SU1390806A2 - Device for measuring reciprocal influence between line sections of cable trunk lines - Google Patents

Description

(61) 611303

(21) 4176193 / 24-09

(22) 1/7/87

(46) 23.04.88. Bul № 15 (71) Leningrad Electrotechnical Institute of Communications im. Prof. M.A.Bonch- Bruevich T7 2) B.K.Gushchin (53) 621.395.44.001.4, (088.8) (56) USSR Author's Certificate No. 611303, cl. H 04 B 3/46, 1976.

(54) A DEVICE FOR MEASURING A MUTUAL SHAFT FOR A MULTI-LINE TRACT-CABLE TRACK (57) The invention relates to a technique of multi-channel long-distance communication. The purpose of the invention is to reduce the measurement time. The device contains a generator 1, a measuring unit 2, a selective conversion unit 3, consisting of a local oscillator 4, a unit 5 of automatic frequency control (AFC),

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amplifiers 6 and 9 high frequency, mixers 7 and 10, amplifiers 8 and 11 intermediate frequency. An automatic unit 12 is introduced, the settings of the selective conversion unit on the frequency of the measuring signal, consisting of switches 13-15, pulse generator 16 and detector 17 of the measuring signal, the influencing path 18 and tract 19, are affected. The settings of node 3 to the frequency of the measuring signal are used in block 12. When the frequency of the measuring signal of generator 1 is changed, the voltage at the output of amplifier 8 disappears and the locking driver 16 constant voltage becomes equal to nulray.

one

Isoooretation refers to the technique of multi-channel long-distance communication, can be used to measure the transfer functions of mutual effects (PFVV) between paths, and is an improvement of the invention according to the author, St. No. 611303.

The purpose of the invention is to reduce the measurement time.

The drawing shows a structural electrical circuit of the proposed device.

A device for measuring mutual splices between linear paths of cable trunk lines comprises a generator - a torus 1, a measuring unit 2, an electropower node 3, consisting of a local oscillator 4, a unit 5 for automatic frequency tuning, a first amplifier 6 for high frequency, a first mixer 7 , the first amplifier 8 intermediate frequency, the second amplifier 9 high frequency, the second mixer 10, the second amplifier 11 intermediate frequency, the unit 12 automatically adjusts the selective-conversion node to the measuring frequency signal, consisting of the first 13, second 14 and third 15 switches, the driver 16 pulses and the detector 1 7 measuring sig90806

In this case, the driver 16 produces pulses for the switches 13-15, to-rye by switching elt of the election circuits of the amplifiers 6 and 9 and the loop of the local oscillator 4 synchronously reconfigure them in frequency. When a signal appears at the output of the overclocking frequency controller 8, the driver 16 stops working and the switches 13-15 stop. From amplifiers 8 and 11, the signals arrive at block 2. The operator at the transmitting end sets the next value of the measuring signal frequency on geyator 1. At the receiving end of the signal from the amplifier 8 disappears, and block 12 converts the tuning of node 3 to the next frequency value. 1 z.p, f-ly, 1 ill.

Nala, and. Also, the influential tract 18 and tract 19 are affected.

The device works as follows.

In order to perform PFVV measurements at the transmitting end of the line, the output of the generator 1 is connected to the input of the influence path 18. The output resistance of the generator 1 and the input resistance of the selective-converting node 3 must be significantly larger than the equiyalent resistance of the influence path 18 and the path 19 affected by the point of them

switching on so as not to disrupt the operation mode of the communication system.

Measuring signal frequency

20

generator 1 is defined by the formula f 4p + 12f (0.1 - 0.14),

1 de n is the number of the communication channel located in the working frequency range of the compression system below the interchannel gap in which measurement is performed (plus sign for the reverse transmission spectrum of communication signals in the influence path 18 and path 19, and minus sign - at direct).

At the receiving end of the trunk input of the first high frequency amplifier 6

They are connected to the output of influencing machine 18, and the input of the second high-frequency amplifier 9 to the output of the affected path 19. The first 6 and second 9 high-frequency amplifiers have a symmetrical high-resistance input, if necessary, provide attenuation or amplification of the incoming signals and their preliminary selection in frequency. The first 7 and second 10 mixers, which can be used, for example, a double balanced modulator, multiply the signal coming from the first 6 and second 9 amplifiers, depending on the channel and the signal of the local oscillator 4. Main selection measuring signals occur in the selective elements of the first 8 and second 11 amplifiers of intermediate frequency. Feature the first amplifier 11 consists in its ultra-narrowband and high selectivity (bandwidth from ± 2 Hz at 3 dB, attenuation during detuning from the resonant frequency at + 50 Hz not less than 60 dB) necessary to extract the measuring signal of a very low level in path 19 on background information signals that are transmitted over communication channels. This is achieved / using multi-stage quartz filters in the second intermediate frequency amplifier t1. To achieve fine tuning of the selective-converting node 3 to the frequency of the measuring signal, it is necessary that the local oscillator 4 generates an auxiliary signal for the operation of the first 7 and second 10 mixers, whose frequency would exceed the frequency of the measuring signal exactly by the value of the intermediate frequency of the first 8 and second 11 amplifiers, which is provided by block 5.

In order to ensure the automatic adjustment of the selective conversion unit 3 of the receiving part of the device to the frequency of the measuring signal, a block 12 is used, which operates as follows.

When setting the selective-conversion node 3 to the first value of the frequency of the measuring signal using block 5, the voltage of the measuring voltage exists at the output of the first amplifier 8 intermediate frequency

with (about 15 20 25 zo Q dg

35

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the signal that is converted by the detector 17 to a constant voltage, blocking the driver 16. When the frequency of the measuring signal of the generator 1 is changed, the voltage at the output of the first amplifier 8 of the intermediate frequency disappears and the blocker 16 constant voltage is equal to zero. In this case, the shaper 1b produces pulses for the operation of the first 13, second 14 and third 15 switches, which by switching elements of the election circuits of both amplifiers 6 and 9 of high frequency and the loop of the local oscillator 4 connected through the additional outputs to the switching contacts of the first 13, second 14 and third 15 switches synchronously adjust the frequency loops of the amplifiers 6 and 9 of the high frequency and the frequency of the local oscillator 4. When a signal appears at the output of the first amplifier 8, the impulse driver The switch will stop working and the first 13, the second 14 and the third 15 switches will be poured.

From the outputs of the first 8 and second 11 intermediate frequency amplifiers, the measuring signals are fed to the corresponding inputs of the measuring unit 2, in which the ratio of the complex amplitudes of two sinusoidal voltages is measured, the operator at the transmitting end sets the following measurement frequency to the generator 1 signal. At the receiving end at the output of the first amplifier 8 intermediate frequency, the signal disappears and block 12 translates the setting of the selective-conversion node 3 to the next value of the frequency of the measuring signal. At other frequencies, the device works in a similar way.

Claims (2)

1. A device for measuring the mutual effects between linear paths of cable lines according to ed. St. No. 611303, characterized in that, in order to reduce the measurement time, an automatic tuning unit of the selective conversion unit is introduced the measurement signal, the input of which is connected to the output of the first intermediate-frequency amplifier of the binary converter unit, and the first, second and third outputs of the automatic tuning unit of the selective-conversion node to the frequency of the measuring signal are connected to the control inputs of the first high-frequency amplifier, local oscillator and second high-frequency amplifier selective conversion node. 2. Device no. 1, characterized in that the automatic adjustment block is selective. conversion node to frequency the measuring signal contains the detector signal connected to the measuring signal, whose input is the input of the automatic tuning unit of the selective conversion unit to the frequency of the measuring signal, and the pulse shaper, the first, second and the third switches, the inputs of which are connected to the output of the pulse generator, and the outputs of the first, second and third switches are respectively the first, second and the third output of the automatic tuning unit of the selective conversion unit to the frequency of the measuring signal.