SU1305881A2 - Device for selecting communication channel - Google Patents

Abstract

The invention relates to radio engineering, is in addition to auth.St. № 1239872 and provides improved accuracy of channel selection. The device contains a receiver 1, a mixer 2, a filter 3, a demodulator 4, a decoder 5 errors, a noise meter 6, a channel selection block 7, adders 8, 25, generators (H) 9, 10, a frequency tuning block 11, element OR 12, shaper 13 time slots, counters 14, 15, test signal sensor 20, modulator 21, attenuator 22, duplexer 23, controlled by G 24, and envelope detector 26. The test signal from the sensor 20 to the input of the receiver 1 and used to evaluate the effect of interference on the transmitted information is changed according to the same law as the information signal. This will increase the reliability of channel selection with minimal interference from the transmitted information. The goal is achieved by introduction. demodulator 4, decoder 5, sensor 20, modulator 21, attenuator 22, duplexer 23, G 24, adder 25 and detector 26. 1 Il. (O (L if co 00 00 N

Description

The invention relates to radio engineering and can be used in adaptive radio links of the shortwave (HF) and ultrashortwave (VHF) ranges and is an improvement of the invention according to aut. St. No. 1239872.

The purpose of the invention is to increase the accuracy of channel selection.

The drawing shows a structure on the electrical circuit of the proposed device.

The device for selecting a communication channel contains a receiver 1, a mixer 2, a filter 3, demodulator A, a decoder 5 errors, a noise meter 6, block 7 channel selection, an adder B ,, generators 9 and 10, block 1 of the frequency tuning element OR 12 , driver 13 time intervals, counters 14 and 15, terminal block 16, filter 17, demodulator 8, recorder 19, test signal sensor 20, modulator 21, attenuator 22, duplexer 23, controlled oscillator 24, adder 25 and detector 26 go around

The device works as follows.

When initially turned on, the receiver 1 is tuned to the first frequency preset in frequency tuning unit 11. At the end of the tuning process, the receiver issues a ready signal, which, via element OR 12, starts the shaper of 13 time intervals and sets counter 14 to its initial state. Each working frequency set in block 11 corresponds to N sub-frequencies in the receiver's transmission band, in which can receive information. The counter 14, when the first pulse arrives at its input from the imaging unit 13, forms the code of the number of the first sub-frequency. This code is fed to the input of adders 8 and 25 and in block 7 channel selection. In adder 25, it is added to the frequency control code with

The transmitter comes from frequency tuning unit 11 and is fed to the control input of the controlled oscillator 24. Under the influence of this code, the controlled oscillator 24 produces the frequency corresponding to the first of the N sub-frequencies falling into the passband of the receiver 1. This frequency modulated with date test signal

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20, through the modulator 21, the attenuator 22 and duplexer 23 is fed to the input of the receiver 1, and from its output to the mixer 2.

Since nothing is supplied to the second input of the adder 8, the code from the counter 14 through the adder 8 is fed to the control input of the generator without change. In this case, the generator 9 outputs to the input of the mixer 2 a frequency that converts to the center frequency of the filter 3, which arrives at the second input of the mixer, the frequency of the controlled generator 24 corresponding to the first subfrequency in the receiver band 1.

The shaper 13 time intervals at each start generates a sequence of N pulses, following with a period equal to the measurement time of interference on each sub-frequency. Each pulse arriving from the imaging unit 13 is reset to the noise meter 6 and is written I to the counter 14. The noise meter 6 counts the number of errors in the test signal at this sub-frequency received through filter 3 to the demodulator 4 connected via decoder 5 to the input meter 6, for the measurement period. These errors are generated when a test signal is interfered with at a given sub-frequency, received from an antenna.

The results of counting the number of errors at each sub-frequency and the codes of the numbers of these sub-frequencies are output respectively from the noise meter 6 and the counter 14 to the channel selection block 7. Upon completion of the process of counting errors at all N sub-frequencies, block 7 selects the sub-frequency at which the number of errors is the smallest, i.e. the frequency at which the distortion of the signal interference is minimal, and stores the code number of this frequency until the end of the next measurement cycle. In addition, when receiving the results of error counting on the last sub-frequency, block 7 through

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OR I2 starts shaper 13 and resets counter 14, after which the described channel selection process with minimal interference to the signal repeats.

Information is received by terminal 16 at the same time as the sub-frequency is selected with minimal interference to the signal. Wherein

the signal from the output of the intermediate frequency of the receiver 1 through the filter 17 and the demodulator 18 enters the recorder 19. If the quality of the received information is below a certain value, then from the output of the recorder, 1 9 a signal is output that records the I to counter 15 and resolves from the block 7 code sub-frequency numbers with minimal interference to the signal.

The code of the number of the selected sub-frequency arrives at the control input of the generator 10. In this case, the generator 10 generates a frequency that, at the input of the external local oscillator of the receiver I, converts the frequency component corresponding to the selected sub-frequency to the intermediate frequency of this receiver, to which the filter 17 is tuned. Thereafter, the reception of information by the terminal unit 16 is performed on this sub-frequency. At the same time, the code of the selected sub-frequency arrives at the second inverse input of the adder 8.

When adding the code of the sub-frequency number, coming from counter 14, with the sub-frequency number code coming from block 7, the output of the adder 8 will be the difference between the values of these codes and the frequency of the generator Yu will be reduced by an amount equal to the difference of the values of these sub-frequencies. This is necessary when changing the value of the frequency component at the input of the receiver 1 converted to the middle frequency of filter 57, the correspondence between the subfrequency code value and the frequency component at the input of the receiver converted to the average frequency of the filter 3 is preserved.

In addition to the demodulator 18, the information signal from the video filter 17 passes through the detector 26 to the control input of the attenuator 22. At the same time, the resistance of the attenuator 22 changes in accordance with the law of variation of this envelope, and the value of the test signal from the sensor 20 to the input of the receiver 1 , amended by the same law.

Thus, the test signal used to evaluate the effect of interference on the transmitted information is changed according to the same law as InformatIng. Order 1466/56

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mation signal, which increases the reliability of channel selection with minimal impact of interference on the transmitted information.

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With every deterioration in quality

receiving below a predetermined level, the recorder 19 writes 1 to the counter 15 and issues a number code from block 7

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generator 10 and adder 8. If within a certain time, which is set by shaper 13, the number of sub-frequencies at which the reception quality is lower than a predetermined level exceeds a predetermined value, then from the output of counter 15 to the input of block 11 a signal will be received by which this block will rearrange receiver 1 to the next frequency. If during this time the number I recorded in counter 13 is insufficient to overflow it, then after a predetermined time has elapsed, this counter is reset by a signal from the other output of the driver 13 and the working frequency does not change.

Claims (1)

Formula of the invention n. 0 A device for selecting a communication channel according to avt.S.N. 1239872, characterized in that, in order to improve the accuracy of channel selection, enter 2 series-connected test signal sensor, modulator, attenuator and duplexer, series-connected adder and controlled generator, and Also, the demodulator and the error decoder are connected in series, the input of the demodulator is connected to the output of the filter, and the output of the error decoder is connected to the input of the noise meter, as well as an illuminating detector whose output is connected to the second input of the attenuator, and d vpsodom connected to the filter, the output of the controllable oscillator is connected to the second input of the modulator, and 0, the first and second inputs of the adder are connected respectively to the output of the frequency tuning unit and to the output of the second counter, while the output of the duplexer is connected to the information input of the receiver. Circulation 639 Subscription