The compensation device interference to receivers broadband phase-shift keyed signals

 

(57) Abstract:

The invention relates to the field of radio and can be used in communication systems with broadband signals. Device for noise compensation includes serially connected first myCitadel, the first multiplier, the first band-pass filter, phase shifter, a second multiplier, a second myCitadel, the third multiplier, the notch filter, the fourth multiplier block with adjustable gain, the output of which is connected to another input of the first myCitadel. Thus the inputs of the first and second vychitala are combined and input devices. The output of the first multiplier connected in series through the second band-pass filter, amplifier and detector 10 is connected to another input of the block. In addition, the output of bandpass filter connected in series through a second phase shifter, the limiter, the fifth multiplier connected simultaneously to the corresponding inputs of the third and fourth multiplier products. The generator output up signal is simultaneously connected to the corresponding inputs of the first, second and fifth multiplier products. The output is the output of the first multiplier. Technical financial p is s relates to the field of radio engineering and can be used in communication systems with broadband noise.

The known device the noise compensation for receivers wideband signals, described in patent N 2000666, H 04 B 1/10, H 04 L 7/00, N 2000669, H 04 B 1/10, N 2000659, H 04 B 1/10, the lack of which is a low immunity to narrowband interference.

The closest in technical essence to the proposed device is "noise suppression Device for receivers wideband signals" in patent N 2034403, H 04 B 1/10, H 04 L 7/00 adopted for the prototype.

The block diagram of the device of the prototype is shown in Fig. 1, where indicated:

1, 6, the first and second myCitadel,

2, 5, the first and the second multiplier,

3, 8, the first and second band-pass filter,

4 - Phaser,

7 - block with adjustable gain,

9 - power,

10 detector AGC,

11 - the generator copy of the signal.

The device prototype includes serially connected first myCitadel 1, multiplier 2, the first band-pass filter 3, the phase shifter 4, a second multiplier 5, the second myCitadel 6 and the block with adjustable ratio transmission 7, the output of which is connected to another input of the first myCitadel. In addition, the inputs of the first 1 and the second 6 vychitala are combined and input devices, and ammatory copies of the signal 11 is connected both to one of inputs of the first 2 and the second 5 multiplier products. The common point of the output of the first multiplier 2 and the input of the first bandpass filter 3 connected in series through the second band-pass filter 8, an amplifier 9, the AGC detector 10 is connected with another input with adjustable gain 7.

The device prototype works as follows.

The input mixture containing a broadband signal and narrowband interference, is fed simultaneously to the inputs of vychitala 1 and 6, with myCitadel 1 from the input mixture is subtracted evaluation of interference, and myCitadel 6 - evaluation of the useful signal. As a result, the output vicites 1 highlights the broadband signal and the uncorrected part of the narrowband interference, which are fed to the multiplier 2. It by multiplying synchronous with a reference signal generated by the generator 11, a broadband signal is minimized in narrowband, which is filtered in the filter 3, is configured to frequency f0carrier broadband signal through the phase shifter 4 is supplied to the multiplier 5. (Hereinafter the term "multiplication" means the procedure phase modulation or remodulate, i.e., blending or eliminate code modulation).

In the multiplier 5 by multiplication with the same oborny is input to vicites 6. Due to the compensation of the broadband signal at the output of vicites 6 estimation of narrowband interference, which through the block 7 is myCitadel 1, where compensates uzkopolosnoi interference in the input mixture. Output vicites 1 highlights the broadband signal and the uncorrected part of narrowband interference.

After multiplication in block 2 with a reference signal generated by the generator 11, the uncorrected part of the narrowband interference is transformed into broadband noise part of the spectrum which comes in strips of filters 3 and 8.

The bandwidth of the filter 8 is chosen equal to the bandwidth of the filter 3 (with the possibility of obtaining a given selectivity filters). In the filter 8, built from the filter 3 by a specified amount, allocated part of the spectrum interference, and the signal does not get into it. The selected voltage noise is amplified by the amplifier 9, is detected by detector 10 and is used to adjust the gain of the block 7. This adjustment is carried out automatically in such a way as to achieve minimum interference voltage in the filter 8.

The disadvantage of this device prototype is a low immunity against strategyeye first myCitadel, the first multiplier, the band-pass filter, phase shifter, a second multiplier, a second myCitadel and block with adjustable gain, the output of which is connected to one of inputs of the first myCitadel, generator backup signal, the output of which is simultaneously connected to the corresponding inputs of the first and second multiplier products, the output of the first multiplier connected in series through the second band-pass filter, an amplifier, a detector connected to one of inputs of the block with adjustable coeffcients transmission, while the inputs of the first and second multiplier products are combined and input device, and its output is the output of the first multiplier, introduced the third, the fourth and fifth multiplier products, the second phase shifter, the limiter and the notch filter. Moreover, the output of the second bandpass filter connected in series through a second phase shifter, the limiter and the fifth multiplier connected to respective inputs of the third and fourth multiplier products, the output of the second vicites connected in series through the third multiplier, the notch filter and the fourth multiplier is connected to one of inputs of the block with an adjustable gear ratio. In addition, the other input of Patoka shown in Fig. 2, where indicated:

1, 6, the first and second myCitadel,

2, 5, 12, 14, 15 - first, second, third, fourth and fifth multiplier products,

3, 8, the first and second bandpass filters

4, 16, the first and second phasers,

7 - block with adjustable gain,

9 - power,

10 detector AGC,

11 - the generator copy of the signal (a pseudo-random sequence generator),

13 - rejection filter,

17 - limiter.

The proposed device comprises serially connected first myCitadel 1, the first multiplier 2, the first band-pass filter 3, the phase shifter 4, a second multiplier 5, the second myCitadel 6, the third multiplier 12, the notch filter 13, a fourth multiplier 14, a block with an adjustable ratio transmission 7, the output of which is connected to another input of the first vicites 1. Thus the outputs of the first 1 and the second 6 vychitala are combined and input devices. The common point of the output of the first multiplier 2 and the input of the first bandpass filter 3 connected in series through the second band-pass filter 8, an amplifier 9 and detector 10 is connected to another input of the block 7. In addition, the common point of the output of the band pass filter 8 and the input of the amplifier 9 through the village of the term to the corresponding inputs of the third 12 and fourth 14 multiplier products. When the generator output up signal 11 simultaneously connected to the corresponding inputs of the first 2, the second 5 and 15 fifth multiplier products. The output device is a common exit point of the first vicites 1 and the input of the first multiplier 2.

Does the proposed device is as follows.

The input mixture containing broadband photomanipulating signal and structural hindrance comes simultaneously to the inputs of vychitala 1 and 6. In the original time reference inputs of the multiplier products 12 and 14 corresponds to the voltage that is equivalent to breaking the circuit between vycitalem 1 and 6. In this case, the output of vicites 1 signal and the interference is coming to the multiplier 2, where due to the multiplier synchronous with a reference signal generated in the generator 11, a broadband signal is folded in narrow-band and narrowband interference becomes broadband.

Rolled narrowband signal and the spectrum of broadband noise fall within the bandwidth of the band pass filter 3, is configured on a carrier frequency of the useful signal f0. The bandwidth of the bandpass filter 3 is equal to the band collapsed useful signal F.

Part of the spectrum of shirokopolosnye, equal to F, the frequency f1selected as close as possible to f0(with the possibility of achieving the necessary degree of selectivity filters 3 and 8).

From the output of the filter 3 narrowband signal and the spectrum of the noise caught in the bandwidth of the filter 3 through the phase shifter 4 are fed to the multiplier 5, where due to the manipulation of a reference signal generated by the generator 11, they turn into a broadband signal and spurious broadband interference, correlated with the useful signal has the same carrier and the same law of formation and differing from it in the initial phase).

Broadband signal and spurious broadband disturbance from the output of the multiplier 5 is fed to the input of vicites 6, where the compensation signal and the selection of the estimation of structural interference and spurious broadband component, which serves to signal input of the multiplier 12.

On the reference inputs of the multiplier products 12 and 14 is energized from the output of the multiplier 15, which is formed as follows.

Part of the spectrum of the broadband noise generated by manipulation of structural interference reference signal in Peremogi is 3. The tuning frequency of the filter 8 is selected as close as possible to the carrier frequency of the broadband signal f0(including hardware capabilities achieve the desired selectivity filters 3 and 8).

From the output of the filter 8 a hindrance through the phase shifter 16 and the stopper 17 is supplied to the signal input of the multiplier 15, which by multiplication with a reference signal from generator 11 becomes broadband photomanipulating obstacle, similar parasitic broadband noise at the output of the multiplier 5, i.e. with the same law of formation, the same spectrum band and differing from it by a carrier frequency equal (fo+KF, K 2), where KF is the frequency detuning of the filter 8 with respect to the tuning frequency of the filter 3, K is an integer.

In the multiplier 12 is the multiplication of a mixture of structural interference and spurious broadband component on the carrier f0parasite broadband component of the same interference at the carrier frequency (fo+KF), K2, K - integer. The results of the multiplication of two correlated broadband spurious interference is their convolution, which registereda in the filter 13, this prevents the circulation of spurious broadband component p is almost without distortion, because the multiplier 12 and the obstacle collides with the manipulation of the reference spurious broadband interference coming from the output of the multiplier 15 and the multiplier 14 it is removed by multiplying with the same reference signal.

At the same time, the broadband part of the spectrum of structural interference at the output of the multiplier 12, which are in a strip of filter 13, is manipulated by the phase reference spurious component in the multiplier 14, which formed a new parasitic broadband interference component at the frequency f0. The level of this noise is determined by the ratio:

< / BR>
The filter 13 allocates the result of a convolution of correlated noise the same structure, and the strip of rejectio should be selected taking into account the possibility of separating the different phases of the interference at the input of multiplier 12, i.e., it is extremely narrow, which confirms the validity of relation (1).

Since the parasitic broadband interference components in the multiplier 12 receives carrier frequency f0the filter 13 is a consistently connected notch filters differential (zero) frequency, and total (double) frequency.

In the prototype, the degree of suppression ogranochlorides the feedback loop.

Uncompensated part of the interference from the output of myCitadel is supplied to the multiplier 2, which is manipulated by the phase of the reference pseudo-random sequence, causing it to become broadband. Part of the spectrum it caught in the bandpass filter 3 through the phase shifter 4 is supplied to the multiplier 5 is manipulated in the same phase reference signal, then it turns into a parasite broadband interference component, correlated with the useful signal (having a similar carrier frequency and the law of manipulation and differs from it only the initial phase).

Parasitic broadband interference component in the feedback loop (through the blocks 6, 7 and 1) is supplied to the multiplier 2, where due to the multiplication with the same reference signal is minimized in the parasitic narrowband interfering component, which is getting into the filter 3, is added to the main ECM component within the filter 3 from the input mixture (through blocks 1 and 2). This process is repeated several times.

Thus in the device prototype is the circulation of spurious noise component and its accumulation in the filter 3, which reduces the stability of the device and the degree of suppression prenium:

< / BR>
where Unthe voltage noise at the input;

F - band spectrum collapsed useful signal (filter bandwidth 3);

fW- band spectrum of the broadband signal;

K - coefficient of the transmission path between blocks 1 and 6.

When K = 1 device-prototype unhealthy, and the increase in K leads to an increase in the duration of the transient.

Constraints imposed on the values of K lead to constraints on the values of Up.

Thus, when K < 0,9, Up> 0,1 Upand taking into account the accumulation of spurious interference component for USPfor the prototype are:

< / BR>
In the proposed device the circuit between vycitalem 1 and 6 in the initial moment of time is torn and opened only after the allocation interference at the output of the multiplier 15.

This means that in the inventive device, the transmission coefficient between blocks 1 and 6 can be set arbitrarily close to 1. The value of K does not affect the duration of transients, and Upcan be arbitrarily small.

The rejection of spurious interference component in blocks 10, 11, 12 eliminates the possibility of accumulation, because of the level of spurious interference component in the proposed ustroistvom to be achieved significantly greater suppression of spurious broadband interference component, than in the prototype.

At the same time, in the inventive device in blocks 12, 13, 14, a new parasite of interfering component, the appearance of which is due to rejection of the spectrum of broadband structural interference in the block 13. However, the band rejectee unit 13 is significantly less bandwidth F, i.e. F130,

as the block 13 rejective the result of a convolution of correlated interference components, different carrier frequencies and initial phases, i.e., has a narrow band emitting phase difference.

While this device eliminates the possibility of the circulation of this noise component, the level of which is determined by:

< / BR>
Thus, the proposed device eliminates the circulation of spurious broadband interference component in the feedback loop and produces a higher degree of noise reduction than in the prototype.

The compensation device interference to receivers broadband phase-shift keyed signals containing serially connected first myCitadel, the first multiplier, the first band-pass filter, phase shifter, the second myCitadel and block with adjustable gain, the output of which is connected with the second input pervogo multiplier products, the output of the first multiplier connected in series through the second bandpass filter, amplifier, detector, AGC is connected with the control input with adjustable gain, the first input of the first and the second input of the second vychitala are combined and input device, and its output is the connection point of the first vicites and the first multiplier, wherein the entered third, fourth and fifth multiplier products, the second phase shifter, the limiter and the notch filter, and the output of the second bandpass filter connected in series through a second phase shifter, the limiter and the fifth multiplier is connected with the control inputs of the third and fourth multiplier products, the output of the second vicites connected in series through the third multiplier, the notch filter and the fourth multiplier is connected to one of inputs of the block with adjustable gain, furthermore, the reference input of the fifth multiplier connected to the output of the generator copy of the signal.

 

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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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