Device for suppressing structural interference to receivers wideband signals

 

(57) Abstract:

The device relates to the field of radio engineering and can be used in communication systems with broadband signals. The technical result is an increase in noise due to the suppression of structural (internal) noise at the input of the receivers included in a base station of a communication system is a code division multiplexing. The invention consists in that the device is a rejection not of the useful signal, and structural interference. If rejectee as the reference signal is the sum of copies of the structural interference. When forming copies of each structural interference is taken into account not only the structure of the modulating information sequence and structure information sequence. This allows you greatly reduce the frequency rejectee notch filter, which does not depend on Finfo. 6 Il.

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

The known device suppressing structural interference, described in the ed.St. USSR N 1338078, patent RF N 2038697, 2034403, H 04 B 1/10 and others, the lack of which is low domehouse device on the bus.St. USSR N 1688416, H 04 B 1/10, a block diagram is shown in Fig. 1, where indicated:

1 - the first multiplier (phase modulator),

2 - generator copy of the signal,

3 - second multiplier (phase demodulator),

4 - rejection filter,

5 - filter output

6 - the first 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 out of her striped F (where F is the band collapsed useful signal) is supplied to the multiplier 3. In the multiplier 3 is widely the COP-8, ensuring alignment delays in the path of the spread of broadband interference and copies of PSS.

By multiplication with a copy of the PSS broadband disturbance is minimized in uzkopolosnoi crosstalk, which is supplied to a frequency channel 17. In each frequency channel 17 escapology 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 obnaruzhivali 14 decided to detection of interference 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 do shirokopolosnyi 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 vychodna in the output filter 5, then transferred to the output device. The delay element 16 is selected in such a way as to ensure synchronicity shirokopolosnogo signal and copies of the PSS at the inputs of the multiplier 15.

Will krupnim structural diagram of the device of the prototype as shown in Fig. 2, where indicated:

1 receiver signal (blocks 2, 5, 15, 16 of Fig. 1),

2, 4 - multiplier products (phase manipulators),

3 - rejection filter,

5 - delay element,

6 - attenuator,

7 - myCitadel,

8 - unit frequency selection interference (n-channel blocks 10 to 14 of Fig. 1),

9 - delay element.

The disadvantage of the prototype is a low immunity to structural (internal) noise.

To address this shortcoming in the device containing the receiver useful broadband signal, connected in series, the first delay element and an attenuator connected in series to the first multiplier, a first input which is combined with the input of the first delay element, the notch filter, the second delay element, a second input connected to the output of the second delay element, is entered n of chains, each of which has connected in series receiver interfering juice control, the first and second inputs which are combined with the first and the second input of the shaper copies interference and connected with the first and second outputs of the receiver interfering signal, the output of each of keys of all n of the chain is connected with the corresponding input of the adder and the corresponding input item (OR, the output of which is connected with the control input of the switch, the first input connected to the output of the attenuator, the second output of the second multiplier and the output from the receiver input signal, the output of the adder is connected to the second input of the first multiplier and the input of the second delay element, the first input of the first multiplier to a fourth delay element connected to the input device.

Structural diagram of the inventive device shown in Fig. 3, where indicated:

1 receiver useful shirokopolosnogo signal

2, 4, the first and second multiplier products (phase manipulators),

3 - rejection filter,

5, 11, 12, 13 - first, second, third and fourth delay elements,

6 - attenuator,

7 - switch

8 - shaper copies interference

9 - receiver interference signal,

10 is a control unit,

14 - adder,

15 - element, OR

16 keys.

the key, one of which contains serially connected delay element 5 and the attenuator 6, and the other connected in series to the first multiplier 2, notch 3, the third multiplier 4. The input of the delay element 5 and the first input of the multiplier 2 and United through the delay element 13 is connected to the input of the device. The second input of the first multiplier 2 is connected to the output of the adder 14, which through the delay element 11 is connected with the second input of the second multiplier 4. To the n inputs of the adder 1 is attached n chains, each of which has connected in series receiver interfering signal 9, the driver copies interference 8, a second input connected to the second output of the receiver 9, the delay element 12, the key 16. To the second inputs of the keys 16 attached control units 10, the first and second inputs which are connected with the first and second outputs of the receiver interfering signal 9. The outputs of the control units 10 of all n-chains are connected to n inputs of the OR element 15, the output of which is connected with the control input of the switch 7.

The inventive device is intended to suppress structural (internal) noise at the inputs of the receivers of the base station of the communication system is a code division multiplexing. Castelino base station. Signals neighbors subscribers create a powerful structural interference to the receivers of the base station, receiving signals from remote subscribers.

The system subscribers use broadband photomanipulation signals, differing structures modulating a pseudo-random sequences that have the same carrier frequency f0and spectrum band fW.

From input devices of the input mixture is supplied to delay element 13, with which it arrives at the first input of the switch 7 through the delay element 5 and the attenuator 6, and at its second input via the first multiplier 2, notch 3, the second multiplier 4. The reference signal for the multiplier products 2 and 4 comes from the output of the adder 14, the input of which is through the keys 15 and the delay elements 12 are served copies of a structural noise generated in the driver copies interference 8. The block 8 is synchronized by the synchronization command is received from the first output of the receiver interfering signal, thereby providing synchronization of copies interference with noise in the input mixture in blocks 2 and 4.

From the output of the adder 14 a mixture copies noise is fed to the reference input of the multiplier 2 directly, and to the reference input of the multiplier 4 is/P> When the multiplication of the input mixture with a copy of the total interference in the multiplier 2 shirokopolosnye structural minimized interference in narrowband interference that rejections in the filter 3. At the same time, the signal in the multiplier 2 is superimposed additional manipulation of the total structural obstacle, which is then removed in the multiplier 4 by multiplication with the same obstacle.

Thus, the signal passes through blocks 2, 3, 4 virtually no distortion (with the exception of rejectio small part of his range notch filter 3), and a powerful structural interference rejections.

Command outputs control units 10 are fed to the inputs of the OR element 15. In the presence of a "1" output at least one of the control units 10 at the output of the OR element 15 is also formed "1", which is supplied to the control input of the switch 7. In this case, the input mix at the receiver input signal arrives after rejectio of its structural interference.

Connecting structural hindrances to the adder 14 is through the keys 16, which is opened by commands generated by the control unit 10. The control unit 10 generates a command "1", the opening key 16 only if the receiver ptx2">

The driver copies interference 8 may be performed as shown in Fig. 4, where indicated:

41 - generator carrier and clock frequencies

42 - driver reference pseudo-random sequence,

43 is a pseudo - random sequence generator,

44 - adder,

45, 46, 48 - multiplier products (phase manipulators),

47 - Phaser 90o.

The device shown in Fig. 4 represents a typical shaper four signal using singaporelovelinks.com formed by the blocks 41, 42, 45, and information pseudorandom sequence generated by blocks 41, 43, 46, which are summarized in the block 44. The carrier frequency generated in block 41, is supplied to the unit 46 through a phase manipulator 48, where it is manipulated by the information signal, at block 45 through the phase shifter 47.

Phasing (setting the initial phase modulating a pseudo-random sequence) is performed by the synchronization signal received at blocks 42 and 43 from the first output of the receiver interfering signal 9. The information signal is supplied to the phase manipulator 48 from the second output of the receiver interfering signal 9. Thus, the reference signal, Faure, the useful signal 1, that provides effective rejection blocks 2, 3, 4.

Block diagram of the receiver interfering signal 9 is shown in Fig. 5, where indicated:

51 - device synchronization

52, 53 - multiplier products (phase manipulators),

54 - driver reference pseudo-random sequence (similar to the block 42),

55 - reference generator pseudo-random sequence (similar to the block 43),

56, 57 - bandpass filters

58 phase detector.

A synchronisation unit 51 is used not only for phasing blocks 54 and 55, but for phasing blocks 42 and 43 shaper copies interference 8. For this purpose, the signal from the receiver 9 is applied to a second input of the shaper 8. At the same time he served on the first input of the control unit 10.

The output signal from bandpass filter 56 is simultaneously supplied to the input unit 58 and the third output of the receiver 9 to the input of the control unit 10.

Embodiment of the control unit 10 shown in Fig. 6, where indicated:

61 - amplifier

62 - amplitude detector,

63 - unit comparison with a threshold,

a 64 - item,

65 - delay element.

The voltage output from the bandpass filter 56 of the receiver 9 is amplified in condition is ha ("1") and the synchronization command ("1") arrive at the item And 64, which generates the command "Enable channel rejectee" ("1") if "1" at both of its inputs. The block 65 is adjustable and contemporaneously ward teams to the input unit 64. The delay elements 5, 11, 12, 13 are adjustable and provide the necessary alignment of the signals in time.

The delay elements 11, 12, 13 provide synchronicity broadband structural interference with a reference signal representing a sum of copies powerful structural interference levels which exceed permissible for this system value. The magnitude of the delay unit 5 and the transfer coefficient of the block 6 are chosen equal to the value of the transfer coefficient and the delay signal in the multiplier products 2, 4, and the filter 3.

In the prototype the powerful structural interference leads to the unlocking of all the frequency channels, and structural interference compensated myCitadel, and the input of the receiver passes the signal and the parasitic component of the evaluation of structural interference, the appearance of which is due to rejection of the spectrum of structural interference notch filter. This parasitic component correlated with useful shirokolashki signal and further processing is not separated from what I spurious component of the evaluation of the structural interference of the prototype is determined by the ratio

< / BR>
where FRF- band rejectee notch filter, which in the prototype is determined by the information bandwidth of the useful signal (Finfo), B - base broadband signal.

In the inventive device is a rejection not of the useful signal, and structural interference, if rejectee as the reference amount used copies of structural interference.

When forming copies of each structural interference is taken into account not only the structure of modulating a pseudo-random sequence and structure information of the sequence.

The latter allows to significantly reduce the frequency rejectee notch filter, which in this case does not depend on Finfo.

Determine the power loss of the useful signal due to rejectee part of its power in the stopband of the filter.

Since FRFFinfoFRFfWthe ratio of the power loss of the useful signal is determined by the ratio

< / BR>
B - base of the useful broadband signal.

At the same time, the suppression ratio of the structural interference is determined by the hardware capabilities of the notch filter and can be 70 - 80 dB, h is ironopolis signals, containing the receiver useful broadband signal, connected in series, the first delay element and an attenuator connected in series to the first multiplier, a first input which is combined with the input of the first delay element, the notch filter, the second multiplier, a second input connected to the output of the second delay element, characterized in that the input of the fourth delay element, the switch element OR adder, n chains, each of which has connected in series receiver interfering signal, the driver copies interference, a second input connected to the second output of the receiver interfering signal, the third delay element, key, a second input connected to the output of the control unit, the first and second inputs of which are connected with the first and second outputs of the receiver interfering signal, the outputs of all keys n chains are connected with the inputs of the adder, the output of which is connected with the second input of the first multiplier and a second delay element with a second input of the second multiplier, the outputs of the control units of all n-chains are connected to the inputs of the OR element, the output of which is connected with the control input of the switch, the first input connected to in the useful broadband signal, the input of the fourth delay element is an input device, and its output connected to the input of the first multiplier.

 

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