SU743209A1 - Adaptive radio noise suppressor - Google Patents

Description

one

The invention relates to radio engineering and can be used to combat radio interference in radio relay and satellite communication systems with angular modulation in difficult reception conditions, in particular, when at the reception site, or using an additional channel connecting radio stations. the house is located a source of interference with the place of reception of useful information, it is possible to allocate radio interference on a separate channel.

Devices are known that allow adaptive compensation of radio interference due to the use of two antennas at the reception site, one of which receives a useful signal and radio interference, and the other practically only receives radio interference.

A device is known which contains two reception channels, in the first of which the reader is connected to the input, a. in the second, the first mixer, the narrowband filter and the second mixer are connected in series, the input of the second reception channel is connected to the input of the second mixer, and the output of the second mixer is connected

with the second input of the subtractor, the output of which is the output of the device 1.

The closest in technical essence is a device containing two reception channels, which consists of a phase detector, a narrow-band filter, the output of which through an adder is connected to

10 to the input of the controlled oscillator, the output of which is connected to the first input of the phase detector, and the phase shifter, and is connected to the second input of the adder in the first reception channel

15 low pass filter output 2.

A disadvantage of the known devices is the low noise immunity, due to the fact that in the allocation channels of the useful signal and radio 20 the interference is not detected by any filtering of the npHHHMaeNCJX messages.

The purpose of the invention is the improvement in mechanical stability.

For this purpose, an adaptive compensator for radio interference, containing two reception channels, each of which consists of a phase detector, a narrow-band filter, the output of which through an adder is connected to the control input 30

mg.). A generator, the output of which is connected to the first input of the phase detector, and a phase detector, and in the first reception channel, the output of the low-pass filter is connected to the second input of the adder, an adder is inserted, an additional low-pass filter and the third reception channel, whose input is the first input of the device, and consisting of a series-connected phase detector, narrow-band filter, adder and controlled oscillator, the output of which is connected to the input of the phase detector, and to each of the first two reception channels The amplitude control unit and the subtractor, the first input of which is connected to the output of the phase shifter of another reception channel, and the output are connected to the second input of the phase detector, the output of which is connected to. to the input of the narrowband filter, and with the first input of the amplitude control unit, the second input of which is connected to the output of the controlled generator, and the output to the input of the phase shifter, while the inputs of the extractors are connected to another input of the device, in the first reception channel the output of the phase detector is connected to the input of the filter the lower frequencies, the corresponding inputs of the addition unit are connected to the outputs of the phase detectors of the second and third reception channels, and the output is connected to the input of an additional low-pass filter, the output of which is connected to the inputs adders of the second and third channels. reception, and also that the amplitude control unit consists of a first amplitude detector, whose input is the first input of the amplitude control unit, the output is connected to the first input of the difference unit, the second input of which is connected to the output of the second amplitude detector, and the output is to the first input of the adjustable amplifier, the second input of which is the second input of the amplitude control unit, and the output is connected to the input of the second amplitude detector and is the output of the control unit vani amplitude.

The drawing shows a structural electrical circuit of the adaptive compensator of radio interference.

The device contains two, connected to the first input of the device, parallel to channel 1 and 2 of the reception, and the third channel 3 of the reception. Each of the first two reception channels contains a serially connected subtractor 4 and a phase locked loop, and the third reception channel 3 contains only a phase locked loop, in which the output of the phase detector 5 is connected to the input of the controlled generator 6 via serially connected narrowband filter 7 and adder 8, and go out

controlled generators 6 in the first two channels through the amplitude control unit 9 and the phase shifter 10 by 90 are connected to the second input of the subtractor 4 in the other reception channel. In addition, in the reception channel 1, the output of the phase detector 5 is connected via a broadband low-pass filter 11 to the second input of the adder 8 in the reception channel 1, and the outputs of the phase detectors 5 in the second and third reception channels are combined in a block

12 complications, the output of which is through an additional broadband filter

The 13 hours of low frequencies, which do not let the constant component through, are connected to the second inputs of the adders 8 in the second and third reception channels, and the second input of each of the amplitude control blocks 9 in the first and second reception channels is connected to the output of the subtractor 4 same reception channel. The amplitude control unit 9 may, for example, be made

"Based on adjustable amplifier 14 whose input is the second input of this block, and the output is the output of the block and is also connected via an amplitude detector 15 to one of the inputs of a difference block 16, the second input of which is connected to an amplitude detector 17, is the first input of block 9, and the output of block 16 of the difference is connected with the control input of adjustable amplifier 14. At the output 18 of the device, a high-frequency signal cleared of interference acts, at output 19 a demodulated useful message operates, Vyhode 20 is a demodulated radio interference message. Signal and noise is input to input 21, only noise is input to input 22.

The device works as follows.

Let the input of 21 channels 1 and 2 receive the sum of two signals

5 ((t)

), (1) and only one signal S (t) operates at the input 22 of the third reception channel 3, t ejtV4 j, (2)

where, ,, and ,, and „, Чс, Чп1иЧп amplitudes and phases of the useful signal and radio interference at the inputs 21 and 22 of the device;

0c (t) and er, (1} —functional modulation, due to messages, useful) about. signal and radio interference. Controlled generator 6 in the first

Canache 1 reception is modulated according to the clock estimate of the useful message and the signal at its output is:

V - V .l (3) The controlled oscillators 6 in the second 2 and in the third 3 channels are frequency modulated by an estimate (S6 (t.) / Dl, the phase adjustment of these generators is carried out by direct current using autonomous circuits, containing narrowband filters 7. Therefore, the output of controlled generators 6

we have: ". yr / l -i;

V% s, pKt (t ,, Y

Considering that the amplitude control units 9 perform precise adjustment of the amplitudes of the controlled oscillators b, we have the following voltages at the outputs of these units 9:

.t.8: {tV c i (5)

(PL After the phase shift by 90 in the phase converter 10, these signals are acquired

 , cosHt.e (.

, co-I-.t- (. Therefore, at the outputs of the subtractors 4

we have 9 tHifJ.t)

.. (t) (

 , V .i.e; w., I

(tV cl-cos a .U9 (If, as is usually the case 0 () and b (. (t, then ocherHottA KWc (t), i.e., the interference level from extraneous signals at the inputs of phase detectors 5 in channels 1 and 2 is significantly attenuated, i.e., they are compensated. As a result of receiving interference in the third channel, the accuracy of estimating the law of changing the phase of interference 9 (t) is very high for any value of the ratio Vc / Vn /, j.3TO leads to a very significant suppression of interference by the input of channel 1, tuned to a useful signal.

The compensator is adaptive, since it provides for monitoring the amplitudes V. and Vnd and the phases C and C of the individual components of the total voltage acting at the input 21 of the device.

The amplitude detection in blocks 9 can obviously be replaced with synchronous.

The device has a higher noise immunity compared to

known, as in it, firstly, the following demodulators are used for information processing in each reception channel, and secondly, the interference suppression, acting on the input 21, is suppressed more completely, without adding additional noise, acting on the input 22 .

The device makes it possible to significantly (by two or three times) reduce the coordination ionic distance between the radio linkers using angular modulation and operating at close frequencies. At present, such interference often occurs in radio relay and satellite lines due to the interaction of directly located objects. To combat them, one has to either allocate to systems that can create mutual interference, different frequency bands, or remove them by a considerable distance. Both of these measures are not always possible and lead to a significant decrease in the efficiency of use of the radio spectrum.

Adaptive compensator allows

5 allocate the same frequencies for angle-modulated radio. Capable of using conventional methods of receiving mutual interference. Thereby its use

d allows significantly (two to three times) to increase the efficiency of using the radio spectrum.

Claims (2)

1. An adaptive radio interference compensator, containing two reception channels, each of which consists of a phase detector, a narrowband filter, the output of which through an adder is connected to the input of the controlled oscillator, the output connected to the first input of the phase detector, and the phase shifter, and in the first the reception channel to the second input of the adder is connected to the output of the low-pass filter, which is characterized by the fact that, in order to increase the noise immunity, an addition block, an additional low-pass filter and a third the reception channel, whose input is the first input of the device, consisting of a series-connected phase detector, narrowband filter, adder and controlled oscillator, the output of which is connected to the input of the phase detector, and an amplitude control unit is inserted into each of the first two reception channels and a subtractor, the first input of which is connected to the output of the phase shifter of another reception channel, and the output to the second input of the phase detector, the output of which is connected to the input bandpass filter, and with the first the input of the amplitude control unit, the second input of which is connected to the output of the controlled generator, and the output to the input of the phase shifter, the inputs of the subtractors are connected to another input of the device; in the first reception channel, the output of the phase detector is connected to the input of the low-pass filter, the corresponding inputs of the adder connected to the outputs of the phase detectors of the second and third reception channels, and the output to the input of an additional low-pass filter, the output of which is connected to the inputs of the adders of the second and third channels iema, i. Compensator pop.1, characterized in that the spline control unit consists of a first amplitude detector, whose input is the first input of the amplitude control unit, the output is connected to the first input of the difference unit, the second input of which is connected to the output of the second amplitude detector, and the output the first input of the adjustable amplifier, the second input of which is the second input of the amplitude control unit, and the output is connected to the input of the second amplitude detector and is the output of the hyohlitude control unit. Sources of information taken into account during the examination 1. Patent of the Association №3202990, cl. 343-100, 1965. 2. The patent of England WHO4436, cl. H 3 A, 1969 (prototype).