SU767980A1

SU767980A1 - Method and device for monitoring amplitude-frequency characteristic of communication channel

Info

Publication number: SU767980A1
Application number: SU782669691A
Authority: SU
Inventors: Владимир Викторович Клюхин
Original assignee: Ташкентский электротехнический институт связи
Priority date: 1978-09-26
Filing date: 1978-09-26
Publication date: 1980-09-30

Description

Изобретение относитс к электросв зи и может использоватьс дл контрол амплитудно-частотных характеристик каналов и трактов св зи. Известен способ контрол амплитудно-частотной характеристики св зи , включающий на передаче формирова ние сигналов контрольных частот, объ единение их с информационным сигналом и подачу в канал объединенного сигнала, а на приеме - выделение из объединенного сигнала сигналов контрольных частот, определение их параметров и оценку амплитудно-частотной характеристики канала 13 Известно устройство дл осуществл ни способа, содержащее в передающей части п генераторов контрольных частот , выходы п-1 из которых соединены с соответствующими входами блока ввода сигнёшов контрольных частот, выход которого соединен с входом канала св зи, а в приемной части объединенных по входу узкополосных фильтров, т+1 блоков сравнени , блок индикации и генератор опорного сигнала, выход которого соединен с первым входом (т+1)-го блока сравнени 23. Однако известные способ и устройство не обеспечивают повышени точности контрол смплитудно-частотной характеристики без уменьшени пропускной способности канала (тракта) св зи. Цель изобретени - повышение точности контрол без снижени пропускной способности канала св зи. Дл этого по способу контрол амплитудно-частотной характеристики канала св зи, включающему на передаче формирование сигналов контрольных частот, объединение их с информационным сигналом и подачу в Ксшал объединенного.сигнала, а на приеме выделение из объединенного сигнала сигналов контрольных частот, определение их параметров и оценку амплитудно-частотной характеристики канала, на передаче определ ют входные параметры информационного сигнала в объединенном сигнале и формируют соответствующий им групповой сигнал , которым модулируют сигналы одной из контрольных частот, а на приеме - одновременно с выделением из объединенного сигнала сигналов контрольных частот определ ют параметры рпттопжашегос в нем информационногоThe invention relates to telecommunications and can be used to control the amplitude-frequency characteristics of channels and communication paths. There is a method of controlling the amplitude-frequency characteristic of a communication, which involves transmitting control signals to a signal, combining them with an information signal and feeding a combined signal to the channel, and receiving control signals from the combined signal at the reception, determining their parameters and estimating amplitude -frequency characteristic of channel 13 It is known a device for carrying out a method that contains in the transmitting part n of control frequency generators, the outputs n-1 of which are connected to the corresponding the inputs of the control frequency signature input unit, the output of which is connected to the input of the communication channel, and in the receiving part of the narrowband filters combined at the input, t + 1 comparison units, the display unit and the reference signal generator, the output of which is connected to the first input (t + 1) unit of comparison 23. However, the known method and device do not provide an increase in the accuracy of monitoring the smp-frequency response without reducing the capacity of the communication channel (path). The purpose of the invention is to improve the control accuracy without reducing the capacity of the communication channel. To do this, according to the method of controlling the amplitude-frequency characteristic of the communication channel, which includes transmitting the formation of control frequency signals, combining them with the information signal and feeding the combined signal to Kschal, and receiving the selection of the control frequencies from the combined signal, determining their parameters and estimating the amplitude-frequency characteristic of the channel, on the transmission, determine the input parameters of the information signal in the combined signal and form the corresponding group signal, by which the signals of one of the control frequencies are stimulated, and at the reception, simultaneously with the selection of the signals of the control frequencies from the combined signal, the parameters of the rtpttoshas in it are determined

сигнала, из выделенного модулированного сигнала контрольной частоты выдел ют модулирующий групповой сигнал, по которому определ ют входные параметры информационного сигнала, которые сравнивают с соответствующими параметрами информационного сигнала в прин том объединенном сигнале и по результатам сравнени и параметрам сигналов контрольных частот оценивают амплитудно-частотную характеристику канала св зи, В устройство дл осуществлени способа, содержащем в передающей части п генераторов контрольных частот, выходы п-1 из которых соединены с соответствующими входами блока ввода сигналов контрольных частот , выход которого соединен с входо канала св зи, а в приемной части - m объединенных по входу узкополосных фильтров, т+1 блоков сравнени , блок индикации и генератор опорного сигнала , выход которого соединен с первым входом (т+1)-го блока сравнени ,signal, a modulated group signal is extracted from the selected modulated signal of the control frequency, which determines the input parameters of the information signal, which are compared with the corresponding parameters of the information signal in the received combined signal and estimate the frequency response of the channel connection, In the device for implementing the method, containing in the transmitting part of the n control frequency generators, the outputs n-1 of the cat are connected to the corresponding inputs of the control frequency signal input unit, the output of which is connected to the input of the communication channel, and in the receiving part m connected along the input of narrowband filters, t + 1 comparison units, the display unit and the reference signal generator, the output of which is connected to the first the input (t + 1) of the comparison block,

введены m амплитудных детекторов, m фильтров нижних частот, п детекторов контрольных частот, блок вьвделёни сигналов контрольных частот , блок разделени группового сиг нала, m дополнительных узкополосных фильтров, m дополнительных амплитудных детекторов, m дополнительных фильтров Нижних частот,блок формировни группового сигнала,дополнительны генератор опорного сигнала и. модул тор , при этом входы m дополнительных узкополоснйх фильтров соединены с выходом блока ввода сигналов контрольных частот, на соответствующий вход которого подан информационный сигнал, а выход каждого дополнительного узкополосного фильтра через последовательно соединенные соответствующий дополнительный амплитудный детектор и соответствующий дополнительный фильтр нижнихm amplitude detectors, m low-pass filters, p control frequency detectors, a block for the selection of control frequency signals, a group signal separation unit, m additional narrow-band filters, m additional amplitude detectors, m additional Low-pass filters, a group signal shaping unit, additional generator reference signal and. the modulator, while the inputs m of the additional narrowband filters are connected to the output of the control frequency signal input unit, to the corresponding input of which an information signal is fed, and the output of each additional narrowband filter is connected through the series-connected corresponding additional amplitude detector and the corresponding additional lower filter

частот соединен с соответотвукхцим входом .блока формировани группового сигнала, управл ющий вход и выход которого средине . ны соответственно с выходом дополнительного генератора опорного сигнала и с первым входом модул тора, второй вход и выход которого соединены соответственно с выходом п-го генератора контрольной частоты и с соответствующим входом блока ввода сигналов контрольных частот, вход блока вьвделени сигналов контрольных частот соединен с выходом канала св зи и с входами узкополосных фильтров , выход ка эдого из которых через последовательно соединенные соот ветстгвуюЩйё амплитудный детектор, фильтр нижних частот и блок сравнени соединен с соответствующим входом блока индикации, соответствующие входы которого соединены с выходомFrequency is connected to the correspondingly twisted input of the group signal shaping unit, the control input and output of which is in the middle. here, respectively, with the output of an additional generator of the reference signal and with the first input of the modulator, the second input and output of which are connected respectively to the output of the nth generator of the control frequency and with the corresponding input of the control frequency signal input unit, the input of the control frequency input unit is connected to the output of the channel communication with the inputs of narrow-band filters, the output of which is through a series-connected corresponding amplitude detector, a low-pass filter and a comparator unit are connected with the corresponding input of the display unit, the corresponding inputs of which are connected to the output

(т+1)-го блока сравнени , с выходами п-1 детекторов контрольных частот входы которых соединены с соответствующими выходами блока вьщелени сигналов контрольных частот, соответствующий выход которого через п-й детектор контрольной частоты соедине с входом блока разделени группового сигнала, выходы которого соединены с вторыми входами соответствующих блоков сравнени .(t + 1) of the comparison unit, with the outputs of the p-1 control frequency detectors, the inputs of which are connected to the corresponding outputs of the control frequency signal selection unit, the corresponding output of which is connected to the input of the group signal separation unit through the nth control frequency detector, whose outputs connected to the second inputs of the respective comparison units.

На чертеже приведена структурна электрическа схема устройства дл реализации предлагаемого способа дл двух сигналов контрольных частот .The drawing shows the structural electrical circuit of the device for implementing the proposed method for two signals of the control frequencies.

Устройство содержит генераторы 1, 2 контрольных частот, дополнительные узкополосные фильтры 3, 4, дополнительные амплитудные детекторы 5, 6, дополнительные фильтры 7, 8 нижних частот, блок 9 формировани группового сигнала, дополнительный генератор 10 опорного сигнала, модул тор 11, блок 12 ввода сигналов контрольных частот, блок 13 выделени сигналов контрольных частот, детекторы 14, 15 контрольных сигналов , блок 16 разделени группового сигнала, узкополосные фильтры 17, 18, амплитудные детекторы 19, 20, фильтры 21, 22 нижних частот, блоки 23, 24, 25 сравнени , генератор 26 опорного сигнала, блок .27 индикации.The device contains 1, 2 control frequency generators, additional narrow-band filters 3, 4, additional amplitude detectors 5, 6, additional filters 7, 8 low frequencies, a group signal generating unit 9, an additional reference signal generator 10, modulator 11, input unit 12 control frequency signals, control frequency extraction unit 13, control frequency detectors 14, 15, group signal separation unit 16, narrowband filters 17, 18, amplitude detectors 19, 20, low-pass filters 21, 22, comparison units 23, 24, 25, the reference signal generator 26, the display unit .27.

Сущность предлагаемого способа заключаетс в следующем.The essence of the proposed method is as follows.

Claims

The channel (path) transmits two signals of the control frequencies, located in the lower and upper parts of the channel bandwidth (path), one of which is amplitude modulated by a group signal. The information signal occupies the spectrum between the monitored frequencies. The input parameters of the information signal is obtained by narrow-band filtering of the information signal, followed by detection and low-frequency filtering. The obtained parameters, whose spectra are limited by a frequency of 0.1-1 Hz, are converted into a group signal by multiplying them by subcarrier oscillations (for example, by non-overlapping pulse sequences with a frequency of 2-20 pulses per second), which modulate one of the signals control frequencies. At the reception, the signals of the control frequencies are detected and detected. Based on the result of the detection of the signal of the first control frequency, the value of the amplitude-frequency .0 characteristic at the first control frequency is determined, and as a result of the detection of the signal of the second control. The rpynnoBO t signal is obtained at the frequency of the frequency, from which the input parameters of the information signal are then extracted. The output parameters of the information signal, as well as the input ones, are obtained by narrow-band filtering of the information signal, detection and averaging (low-frequency filtering). The input and output parameters of the information signal are compared, the ratio of the input parameter to the output one is determined under the condition that both parameters exceed a certain threshold value, after which the value of the amplitude-frequency characteristic at frequencies corresponding to narrowband filtering is determined as values proportional to the logarithm found relationships On the basis of the found values of the amplitude-frequency characteristic, the entire amplitude-frequency characteristic of the channel (path) is judged. A device for implementing the proposed method works as follows. In transmission, the information signal is fed to the input of the input unit 12 from the control frequency signals, which performs band-stop filtering at frequencies f and fj, lying respectively below and above the frequency range of the information signal, the barrier bandwidth being 10-100 Hz depending on the band h that channel (tract). At the output, the block 12 of the input of control frequency signals with additional narrowband filters 3 and 4 with high input impedance, tuned to frequencies fj, and f4, lying in the information signal range, and having pass bands of 50–4000 Hz wide, separate narrowband signals which are detected by additional amplitude detectors 5 and 6 and are averaged by additional low pass filters 7 and 8, and upper levels of 0.1 to 1 Hz. The signals from the outputs of the filters 7 and 8, the lower frequencies and the reference DC voltage from the additional generator 10 of the reference signal are multiplied in the group signal generating unit 9 by the pulse sequences and summed, resulting in the output signal of the group signal generating unit 9 the following sequence of pulses; the pulse multiplied by the reference voltage; the pulse multiplied by the signal from the output of the additional low-pass filter 7; pulse multiplied by the signal from the output of an additional 8 low-pass filter, etc. The duration of the first (reference) pulse is 1.5–2 times greater than the duration of other pulses, the duration of the pulse follow-up period is 0/5 5 s. With this pulse train, the signal of the second control frequency f / 2 is modulated in the modulator 11. The amplitude-modulated signal with the frequency fj and the signal of the first control frequency f are together with the information signal introduced into the channel (path). At the reception to the input of block 13, the selection of control frequency signals receives an information signal and control frequency signals. The information signal from the output of the block 13 of the selection of control frequency signals goes further to the receiver, and the signal of the first control frequency is fed to the input of the detector 15, and the amplitude-modulated signal of the second control frequency is fed to the input of the detector 14. The signal from the output of the detector 15, the value of which unambiguously corresponds to the value of the amplitude - frequency characteristic at the frequency f, is fed to the input of the display unit 27, and the group signal from the output of the detector 14 is fed to the input of the block 16 separation unit. Narrowband filters 17 and 18, connected by high-resistance inputs to the input of a control frequency selection block, tuned to frequencies f and ft, respectively, narrowband signals are extracted from the information signal, which are detected by amplitude detectors 19 and 20 and averaged by low-pass filters 21 and 22 , having the same characteristics as the additional filters 7 and 8 of the lower frequencies. From the outputs of the group signal separation unit 16, the first reference impulse is fed to the input of the comparison unit 25, the second and third pulses are respectively to the inputs of the units 23 and 24 of the comparison. The second input of the comparison unit 25 receives the reference voltage from the reference signal generator 26, and the inputs of the comparison units 24 and 23 receive signals from the outputs of the low-pass filters 21 and 22, respectively. The signals at the outputs of the comparison blocks 23, 24, and 25 are proportional to the ratio of the signals at their inputs, provided both signals exceed a certain threshold value. The signal from the output of comparison unit 25, unambiguously corresponding to the value of the amplitude-frequency characteristic at frequency fj, the signal from the output of comparison unit 24, unambiguously corresponding to the difference between the values of the amplitude-frequency characteristic at frequencies fij and f, the signal from the output of comparison unit 23, uniquely corresponding to the difference of the values of amplitude-frequency characteristic The frequencies fJ and f I are fed to the inputs of the display unit 27, which determines the magnitude and nature of the deviation of the amplitude-frequency characteristic of the path channel from ominalnoy. The proposed method of monitoring the amplitude-frequency characteristics of the channels and the communication path and the device for its implementation provide, in comparison with the existing methods and devices, the following advantages: a) the possibility of monitoring the amplitude-frequency characteristics of the channels and communication paths occupied by the transmission of information, over the entire frequency range when transmitting the minimum number of control frequency signals (one or two); b) eliminating the need to locate the control frequency in the middle of the channel frequency band and the path s that reduces the complexity of the receiver and transmitter of information signals; c) the possibility of using control results for accurate correction of the amplitude-frequency characteristics of the channels of the channels during the transmission of information through them, which improves the quality and efficiency of using the channels and paths of the LINK. -, -: Formula of the invention 1 .. A method for controlling the amplitude-frequency characteristic of a communication channel, including the formation of control frequencies at the transmission, combining them with the information signal and feeding the channel a combined signal, and receiving - selecting the signal from the combined signal frequencies, determining their parameters and estimating the amplitude-frequency characteristic of the channel, characterized in that, in order to increase the accuracy of the control without reducing the capacity of the communication channel, the input e the parameters of the information signal in the combined signal and form the corresponding group signal with which the signals are modulated. One of the control frequencies, and at the same time as the control frequencies in the combined signal, determine the pargilletres of the information signal contained in the selected modulated signal. the signal of the control frequency is allocated a modulated group signal by which the input parameters of the information signal are determined, which are correlated with the corresponding parameters The parameters of the information signal in the received combined signal and by the results of comparison and the parameters of the signals of the control frequencies estimate the amplitude-frequency characteristic of the communication channel. 2. A device for carrying out the method according to claim 1, comprising in the gears part of the n generators, the control -. frequencies, p-1 outputs from which are connected to the corresponding inputs of the control frequency signal input unit, the output of which is connected to the communication channel input, and narrow-band filters connected at the input, m + 1 comparison units, display unit, and reference signal generator The output of which is connected to the first input of the (t + 1) -th comparison unit, which is based on the fact that m amplitude detectors, m low-pass filters, n control frequency detectors, a control frequency selection unit, a group signal separation unit are entered a, m additional narrow-band filters, m additional amplitude detectors, ditch, m additional low-pass filters, a groupover unit, an additional reference signal generator, and a modulator, while the m inputs of the additional narrow-band filters are connected to the output of the control frequency signal input unit , to the corresponding input of which an information signal is fed, and the output of each additional narrow-band filter through the corresponding additional amplitude component in series The vector and the corresponding additional low-pass filter are connected to the corresponding input of the group signal generating unit, the control input and output of which are connected respectively to the output of the additional reference signal generator and to the first input of the module, the torus, the second input and output of which are connected respectively to the output n of the reference frequency generator and with the corresponding input of the control frequency signal input unit, the input of the reference frequency selection unit is connected to the q output of the communication channel and to the inputs narrowly band-pass filters, the output of each of which is through a series detector, consistently connected to each other, filter | the low frequencies and the comparison unit are connected to the corresponding input of the display unit, the variety of which is connected to the output of the (n1 + 1) th comparison unit, to the outputs of n-1 detectors of the horizontal frequencies, whose inputs are connected to the corresponding exit block control frequency signals corresponding to the output of which is connected via the pth detector of the control frequency to the input of the splitgroup separation unit whose outputs

connected to the second inputs of the respective comparison units. Sources of information taken into account during the examination 1. Multichannel communication. Under. ed.

Abolitsa I.A. M., Sve, 1971, p. 277273 (prototype of the method),

2. USSR author's certificate in application number 2617809 / 18-09, cl. H 04 B 3/46, 1978. (prototype)