DE1088564B - Panel to compensate for crosstalk in symmetrical telecommunication lines, especially for carrier frequency operation in the range of 550 kHZ - Google Patents

Description

GERMAN

The invention relates to a panel for balancing crosstalk in symmetrical communication lines, especially for carrier frequency operation in the range around 550 kHz, which requires wiring from right angles contains crossed wires, has changeable compensation elements, their additional operating capacity (»/ ^ - capacity) is kept small and in which the compensation elements as evenly as possible are distributed over the line pairs to be compensated. These panels are usually either only for fine and post-adjustment or for concentrated two-point or one-point adjustment used (as so-called compensation panels). It is known for this purpose variable differential or also To use single capacitors, arranged according to a certain scheme on a circuit board and with the cores of the telecommunication cable to be compensated through two perpendicularly intersecting, in parallel Planar groups of parallel wires are connected. But it is also possible instead, turn on inductive or complex compensating elements. Do you want every double line Can compensate against each other, the arrangement of the compensation elements is in the form of a Triangle close. Since a rectangular shape of the panel surface is spatially more favorable, it has become known transform the triangle shape into a rectangular shape by cutting off the tip of the triangle and is advanced so that a rectangle is created. However, additional jumper wires are required for this; also is the designation of the crossing points no longer uniform. An arrangement is known which avoids these disadvantages. The compensation elements are on the rectangular circuit board based on the distribution of the black and white fields on a chessboard so that on one side of the diagonal only the white fields, on the other side only the black ones Fields corresponding to the fields of the chessboard are equipped with compensating elements. It is also a Compensating panel has become known, which is preferably used for cables that as a result of their Structure requires fewer compensation elements than normally required for decoupling. Be at this the two wire groups of the panel in parallel planes one above the other at an oblique angle to each other. In this case, if one uses the compensation options on the Imviererkouplungen and can limit the coupling to the closest fours, thereby saving space, that the necessary compensation elements occupy a rectangular area, while they are vertical Crossing the wire groups would cover an oblique parallelogram. After another Panel to compensate for crosstalk in symmetrical communication lines,

especially for carrier frequency operation

in the range around 550 kHz

Applicant:

Feiten & Guilleaume Carlswerk

Corporation,
Cologne-Mülheim, Schanzenstr. 24

Dipl.-Ing. Heinz Freytag, Forsbach (Cologne district),
has been named as the inventor

known arrangement, the couplings in

as the wiring itself are avoided that the lines of the panel are particularly similar and symmetrical, with each other are twisted and crossed.

The known compensation devices described have a twofold disadvantage, particularly when used for cables with high carrier frequencies that are above 250 kHz. On the one hand, due to the usual connection of the compensating elements in the known arrangements, the individual line pairs and their wires are unevenly loaded with capacitance in relation to the environment. So there are undesired asymmetries in the compensation panels with respect to the environment or to earth. Although these can be eliminated by adjusting the compensating elements, this reduces the usable control range of the compensating elements. On the other hand, the compensating elements and the wiring create a capacitance between the two wires α and b of a pair (hereinafter referred to as a / & capacitance), which changes the impedance of the line to an undesirable extent, generally in the various line circuits at different heights. This creates joints in the lines at the location of the compensation panel, which, as is known, can generate additional far-end crosstalk in conjunction with the near-end crosstalk, which calls into question the usefulness of the compensation panel, which is supposed to reduce the crosstalk.

009590/281

3 4

Fig. 1 shows the wiring diagram of a cable It is known that a cable with η double wires

known compensation arrangement for a cable with eight - n- (nl) . . .,,.

Pairs 1 to 8, of which each pair must have the cores α and & ^{Ä =} Z ~ compensation elements in order to

contains. Differential - all possible combinations between the capacitors are used as compensation elements. They each have three 5 η double lines to be able to compensate. To these connections on. Since the capacitors are necessary number of A compensation elements belonging two-pole way to the one pair of lines two-pole and to the and A single-pole connections. With ideal distribution, other pairs of lines ^; be connected single-pole on the 2 m wires of the cable result in the ideal must, if there is no special incident per pair

takes precautions, circuit asymmetries. So io 7 _ λ .-, _ /., \\ · ο

ζ. B. to the leads coming from pair no. 8 ^ld ' ^ '

seven differential capacitors two-pole, two-pole connections and each wire

closed and no differential capacitor single pole. ρ = A'2n = (n IV 4

On the other hand, on pair no.3 there are only two differential ^ld '^'

two-pole capacitors and five single-pole 15 single-pole connections, so a total of

closed. But now only the two-pole an- 7 ± ip -, 1 α ^ -λι, «« »
,, 1 ^ -ji · , · 11 j. · 1 ^ id ^^ - ^ id - ⁿ —1 connections,
closed differential capacitors make a noticeable contribution to the a / & capacitance, so that the. Usually η is an even number, so that the calculation α / δ-capacitance of pair No. 8 is considerably higher than that of pair No. 3 because of the above relationships for Z _id '. The same phenomenon gives 20 numbers.

also occurs when, as compensation elements, depending on the will, the deviation from the ideal case to the

two changeable single capacitors used, limit the achievable minimum, so one must

which are connected like differential capacitors. according to the further invention for the practical too

The present invention avoids the two choosing values Z and B, minimum and maximum values

Disadvantages of the known arrangements set at the same time 25. These are those adjacent to Z _id and E _id

and creates a compensation panel, in which the next higher or next lower whole numbers according to the invention,

According to on the one hand, all line pairs to be compensated, expressed mathematically, are therefore the

approximately with the same number (Z _id ) of two-pole maximum values Z _n and E _n between the limits

Connections of the compensation elements is loaded, the ₇ ^ ₇ ^ - ~,.,. j, ^ - -n ^ - -n _i_i

results from the formula Z _id = A: n , and that an- 30 4ä ^ B <* u + l, E _{id =} E _n <E _id + l

on the other hand, the ß- and & -wires of all pairs approximated and the minimum values Z _M , E _M between the limits

with the same number (E _id ) on single-pole connections ₇ 1 <· "7 <7 F 1 <r" F <-p

the compensating elements are connected, which consist of the ^{id l} ^ ^z 'M = ^ id, ^ u ^% ^ ^ u.

Equation E _id - A: 2 η , where A = η for the ideal case of the distribution of the connections

(n-1): 2 in a known way the number of compensation 35 becomes

represents elements that are necessary to produce a z _id = Z _n —Z _M or E _id = E _n = E _M

Cable with η line pairs all possible

Compensate for couplings. One chooses the number of pairs of the cable for

It is easy to see that the requirements for the maximum value on two-pole or single-pole

as even as possible distribution is used by the 40 connections, always in such a way that the

two-pole connections ■ conditional load the mean value formed over the total number of pairs

Pairs and, after distributing the Z and E values as evenly as possible, the ideal values Z _id or

the single-pole connections on all cores of the pairs E _{id comes} as close as possible.

must only be strictly fulfilled if the number of _{those following I m} is supposed to be based on two

Pairs of the cable multiplied by 4 multiplied by 1 45 play are explained in more detail:

is. This applies to five, nine, thirteen, seventeen 1. With a cable with n = 15 pairs this results

etc. pairs. In the case of other pair numbers, one must, since A = 105 for the number of compensating elements. From this

the number of supply lines can only be an integer, follows from the above-mentioned relationships Z _id = 7

certain small deviations from the ideal equal and E _id = 3.5. Z _id is an integer and thus

allow a moderate distribution, but this is feasible in its we- 50. So it becomes the number Z of the bipolar

are negligibly small. Connections for all pairs must be Z = Z _W = 7. E _id da-

Fig. 2 shows an embodiment of the invention. against is not an integer. According to the above

It is assumed there that the cable results from four for the maximum value E _n and the minimum

Star fours or eight double lines 1 to 8, E _{M evaluates} the limits

stands. The two wires of the pairs are marked with α and & 55 u <tp <r "? Iii α ς _ 1 ^ - ρ ^ - <? Σ
designated. The differential capacitors used '- ^H ^'"·"'' ^ ^M = '
are in each case surrounded by their three 'from a circle- This implies E _n = 4; E _M = 3. The number of connection points included is shown. They are so pole connections per wire must be partly three, partly connected to the individual wires of the cable that four. In the present case it does not matter whether the number of two-pole connections of the compensating 60 is carried out for the α-cores of seven pairs, three single-element connections for one half of the line pairs and three-pin connections for the »cores for the other half four and the number of one-eight pairs four single-pole connections or reversible connections with a quarter of the inverted each. The mean of the E _n and .E ^ values from a and & cores is one and in three quarters of the a and both combinations is equally close to the & cores is two. The example chosen represents 65 ideal values.

therefore represents a case in which the ideal DC 2. One cable with n = 14Paaren are ^ i = 91 Ausmäßigkeit can not be fully achieved. equal elements necessary. Z _id corresponds to the number 6.5, and

In general the following rule for the E _id corresponds to the number 3.25. Seven pairs of the cable according to the invention distribution of the connections to the seven, the other seven pairs must indicate six two individual pairs or wires: 70-pin connections of the differential capacitor

keep. The greatest uniformity is achieved if three single-pole connections are made for each wire in the seven pairs with seven two-pole connections, whereas with the seven pairs with six two-pole connections the a and fr wires alternately three and four or four and three single-pole connections allocates.

Variable differential capacitors can be used as compensation elements for a panel according to the invention use, which are known to have three connections. But you can use a differential capacitor in place of each also arrange two changeable single capacitors, which form a differential capacitor are interconnected.

Claims (4)

15 claims: 1.Panel to compensate for crosstalk in symmetrical telecommunication lines, especially for carrier frequency operation in the range around 550 kHz, which contains wiring made of wires crossed at right angles, has variable compensation elements whose additional operating capacity (a / fr capacity) is kept small and in which the Compensating elements are distributed as evenly as possible over the line pairs to be compensated, characterized in that on the one hand all line pairs to be compensated are loaded approximately with the same number (Z _id ) of two-pole connections of the compensating elements, which results from the a ° formula Z, ^ = A: η , and that on the other hand the a and fr wires of all pairs are connected approximately with the same number (E _id ) to single-pole connections of the compensating elements, which results from the equation E _id —A: 2n , where A = η (ft— 1) : 2 represents, in a known manner, the number of compensating elements that are necessary in a cable with % line pair to compensate for all possible couplings. 2. Panel according to claim 1, characterized in that for cables that because of the number of their line pairs an exactly uniform ideal load of the pairs by two-pole connections (Z _id ) and / or an exactly even distribution of the single-pole connections (B _id ) on the a- and fr-cores of the pairs do not allow the maximum values Z _H , E _n and the minimum values Z _M , E _{M of} the two-pole or single-pole connections to differ from the relevant ideal values Z _id , E _{id by} no more than one unit. 3. Panel according to claim 1 or 2, characterized in that the distribution of the maximum and minimum values on the pairs is chosen so 'that the mean value formed over the total number of pairs from the maximum and minimum values corresponds to the ideal values (Z _id or E _id ) comes as close as possible. 4. Panel according to claims 1 to 3, characterized in that the compensating elements from There are two changeable single capacitors each, which are electrical, like a differential capacitor are interconnected. Considered publications:
German patents No. 912 108, 910 678,
812. 1 sheet of drawings © 009 590/281 8.