RU1774506C - Method of transmission of pulse signals over communication line with intermediate points - Google Patents

Abstract

The invention relates to digital communications technology. The goal is to increase security against intersymbol interference. A device implementing the method comprises, at an intermediate amplification point, an amplifier, a clock frequency allocation unit, a key, an output transformer. The goal is achieved due to the fact that the pulses in two adjacent amplifying sections of the adjacent one have either the same or opposite polarities, as a result of which the maximum interference arising in one amplifying section is compensated by the intersymbol interference that occurs in the adjacent section, since they have the same amplitude and different polarity. 2 ill.

Description

The invention relates to telecommunications and can be used for transmitting pulsed signals over communication lines containing intermediate points.

There is a known method of transmitting pulse signals via communication lines containing intermediate points, in which at intermediate points the pulses are amplified and corrected by correlation of the frequency characteristics of the line section, after which the pulses are regenerated and transmitted to the next section of the line.

The disadvantage of this method is that correlation does not completely eliminate intersymbol interference caused by distortions in the line section, i.e. mutual influences of transmitted pulses, especially neighboring ones. In communication lines containing several sections, intersymbol interference is accumulated, which leads to a deterioration in communication quality. The elimination of intersymbol interference accumulation in this method provides pulse regeneration at intermediate points. However, it is only possible in digital systems in which the nominal pulse amplitudes are rigidly determined. Therefore, the use of this method is limited to digital systems.

The purpose of the invention is to improve immunity to intersymbol interference.

 The goal is achieved in that at the intermediate points the pulses are amplified, after which the polarity of each second pulse of the information sequence is changed and the pulses are transmitted to the next section of the line.

The technical usefulness of the method lies in the fact that the mutual influences of adjacent pulses arising in one section

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the lines are mutually compensated by the same influences arising in another section, since the pulses affecting each other in neighboring sections of the line have different signs relative to each other.

Fig. 1 shows a communication line comprising a transmitter 1, intermediate points 2 and a receiving point 3; figure 2 shows the shape of the transmitted pulses at various points in the transmission path; the influence of the impulses of one another on the other, which appeared in the first section of the line, is shown by hatching with a slope of 45 ° to the time axis, and the mutual influences that appeared in the second section of the line are shown by hatching with a slope of -45 °. As a result of a change in the polarity of every second pulse at the output of the first intermediate point

the mutual influences of the pulses arising in the first and second sections of the line are mutually annihilated, as can be seen from the fourth line of Fig. 2, such that the pulses do not have mutual influences at the output of the second intermediate point.

Claims (1)

SUMMARY OF THE INVENTION Pulse Signal Transmission Method along a communication line containing intermediate points, in which at all intermediate points the information sequence signals are amplified, characterized in that, in order to increase protection against intersymbol interference, at each intermediate point the polarity of every second pulse of the information sequence is changed.