RU2000660C1 - Device for suppressing radio transmitter noise in receiver channel - Google Patents

Abstract

Usage: signal transmission, radio systems with broadband noise-like signals. SUMMARY OF THE INVENTION: In a device for suppressing an interference signal of a radio transmitter in a receiver channel, an increase in speed is achieved by automatically adjusting the amplitude and phase of the compensation signal. 2 ill.

Description

The invention relates to the field of signal transmission and can be used in radio systems with wideband noise-like signals.

A noise compensation device is known that comprises a phase splitter connected in series, the input of which is the input of the interference signal, the first controlled attenuator, adder, phase shifter and subtractor, the other input of which is the input of the useful signal, and the output is the output of the device, the first connected in series a synchronous detector, the first input of which is connected to the other output of the phase splitter, and the first strip amplifier, connected in series to the second synchronous detector, the first input of which connected to the output of the phase splitter, and a second strip amplifier, between the other output of the phase splitter and the other input of the adder included a second controlled attenuator, a generator, between the output of the subtractor and the second inputs of the first and second synchronous detectors, a modulator is included, the modulating input of which is connected to the output of the generator , between the output of each strip amplifier and the control input of the corresponding, controlled attenuator, an additional synchronous detector is connected in series, the other input to which is connected to the output of the generator, and an integrating amplifier.

However, this device has a significant drawback associated with limiting the interference compensation frequency band due to the choice of the modulation frequency of the interfering signal in the frequency band of 15-20 kHz, which does not allow to compensate for interference in the ultra-long wavelength range.

An interference suppression device is also known comprising an oscillator, an amplifier, a directional coupler, three phase shifters, two low pass filters, four mixers, an adder and a switch.

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However, this device also has a disadvantage due to the low speed caused by manual operations to compensate for the necessary interference level.

The closest in technical essence and the achieved effect is a device for suppressing the parasitic signal of its own transmitter in the receiver channel, comprising a transmitter with a circulator, a receiver with automatic adjustment of the suppression level and a mixer, a channel for compensating for the parasitic signal, and the input of the receiver mixer connected via an adder to the waveguide path of the receiver channel and through the same adder, attenuator and tunable phase shifter - with the output of the transmitter, and the control input of the tunable The rotator is connected through a DC amplifier to a detector, the input of which through the adder and the directional coupler is connected to the output of the waveguide path of the receiver channel and through the same adder, the phase shifter and the directional coupler with the output of the tunable phase shifter.

However, this device also has a disadvantage caused by the low speed of noise compensation, caused, in particular, by manual operations to set the equal amplitudes of the signals at the inputs of the adders.

An object of the invention is to increase speed.

Fig. 1 is a structural electrical diagram of an apparatus for suppressing an interference signal of a radio transmitter in a receiver channel; figure 2 is a timing diagram illustrating the operation of the device,

The device contains a first directional coupler 1, rectifier 2, first threshold element 3, first differentiation element 4, inverter 5, second directional coupler 6, tunable phase shifter 7, phase shifter 8, controlled attenuator 9, second differentiation element 10, OR element 11, adder 12, third directional coupler 13, phase detector 14, first key 15, phase balance indicator 16, binary counter 17, digital-to-analog converter 18, square-wave generator 20, corrector 21, second threshold element 22, a second key 23, as well as a first communication line 24 between the output of the second directional coupler and the transmitting system, a second communication line 25 from the output of the receiving antenna to the input of the first directional coupler and a third communication line 26 between the output of the second directional coupler 6 and the input tunable phase shifter 7. The device operates as follows.

At the initial time, the length I of the transmission line 26 is selected from the calculation of I Kl0-Hi + l2

where 10 is the distance between the transmitting and receiving antennas;

And is the length of the first communication line 24;

2 - length of the second communication link 25;

K - coefficient of shortening the wavelength

when transmitting electromagnetic energy

from free space to the transmission line.

Through the first communication line 24 of length AND, the signal of the radio transmitter is input

a transmit antenna that emits electrical energy into the free space. Part of the radiated transmitting antenna of electromagnetic energy is supplied to a receiving antenna located

from the transmitting antenna at a distance of 0. From the output of the receiving antenna, the interference signal un is fed to the input of the first directional coupler 1. In this case, from the second output of the first directional coupler

1 part of the interfering signal 1) n goes to the input of rectifier 2, and from its first output to the second input of adder 12. From the output of adder 12, the remaining part of signal Un is fed to the input of the third directional

the coupler 13, and from its second output, part of the energy of the interfering signal Un is supplied to the information input of the first key 15, one of the inputs of the phase difference indicator 16 and one of the inputs of the phase detector 14.

By changing the length of the first transmission line 24, made by the telescopic method, by the operator using the indicator. phase equalizer 16, the phases of the reference DM are roughly aligned

interference Un signals generated at the second outputs of the phase shifter 8 and the third directional coupler 13, respectively. If the alignment of the phases by the operator is not enough, then on

the output of the phase detector 4 produces a voltage which, upon entering the control input of the tunable phase shifter 7, brings the phase difference of the interference Un and the reference signal Uki to

necessary size. In this case, the following cases of exposure to radio transmitter interference occur.

The case of exposure to interference is below the acceptable level.

In this case, an interference level Un is generated at the second output of the first directional coupler 1, which produces a voltage level at the output of the rectifier 2 that does not trigger the first threshold element 3, and the circuit only consists in automatically adjusting the phase of the reference signal Uki.

The case of interference is above the acceptable level.

In this case, a positive voltage Ui is generated at the output of rectifier 2 (see Fig. 2a), which generates a voltage U2 of logic 1 at the output of the first threshold element 3 (see Fig. 26). From the output of the first threshold element 3, the voltage U2 enters the input of the first differentiation unit 4 and the control input of the first electronic key 5. At the output of the first differentiation unit 4, a positive pulse is generated, which, passing through the inverter 5 and the OR element 11, in the form of a negative pulse is supplied to the installation input of the binary counter 17. The binary counter 17 does not work, and the first electronic key 15 is opened by connecting one of the inputs of the correlator 21 to the second output of the third directional coupler 13, the other input of which receives a reference signal Uki. If the phases of the reference Uki and the interference Un signals coincide in time, then the output voltage of the correlator 21 generates a positive voltage Uz, which triggers the second threshold element 22. If the phases of the reference Uki and the interference Un signals do not coincide, then the phase detector 14 produces a corresponding voltage, which is applied to the control input of tunable phase shifter 7, which changes the phase of the reference signal Uki to the phase value of the interfering signal Un. When the phases of the reference Uki and the interference Un signals coincide, the voltage from (see Fig. 2c) at the output of the correlator 21 reaches its maximum and the second threshold element 22 is triggered. At the output of the second threshold element 22, a voltage U4 of logical 1 is generated (see Fig. 2d), which is fed to the control input of the second electronic key 23 and the input of the second differentiation unit 10. The front voltage front U4 is differentiated by the second differentiation unit 10 and, in the form of a pulse Us (see Fig. 2e), is supplied via the OR element 11 to the installation input of the binary counter 17, its initialization, and the second electronic key 23 is opened.

connect the output of the rectangular pulse generator 20 to the counting diode / double-HOI about the counter 17. The volume of the binary counter 17 is smoothly filled, and at its output also the binary pulses are calculated smoothly in the binary code from the output generator 20. From the binary outputs of the binary counter 17, the current value of the digital code is fed to the input of the digital-to-analog converter 18, and the output of which generates an analog sawtooth voltage UG (see Fig. 2e), which is supplied to the control stroke controlled attenuator 9, the information input with the inverted output of which phase shifter 7 enters compensating signal Uk2.

The attenuation of the controlled attenuator 9 decreases in proportion to the voltage UG, and the amplitude of the compensation signal Uk2. entering the first input of adder 12 is increased. When adding equal in magnitude but opposite in phase signals Uk2 and Un, the voltage of the interfering signal at the input of the third directional coupler 13 becomes minimal.

At the Persian input of the correlator 21, the voltage of the interfering signal also becomes minimal, and the voltage Ua at its output also decreases. The second threshold element 22 returns to the logical O position (see Fig. 2a), the second electronic key 23 closes, and the rectangular pulses from the output of the generator 20 do not arrive at the counting input of the binary counter 17.

If the radio transmitter is excluded or its level is reduced to an acceptable standard, the voltage at the output of the rectifier

2 decreases, the first threshold element

3 returns to position O, and the first electronic key 15 closes. In this case, the trailing edge of the voltage U4 is differentiated by the differentiation unit 4 and, in the form of a negative pulse Us (see Fig. 2e), enters the inverter 5. A positive pulse U (see Fig. 2g) is generated at the output of the inverter 5, which is transmitted through the OR element 4 is supplied to the installation input of the binary counter 17. The binary counter 17 is returned to its initial state, the voltage UG at the output of the digital-to-analog converter 18 drops to zero, and the attenuation of the controlled attenuator 9 reaches its maximum.

In case of repeated switching on of a radio transmitter with a high level of interference

Claims (1)

the process of suppressing an interfering signal in a channel of a radio receiver is repeated. SUMMARY OF THE INVENTION A device for suppressing an interference signal of a radio transmitter in a receiver channel, comprising a first directional coupler, the input of which is an input for connecting a receiving antenna, a second directional coupler in series, an input of which is an input for connecting a transmitter input, and a first output is an output for connecting a transmitting antenna, a tunable phase shifter, a controlled attenuator, an adder, the second input of which is connected to the first output of the first a coupled coupler, and a third directional coupler, the first output of which is a receiver input, characterized in that, in order to improve performance, a rectangular pulse generator, a phase equality indicator, the first and second inputs of which are connected respectively to the second outputs of the third directional coupler and a phase coupler, a rectifier connected in series, the input of which is connected to the second output of the first directional isolator, the first threshold element, the first differentiation unit, ver- a torus and an OR element, a binary counter and a digital-to-analog converter are connected in series, the output of which is connected to the control input of the controlled attenuator, the first electronic key is connected in series, the control and information inputs of which are connected respectively to the output of the first threshold element and the second output of the third directional a coupler, a correlator, the second input of which is connected to the second output of the phase shifter, and a second threshold element, a second electronic key, an information input and the output of which is connected respectively to the output of the rectangular pulse generator and the counting input of the binary counter, and the control input is connected to the output of the second threshold element, a second differentiation unit connected between the output of the second threshold element and the second input of the OR element, and a phase detector, the first and second inputs of which are connected to the second outputs of the third directional coupler and phase shifter, respectively, and the output is connected to the control input of the tunable phase shifter, while the course of the OR element is connected to the binary counter reset input.