DE1591017C3 - Broadband line transmitter - Google Patents

Description

ÜR -

(A)

35

is met within an approved error limit for Ur .

d) The characteristic impedance Z between any two adjacent individual conductors of the lines, all of which are arranged side by side or one above the other, is the same and is calculated according to the equation:

2 = R _F -

S-M

45

or

S-M

(B, C)

measured.

e) The connections of the output (3, 4) of the transformer must be connected to taps (11, 12) of the winding in such a way that one is at the center of the turn (M - k) and the other at the center of the turn (Sk ) , where k is any integer from zero to ^ ₀ (M- 1).

If high-frequency devices are to be connected to one another, their output or input resistance does not match, broadband matching transformers are used. Is it very much High frequencies, for example around television frequencies, are lines with certain wave impedances used as a transformer; NTZ, 1966, pages 527-538.

Known line transformers usually have a transformation ratio of 1: 1 or 4: 1, the through Double cables of a certain length and wave resistance, each consisting of two individual conductors is realized. For example, you can connect two double lines at the input of the transformer in series Connect the output in series and at least one double line through a ferromagnetic core to lead; this gives a 4: 1 transformer; NTZ, 1966, p. 533.

Furthermore, it has been proposed to achieve transformation ratios other than 4: 1 several the transformer just described, each consisting of two double lines, in parallel and / or in series switch; NTZ, 1966, page 535, section 5. However, this inevitably creates joints and shunt paths, which severely impair the functioning of these facilities. Plus are the effort and the space required is too large.

The invention is based on the object of creating a broadband line transformer, of which Dimensioning and production with arbitrarily selectable, i.e. also uneven transformation ratio is as simple as possible.

According to the invention, this object is achieved in a line transformer of the type mentioned in that the line transformer has two lines, each containing a number exceeding 2, of individual conductors, one of which is led through a ferromagnetic core and, in order to form an arbitrarily selectable transformation ratio the other runs outside the core, and that the S individual conductors of the lines are formed in that a conductor with 5 turns isolated from one another, one above the other or adjacent turns is continuously wound on the ferromagnetic toroidal core, the beginning and the end of this winding being the connections for are the input of the transmitter, and that the following relationships apply:

a) The sum of all currents in the 5 individual conductors of each of the two lines must be zero.

b) In M individual conductors of one line the currents Im must flow in one direction and in M individual conductors of the other line in the opposite direction, while in the remaining (S - M) = N individual conductors of each line the currents In the currents In the same line are opposite.

c) 5 and M are chosen according to the given ratio Ur of the transformation of the resistances so that the relation:

The invention relates to a broadband line transformer that has an input resistance /? _{t transformed} to an output resistance R,% .

Oη + I'Cf R Oo - 1

is fulfilled within an approved error limit for Ür.

d) The wave resistance Z between each /.v/ei adjacent to each other or one above the other

the arranged individual conductors of the lines is the same and is calculated according to the equation:

or

Z = R ,. _:

Z * - H.,

S-M

The relation (, 4JiSt can be derived from the fact that the following

S - M '

Equations apply:

(B, C)

measured.

e) The connections of the output of the transformer must be connected to the winding taps in such a way that one is at the center of the turn (M - k) and the other at the center of the turn (S - k) , where k is any whole Number from zero to (M- 1).
The broadband line transformer according to the invention has the advantage that it can be designed for any transformation ratio.

Embodiments of the invention are shown in more detail in the drawing using several winding schemes explained. The drawing shows in

F i g. 1 a winding diagram of a transformer with three Single conductors for a transformation ratio of 9: 1,

F i g. 2 a winding diagram of a transformer with four individual conductors for a transformation ratio of 1.8: 1,

F i g. 3 and 4 each have a winding scheme for a transformer with seven individual conductors for a transformation ratio of 3: 1 or 2: 1 and

F i g. 5 shows an angle diagram according to FIG. 2, in which all wave resistances between the individual conductors are drawn are.

If you need a broadband line transformer for a certain task with the ratio Ür of the transformation of the input resistance Re to the output resistance Ra, the number of individual conductors per line can be calculated as follows:

Ü _R

determine. M denotes the number of those individual conductors in which, according to F i g. 1 to 4 of the current Im flows, and this current is identical to the current flowing at the input terminals, for example, at 1 and 2 of the transformer of Fig. 1 Ie-SM = Λ / represents the number of the separate conductors in which the current I _n flows.

For example, for Ür = 9 the ratio S: M = 3: 2 and from this S = 3 individual conductors, M = 2 individual conductors and N = 1 individual conductors. The ratio S: M = 3: 2 could also be achieved with higher numbers for Sund M ; however, it would be inexpedient to do so. From the winding diagram of a transformer with 3 individual conductors (Fig. 1) it can be seen without further ado that, according to condition (A), the sum of all currents of each of the three individual conductors 5,6,7 or 8, 9, 10 line 14 or 15 is equal to zero because in the upper line 14 the two conductors 5, 6 each carry a current Im flowing from left to right and because in the conductor 7 a current 2 Im is called from right to left. The origin of the size of the individual streams was already discussed above.

S-M

This results in:

It

= u _R =

This results in the quadratic equation: 0 = (S ² - 2MS + M ²

If one regards 5 as the only unknown, the solution is:

= - ^ - \ m ± M I / I - _ «iLZ_L]" R - 1 L V ü _R J

and it

- 1

(A)

It will now be demonstrated with reference to FIG. 1, that in choosing the number of turns 5, M according to the relation (A) azs, ÜR ratio of input resistance /? F of the line transformer to the output resistor Ra has the required value. As in the case of transformers with coil windings, the ratio of the voltages ü _{u is} equal to the square root of ür or, conversely, ür is equal to the square of ü "-

According to relationship (A), with a required ratio ür - 9, the values for 5 = 3 and for M = 2 are determined, from which N = 1 results. Furthermore, according to the winding scheme proposed above, the arrangement of the line transformer is assumed in accordance with FIG. 1 executed.

If, according to the above-mentioned rule for the arrangement of the tapping points, one takes k -Ό as an arbitrarily selectable number, then one tap 12 of the winding consisting of three continuous turns (S = 3 and M = 2) of the line transformer is in the middle of the (M - k} -len, i.e. the second turn, and the other tap 11 in the middle of the (S - &) - th, i.e. the third turn. Choosing k - 0 is useful, as will be shown later 1 to 4, the windings, each starting at the input terminals 1, 29, 46, are viewed continuously in a clockwise direction.

Between two input terminals 1, 2 of the line transformer of FIG. 1 there is a high-frequency voltage Ue. This voltage is the sum of partial voltages Ui plus U2 or Uj plus L / 4. It can be assumed that between any two immediately adjacent individual conductors, e.g. B. between the conductors 5,6 or

Ιό

017

6, 7, an individual voltage that is always the same due to the characteristic impedance Z of the two conductors Height and that between two separate conductors by another conductor, e.g. B. between the conductors 5,

7, both a characteristic impedance of 2Z and, as a result, a voltage that is twice as high as that between two directly adjacent conductors. The partial voltage U \ has the value of 2/3 Ue and the partial voltage £ /? the value of 1/3 Uf. The short, transverse conductor 16 switches Ui and U2 in series. From Fig. 1 it can be seen that the voltage U _A = U% = 1/3 Ue'isl The ratio of the voltages Ue to Ua is therefore 3: 1. This results in ür = 9: 1, because ür = (ü _u ) ² . This proves that the required value for ür is achieved by a line transformer of FIG.

If, for example, one assumes the values R _A = 60 Ω and Ua = 1.8 V for this line transformer with ür = 9, the values Re = 540 Ω and Ue = 5.4 V result from the given relationships, from which one can derive the at the Input terminals 1, 2 of the transformer determined the current flowing with Ie = 0.01 amps and the current flowing at the output terminals 3, 4 with Ia = 0.03 amps. While from the winding scheme of FIG. 1 without further ado results in Im = Ie = 0.01 amperes, one must apply Kirchhoff's law to the calculation of the other currents for the tapping points 11, 12 and obtain the outflowing current Ia = 0.03 amperes as the sum of the inflowing currents for point 12 Im = 0.01 amps (from the individual conductor 6) plus In from the individual conductor 9. So In must be 0.02 amps. As a result, In = 2 Im and, taking into account the current directions, the sum of both the currents in the conductors 5, 6, 7 of the upper line 14 and the sum of the currents in the conductors 8, 9, 10 of the lower line 15 are both equal to zero. One can easily convince oneself that Kirchhoff's law is also fulfilled for tapping point 11.

The wave resistance Z between two immediately adjacent individual conductors, e.g. B. between 5.6 or 6, 7, for the winding diagram of FIG. 1 with ür = 9, 180 Ω can be determined further above from equation (B). If a cable is connected as the output resistance R _A , its wave resistance must be 60 Ω.

The upper, consisting of the three individual conductors 5, 6, 7 line 14 is through the opening of a ferromagnetic toroidal core 13 out, which is indicated in Fig. 1 with dashed lines.

A similar procedure can be used for a line transformer with a required ratio of ü _R = 1.8 (FIG. 2). From relation (A) we get:

ÜR +

Ür - 1

1.8 + 1.34
0.8

3.93

of these are L ^ and Ub, where £ / 5 = 1/4 Ur and Ub = 3/4 Ui . Next follows

Ua = U _b = 3/4 U /. and from this ü " = Ue: U _A = 4: 3.

Finally ür = U ₁ ? = (4: 3) ² = 1.78, which corresponds to the numerical value 1.8 of the requirement with sufficient approximation. The wave resistance is calculated according to equation (C) to Z = 80 Ω, assuming R _A to be 60 Ω.

If, for example, a line transformer is also required for Or = 3, the relationship (A) results:

One can

S = 4, M = 1 and / V = S - M = 3

Select. The magnitude of the currents Im and In in mutual comparison is shown in FIG. 2 entered, and the sum of the currents for each line is zero. Kirchhoff's law also applies to the tapping points 17, 18. The high-frequency voltage Ue at the input terminals is divided into several partial voltages within the lines 20, 21, each consisting of four individual conductors; two partial voltages cn 3 + 1.73

2.36

Or- 1

Since the number of individual conductors must of course be an integer, the fraction -V- must be expanded so that

at least an approximate whole number appears in its counter. This is the case with an extension of the

7 08
Fraction with 3 is the case, namely with -V-. Thus results

(with an error of approx. 1%) S = 7, M = 3 and N = A. The error limit mentioned should be entirely permissible.

The magnitude of the currents Im and / yvais comparative values and the winding scheme are entered in FIG. 3 (LIr = 3). One can easily see that the sum of the currents of each line consisting of seven individual conductors is equal to zero and that Kirchhoff's law applies to the two tapping points 38, 39. Two partial voltages of the high-frequency voltage Ue effective at the input terminals 40, 41 are U ₁ and Ug, where

V-, = -y- U _E

= ^ T Ve

is. The other partial voltages are not shown. Others, on the output terminals 42-43 is identical to

4th
Us, that means = - = - Ue- It follows from this

U _i :: U _A = -L.

and thus ü _R = ü \ - approximately 3.

According to equation (C), the characteristic impedance Z results in 105 Ω when R _A = 60 Ω.

Finally, if ür = 2 is required, the relationship (A) can be used to calculate:

- 1

2 + 1.414
1

3.414

6.828

= approx.

S = 7, M = 2, N = 5.

The magnitude of the currents Im as well as // vals comparative magnitudes and the winding scheme are entered in Fig. 4. The SIimmc of the currents of each out of seven

Line is zero, and Kirchhoff's law is fulfilled for the two tapping points 44, 45. The high-frequency voltage Ue at the input terminals 46, 47 can be composed of two partial voltages Ug and t / 10, the voltage Ua at the output terminals 48, 49 being identical to t / 10 and y being Ue . This results in

UU ü

and thus ü _R - ü ² _u = approximately 2.

The characteristic impedance Z is calculated according to equation (C) as = 84QJHtRa = 60 Ω inserted.

In the winding schemes of FIGS. 1 to 4, the above-mentioned rule for the arrangement of the tapping points was applied in such a way that k was taken as zero as an arbitrarily selectable number. This resulted, for example, in the winding diagram in FIG. 3 with S = 7 and M = 3, that one tapping point 39 is in the middle of the (M - k} th, i.e. the third turn, and the other tapping point 38 is in the middle of the (S - A) th, that is, the seventh turn, is of course, one could also choose another integer from 0 to (M-1) for k , that is, besides zero, also 1 or 2. Then the one tapping point 39 would be in the middle of the second or The first turn and the other tapping point 38 lie in the middle of the sixth and fifth turn, respectively, so that the electrical function of the transformer is not impaired.

The wave resistance Z between two adjacent individual conductors, for example insulating strips with a metal layer applied on one side, is defined as:

where dielectric constant of the tape's insulating material, d = distance between the two conductors and b = width of the two conductors.

If the wave resistance between two immediately adjacent individual conductors, e.g. B. between the conductors 5, 6 or 6, 7 of Fig. 1, has the value Zl , so should, as assumed above, the characteristic impedance between two conductors separated by another conductor, such as. B. between the conductors 5, 7, twice as large, i.e. equal to 2 Zl. Of course, the distance d between the individual conductors should remain constant. As can be seen from the formula (D), however, Zl will not increase to twice the value if the width b is maintained and twice the value of d is used in the formula (D) as the effective distance between the conductors 5, 7. For example, if d = 0.5 mm and b = 4 mm, the value of the fraction is

d + b

= 0.111.

can come to the latter value for the break if the width b for the third turn is reduced to about 3.5 mm. Correspondingly, with an exact design, the winding would have to have different widths for each turn. Measurements have shown, however, that even if the width of the strip 28 is constant, the error of the size of ür is entirely permissible.

That the ratio ÜR the transformation of the input resistance Re on the output resistor Ra can be calculated from the pressure prevailing between the individual conductors impedances, will be shown for the line transformer of Figure 2, for example. Here ür = 1.8, 5 = 4, M = 1 and N = 3.

In Fi g. 5, all of the wave resistances Z \ to Zn coming between the individual conductors are shown as double arrows of different lengths. _{The wave resistances Zi, Z 6} , Z ₇ , Zn prevailing between two immediately adjacent individual conductors have the value calculated above of Z = 80 Ω each; _{the wave resistances Z 2} , Zs, Z ₈ , Zi ₀ valid between two individual conductors separated by another individual conductor have the value of 2 Z = 160 Ω each and the wave resistances Z3, Zt, Z ₉ to be applied between two individual conductors separated by two other individual conductors, Z _n have the value of 3 Z = 240 Ω each.

At the input of the line transformer of FIG. 5, i.e. between the input terminals 29, 30, the characteristic impedances Zi to Ze are effective, of which a first series connection with Zi = Z and Zt = 3Z, a second series connection with Z2 = 2 Z and Z5 = 2 Z and a third series connection with Z3 = 3 Z and Z% = Z are connected in parallel to one another. Since each series circuit has a resulting characteristic impedance of 4 Z and the three series circuits are connected in parallel, this results in an input resistance

Rezu-j Z.

At the output of the line transformer of FIG. 5, i.e. between the output terminals 31, 32, are the wave resistances Zj to Z12, of which the wave resistances Zg = 3 Z and Z12 = 3 Z are directly effective between the terminals 31, 32, while the wave impedance Z ₇ = Z with Z _t0 = 2 Z form a fourth series connection and the characteristic impedance Zg = 2 Z with Zn = Z form a fifth series connection. Each of these two series circuits has a resulting wave impedance of 3Z, and the two series circuits are both mutually and _{parallel to the two wave resistances Z 9} , Z12 of 3 Z each at the output terminals 31, 32. The output resistance Ra is therefore a parallel connection of four wave resistances of 3Z each, i.e.

R, =

Z.

From this you get

" ^R =

16

Z = 1.78.

When the distance is doubled to d = 1 mm, the fraction is given the value 0.2, while for doubling Zl a value of 0.222 would have to be achieved. The same value could be found above by calculating with the partial voltages Us, Ue in FIG . 2 can be determined.

For this purpose 3 sheets of drawings

709 633/13

Claims (1)

Claim: Broadband line transformer which transforms an input resistance Re to an output resistance Ra , characterized in that the line transformer contains two lines (14, 15) each containing a number of 5 individual conductors (5, 6, 7) in excess of 2 in order to form an arbitrarily selectable transformation ratio ), one of which is led through a ferromagnetic core (13) and the other runs outside the core, and that the 5 individual conductors (5, 8) of the lines are formed by a conductor (28, 36) starting with S. isolated from one another, one above the other or adjacent turns is continuously wound on the ferromagnetic toroidal core, the beginning and the end of this winding being the connections (1 and 2) for the input of the transformer (26), and that the following relationships apply: a) The sum of all currents in the 5 individual conductors of each of the two lines must be zero. b) In M individual conductors of one line the currents Im must flow in one direction and in M individual conductors of the other line in the opposite direction, while in the remaining (SM) = N individual conductors of each line the currents In the currents / « the same line are opposite. c) 5 and M are chosen according to the given ratio Ur of the transformation of the resistances so that the relation: