conditions of moving objects and multipath signal propagation and to determine the quality.

A radio receiver is known that contains two tuners, each of which consists of a series-switched switched preselector, a first mixer, a selective amplifier of the first intermediate frequency, a second mixer, a selective amplifier of the second intermediate frequency and an analog-to-digital converter, and also containing a reference frequency synthesizer, corresponding outputs which are connected to the second inputs of the first and second mixers of each tuner, and PC, introduced the first shaper quadrature components NT, first digital filtering unit, first resampler, spectrum regenerator, energy analyzer, panoramic analysis unit, output data generating unit, second quadrature component shaper, second digital filtering unit, second resampler, detector, carrier corrector, clock corrector, equalizer, block software and a fully accessible switch (description of patent RU 94096, IPC Н04В 17/00 (2006.01) H04J 1/16 (2006.01), published on 05/10/2010).

The known device can be used for radio monitoring of signals, in particular for automated radio monitoring of radio signals of various sources of radio emissions in a wide frequency range.

The objective of the invention is the development of a receiver for dual reception of randomly distributed frequency-modulated frequencies.

EFFECT: increased noise immunity of receiving messages and determining the quality of a communication channel by adding or connecting a channel with a better signal to noise ratio.

The technical result is achieved in that in a radio receiving device including two antenna inputs, each of which consists of a preselector filter, a first amplifier, a mixer, an intermediate frequency filter, a second intermediate frequency amplifier, an analog-to-digital converter, a complex mixer, and also including local oscillator, the outputs of which are connected to the second inputs of the mixers of each antenna input, an analysis unit with software and an output data generation unit, the first output The complex mixers are connected to the output data forming unit through the signal-to-noise ratio analysis unit and through the corresponding delay blocks, and the second inputs of the complex mixers are connected to a digital local oscillator.

The figure shows a functional diagram of a radio receiver.

1, 2 - the first and second antenna inputs (antennas not shown), including, respectively:

3, 4 - preselector filters;

5, 6 - the first amplifiers;

7, 8 - mixer;

9, 10 - intermediate frequency filter;

11, 12 - second amplifiers of intermediate frequency;

13, 14 - analog-to-digital converters (ADC);

15, 16 - complex mixers;

17 - local oscillator;

18 - digital local oscillator (NCO);

19, 20 - blocks of the delay line;

21 is a signal to noise ratio (SNR) analysis unit;

22 - output data generating unit (dual reception unit);

23 - block demodulation and clock synchronization.

The signals supplied to the antenna inputs 1, 2, respectively, go to preselection filters 3, 4, after which they are amplified by a low-noise amplifier 5, 6, are filtered again on filters 7, 8 to remove side components, and go to mixer 7, 8. Mixer 7, 8, made according to the double balanced scheme, forms an intermediate frequency by means of a local oscillator 17 signal. Then the intermediate frequency signal is amplified and gets to sixteen-bit high-speed ADCs 13, 14. Digital signals from the ADCs 13, 14 fall into the complex mixer 15, 16, in which the necessary channel with a given band (25-50 kHz) is allocated using digital filtering. Also in this block, the signal is decomposed into vector components, over which various operations are further performed. In block 21, the vector signal projections calculate the signal-to-noise ratio (in arbitrary units) for each of channels 1, 2 and their total signal. SNR signals about the quality of signals from block 21 are sent to block 22 and they select the channel with the best signal quality.

In block 21, the complex vector of the received signal is preliminarily estimated by the absolute value with its further averaging. Next, the calculation of the change in the absolute value of the vector is performed, which gives information about the noise component of the vector. The average value is a useful component of the signal. The noise component of the vector is calculated by taking the first derivative of the absolute value of the vector. In this case, the constant component of the vector, which is the amplitude of the useful signal, becomes equal to zero. Next, the absolute value of the noise component is taken and averaged over time. After these calculations, the ratio of the two components is determined and the signal-to-noise ratio for the signal with a continuous phase is obtained by the formula

where I and Q are the projections of the signal vectors onto the complex plane,

ABS is a function that calculates the absolute value.

Vector projections pass in parallel (10 ms) through blocks 19, 20 of the delay line, which is necessary to compensate for the time taken to calculate the signal-to-noise ratio.

Next, the delayed signals come to the vector addition circuit of the unit 22 for dual reception and generation of output data. After block 22, the signal enters block 23 demodulation and restoration of clock synchronization. From the block 21 comes the signal quality of the communication channel, which is tied to the number of errors in the channel (bit error).

In this case, before addition, phase-matching of signals from two channels 1, 2 of the receiver occurs. Subsequently, the signals from each channel 1, 2 arrive at block 22, in which a comparison and analysis of the calculated signal-to-noise ratios and switching of one of the channels occurs if the signal-to-noise difference is above a certain threshold, or the total channel (two channels), if signal to noise ratios are close or equal.

The operation of blocks 21 and 22 is provided by special software.

In the event of a sharp deterioration in the signal quality in one of the receiver channels, the data affected by the interference will not pass to the output of the demodulator 23 due to the operation of the delay line 19, 20. This allows working in conditions of moving objects and multipath signal propagation.

Claims (1)

A radio receiver including two antenna inputs, each of which is connected to a corresponding channel containing a preselector filter, a first amplifier, a mixer, an intermediate frequency filter, a second intermediate frequency amplifier, an analog-to-digital converter, an integrated mixer and a local oscillator, the outputs of which are connected to the second inputs of the respective mixers, as well as including an analysis unit with software and an output data generating unit, characterized in that the outputs are plex mixers are connected to a signal-to-noise ratio analysis unit, which calculates the signal-to-noise ratio for each of the channels and their total signal, and through the corresponding delay units to an output data generating unit, which is connected to the output of the signal-to-noise ratio analysis unit, the second inputs of the complex mixers are connected to a digital local oscillator, the signal-to-noise ratio analysis unit calculates the signal-to-noise ratio by estimating the complex vector by the absolute value with its further averaging, while obtaining the useful component of the signal, calculating the change in the absolute value of the vector, obtaining the noise component of the vector, calculating the absolute value of the noise component and its averaging, and then determines the ratio of these components, obtaining the signal-to-noise ratio for each channel, and the block generating output data compares the calculated signal-to-noise ratios and, if the signal-to-noise ratios are close or equal, performs switching of the total channel.

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