RU2371845C1 - Radio receiver of digital information - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: device comprises band filter, matched filter, balance modulator, demodulator, unit of memory for digital counts of amplitude phase detector signal, solving symbol unit, two block decoders, reception interrupter of signal unit, unit of phase signal processing, unit of frequency band shift, receiver of information, at the same time one of inlets of balance modulator is connected to outlet of generator of pseudonoise signals.

EFFECT: accounting and compensation of parasite shift of phase signal from Doppler effect.

3 cl, 13 dwg

Description

The invention relates to radio engineering and can be used in radio systems with a phase modulation method for receiving blocks of information over communication channels. At the input of the radio, the sum of the signal and interference x (t) = uk (t) + n (t) acts, reception occurs in the absence and presence of the Doppler effect. The receiver provides entry into the communication on the carrier frequency and tracking the carrier frequency, amplifies the received signal, transfers the signal to the region of intermediate frequencies and video frequencies, demodulates the signal and converts it into blocks of digital information that transmits to the recipient of information.

Close in technical essence to the proposed device is a receiving device [1, p.69-83], containing signal filters that perform optimal signal processing, which are aimed at reducing the influence of noise affecting the input of the receiver. In this case, the noise due to the Doppler effect is not suppressed.

The indicated drawback, namely: noise caused by the Doppler effect, is partially eliminated in the receiving device [2].

The noise caused by the Doppler effect is most completely eliminated in the radio receiver [3], adopted for the prototype, which contains (see Figure 1) a receiver (PR), the input of which is the input of the bandpass filter, which is connected to the matched filter, the output of which is the output the receiver and is connected to the first (signal) input of the balanced modulator (BM), the second input of which is connected to a broadband signal generator (GPS), the output (BM) is connected to the input of the demodulator (DM), the first output of which is connected to the input of the decoder (DC), from the second you ode (MM) samples are taken of the phase signal output (DC) coupled to the receiver of information (PI). The series-connected bandpass filter (PF) with the passband F and the matched filter (SF) limit the reception band at the radio frequency, which limits the effect of other radio systems for various purposes on the useful received signal of the receiver. The choice of filter parameters (PF) and (SF) depends on the optimal processing method:

- creating a uniform amplitude-frequency response, linear phase-frequency response in a given frequency range;

- the use of gating;

- the use of optimal, quasi-optimal signal reception schemes in the presence of intersymbol distortions;

- A linear harmonic signal corrector to attenuate intersymbol interference.

The receiver enters into communication on the carrier frequency and monitors the carrier frequency, amplifies the received signal, transfers the signal to the region of intermediate frequencies and video frequencies, performs demodulation by filtering the received signal from interference, and decodes the received signal by noise-correcting decoding of information blocks, eliminating incorrectly received symbols . Incorrectly received characters may result from the Doppler effect.

To synchronize the transmitted signal in frequency and delay from the Doppler effect [2], the receiver contains a balanced modulator (BM), which performs the functions of a multiplier, and a broadband signal generator (GSPS). The modulator unit (BM) determines and takes into account the value of the Doppler frequency for the signal carrier frequency f _c , determines the required local oscillator frequency f _g , transfers the signal to the intermediate radio frequency f _p , compensates for the Doppler shift of the carrier frequency f _c ± f _d and signal delay, converting the radio signal into video signal. The technical result of this device is that in the presence of noise interference and the Doppler effect, it is possible to avoid the synchronism of the received signal and the reference signal.

. Если

, то осуществлен правильный прием, если

, то при принятии решения была совершена ошибка из-за помехи на входе приемника. Демодулятор (ДМ) определяет каждый сигнал блока информации. Декодер (ДК), использующий помехоустойчивое кодирование, исправляет ограниченное количество ошибок бит информации в кадре, вызванных шумами и эффектом Доплера. С выхода декодера (ДК) получателю информации (ПИ) передается блок информации в зависимости от сформированной в ДК статусной информации.The demodulator (DM) analyzes x (t) and decides which signal was transmitted, and in accordance with the decision it gives an evaluation symbol

. If

then the correct reception is made if

, when making the decision, an error was made due to interference at the input of the receiver. A demodulator (DM) defines each signal of an information block. A decoder (DK) using noise-correcting coding corrects a limited number of information bit errors in a frame caused by noise and the Doppler effect. From the output of the decoder (DC) to the recipient of information (PI), a block of information is transmitted depending on the status information generated in the DC.

However, in the known prototype device, the frequency change is evaluated

f _∂ for auto-tuning from the Doppler effect for one of the frequencies (carrier frequency, center frequency of the spectrum, spectrum frequency, by which the sync pulses of the information bits are determined, etc.). The signal is transmitted by spectral components, each of which receives its offset f _di from the Doppler effect (according to the Doppler frequency shift formula). Converting the signal to the region of video frequencies completely removes the frequency change from the Doppler effect for only one frequency. For all other spectral components, the local oscillator does not completely eliminate the Doppler shift, the transfer along the frequency axis by the frequency converters occurs by the local oscillator frequency equal to f _∂ . As a result of incomplete compensation, frequency-phase shifts of the spectral components of the phase signal from the Doppler effect occur, which explains the occurrence of spurious phase shifts (SFC) of the video signal, which entail the occurrence of errors in the information symbols. SFCs can be constant and change, including periodically, within the frame of information. The SFC period can be 1.1 ms. That is, the prototype does not give the same compensation for the Doppler effect for all components of the spectrum of the transmitted signal. SFCs in the frame are random in nature, since they depend on the Doppler effect and on the spectrum of the transmitted signal in the frame. SFCs distort information like noise, and therefore are classified as noise.

The technical result of the proposed digital information radio receiver (FIG. 2, FIG. 3, FIG. 4) consists in taking into account and compensating for stray phase signal displacement from the Doppler effect.

Figure 2 presents the structural diagram of a digital information radio receiver containing the following blocks:

1 - band-pass filter (PF);

2 - matched filter (SF);

3 - balanced modulator (BM);

4 - demodulator (DM);

5 - block decoder (DK);

6 - recipient of information (PI);

7 - chopper receiving signal blocks (PPBS);

8 - phase signal processing unit (BOFS);

9 - block shift the frequency band (BSPCH);

10 - decisive block character (RBS);

11 - second block decoder (VDK);

12 - memory block (PAM).

Figure 3 shows a first embodiment of a demodulator 4, comprising:

13 - energy detector (DE);

14 - amplitude phase detector (FDA);

15 - analog-to-digital Converter (ADC).

Figure 4 shows a second embodiment of a demodulator 4, comprising:

16 - second amplitude phase detector (VFDA);

17 - analog-to-digital Converter (ADC);

18 - the second decision block character (VRBS).

Considering the reception of information blocks in the proposed receiver with the phase modulation method (KIM-FMn), the following notations are accepted:

принимает значения "0" или "1", решение принимается «решающим правилом» демодулятора ДМ;- symbol

takes the values "0" or "1", the decision is made by the "decisive rule" of the DM demodulator;

- блок символов, который подлежит декодированию декодером ДК;- characters

- a block of characters that is to be decoded by a decoder DC;

- блок символов после декодирования декодером ДК, если применялось декодирование с исправлением ошибок, и все ошибки в блоке были исправлены, или ошибок в блоке не было.- characters

- a block of characters after decoding by a decoder of a recreation center, if decoding with error correction was applied, and all errors in the block were corrected, or there were no errors in the block.

A digital information radio receiver comprises a band-pass filter (PF) 1 connected in series, a matched filter (SF) 2, a balanced modulator (BM) 3, a demodulator (DM) 4, a block decoder (DB) 5, an information receiver (PI) 6, and the second input balance modulator (BM) 3 is connected to the output of a noise-like signal generator (GSHPS), the phase signal samples are taken from the second output of the demodulator (DM) 4, it differs in that a signal block receiving chopper (PPBS) 7, a phase signal processing unit ( BOFS) 8, block shift the frequency band (B IF) 9, the decisive character block (RBS) 10, the second block decoder (VDB) 11, the memory block (PAM) 12, and the input of the signal block receiving circuit breaker (BPS) 7 is connected to the second output of the block decoder (DB) 5, and the output connected to the first inputs of the phase signal processing unit (BFS) 8 and the frequency band shift unit (BSPCH) 9, the output of which is connected through a symbol decision block (RBS) 10, the second block decoder (VDC) 11 is connected to the second input of the information receiver (PI ) 6, and the second output of the demodulator (DM) 4 is connected to the input of the memory unit (PAM) 12, the output of which is connected to the second input of the phase signal processing unit (BOFS) 8 and the third input of the frequency shift unit (BSPCH) 9, the second input of which is connected to the output of the unit (BOFS) 8.

According to the first embodiment of the demodulator (DM) 4, from the output of the balanced modulator BM (3), the signal is fed to the input of the demodulator (DM) 4, which is the input of the phase amplitude detector (PDA) 14 and the input of the energy detector (DE) 13, the output of which is the first the output of the demodulator (DM) 4, the second output of which is connected to the output of an analog-to-digital converter (ADC) 15, the input of which is connected to the output of the phase amplitude detector (FDA) 14.

According to the second embodiment of the demodulator (DM) 4, from the output of the balanced modulator BM (3), the signal is fed to the input of the demodulator (DM) 4, which is the input of the second phase amplitude detector (VFDA) 16, the output of which is connected to the input of the analog-to-digital converter (ADC) ) 17, the output of which is connected to the input of the second decision block character (VRBS) 18, the output of which is the first output of the demodulator (DM) 4, the second output of which is connected to the output of the analog-to-digital converter (ADC) 17.

A digital information radio operates as follows.

Blocks (PF) 1, (SF) 2, (BM) 3 receivers make receiving information in real time.

Using a band-pass filter (PF) 1, the reception bandwidth at the radio frequency is limited, which limits the effect of other radio systems for various purposes on the useful received signal of the receiver. However, a filter with a limited bandwidth causes transients and bit distortion of the transmitted signal. The choice of filter parameter depends on the optimal processing method. When receiving signals [1, pp. 69-83] apply the optimal processing at the video frequency by the integrator installed at the output of the synchronous detector. The optimal processing methods take into account: the effect of white Gaussian noise on the input of the receiver, the appearance of intersymbol distortions of the code combination pulse from the overlapping responses from previous pulses. In this case, the optimal processing may contain:

- creating a uniform amplitude-frequency response, linearity of the phase-frequency response in a given frequency range;

- the use of gating, the use of optimal, quasi-optimal signal reception schemes in the presence of intersymbol distortions;

- the use of gating pulses allocated as a result of preliminary clock synchronization;

- A linear harmonic signal corrector to attenuate intersymbol interference.

It can be seen from the above that optimal processing is aimed at reducing the influence of noise interference and a limited bandwidth from intersymbol interference.

Balanced modulator (BM) 3. An example of a balanced modulator is a balanced modulator of an FM signal receiving device according to [2], the correlator block of which contains multipliers and integrators that provide the functions of search, capture and tracking of the signal spectrum. To enter the connection, a reference signal is used in the form of FM SHPS. In the presence of the Doppler effect, the frequency of the local oscillator of the main channel is adjusted and the pulse width of the reference signal is applied. The technical result of this device is that the device contains circuits that allow, in the presence of the Doppler effect, to avoid the synchronism of the received signal and the reference signal. The value of the difference frequency, the sign of the difference frequency is determined and taken into account, the average frequency of the radio signal f _c , the frequencies of the local oscillators f _g , the intermediate radio frequencies f _p are taken into account.

The energy phase detector (DE) 13 of the demodulator (DM) 4 operates on the basis of the ratio P _s / P _w . An example of an energy detector is a phase detector, which is based on a kinematic filter. The circuit solution provides for measuring the signal-to-noise ratio along the carrier, setting the level of the received signal at the input of the integrator with a reset. (DE) 13 decides that there is a bit from exceeding the signal level accumulated by the integrator with respect to the noise level. Integrator reset times are generated by a symbol synchronization circuit. The amplitude values of phase readings are not determined.

где обозначена амплитуда полезного фазового сигнала

.Amplitude phase detector (FDA) 14 converts the output signal of the demodulator (DM) 3 into an amplitude phase signal

where the amplitude of the useful phase signal is indicated

.

The demodulator (DM) 4 contains (Figure 3, Figure 4) analog-to-digital Converter 15 (17). An analog-to-digital converter converts the phase signal of a changing voltage into a sequence of digital samples. Let the block contain k bits of information, then for the information block there will be mk samples, m is the number of samples per information symbol by Kotelnikov’s theorem.

Digital samples (ADC) from the output 4 _{-2 of} block 4 are recorded in the memory block 12 (PAM).

Filters used to combat noise do not completely eliminate the distortion and loss of received information. To reduce losses, a block decoder (DK) 5 error-correcting coding is used, which corrects block symbol errors arising from noise and the Doppler effect. An example is a Reed-Solomon decoder (R-S).

A decoder with an R-S code (255, 223) has a good corrective ability for burst errors. When decoding the R-S code block at the receiving end, up to 16 errors per block are corrected. If the number of erroneous characters per block exceeds 16 errors, then erroneous characters are detected during the decoding process and status information on the quality of the decoded data is set.

Decoder (DK) 5 contains two outputs. A block of bits is transmitted to the first output of DM 4 if errors are not detected or corrected. A signal of status information is transmitted to the second output of DM 4, meaning that the code block is rejected and erased. The second output signal opens the operation of other devices with the “Enabled” command.

Decoder 5 (DK) determines the suitability of a data block for its intended use, depending on the number of correctly received bits. A correctly received information block is transmitted without delay from the output 5 _-1 of the block decoder (DC) 5 to the first input 6 _{-1 of} the information receiver (PI) 6, and the status information is transmitted through the output 5 _-2 to the input of the signal block receiving interrupter (PPBS) 7 , the output of which the signal is fed to the first inputs of the phase signal processing unit (BOFS) 8 and the frequency band shift unit (BSPCH) 9. The phase signal processing unit (BOFS) 8 determines the initial offset υ _{see the} phase signal in the unit and the frequency parameters of the bias of the constant component υ _smf (t) phase signal; and the block shift the frequency band (BSPCH) 9 compensates for these offsets.

The memory unit (PAM) 12 stores the samples of the phase signal e _c (t _i ).

Phase Signal Processing Unit (BOFS) 8.

The first 8 _-1 input of the phase signal processing unit (BOFS) 8 receives the signal "Enabled", which opens the BOFS. The operation of the BOFS starts when (DK) 5 an unrecoverable number of errors is detected in the block. Samples of the phase signal from the memory unit (AMP) 12 provided to the second input unit 8 _-2 BOFS 8. The processing phase samples determined phase estimate φ ₁ a phase signal at the beginning of the block and is estimated by the phase offset signal frequency compensated speed. According to the samples recorded in the memory, the BOFS determines the parameters of the phase signal displacement by the method [4, p. 428]. Transformations contain the following computational operations:

- assessment of the phase φ ₁ at the beginning of the measuring interval on the interval T ₁ ;

- evaluation of the phase φ ₂ at the end of the measuring interval on the segment T ₂ ;

и компенсируемой фазы сигнала в начале мерного интервала φ_г=φ_ср-φ₁; n - число перескоков фазы на 2 π; φ_ср - требуемое положение начального уровня. Оценки φ_г и Ω_г передаются с выхода БОФС в БСПЧ.- definition of compensated frequency

and the compensated phase of the signal at the beginning of the measuring interval φ _g = φ _cf- φ ₁ ; n is the number of phase jumps by 2 π; φ _cf - the required position of the initial level. Estimates of φ _g and Ω _g are transmitted from the output of the BOFS to the BSPH.

The frequency band shift unit (BSPCH) 9 uses the frequency band shift device according to [5], which performs SFC compensation. In the literature, this is called the application of a method for improving the noise immunity of a digital demodulator using bias voltage and multi-level quantization 161. The compensation algorithm is as follows. The samples of the phase signal from the PAM block 12 are fed to the third 9 _-3 input of the BSPCH 9, the “Work” signal is supplied to the first input 9 _-1 , the estimates of the shift parameters φ _g , Ω _g are received at the second input 9 _{-2 of the} BSPCH 9. BSPCH 9 performs compensation for the mixing shift of the frequency band. In this case, the samples of the phase signal e _c (t _i ) are converted by the local oscillator signal e _g (t _i ) = mod _2π [φ _g + Ω _g (t _i )] according to the formula e _pr (t _i ) = mod _2π [e _c (t _i ) + e _g (t _i )].

Symbol decision block (RBS) 10 according to the converted samples of the phase signal e _pr (t _i ) "decisive rule" determines the binary codes of the information block.

The second block decoder (VDC) 11 performs noise-decoding and transmits a block of information to the consumer. An example of a VDK is a Reed-Solomon decoder (R-S).

PPS component of the Doppler effect.

The SFC component from the Doppler frequency offset affects the occurrence of errors in the bit stream at the phase signal level, before the formation of the bit stream. The PPS component is formed by the shift of the zero level of the phase signal from the Doppler frequency shift and is manifested the stronger, the wider the spectrum of the modulating signal and the farther it is offset from the carrier frequency, which is illustrated as follows.

The formula for the Doppler frequency shift is F _∂i = (2W / λ) cos _γi [7, p. 7], where Wcosγ _i is the radial velocity of the spacecraft relative to the superlattice, λ is the wavelength. The formula is applicable to the carrier, to the components of the spectrum and groups of the components of the spectrum. Let f = 1 / λ = 11000 · 10 ⁶ Hz be emitted — the carrier frequency, F _τ = 40 · 10 ⁶ Hz — the average frequency of the group of components of the spectrum of signals of duration τ, F _τo ⁼ 80 · 10 ⁶ Hz — the average frequency of the group of components of the signal spectrum duration τ _about . Then, with the Doppler shift F = 50,000 Hz, at the carrier frequency f, the spectral components of the emitted signal f + F _τ and f + f _τo at the receiver input will have the values f _Fτ = (11000 * 10 ⁶ + 50000 + 181.8) Hz and f _Fτo = (11000 · 10 ⁶ + 50000 + 363.6) Hz and differences in the difference frequency occur f _Fτо -f _Fτ = 181.8 Hz, and when the clock frequency of the readout is _{automatically tuned} to the frequency f _Fτо , a phase signal with a period T _∂ appears = 1 / F _∂ = 5.5 ms (see Figure 5), where F _∂ = f _Fτo -f _Fτ .

The influence of the Doppler effect in continuous radiation is known [7, p.10]. The effect is manifested in a shift of the spectral components of the oscillations by the Doppler frequency and in a change in the phase of the oscillations with the Doppler frequency over time relative to the transformation of the coordinates of the stationary system into the mobile. The phase of a plane wave of an electromagnetic field is invariant with respect to transformations of the coordinates of one system into another.

We will consider the effect of the Doppler effect for a transmitter located in a fixed coordinate system. The receiver can be in the same fixed coordinate system or go into a moving coordinate system. In the latter case, it moves at a constant speed in the direction of the receiver or from the receiver.

Isolation of information from a radio signal is achieved by detection (demodulation). The study of signal conversion during detection in the literature was considered on the sum of two sinusoids. It is shown that upon detecting the oscillations x = sinω ₁ t + ε sinω ₂ t, where ω ₁ and ω ₂ are the sinusoid frequencies, a signal with a difference frequency ω ₁ -ω _{2 is formed} . When sinusoids with different ω ₁ , ω _2, and ε are added, beats occur, the beat frequency is determined by the period T _{D of the} repetition of the maxima or minima of the resulting oscillation, at incommensurable frequencies of the generating oscillations, the resulting oscillation is not periodic at all. The main types of detectors: a “linear” detector and a quadratic detector. Quadratic detection gives a result in the detection of beats in a more complicated case, when the amplitudes of the generating oscillations are not equal, i.e. (ε> 1 and ε≤1). Costas detection scheme is built on the principle of quadratic detection [1, p.240].

When the carrier frequency is modulated by a sinusoid of frequency ω ₁ , frequencies f-ω ₁ / 2π, f, f + ω ₁ / 2π appear on the frequency axis.

Let: f = 11000 · 10 ⁶ Hz, (f-ω ₁ / 2π) = 10900 · 10 ⁶ Hz, (f + ω _{1/2 π} ) = 11100 · 10 ⁶ Hz, the amplitude of the mirror component (f-ω _i / 2π) and the component (f + ω ₁ / 2π) are equal, and the remainder of the carrier (f) is suppressed. At a Doppler frequency of 50,000 Hz at the carrier frequency, the component frequencies will take offsets of 49545.4 Hz and 50454.5 Hz. The difference frequency is 909 Hz. The period of the difference frequency Td = 1.1 ms.

As an illustration for equal amplitudes, a graph of the resulting oscillation on a computer is constructed (Fig. 5b), where T3 is the region of interference fading, when the ratio P _c / P _w falls to a threshold value, information that can be modulated by the carrier will not be accepted. The graphs shown in Fig.5-Fig.11, built on a computer in the Delphi 3 Standart system.

If the read cycles of the phase samples of the phase-modulated signal are synchronized with the frequency (f + ω ₁ / 2π), then the phase demodulator will give a picture (Fig. 5c) with Td = 1.1 ms.

The distortion of the phase signal during pulse modulation from the manifestation of the Doppler effect is shown in Fig.9.

The influence of the Doppler effect in pulse modulation is known [7, p.15]. The effect manifests itself in a shift of the frequency spectrum of the oscillation pulse by the Doppler frequency and in a change in the phase of the oscillations with the Doppler frequency from one pulse repetition period to another relative to the initial phase of the emitted oscillations. Phase change over the repetition period Δφ _t = ω _d T _p , where T _p is the pulse repetition period, ω _d is the Doppler frequency at the receiving side.

We show the distortion of the phase signal during continuous phase modulation by the meander. The signal contains discrete spectral components with an amplitude c _k , phase φ _k and a constant component c _o , expressing the average value of the function over a period. The spectrum is discrete. For the meander, the pulse repetition period is T _p = 2τ, where τ is the pulse duration. The main modulating frequency ω ₁ = 2π / τ. The frequencies of the spectral components kω ₁ . Let the phase-modulated signal of the transmitting device has υ _Н = 0; υ _В = 90 deg. On figa shows a signal containing three harmonics and a constant component according to the formula 1 + sin (ω ₁ ) + 0.3 · sin (3 · ω ₁ ) + 0.15 · sin (5 · ω ₁ ). Figure 6 shows a signal containing two harmonics ω ₁ and 3ω ₁ .

Consider two cases of synchronization of pulses with a frequency of 3ω ₁ or ω ₁ on the receiving side:

A - transmission of information bits in the form of a sequence ... 111000111000 ... 111000 ... containing a repeating sequence consisting of six 111000 characters. The sequence is transmitted by the sum of two frequencies ω ₁ and 3ω ₁ . The clock pulses of the information bits are generated (on the transmitting and receiving side) from the frequency signal 3ω ₁ and are synchronized, as shown in Fig.7.

B - transmission of information bits in the form of a sequence ... 10101010 .... The sequence is transmitted by the sum of two frequencies ω ₁ and 3ω ₁ . The clock pulses of the information bits are generated from the frequency signal ω ₁ and synchronized, as shown in Fig. 8.

To record the signals used notation: x = ω ₁ ; (1), (0) - coefficients indicating the presence or absence of a signal component; the Doppler frequency shift Δω is taken into account by the coefficient Δω / ω, is written in the form x · (1 + 0.015), where 0.015 = Δω / ω; the phase of the component at time t is written in radians, provided that 2π corresponds to the period of the beat frequency. On figv in the period of beats T _{B the} oscillatory process shows 28 periods of frequency 3ω ₁ , 168 bits of information. For a moving coordinate system, the phase φ _B = 0 rad beat frequency Δω is equal to zero at moment t ₁ , the phase signal for the first six bits is shown in Fig. On Figg: fig.ga; pic gb; fig. guards; Fig. gg and Fig. gd shows the type of phase signal at phase values: 0; 1.36; 3.14; 4.5 and 6.28 rad (for a beat period of 168 bits). For the beat frequency of 181.8 Hz, the carrier frequency of 11000 · 10 ⁶ Hz, the bit rate of the information is 60 Mbit / s, the beat period is 5.5 ms. On the beat period there will be 330 · 10 ³ bits of information. With the values of the phases of the difference frequency: 1.36; 3.14; 4.5 and 6.28 rad the form of the phase signal will be, as in fig. GB; fig. guards; fig.yy and fig.yy

11 shows a phase driven signal having a constant component oscillation in a moving coordinate system, a constant component oscillation with a period T _D , a beat with a period T _B. When the Doppler frequency f _d is reduced to zero, the Doppler shift of the difference frequencies of the spectrum components also decreases to zero, and the component of the phase signal offset from this disappears.

Illustration of phase signal compensation by a frequency shift unit (BSPH) 9.

On Fig _a presents the implementation of the emitted phase signal in the interval T, is shown (in dashed lines) the envelope of the emitted signal in the time domain on the segment T, phase modulation 0; 90 °.

On Fig _b presents the clock pulses of the phase samples. For simplicity, it is assumed that during the information bit the digital phase detector takes two phase samples, the first (υ ₁ ) zero level sample, the second (υ ₂ ) signal sample. To explain the occurrence of inversions, we use the “decisive rule” for determining the information bit: (υ ₂ -υ ₁ )> 0 - there is a bit, (υ ₂ -υ ₁ ) ≤0 - there is no bit.

On Fig _in the code of the emitted signal.

12 _g shows the implementation of the received signal in a mixture with SFC. In FIG. it is seen that the useful signal (with modulation 0; 90 °) in total with the interference reaches the level of 2π and the inversion of the characters is observed.

Character inversion occurred on the fourth, fifth and sixth bit characters.

On Fig _a presents the signal from the output of the phase detector recorded in RAM.

On Fig _b presents the clock of the phase samples.

On Fig _in presents the character code of the information block, which would be fixed if there were no transformations recorded in the random access memory of the samples.

13 _g shows the calculated phase displacement.

13 _d shows converted phase samples.

On Fig _e presents the character code of the information block obtained by the "decision rule" after the execution of the conversion algorithm.

For given acceptable signal-to-noise ratios, the probability of errors in the digital stream codes is small, errors are corrected by decoding. In this time delay, information reception does not occur.

The delay in the appearance of a block bit at the second input of the information recipient (PI) 6 occurs when the blocks providing compensation are included in the operation by the “Enabled” command, which is generated by the demodulator (DM) 4, which occurs when the Doppler effect is strong, bursts of noise occur, including from a drop in signal power. As a result of the BOFS and BSPCH operation, the number of errors for correction by the decoder decreases, decoding becomes effective and the loss of information blocks by the radio receiver is reduced.

Information sources

1. I. M. Teplyakov and others. "Radio transmission systems", M .: "Radio and communication", 1982, p. 69-83, 230-234.

2. The device according to the patent of the Russian Federation No. 2197064 (application 2001105566/09 of 02.27.2007, IPC Н04В 1/10, H04L 27/22).

3. L.E. Varakin “Communication systems with noise-like signals”, M .: “Radio and communication”, 1985, p.154, 173, 205, fig. 7.1, fig. 9.1.

4. Berezin L.V. and Weitzel V.A. Theory and design of radio systems. “Owls. Radio ", 1977, p. 428.

5. Meleshkov G.A. The device for shifting the frequency band, according to the copyright certificate of the USSR No. 824401, 1979.

6. Aces G.I. and others. Interference immunity of radio systems with complex signals. “Radio and communication”, 1985, p.186, 204.

7. Kolchinsky V.E. and others. Autonomous Doppler devices and aircraft navigation systems. “Owls. Radio ", 1975, p.10-11.

Claims (3)

1. A digital information radio receiver comprising a series-connected band-pass filter, a matched filter, a balanced modulator, a demodulator, a block decoder, an information receiver, the second input of the balanced modulator connected to the output of the noise-like signal generator, and the signal from the amplitude amplitude phase detector being taken from the second output of the demodulator, characterized in that a breaker for receiving a block of signals, the input of which is connected to the second output of the block decoder, is inserted into it, a digital memory block of accounts of the amplitude phase detector signal, a phase signal processing unit that performs the function of determining estimates of the compensated frequency and phase from the samples of the memory block signal, a frequency band shift unit that performs the functions of compensating for stray phase displacements in the recorded samples of the memory unit signal, the decider block is character, the second block decoder moreover, the output of the chopper receiving the signal block with the “On” command opening the operation of the blocks is connected to the first inputs of the phase signal processing block and the shift block in a frequency axis, the output of which, through a decimal unit connected in series, the character and the second block decoder is connected to the second input of the information receiver, the second output of the demodulator is connected to the input of the memory block, the output of the digital samples of which is connected to the second input of the phase signal processing unit and the third input of the frequency band shift unit , the second input of which is connected to the output of the compensated frequency and phase of the phase signal processing unit. 2. The digital information radio receiver according to claim 1, characterized in that the demodulator input is an input of an amplitude phase detector and an energy detector input, the output of which is the first output of a demodulator, the second output of which is connected to the output of an analog-to-digital converter, the input of which is connected to the phase output amplitude detector. 3. The digital information radio receiver according to claim 1, characterized in that the demodulator input is the input of a second amplitude amplitude phase detector, the output of which is connected to the input of an analog-to-digital converter, the output of which is connected to the input of the second symbol decoding unit, the output of which is the first output of the demodulator, the second output of which is connected to the output of an analog-to-digital converter.

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