The noise suppression device method of compensation

 

The invention relates to the field of radio and can be used in communication systems with broadband signals. Technical result achieved - increased degree of noise suppression in comparison with the device prototype. The noise suppression device method of compensation includes three band-pass filter (1, 2, 6), two adder (3, 10), the block select minimum (12), two vicites (5, 11), two rectifier (4, 7), the shaper function cos (8), the divisor (9). 5 Il.

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

The known device noise suppression method of compensation described in the patents of the Russian Federation No. 2038697, No. 2034403, N 04 1/10.

The disadvantage of these devices is the low degree of noise suppression.

The closest in technical essence to the proposed object is the Device noise compensation” for U.S. patent No. 4739518, N 04 1/10 adopted for the prototype.

The structural scheme of the device of the prototype is shown in Fig. 1, where the following notation:

1 - attenuator;

2 - the first amplifier;

3 - limiter;

4 - unit delay signal; and

5 - myCitadel (compensation is E. communication: the input device is the input of the attenuator 1, the first output of which is connected in series through the first amplifier 2 and the unit delay signal 4 is connected to the first input of vicites (compensator) 5, and the second attenuator output 1 via the limiter 3 is connected to a second input of vicites 5, the output of which is connected in series through the band-pass filter 6 and the second filter 7 is connected to the output device.

Function prototype as follows.

The received signal is fed to the input of the attenuator 1. This attenuator 1 is used as a matching device for the input of the first amplifier 2 and the stopper 3 and eliminates the influence of these inputs on each other. From the first attenuator output 1 signal is input to the first amplifier 2, where it is amplified to the required size and is fed to the input of the delay block signal 4.

From the second attenuator output 1 signal to the input of the limiter 3, where the suppression of a strong interference signal is weak, and thus, at the output of the limiter 3 remains almost the only obstacle. The delay time in the delay unit signal 4 is set so that myCitadel 5 was used to compensate for interference present in the useful signal coming from the output of the unit delay signal 4 on the signal is input to a bandpass filter 6, where are filtered from out-of-band components. Then the signal goes to the input of the second amplifier 7 for amplifying to the required size. The output of the second amplifier 7 is the output device.

A disadvantage of this device prototype is a small degree of noise suppression, as it only suppresses interference exceeding the amplitude of the useful signal, and, in addition, does not suppress the noises.

To eliminate this drawback in the device containing the first myCitadel and the first band-pass filter, connected in series introduced the second bandpass filter, the second myCitadel and a second rectifier connected in series, the third band-pass filter, the first adder, the first rectifier, the shaper function cos and the divider, and connected in series to the second adder and the block select minimum, the output of which is output, and the inputs of the first, second and third bandpass filters are connected and are the input devices. The output of the first bandpass filter connected to the inputs of the second adder and the first myCitadel, the output of which is connected with the second input of the block selecting at least. The output of the second bandpass filter connected to the second input of the first adder. Vienen with the second input of the shaper function cos. The output of the first adder is connected to the second input of the divider, the output of which is connected with the second inputs of the second adder and the first myCitadel.

The structural scheme of the device is shown in Fig. 2, where indicated:

1, 2, 6 - first, second, and third bandpass filter (PF);

3, 10, the first and second adders;

4, 7, the first and second rectifiers;

5, 11 is the first and the second myCitadel;

8 - shaper function cos;

9 - divisor;

12 - unit selection minimum.

The proposed device comprises serially connected first PF, the second adder 10 and a block of at least 12 whose output is the output device. Connected in series to the second PH, the second myCitadel 11 and the second rectifier 7, the output of which is connected with the second input of the shaper function cos. Serially connected third PF6, the first adder 3, the first rectifier 4, the shaper function and the divider 9, the output of which is connected with the second inputs of the second adder 10 and the first vicites 5, the output of which is connected with the second input of the block selecting at least 12. In addition, the output of the second PF connected with the second input of the first adder 3, the output of which is connected with the second input of the divider 9, the output of the third PF6 connection is carried out by the input device.

The proposed device operates as follows.

Adopted broadband signal (interferer) arrives at the inputs of the first 1, second 2 and third 6 PF, identical in amplitude-frequency characteristics (AFC), andfF, where

F is the bandwidth of each bandpass filter;

f - band width between centre frequencies of adjacent bandpass filters.

The Central band-pass filter is configured to receive the useful signal and in the presence of interference must be removed.

The input device receives an obstacle in the form of a sequence of impulses arising in the process of multiplying the received signal SRP and the reference signal in the multiplier correlator, which is removed from the signal modulation of the SRP and is further filtering the intermediate frequency. It should be emphasized that under these conditions, all three filters perturbing the input interference effect is almost identical, since there is a spectrum from pulse is much wider than the sum of the bands and shift between filters. In addition, given the brevity of exposure to the fronts of the pulses on the filters (

Where M<N, where N is a discrete length of the SRP.

Since N contains blocks with the same phase, the number of such blocks M<N;the duration element of the SRP;

G(t)cost - pulse response of the filter.

The expression (1) accept as a control, and combinations of expressions (2) and (3) will try to get the expression in its final form, similar to the expression (1). Because this combination does not contain signal components, then using the result of this combination, the expression (1) can be compensated.

To get the desired result transform expressions (2) and (3) respectively:

Adding and subtracting (4) and (5), we obtain after summing up:

after subtraction

Comparing (1) and (6), we see that (6) differs from (1) is slowly oscillating multipliercharacterizing the phase shift due to the detuning between the contours.

Further transformations (6) and (7) can be found required is to be an oscillating function. After straightening (6) we get:

After the expression (7) we get:

Using expressions (8) and (9), it is possible to generate theFor this reason, the unit 8 receives voltage described by expressions (8) and (9), and the output unit 8 receives the value of the function:

However, it remains unknown initial sign of this expression, so this fact should be taken into account in the subsequent design of the proposed device.

Now it is easy, using (6) and (11), find the value, similar to (1).

Consider the relation (6) to (10), we obtain:

However, initial mark (11) not known to us.

Due to the unknown initial sign of the amount of noise in (1) and (11) do the following:

Adding (1) and (11), we obtain:

Subtract from (1) to (11), we obtain:

The correct solution is the one that is minimal, that is, (12B).

In the ideal case, the interfering component should be reduced to zero, i.e. the result equal to zero, the signal is much less interference, as can be seen insinuate interference filter, where is the signal.

These considerations allow us to represent a block diagram of the proposed device, which is shown in Fig. 2, where 1, 2, 6 - bandpass filters, the signal passes through the main filter 1 and the side filters are upset in relation to the Central bandwidth (Fig. 3).

Other blocks perform the following functions.

Unit 3 - the first adder sums the signals from the filter 6 and filter 2 according to the expression (6).

Unit 5 - the first myCitadel from (4) subtracts (5), we obtain the expression (7).

Unit 4 - first rectifier rectifies the signal from the output of block 3, the result will be an expression (8).

Unit 7 - second rectifier rectifies the signal from the output of block 5, the result will be an expression (9).

Unit 8 analyzes the signals from the first 4 and 7 second rectifiers, resulting in possible to generate

Unit 9 - divisor - divides from the output of the adder 3, the outputs of the shaper function cos, resulting in expression (11).

Block 10 - second adder - summed signal output from the main filter 1 (Central channel) signal the h signal at the output of the main (Central) filter 1 subtraction of the signal at the output of the divider 9, the result is a signal equal to zero according to expression (12B).

Unit 12 unit selection minimum, which selects the minimum of the signal from the outputs of the adder 10 and myCitadel 11. The output of block 12 is the output of the device.

Thus, by using two additional filter detunedF - bandwidth - shows the ability to compensate for the instantaneous values of impulse noise in the main channel.

For implementation of block 8 of the shaper function cos one can propose the following algorithm, using the expressions derived earlier, namely, the rectified envelope values of sum and difference channels (expressions (8) and (9) respectively):

Put (1) and (2) the square (blocks 8.1 and 8.2, respectively) and folded (unit 8.3), we obtain:

Get the square root of (3) unit 8.4, get:

The expression (1) divided by (4) unit 8.5, get:

As a result of this functional block circuit diagram of the shaper function cos will look as shown in the of prameela);

8.3 - adder - signals are summed with the outputs of the first and second Quad;

8.4 - block extracting the square root is extracted the square root of the total signal, resulting in the received signal envelope, i.e.:

8.5 - divisor - divides (1) to (4), the result will be (5), this signal is shown in Fig. 5B;

8.6 - time selector is derived from the signal of Fig. 5A, the signal shown in Fig. 5B.

Claims

The device noise suppression method of compensation, containing the first myCitadel and the first band-pass filter, characterized in that the introduced sequentially connected to the second bandpass filter, the second myCitadel and a second rectifier connected in series, the third band-pass filter, the first adder, the first rectifier, the shaper function cs and the divider, and connected in series to the second adder and the block select at least whose output is the output, with the inputs of the first, second and third bandpass filters are connected and are the input devices, the output of the first bandpass filter connected to the inputs of the second adder and the first myCitadel, output motordom first adder, the output of the third bandpass filter connected to the second input of the second myCitadel, the output of the second rectifier is connected to the second input of the shaper function cs, the output of the first adder is connected to the second input of the divider, the output of which is connected with the second inputs of the second adder and the first myCitadel.

 

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