The noise suppression device for receivers wideband signals

 

(57) Abstract:

The invention relates to electrical engineering and can be used in communication systems with broadband signals. The technical result - increased robustness to structural interference. The invention consists in that the chain consisting of the fourth multiplier, block rejectee and the fifth multiplier, allows to increase the degree of suppression of spurious broadband component of the interference, as the bandwidth of an additional unit of rejectio significantly less than the bandwidth of the main notch filter. 4 Il.

The present invention relates to the field of radio and can be used in communication systems with broadband signals.

The known device suppressing interference to receivers wideband signals described in the patents of the Russian Federation N 2000666, H 04 B 1/10, H 04 L 7/00, N 2000669, H 04 B 1/10, N 2000659 H 01 B 1/10, the lack of which is a low immunity to structural interference.

Closest to the claimed device is a device correlation processing of broadband signals.with. N 1688416, H 04 B 1/10, block diagram which presents >/BR>3 - second multiplier (phase remodulator),

4 - rejection filter,

5 - filter output

6 - attenuator,

7 - myCitadel,

8 - the first delay element,

9 - second delay element,

10 - bandpass filters

11 - keys,

12 - second attenuators,

13 - the fourth delay elements,

14 - detectors narrowband interference,

15 - the third multiplier,

16 - the third delay element,

17 - frequency channels.

The device operates as follows.

Input wideband pseudonoise signal (PSS) and the disturbance is fed to the input of multiplier 1, which are multiplied together with a copy of the PSS, synchronous with the incoming PSS generated in the generator 2. Due to this PSS is folded in narrow-band signal, which registereda notch filter 4 and the narrowband interference is concentrated in broadband noise, which through the notch filter 4, the clip of her band F (where F is the band collapsed useful signal) is supplied to the multiplier 3. In the multiplier 3 broadband disturbance is multiplied by the synchronous her a copy of the PSS supplied to it from the output of the generator 2 through 8, ensuring alignment delays in the path of the spread is minimized to narrowband interference, which is supplied to the frequency channels 17. In each frequency channel 17 narrowband interference is filtered in partial-band bandpass filter 10, is

< / BR>
where FW- band PSS, then served on a key 11, which is opened only if the detector 14 decided to discovery in this partial channel. The disturbance passed through the key 11 through the attenuator 12 and the delay element 13 is supplied to one of inputs of vicites 7, which compensates for the interference received at the other input vicites 7 from the input device through the attenuator 6 and the element 9. Items 9, 13 and attenuators 6 and 12 aligns the amplitude and time of the interference received at different input vicites 7. Since one input of vicites 7 receives a broadband signal and narrowband interference, and on the other only the narrowband interference, the interference is compensated, and a broadband signal passes to the output of vicites 7. After multiplication in the multiplier 15 with a copy of the PSS, coming from the output of the generator 2 through the element 16, the broadband signal "folds" in the narrow-band signal, which is filtered in the output filter 5, and then supplied to the output device. The delay element 16 is selected such clicks is P> The disadvantage of this device is the low robustness to structural interference.

To address this shortcoming in the device containing sequentially connected to the first multiplier, the notch filter, the second multiplier, a third multiplier and the generator copy of the signal, the output of which is connected to the reference inputs of the first and second and third multiplier products, attenuator, band-pass filter, connected in series delay elements and myCitadel, and the first input of the first multiplier connected to the input device, connected in series introduced a fourth multiplier, block rejectee, the fifth multiplier and the limiter and the input of the fourth multiplier is connected to the output of the second multiplier, the output of the fifth multiplier connected to the input of the attenuator, the output of which is connected with the second input myCitadel, the output of the first multiplier connected to the input of a bandpass filter, the output of which is connected to the input of the limiter, the output of which through the third multiplier connected to the reference inputs of the fourth and fifth multiplier products, in addition, the input of the delay element is connected to the input device.

In Fig. 2, where opositely (phase remodulator),

4 - the fourth multiplier (phase modulator),

5 is a block rejectee,

6 - the fifth multiplier (phase remodulator),

7 - attenuator,

8 - myCitadel,

9 - generator copy of the signal generator reference pseudo-random sequence),

10 - delay element,

11 - band-pass filter,

12 - the third multiplier (phase manipulator),

13 - limiter.

The device comprises serially connected first multiplier 1, the first input of which is connected to the input of the notch filter 2, the second multiplier 3, the fourth multiplier 4, block rejectee 5, the fifth multiplier 6, the attenuator 7, myCitadel 8, the second input is through the delay element 10 is connected to the input device. The output of vicites 8 is an output device. The reference inputs of the first 1, the second 3 and the third 12 multiplier products connected to the generator output copies of the signal 9. The output of the first multiplier 1 is connected also to the input of bandpass filter 11, the output of which is connected to the input of the limiter 13. The output of the limiter 13 is connected to the first input of the third multiplier 12, the output of which is connected to the reference inputs 4 fourth and fifth multiplier products 6.

Does a verbal signal and structural obstacle to the input of vicites 8 through delay element 10 and to the input of the first multiplier 1, where are multiplied with the reference pseudo-random sequence, synchronous with the useful signal generated by the generator 9. The result of this procedure, the useful signal is folded in narrow-band signal, which registereda unit 2. At the same time a structural hindrance in the first multiplier 1 receives additional manipulation, i.e. not minimized, and it becomes even more broadband. Part of the spectrum of structural interference registereda unit 2, and the rest of its spectrum is supplied to the second multiplier 3, which is multiplied by the same reference signal. Due to this, the output of the second multiplier 3 are formed of two components structural interference: first, similar to the interference in the input mixture, and second, correlated with the useful signal, i.e. having the same law manipulation and the same carrier frequency and differs from it only the initial phase. The presence of the second component is due to rejection of the spectrum block 2, and this component is unwanted (parasitic).

Two components of the interference served on the signal input of the fourth multiplier 4, the reference input of which a reference signal is generated as follows. Rolled useful signal and Tr 11, configured on a carrier frequency of the useful broadband signal and having a bandwidth equal to the bandwidth of the spectrum minimized the useful signal, i.e. the bandwidth of the block 11 and the strip rejectee block 2 are chosen equal. From the output of the band pass filter 11, the result of filtering through the limiter 13 is input to the third multiplier 12 where is manipulated reference signal generator 9. With an output of the third multiplier 12, the voltage supplied to the reference input of the fourth multiplier 4, which manipulates the phase (0, ) the voltage supplied from the second multiplier 3.

Thus, in the fourth multiplier 4 is multiplied by the parasitic component of the interference, correlated with the useful signal generated in the third multiplier 12, which is also correlated with the useful signal has the same law of formation and the same carrier and different from negatives only the initial phase). As the band rejectee block rejectee (F2) and the bandwidth of the band pass filter 11 are chosen equal, the delay parasitic broadband components at the inputs of the fourth multiplier 4 are the same, i.e. they are not only correlated with each other but also synchronous. That is, the fourth peyrovani processes registereda block rejectee 5. At the same time a structural hindrance (the first component at the output of the second multiplier 3) in the fourth multiplier 4 receives additional manipulation, which is removed in the fifth multiplier 6 by multiplication with the same reference signal. Thus, at the output of the fifth multiplier highlighted structural hindrance and a new parasitic broadband component structural interference that through the attenuator 7 is fed to the input of vicites 8, where structural interference is compensated, and the second parasitic component structural interference and useful broadband signal to pass to the output device. The degree of suppression of spurious broadband interference component, correlated with the useful signal is determined by the ratio

< / BR>
fW- band spectrum efficiency of the wideband signal;

F5- band rejectee block.

Block rejectee 5 performs the rejection of the convolution correlated processes differ only in the initial phase), it should highlight the differential signal phases. This means that the strip rejectee unit 5 F5F2where F2- band rejectee notch filter 2, is equal to the information band of the useful signal.

the e fowhere fothe carrier frequency of the useful signal, the block rejectee 5 may be made in the form of two series-connected notch filters, one of which is configured for differential (zero) frequency, and the other on the total (double the frequency).

Option execution unit rejectee 5 shown in Fig. 4, where indicated:

41 is a lowpass filter,

42, 44 - myCitadel,

43 - bandpass filter.

The limiter 13 provides a constant voltage level on the reference inputs of the multiplier products 4 and 6, which ensures the constancy of the coefficient of transmission for interference assessment.

In the prototype evaluation of interference, as in the inventive device consists of two components: first, similar to the interference in the input mixture, and a second parasitic broadband component, correlated with the useful signal.

When the action at the input device prototype powerful structural interference all channels open, the degree of suppression of spurious broadband interference component (KpCRin this case, is determined by the ratio

< / BR>
where F4- band rejectee unit 4 prototype equal to the information band of the useful signal.

Finfoinformation band of the useful signal, you will get

< / BR>
< / BR>
KPZKpCR.

That is, when exposed to structural interference or when exposed to a large number of narrowband interference suppression spurious interference component in the inventive device is significantly greater than in the prototype.

Option execution unit 3 shown in Fig. 3, where indicated:

31 - band-pass filter,

32 - myCitadel.

Presents a structural diagram is used to explain the formation of parasitic broadband component as follows. Broadband disturbance formed in the multiplier 1 of narrowband interference, comes to the input of vicites 32 and its output directly. This component of the interference at the output of block 3 is converted to narrowband interference, similar to the interference in the input mixture. At the same time, part of the broadband noise due to the filtering unit 31 becomes narrow. In block 32, it changes phase by 180o. Due to the multiplication in block 3 with broadband reference signal, it becomes parasitic broadband interference component.

The noise suppression device for a receiver of a broadband signal containing a sequence is Roy multiplier, and the third multiplier, the generator copy of the signal, the output of which is connected to the reference inputs of the first, second and third multiplier products, attenuator, band-pass filter and sequentially connected delay element and myCitadel, characterized in that the input limiter, connected in series to the fourth multiplier, block rejectee, the fifth multiplier, connected between the output of the second multiplier and the input of the attenuator, the reference inputs of the fourth and fifth multiplier products connected to the output of the third multiplier, the output of the attenuator is connected to a second input of vicites whose output is the output device and the input of the delay element is connected to the input device, the output of the first multiplier through a band-pass filter connected to the input of the limiter, the output of which is connected to the input of the third multiplier.

 

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