Line radio reuse frequency

 

(57) Abstract:

Line radio reuse frequency relates to the field of radio communications and can be used in space and terrestrial Radiocommunication systems with reuse frequency. Technical result achieved - increased protection against concentrated interference affecting the inputs. This line radio contains on the transmission side signal generator key messages, power splitter, two amplitude modulator, paraphase amplifier, transmitting antenna and two irradiator, at the receiving side receiving antenna and its two irradiator, two adder, subtractive device, a synchronous detector, detector, amplitude limiter, low-frequency narrowband filter, pre-filter selection, filter, tuned to the frequency of the main signal, the filter of the local oscillator, demodulator messages for the device to rotate the polarization of the lo amplifier high frequency, an adjustable amplifier, a mixer, a control device, the delay line. 3 Il.

The proposed device relates to the field of radio communications and can be used in space and NASA who eat polarization modulation signals, in particular elliptical polarized wave by changing the parameters of the polarization ellipse (K., Gusev, A. D. Filatov, A. P. Sobolev "Polarization modulation". M, Owls. radio, 1974, page 63-161).

The disadvantage of these devices is that they can be used in conditions when the parameters of the distribution of signals on the highway and the mutual position of the transmitting and receiving antennas is constant, since otherwise there is a great level of mutual interference between individual channels of the radio link. However, in most practical case, change as the parameters of the distribution of signals, and the relative locations of the antennas.

It is also known device for U.S. patent N 4087818, in which the reuse of frequencies in a changing environment parameters of the distribution of signals and the relative position of the antennas is achieved by ensuring the orthogonality of the polarization of the two transmitted signals simultaneously with circular or linear polarization. This orthogonality is maintained with the help of automatic circuit in the form of a closed loop using a special pilot signals. It contains a transmitting device that generates two signals with the same CY receive these signals through orthogonal polarization.

However, this device due to the high requirements on the polarization of the transmitted signals is a complex system-locked loop. In addition, the implementation of this device requires special additional communication lines.

The closest to the technical nature of the claimed object is "radio System".with. N 1385305 adopted for the prototype.

In Fig. 1 shows a functional diagram of the device of the prototype, where we have introduced the notation:

1 - generator main signals;

2 - splitter power;

3 and 4, the first and second amplitude modulators, respectively;

5 - phase with the amplifier;

6 and 7, the first and second irradiators transmitting antenna, respectively;

8 - transmit antenna;

9 and 10, the first and second irradiators (pathogens) receiving antenna, respectively;

11 - receiving antenna;

12 - sum-dierence block;

13 - adder;

14 - subtractive block;

15 - a synchronous detector;

16 - demodulator primary message;

17 - amplitude limiter;

18 and 19, the first and second low pass filters, respectively;

20 - unit control position of the axes of polarization of irradiators receiving antenna.

21 - key;
26 comparator.

The device prototype has the following functional relation.

On the transmission side output of the signal generator 1 is connected to the input of the power splitter 2, the first and second outputs of which are connected with the first inputs of the first 3 and second 4 amplitude modulators, the second inputs of which are connected respectively with the first and second outputs of opposite phase of the amplifier 5, the inlet of which is the entrance for more information Sdthe outputs of the first 3 and second 4 amplitude modulators are connected respectively with the first 6 and second 7 irradiators transmitting antenna 8; at the receiving side: the outputs of the first 9 and second 10 irradiators (pathogens) receiving antenna 11 connected respectively to the inputs of the control unit the position of the axes of polarization of irradiators receiving antenna 20, the two outputs of which are connected respectively to two inputs of the adder 13 and two inputs respectively subtractive unit 14; the output of the adder 13 through the amplitude limiter 17 is connected to the inputs of the phase detector 22 and the first delay line 24; the second output of the phase detector 22 is connected to the output of the phase shifter 23 and one of the inputs of the synchronous detector 15, the second input is sondigo detector 15 through the first low pass filter 18 is connected with the control input of the control unit the position of the axes of polarization of 20 irradiators receiving antenna. The output of the first delay line 24 is connected with one input key 21, the second input of which is connected to the output of the comparator 26, an input connected to the output of the second lowpass filter 19, an input connected to the output of phase detector 22. The input of the phase shifter 23 is connected to the output of the demodulator key messages 16, an input connected to the output of the key 21, the second output of the demodulator 16 is removed basic information Soand additional information Sdremoved from the output of the synchronous detector 15.

Function prototype as follows.

The signal generator 1 generates a signal to the main message, modulated in frequency or phase of the main messages. This signal is

Uc(t) = Ucos[t+(t)], (1)

where U is a constant signal amplitude;

(t) is a function of the phase change signal corresponding to a frequency or phase modulation of the main messages Sabout;

angular frequency.

Signal (1) is fed to the input of the power splitter 2, the output of which the signal branches into two channels that have amplitude modulators 3 and 4, is made in the form of high-frequency amplifiers. In them the amplitude of the transmitted signals and tivotogo amplifier 5. The signals at the outputs of the amplitude modulators 3 and 4 the following:

U3(t) = U1[1+f(t)]cos[t+(t)], (2)

U4(t) = U1[1-f(t)]cos[t+(t)], (3)

where U3(t) and U4(t) - signals from the outputs of the modulators 3 and 4, respectively;

U1- constant amplitude;

f(t) function changes the amplitude of the signal corresponding to the additional messages Sd.

Signals (2) and (3) are fed to the inputs of irradiators 6 and 7 of the transmitting antenna 8. The transmitting antenna 8 may be made in the form of a reflector antenna with two irradiators 6 and 7 or in the form of array antennas with appropriate agents. Irradiators 6 and 7 create fields with orthogonal one with respect to another linear or circular polarization. The signals emitted by the transmitting antenna 8, are receiving antenna 11. It irradiators (pathogens) 9 and 10 are mutually orthogonal linear or circular polarization. Receiving antenna 11 with irradiators (pathogens) 9 and 10 are identical transmission.

Outputs irradiators 9 and 10 receiving antenna 11 is received the signal

< / BR>
where nx(t) is the fluctuation of the obstacle in the form of a normal Gaussian noise component of the x-axis;

nxu(t) - pulsed interference is the main obstacle in the form of a normal Gaussian noise component of y;

nyu(t) - pulsed interference component of the y-axis.

With the output of the adder 13 received the signal

< / BR>
Output subtractive unit received the signal

< / BR>
As a demodulator 16 is used synchronous phase demodulator (IFD) with device rejection of anomalous distortions phase multiple of 2 radians occurring in the input mixture signal interference under the action of both fluctuation and pulse interference that can improve the noise immunity when exposed to complex interference on the units and tens of decibels depending on the base signal.

At the output of demodulator 16, operating in synchronous mode, there is a voltage varying according to the law of variation of the frequency or phase of the input signal that is demodulated message.

To compensate for the constant phase shift used the phase shifter 23 90o, the output of which feeds the reference signal that does not contain information about the interference to the synchronous detector 15.

When exposed to the input of the system fluctuation noise and impulse noise (PI) at the first input of phase detector 22 receives the total output signal of the amplitude limiter 17, and to the second input of phase detector 22 supports the s at the output of LPF 19 voltage interference.

In case of exceeding the threshold comparator 26 at its output a signal of the ban, which covers the key 21 and the signal Impressed FE" does not pass to the input of the demodulator 16 for the duration of PI. In this case, as a rule, the time constant of LPF 18 is greater than the duration of PI. Thus, the demodulator 16 is not released from the condition of synchronism for the duration of PI.

In case of absence at the input of the PI at the output of the comparator 26, the prohibition signal is absent and the key 21 is opened.

At the time of analysis jamming environment and generate a signal control key 21 is necessary to detain the total signal processing channel with an angular modulation. At the same time it is necessary to delay and the differential signal in the other channel, what are the lines 24 and 25 of the delay. The delay lines 24 and 25 of the delay is chosen the same. This time is mainly determined by the bandwidth of the LPF 19.

From the output of the synchronous detector 15, the signal is narrowband low-pass filter 18, which is allocated a permanent component, the sign of which depends on the sign of the angle of misalignment. Output from the LPF 18 this component is supplied to the control unit the position of the axes of polarization of irradiators (vozbudimoi (angle - negative) said component is positive, irradiators rotated in the opposite direction.

Low-pass filter 18 has a bandwidth substantially less than the width of the spectrum of functions. Therefore, low-pass filter 18 can pass only slowly changing signals, due to changes of the relative position of the antenna.

The block 20 with the voltage removed from the low-pass filter 18 eliminates misalignment between the polarization of the incoming signals and polarization irradiators receiving antenna. When this control system operates on the received signal, carrying information about the transmitted messages.

But this device is a prototype has low immunity in relation to focused on the spectrum of noise, as if his entry is quite powerful concentrated on the spectrum of noise (even out of band), exceeding the dynamic range, the inputs go into the nonlinear regime, forming a parasitic amplitude and phase modulation, thereby clogging the main signal.

To increase noise immunity in relation to concentrated interference affecting the inputs, and offers a Line of communication with reuse frequent the>/BR>2 - splitter power;

3 and 4, the first and second amplitude modulators, respectively;

5 - paraphase amplifier;

6 and 7, the first and second irradiators transmitting antenna, respectively;

8 - transmit antenna;

9 and 10, the first and second irradiators (pathogens) receiving antenna.

11 - receiving antenna;

12 - the first adder;

13 - subtractive block;

14 - synchronous detector;

15 - amplitude limiter;

16 - filter pre-selection;

17 - narrowband low-pass filter;

18 - device rotation polarization;

19 - heterodyne;

20 - the second adder;

21 - filter, tuned to the frequency of the main signal;

22 - amplifier high frequency;

23 - mixer;

24 - adjustable amplifier;

25 filter lo;

26 - detector;

27 to the control device;

28 - delay line.

Functional communication on the transmission side similar functional relations for the device prototype.

The proposed device has the following functional communication at the receiving side: the first 9 and second 10 agents of the receiving antenna 11 are connected respectively with the first and second inputs of the device rotation is DAMI subtractive device 13, the output of the first adder 12 through the pre-filter selection 16 is connected to one of inputs of the second adder 20, the second input of which is connected to the output of the local oscillator 19, the output of the second adder 20 via UHF 22 is connected to the inputs of filter local oscillator 25 and filter the main signal 21, the output of which is connected to one input of mixer 23, a second input connected to the output of the limiter 15, the input of which is connected to the input of the filter local oscillator 25 and the input of the detector 26, the output of which through the control device 27 is connected with one input of the controlled amplifier 24, a second input connected to the output of the mixer 23, the output of the controlled amplifier 24 is connected to one input of a synchronous detector, the second input is through the delay line 28 is connected to the output of subtractive device 13, and the output of the synchronous detector 14 through a narrow-band low-pass filter 17 is attached to the driven input device to rotate the polarization of 18, the output of the controlled amplifier 24 is output to the main information, and the output of the synchronous detector 14 is output to the additional information.

The proposed device is as follows.

The goal of improving efficacia current (see for example, Bogdanov, B. M. "Nonlinear distortion in the receiving-amplifying devices, Meters , Communication, 1980 , Tikhonov C. I., Coleman N. K. "Nonlinear filtering and quasicoherent reception of signals, M, Owls. radio, 1975). In many practically important cases, the level of mutual interference can substantially exceed the dynamic range of the gain blocks of the receiver, causing them to overload, and this gives rise to spurious amplitude and frequency modulation of the useful signal.

The operation of the transmitter in the proposed device is identical with the operation of the transmitter in the device prototype.

The receiving device operates as follows.

The signals emitted by the transmitting antenna 8, are receiving antenna 11. Its agents 9 and 10 are also orthogonal linear or circular polarization. Receiving antenna 11 with pathogens 9 and 10 are identical transmission.

The outputs of pathogens 9 and 10 will signal

< / BR>
< / BR>
These signals arrive at the inputs of the first adder 12 and subtractive device 13. At the output of adder 12 will be

< / BR>
At the input of the amplifier high frequency UHF 22 applies an additive mixture of the useful signal Uc(t), thermal Low transmission filter pre-selection 16 and UHF receiver 22. Therefore, the signal at the input UHF 22 (excluding lo signal 19) can be written as

< / BR>
where Up(t) andp(t) is the envelope and phase of the resulting oscillations.

For convenience, we assume

e(t) = Uc(t)+UW(t) = E(t)cos[0(t)+(t)],

where E(t) and (t) is the envelope and phase fluctuations;

0- the average frequency of the useful signal.

Take into account the fact that the overload UHF, i.e. non-linear mode of operation occurs when the amplitude of the interference is substantially greater than the amplitude of the signal and thermal noise.

Let us introduce the notation

= E(t)/Un(t).

When 1 , which occurs when the overload UHF, envelope and phase of the resulting oscillations can be represented in the form

< / BR>
< / BR>
where = (n-o)t+an(t)-(t).

With that said, the resulting oscillation input UHF (excluding lo signal) can be written

< / BR>
Consider the case where UHF can be implemented on BW. The amplitude characteristic in this case would be as shown in Fig. 3.

Let us assume that the amplitude of the noise is constant and equal to Up- flat plot characteristics 2E and phase of the signal when the effect of overloading the interference does not change.

This ampliado oscillation output UHF can be written

< / BR>
where

(Gonorovski I. S. "Radio engineering circuits and signals", M., Owls. radio, 1977).

The last expression can be represented as

< / BR>
where Jkn - Bessel function.

With regard to 1 after conversion will receive

< / BR>
where

< / BR>
< / BR>
Or in expanded form

< / BR>
In the functional diagram in Fig. 2 uses the reference signal is the signal of the local oscillator 19, designed to determine the functions of parasitic modulation (amplitude and phase) of the useful signal. Moreover, the frequency reference signal is outside the bandwidth of the filter pre-selection 16, and the reference voltage lo Ug< < Upat the same time , the amplitude Ugselected significantly more noise receiver Ug> > UW.

The reference signal passing through the congested UHF receives spurious amplitude and phase modulation along with the useful signal and is filtered by the filter of the local oscillator 25.

The possibility of using the reference signal to determine the features of parasitic modulation as the useful signal due to the fact that the transmission coefficient UHF weakly depends on frequency shift is within the bandwidth. So the a priori signal.

Taking into account (18) and the limitations specified above, the output signal UHF 22 without regard lo will be

< / BR>
whereWis determined by the amplitude noise and amplitude-phase characteristic of the UHF.

Taking into account (19) oscillation at the output of the filters 21 and 25 will be

< / BR>
Passing through the UHF reference signal lo taking into account (19) will be

< / BR>
where Uc1(t) = Uc(t)cos[ot+ae(t)+aW(t)],

UG1(t) = Ugcos[g(t)+ag+W(t)],

< / BR>
< / BR>
whereW(t) is the phase modulation of the useful signal and noise in the UHF when exposed to intense interference.

The reference signal from the output of the filter 25 is supplied to the limiter 15 amplitude amplitude detector 26 to the control unit 27, where a voltage that is designed to regulate the gain of the controlled amplifier 24 in accordance with a function of time

< / BR>
where Kabout- the average gain.

This eliminates spurious amplitude modulation of the useful signal.

The reference signal after limiting the amplitude of the limiter 15 is supplied to a mixer 23, which is a useful conversion mixer 23 is

< / BR>
Signal-to-noise ratio at the output of the adjustable amplifier

< / BR>
where qabout- signal-to-noise ratio at the input UHF.

Thus, in the proposed device are eliminated spurious amplitude and phase modulation.

Line radio reuse frequency, containing on the transmission side connected in series signal generator key messages, power splitter, two outputs which are connected to the corresponding inputs of the first and second amplitude modulators, other inputs which are connected respectively to the outputs of the paraphase amplifier, whose input is connected to the source of additional information, the outputs of the amplitude modulators are connected respectively to the first and the second horn of the transmitting antenna, the signal generator key messages generates the signal, phase modulated main message at the receiving side is the amplitude limiter, the first and second irradiators receiving antenna attached respectively to first and second inputs of the device rotation of polarization, two outputs which are connected respectively to two inputs of the first adder with two inputs which subtract through a narrow-band low-pass filter is connected with the control input of the rotation of polarization, characterized in that the input at the receiving side filter pre-selection, the input connected to the output of the first adder, and the output to one of the inputs of the second adder, the other input connected to the output of the local oscillator and the output to the input of the amplifier high frequency, the output of which is simultaneously connected to the inputs of filter that is configured on the frequency of the main signal, and filter local oscillator, the output of which is connected in series through the detector and the control unit is connected with one input of the adjustable amplifier and simultaneously through the amplitude limiter to one of the inputs of the mixer, the other input connected to the output of the filter that is configured on the frequency of the main signal, and the mixer output connected to another input of the adjustable amplifier, the output of which is connected with the corresponding input of synchronous detector and is output to the main information, the output of the synchronous detector is output to the additional information.

 

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FIELD: radio engineering; construction of radio communication, radio navigation, and control systems using broadband signals.

SUBSTANCE: proposed device depends for its operation on comparison of read-out signal with two thresholds, probability of exceeding these thresholds being enhanced during search interval with the result that search is continued. This broadband signal search device has linear part 1, matched filter 2, clock generator 19, channel selection control unit 13, inverter 12, fourth adder 15, two detectors 8, 17, two threshold comparison units 9, 18, NOT gates 16, as well as AND gate 14. Matched filter has pre-filter 3, delay line 4, n attenuators, n phase shifters, and three adders 7, 10, 11.

EFFECT: enhanced noise immunity under structural noise impact.

1 cl, 3 dwg

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