SU1252953A1 - Device for checking non-linearity of non-serviced amplifying stations - Google Patents

Abstract

The invention relates to telecommunications and provides improved control accuracy by separately controlling the forward and reverse transmission paths while simplifying the device. At the serviced amplifying station (PMO) 1, three pilot signals (CS) are generated from the signals of the generators 10, 13 and 14. All three CSs from the driver 15 pilot signals through the level 12 controller enter the forward 2 transmission path. In the first control phase, when the low-level QS is fed into the forward path 2, the non-linear amplification points (LLP) 4 are monitored in the reverse transmission path. In the last NUP 4, the control signals through the amplifier 16, the filter 19 of the control signals and the amplifier 17 arrive in the reverse path of the 3rd gear with a high level. At the PMO 1, these CCs are separated by the filter 7 of control signals and, through the delay unit 11, are fed to the level 12 regulator. The second control phase begins, during which a high level CS is formed and the LLP is monitored in the forward path. In this case, the QS does not pass through the last NUP 4. In the presence of a NUP with a non-linearity, the combination frequencies form at its output. They are allocated by the filters 6 and 18 of the combination frequencies and are fed to a two-channel receiver 8. The comparison unit 9 gives the signals of the corresponding value to the indicator 5. 3 pcs. with ate h U1 tsd co w ate 00 "" Fi. (

Description

112

The invention relates to telecommunications and can be used to control the nonlinearity of the equipment of unattended amplifying stations (LBF) of frequency division multiplexed transmission systems.

The purpose of the invention is to improve the accuracy of control by separately controlling the forward and reverse transmission paths while at the same time simplifying the device.

FIG. Figure 1 shows the structural electrical circuit of the device for controlling the non-linearity of the LLP; 2 shows an example of a pean ii3a4HH pilot of the pilot signals, a level controller and a two-channel receiver; FIG. 3 is a graph explaining the principle of localization of a faulty LLP.

The device (Fig. 1) contains a serviced amplifier point (FCS) 1, forward 2 and reverse 3 transmission paths and LLL 4, -4ts, moreover, the RCS 1 includes indicator 5, the first combinational filter 6, the first filter 7 control signals , two-channel receiver 8, comparison unit 9, control signal generator 10, block AND delays, level controller 12, first 13 and second 14 additional signal generators and driver 15 control signals, each NUP 4, -4 / turns on amplifier 16 and the amplifier 17 of the reverse transmission paths, and the NUP 4 // includes the second filter 18 combinational frequencies, the second filter 19 control signals and the threshold unit 20. The driver 15 control signals (Fig. 2) contains the first adder 21, the mixer 22, the band-pass filter 23 and the second adder 24 level regulator 12 contains the key 25 winding 26 relay, resistor 27 and relay contact 28, and two-channel receiver 8 - first 29 and second 30 mixers, first 31 and second 32 band-pass filters, first 33 and second 34 connectors and first 35 and second 36 threshold elements.

The device works as follows.

At the PMO 1, three pilot signals are generated. The first pilot signal is generated directly by the pilot signal generator O, and the second and third pilot signals, f X; and f ,, are formed into odds

ten

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worldviewer 13 as 1) szu. i.k.t. iptometry of generator 10 and signals of additional generators 13 (f) and 14 (fn) Signals from op-5 generator generators 13 and 14 are combined in the first adder 21 of the former 5 and are fed to a mixer 22. To another input of the mixer 22, a signal from the generator 10 is applied. At the output of the mixer 22, pilot signals are generated

f f K-z KI

k, f, „t -Ч, 32

which are separated by the filter 23. All three pilot signals are combined by the second adder 24 and are fed through the level controller 2 to the input of the forward path of the 2nd gear.

It is essential that the frequencies of the auxiliary signals are chosen outside the working frequency band to the left of the lower boundary and slightly different from each other (so that their difference is approximately 0.5-1 kHz). The frequency of the first pilot signal should be chosen in such a way that all three pilot signals are located to the right of the working frequency band (Fig. 3). With such a choice of frequencies of control signals, the proposed device does not affect the transmission of the received information, i.e. LLP can be monitored without interruption.

In the first phase of control, the control signals go to the forward transmission path 2 at a low level, since they pass through the resistor 27 of the controller 12, In this case, the combination frequencies in the forward path 2 transmissions almost do not occur even in the presence of NUP with linear nonlinearity. The control signals in the last controlled LLP 4 are separated by the filter 19 of control signals and through the threshold unit 20 arrive at the input of the reverse path of the 3rd gear. At the input of the reverse transmission path 3, the levels of pilot signals are set high enough to form combination frequencies with a PMU with increased non-linearity. Providing high levels of control signals in the reverse transmission path 3 is achieved in a simple way by turning on a loop between the output of the forward path amplifier 16 and the input

amplifier 17 inverse path, i.e. by naturally amplifying the LLP itself. The high level control signals through the reverse path 3 of the transmission arrive at the PMO 1, are filtered out by the filter 7 of the control signals, and through the block 11 of the delay arrive at the control input of the level controller 12. In controller 12, the control signals act on the key 25, as a result: during which the current passes through the winding 26 of the relay and the contact 28 is closed. The second control phase begins. In this case, the control signals begin to enter the forward path of the 2nd transmission through the relay contact 28, the resistor 27 is mined, i.e. High level tell-tales are input to the forward link 2 transmission. The high-level control signals that pass the forward path of the 2nd transmission are separated by a filter 1 9 and are locked by a threshold unit 20. Consequently, in the reverse transmission path of the 3rd transmission, the control signals are absent.

Thus, in the first phase of control, the proposed device monitors the non-linearity of the LLP in the reverse path 3 of transmission 3, and in the second phase of control, in the direct path 2 of transmission.

In the absence of control signals-J10B in the reverse path of the 3rd transmission and, accordingly, at the input of the PMO I, the controller 12 returns to the initial state and the first phase of the control begins again. The forward 2 and reverse 3 transmission paths are alternately monitored. By means of a delay unit 11, a time gap is provided. By means of a delay unit 11, the time required for localizing the faulty LCP in each monitoring phase is provided. If there is an LLP in one of the paths with the increased nonlinearity, the combination frequencies form at its output (second-order nonlinearity products)

H (K1 k2

f f - f

 14 ka

If the combination frequencies occur in the forward path of the 2nd gear, then they enter the PMO through filter 1 of the combination frequencies and the reverse path of the 3rd gear, but if they occur in the reverse track of the 3rd gear, then

Ogn arrive at the PMO 1 directly. In the PMO 1, the combinational frequencies are separated by a filter of 6 combinational frequencies and are fed to a two-loop receiver 8. In the receiver 8, signals are fed to mixers 29 and 30. The other inputs of the mixers are fed by additional generators 13 and 14, the frequencies of which are respectively the frequencies f and f .

At the outputs of the mixers 29 and 30, differential side frequency signals are generated, which are equal. The signals are extracted by bandpass filters 3 and 32, which are coBeppieHHo identical, tuned to the same center frequency and have the same bandwidth. The principle of separating and separating the combinational nonlinearity products with the help of auxiliary signal frequencies of which are equal to the frequencies of these nonlinearity products makes it quite easy to implement bandpass filters 31 and 32 on standard LC elements. In addition, this principle allows, if necessary, changing the frequencies of the signals of additional generators 13 and 14 without changing the parameters of the bandpass filters 31 and 32. Such a need may arise when interference frequencies that reduce the accuracy of control appear on the control frequency. The signals extracted by the bandpass filters 31 and 32 through the rectifiers 33 and 34 and the threshold elements 35 and 36 are fed to block 9 of the comparison. The threshold elements 35 and 36 prevent the combination of non-linearity products to block 9 below a certain, predetermined level and any parasitic interference in the controlled frequency band. The difference in the levels of the lateral frequency currents (la) corresponds to the difference in the levels of the currents of the frequencies of the nonlinearity products and is determined by the LEL number at which the fault occurs and the direction of transmission (direct or reverse path). For example, if the nasal 17 on the SIS 4 is faulty, the level difference is determined only by the steepness of the attenuation frequency characteristic of the amplifier 16 of the SFS 4, i.e. ya i a, - (4mg. 3). If the amplifier 16 is faulty on the same LCP t, the level difference is determined by the total steepness of the frequency characteristics.

attenuation of all NUP after NUP j. The direct path has 2 gears and all the RUPs in the reverse path 3 gears. Comparison unit 9 evaluates the difference in current levels and assigns a signal of the corresponding magnitude to indicator 5, which records the number of the faulty LBF and the direction of transmission.

The control of the LLP using the proposed device is based on the premise that the probability of the simultaneous occurrence of two or more LLPs with increased nonlinearity is extremely small. The possibility of the simultaneous occurrence of a fault on one LLP in both directions of transmission is not excluded, since one of the reasons for the increase in nonlinearity in LLP equipment is the effect of lightning discharges of a local nature. That is why separate-sequential control of both directions of transmission is especially important.

Claims (1)

Invention Formula Device for nonlinearity control is not serviced}: amplifying points containing a generator of control signals at the serviced amplifier point, a delay unit, the first combinational frequency filter, whose input is connected to the output of the reverse transmission path, and successively connected comparator unit and an indicator, and at the last monitored maintenance-free amplifier point - the second combinational frequency filter, the input and output of which are connected respectively with the direct output and the input of the reverse transmission paths characterized In order to improve the control by means of separate control of the forward and reverse transmission paths while simplifying the device, two additional signal generators were introduced at the serviced amplification station, the first filter of control signals, the two-channel receiver and the series-connected driver of control signals and the level controller , and at the last controlled maintenance-free amplifying point, the second filter of control signals and the threshold are sequentially connected In this case, the information input and the outputs of the two-channel receiver are connected respectively to the output of the first combinational frequency filter and to the inputs of the comparison unit, the output of the pilot signal generator is connected to the first input of the pilot signal processor, and the outputs of the first and second additional signal generators are connected to the second and second signals respectively. the third inputs of the pilot signal generator, combined respectively with the first and second control inputs of the two-channel receiver, the output of the first ph Iltra of pilot signals, the input of which is connected to the output of the reverse transmission path, is connected via a delay unit to the control input of the level regulator, the output of which is connected to the input of the forward transmission path, and the input and output of the second combinational frequency filter are connected respectively to the input of the second control filter signals and the output of the threshold unit. From dJJOHa 7J From 5klok To mpanmtf 2 a, dB N /I; Kj - // fj Working frequency band  L .2 Lld // G, CC, f, Compiled by V. Slepakov Editor A. Kozoriz Tehred I. Veres Proofreader A. Zimokosov Order 4632/58 Circulation 624 Subscription VNIISH-1 USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5 Production and printing company, Uzhgorod, st. Project, 4 Fig.Z