DE2439432C3 - Hybrid circuit - Google Patents

Description

The invention relates to a hybrid circuit in which a first transformer, each with a winding longitudinally in every wire of a symmetrical two-wire path is switched on and at least one of the two windings has several taps for the variable connection of a symmetrical two-wire line and in the a quadrupole, preferably a second transformer, across the two-wire path at taps of the first Transformer is switched on.

The object of the invention is to create a hybrid circuit which can be connected in a simple manner to several Wave resistance is adaptable and for this purpose occurring earth unbalance within permissible limits is switchable with a minimum of effort.

According to the invention, this object is achieved through the application of the characterizing features of the Claim 1 solved.

A first further development of the hearing lies in the Use with an NLT amplifier (NLT: negative line with transistors) and is characterized by the features of patent application 2.

A quadrupole consisting of negative resistors to reduce anechoic attenuation of a Two-wire line with the negative series resistance via a first transformer lengthways into the line switched on and the negative transverse resistance via a second transformer across the taps of the first transformer is switched on, is also called NLT amplifier in the literature and is from the Publication »Educational Leaflets of the German Federal Post Office«, 1957, No. II-12, pages 149-154 known.

Furthermore, an N LT amplifier of the aforementioned type, in which the first transformer has several taps for the variable connection of the negative shunt resistance (Z \) and / or for the variable connection of the two-wire line, has already been described in DE-AS 23 20 191.

Finally, there is a second development of the

Invention in use as decoupling formwork, in which a pair of terminals of the first transformer from a pair of terminals of the quadrupole, preferably

of the second transformer is decoupled.

The invention is explained in more detail below with reference to the drawing. Here shows

Fig. 1 shows an NLT amplifier according to DT-AS 23 20 191,

2 and 3, known details of the arrangement according to FIG. 1,

4 and 5 simplified representations of NLT amplifiers with different number of turns ratios to explain the problem according to the invention,

F i g. 6 is a simplified representation of an N LT amplifier with a first exemplary embodiment preferred dimensioning of the number of turns ratios, F i g. 7 a decoupling fork as a second embodiment with the dimensioning of the number of turns ratios according to FIG. 6th

The in Fi g. 1 shown NLT amplifier as well as the simplified form in Figures 4 to 6 shown NLT amplifier each comprise for the purpose of uniform distribution of the negative longitudinal resistance - Zi 'on the two wires of two-wire lines to the longitudinal transformer UEI, whose second winding W2 in the one Wire 1-3 and its third winding W3 is switched into the other wire 2-4 of the two-wire line. The negative series resistance —Z \ is connected to the first winding Wi of the series transformer Üi and is determined by the in F i g. 2 realized arrangement. The negative transverse resistance - Ζΐ, which by the arrangement according to F i g. 3 is implemented, is by means of the transverse transformer Ü2 across the taps 11, 12 of the first transformer, the capacitor C preventing the short circuit of the DC voltage between the two wires via the transformer Ü2.

Fig. 2 and Fig.3 each show an arrangement for

Implementation of the negative resistors -Zi 'or - ZJ by means of the negative impedance converter K 1 and K 2 having the adjustable transmission ratio - k]: 1 and - At2: 1. Here, the first converter K 1 with the The impedance Zi simulating the frequency-dependent series resistance of the line and the second converter K 2 with the impedance simulating the frequency-dependent transverse resistance of the line

(15 room completed.

The attenuation of a cable or a two-wire line can, however, be made up of negative by a quadrupole Resistances (NLT amplifier) only approximate

cancel completely if the amplifier is sufficiently adapted to the characteristic impedances of the cables on both sides. When using the N LT amplifier in the middle of a homogeneous cable, adaptation to the wave impedance is also largely possible. However, if the NLT amplifier is used between cables of different diameters and therefore different wave impedances, reflections on both sides of the amplifier occur on both sides of the amplifier even with the best possible setting of the terminating resistors Z \ and Zi or the associated converters Ki and K 2 to the mean value of the two cable wave resistances . These reflections reduce to a considerable extent that permissible gain of the N LT amplifier at which the entire transmission system is still stable. The purpose of the invention is therefore, as already mentioned at the beginning, to make the NLT amplifier or another hybrid circuit adaptable to different wave resistances on both sides.

In DE-AS 23 20 191 it is already proposed for an NLT amplifier for this purpose to provide several taps or taps for the variable connection of the two-wire line at the first transformer Ü \. Such an arrangement is shown in FIG. 1 in detail and FIG. 2 greatly simplified. The left part of the winding W2 has a number η of turns between the connection 1 and the tap ti, as does the left part of the winding W3 between the connection 2 and the tap 12. The two-wire line connected on the right-hand side has the same characteristic impedance as the one connected on the left is connected to connections or taps 3 and 4. A line with a smaller wave impedance is connected to connections 5 and 6, which lead to taps 15 and 16, respectively. The tap 15 divides the right part of the winding W2 into an inner partial winding with the number of turns n - n \ and an outer partial winding with the number of turns nw in total, the number of turns η remains for the entire right part of the winding W2 between the tap 11 and the tap or connection 3 received. In the same way, the tap 16 divides the right part of the winding WZ. By dividing the right-hand parts of the winding W2 and Wi in the aforementioned, symmetrical manner, perfect symmetry with respect to earth is achieved, so that the earth symmetry attenuation a »is very large, which is of great importance because of the guarantee of sufficient interference voltage attenuation.

A disadvantage of the symmetrical arrangement of the taps 3 and 4 on the one hand and the taps 15 and 16 on the other hand represents the fact that two switching or soldering elements are used for switching must be provided.

If the difference between the wave resistances to be switched and / or the requirements for symmetry attenuation are very small, the arrangement according to FIG. 5 can be made use of, in which only the wire from connection 3 has to be moved to connection 5 and the wire of the two-wire line lying at connection 4 remains at this point. The subdivision of the right part of the winding W2 by the tap 15 must be provided here for the purpose of the same wave resistance adjustment as in the arrangement according to FIG. 4 in such a way that the inner partial winding has the number of turns n-2 n and the outer partial winding the number of turns 2 n, have.

The earth symmetry attenuation that occurs is general

where Δη is the difference between the turns for the tip and ring, ie the difference in the effective turns in the right-hand part of the

ίο windings JV2 and W3. If the arrangement according to FIG. 5, the earth symmetry attenuation a is very good when the line is connected to connections 3 and 4 (Δη = 0), but significantly lower when connected to connections 5 and 4 and becomes worse very quickly with increasing adaptation ratios = 2 n \).

The embodiment according to FIG. 6 corresponds to the arrangement according to FIG. 5 with regard to the pure circuit arrangement, but the number of turns of the respective right-hand parts of the windings W2 and W 3 is chosen so that the symmetry-to-earth attenuation is at least 6 dB better with the same ratio of the wave resistances to be switched. In detail, the number of turns in the right part of the winding is W3 between the tap 12 and the tap 4

71 - y "1

The total number of turns of the right part of the winding W2 is

"+ y" i

and is divided up in such a way that between the tap 3 and the tap 15 the number of turns is 2 n \ and between the tap 15 and the tap 11 the number of turns

«- y" 1

is. With this type of division of the windings, the earth symmetry with or without a tap becomes the same, ie it becomes Δη = ± n \. Thus, with the same earth symmetry, the tap can have twice the number of turns of the arrangement according to FIG.

As a generalization of the aforementioned special technical teaching, it can be said in the case of an NLT amplifier that the number of turns between the single tap 4 and the tap 12 of one winding W3 serving to connect the negative transverse resistance is between the two numbers that correspond to the respective number of turns between one of the two taps 3 and 15 of the other winding W2 and the tap 11 of the other winding W2, which is used to connect the negative transverse resistance. This technical teaching can also be applied to decoupling circuits, as shown below with reference to FIG. 7 will be explained in more detail.

7 shows a second embodiment Decoupling fork with the dimensioning of the winding

(, s number ratios according to FIG. 6. A single-directional , outgoing two-wire path is connected to the pair of terminals 21, 22 on the winding W \ of the first transformer Ü \ , and to the pair of terminals 23, 24 the

second winding of the second transformer f7 2 a single-direction, incoming two-wire route. Is now on the pair of terminals 3, 4 or on the Terminal pair 5, 4 connected a double-wire path and the terminal pair 1, 2 with the Replica 25 is completed, the terminal pairs 21, 22 on the one hand and 23, 24 on the other hand decoupled from each other.

With (jabel amplifiers. In which the two transmission directions a double twist can be cntdamped by separate ring amplifiers are two Hybrid circuits according to FIG. 7 with advantage derail can be used that on the pair of clamps3,4 and 5,4 of the the two-wire line can be connected adapted to the respective hybrid circuit.

For this purpose 3 lilatl drawings

Claims (3)

Patent claims: 1. Hybrid circuit in which a first transformer with a winding lengthways in each core of a symmetrical two-wire path is switched on and at least one of the two windings has several taps for the variable connection of a symmetrical two-wire line, and in which a four-pole, preferably a second transformer, is connected across the two-wire path to taps of the first transformer, characterized in that a single tap (4) of one winding (Wd) of the first transformer (Ü 1) for one wire of the line two taps (3, 15) of the other winding (W2) of the first transformer (Üi) is assigned to the other wire of the line and that the number of turns between the single tap (4) and the tap (12) serving to connect the four-pole, preferably the second transformer (Ü2) the one winding (WI) of the first transformer (O 1) lies between the two numbers, the respective number of turns between each of the two Taps (3, 15) of the other winding (W2) and the tap (11) of the other winding (W2) serving to connect the four-pole connection correspond to (F i g. 6). 2. Hybrid circuit according to claim 1, characterized in that for the purpose of anechoic attenuation reduction of the two-wire line to the first transformer (Ü 1) a first device (K 1) for generating a negative series resistance (-Zi ') and to the second transformer ( Ü2) connected quadrupole a second device (K 2) for generating a negative transverse resistance (- ZJ) is connected. 3. Hybrid circuit according to claim 1, characterized by the use as a decoupling circuit in which a pair of clamps (21, 22) of the first transformer (Oi) is decoupled from a pair of clamps (23, 24) of the four-pole, preferably the second transformer (Ü2) (Fig. 7).