DE1804966C3 - High-pass filter designed in the manner of a quadrupole for electrical oscillations - Google Patents

Description

U ₁ = U ₂

L ₁ + L ₁

L ₁ = U ₂ U ₁ L ₁ =

U + L ₂

(L ₁ + L ₂ ),

/ _ (^ i + L ₂ ) L ₃ ^ - L ₁₊ L _{2 +} LT

Γ -

—J—

_ L ₂ C ₂

(L ₁

U _{2 means} the transmission ratio of the secondary winding (7, 5) of the second transformer (t / 2), U ₃ the transmission ratio of the primary winding (4) to the first secondary winding (S) of the second transformer (U2), u, the transmission ratio of the secondary winding (6) to the primary winding (3) of the first transformer (Ul), L _{1 is} the self-inductance of the secondary winding (6) of the first transformer (U 1), L _{n is} the self-inductance of the first secondary winding (5) of the second transformer (U 2), C is the capacitance of the series capacitor and L ₁ , L ₂ , L ₃ and C ₂ are the inductance or capacitance value of the switching elements of an equivalent π-element whose series branch consists of the coil L ₂ and the capacitor C ₂ and its cross branches the sinks L ₁ and L ₃ are located.

3. HochpaßfiUer according to claim 1 or 2, characterized in that the circuit is balanced to ground is trained.

4. High-pass filter according to one of the preceding claims, characterized in that the second transformer (U 2) is designed as an economy transformer.

5. High-pass filter simulating the previous one Claims, characterized by the mirror image ^ · lichft chain connection of two structurally equal dies The invention relates to a four-poise type

ZO designed high-pass filter for electrical oscillations, the input terminals of which are connected to one another via the series connection of the primary windings of two transformers.
So-called high-pass filters are required for many applications of electrical circuit technology, ie filters that dampen electrical vibrations below a certain limit frequency with a predetermined damping, while electrical vibrations whose frequency is above this limit frequency should be allowed to pass with as little attenuation as possible. As is well known, the frequency range below the cutoff frequency is called the stop band and the frequency range above the cutoff frequency is called the

Passband of the high-pass filter. To set up such high-pass filters, it is known that circuits designed as so-called four-pole circuits are used, which in the simplest case consist of a coil in the shunt arm and a capacitor in the series arm of the four-pole circuit. Such so-called half-links can be supplemented according to known regulations to form full links, which are then designed in the form of a τι- or a T-circuit. It is often necessary to adjust the damping at a certain

4S in the restricted area as high as possible drift, d. H. thus to generate a pole of attenuation in the attenuation characteristic of the filter. One of the Possibilities for this are to pass through the capacitor lying in the series branch of the circuit Connect a further coil in parallel to form a parallel resonance circuit in such a way that the resonance frequency this parallel resonance circuit is at the desired pole frequency. Such a circuit is in FIG. 1 shown.

The circuit according to FIG. 1 shows a high-pass filter. whose input terminals are labeled 1 and 1 'and whose output terminals are labeled 2 and 2'. The coils L ₁ and L ₃ are located in the shunt arm of the circuit, in the series arm is the parallel resonance circuit consisting of the coil L ₂ and the capacitor C ₂ , the parallel resonance frequency of which, as already mentioned, lies in the blocking range of the damping characteristics be carried out according to known regulations, for example according to the book by Feldtkeller: "Introduction to the filter circuit theory of electrical communications technology", 3rd edition, S. Hirzel Verlag, Stuttgart, 1950.

given design regdn. then one obtains a - * - the so-called wave parameter theory be-high-pass filter. Furthermore, with the [CSSiUIg of the switching elements there is the possibility of preferring according to so-called operating parameter theory. Information about this can be found, for example, in Ca uer's Sembuch: "Theorieder linearen Wechsel- ^, jaaschaltung". Akademische Verlagsgesellschaft flecker & Erler, Leipzig, 1941. If, on the basis of the requirements imposed by the high-pass filter, the frequency sequence at relatively low frequencies must be K <* n »n. for example below 2 kHz, then

'Blessings must, for example below 2 kHz, then ^; It turns out that the capacitor C ₂ must assume a relatively high capacitance value. However, capacitors with such a happy capacitance value are only available with a relatively large tolerance for the capacitance value ^; "We let usually several capacitors in parallel", or must be connected in series to obtain the specified ^J capacitance value. Although it is Möglichkeit.die coil L form ₂ as the transformer, to whose secondary winding a capacitor harbors whose capacitance value a to the Square of the transmission ratio can have a smaller capacitance value, but this circuit has the disadvantage that there are still three coils or two coils and a transformer in the circuit the coils assume relatively large mechanical dimensions, but with a circuit according to FIG. 1, a certain minimum volume of the entire circuit cannot be undershot.

A transformer arrangement has already become known from I SA.-Patentschnft 2 244 001, their entrance terminals via the series connection of the primary windings of two transformers with one another are connected. In this known circuit, however, the object is to be achieved in one as possible large frequency range, a transmission ratio of the transformer arrangement that is as constant as possible to achieve. It is also, for example, from the magazine "Cables et Transmission", 1966. pp. 29 to 35, known. To use transformers in filter circuits.

The invention is based on the object. one Specify Hocepass circuit in which opposite the "n of FIG. 1 still shown can save a coil and at the same time the capacitor lying in the series branch of the circuit Assumes capacitance values, if possible, capacitors with standardized capacitance values and with relatively small tolerances of the capacitance value are available.

Based on a four-pole high-pass filter for electrical oscillations, the input terminals of which are connected in series to the primary windings of two transformers are connected to one another, this object is achieved according to the invention in that the output terminals of the quadrupole via a secondary winding of the second transformer are interconnected that the series connection of the secondary winding of the first transformer with a capacitor and a second secondary winding of the second transformer form a closed circuit and that the The winding direction of the secondary winding of the first transformer is selected such that the voltage induced on this secondary winding is directed in the opposite direction to that on the second secondary winding of the second transformer.

The invention is explained in more detail below with reference to exemplary embodiments.

It shows in the drawing the

F i g. 1 the already explained basic element of a »O controlled high-pass filters that

FIG. 2 shows a high-pass filter basic element according to FIG Invention that

F i g. 3 the chain connection of two earth-synuaetric basic links using an economy transformer, the

F i g. 4 the chain connection of a balanced-to-earth and a basic element unbalanced by the earth.

The circuit according to FIG. 2 shows a four-pole circuit, the input terminals with 1 and Γ and

* 0 whose output terminals with 1 nnri V hfwjrhnrt <άηή

Two transformers U1 and V1 are provided in the circuit, the primary winding of the transformer CI is labeled with the reference number 3 and the primary winding of the transformer U 2 is labeled with the reference number 4. The transformer L ' 1 has the secondary winding 6, the transformer I "2 has the secondary windings 5 and 7. The beginning of each winding is marked with a dot (» «). The self-inductance of the secondary winding 6 of the transformer L" 1 has the Wen L ₁ . the self-inductance of the secondary winding 5 of the transformer t ^? 2 has the value L ₁₁ . The circuit now takes place in such a way that the input terminals 1. Γ of the quadrupole are connected to one another via the primary windings 3 and 4 of the transformers l'l and L'2. Furthermore, the secondary winding 6 of the transformer V 1 and the secondary winding 7 of the transformer i 2 with the interposition of a capacitor C form a self-contained circuit. The output terminals 2, 2 'of the quadrupole are connected to the second secondary winding 5 of the transformer L' 2. When setting up the circuit, care must be taken that the winding direction of the secondary winding 6 of the transformer U 1 is chosen such that the voltage induced on this secondary winding of the primary winding 3 is directed in the opposite direction. ^{to the voltage of the second transformer L -} 2 induced at the second secondary winding 7 from the primary winding 4. This can be done, for example, in the form shown in FIG. 2 by the dots in such a way that the winding starts of windings 6 and 7 are directly connected to one another via capacitor C, whereby at the same time the winding start of the primary winding of transformer U1 is opposite winding 6 at the opposite end, while the winding starts of windings 4 and 7 of the transformer U 2 are at the same end. Of course, other arrangements with regard to the winding direction of the windings 3, 6, 4, 7 are also conceivable, if only care is taken that the voltage induced on the secondary winding 6 is directed in the opposite direction to the voltage induced on the winding 7. The transmission ratio of the transformer Ul is _{denoted by 1 / U 1} , ie the primary winding ig3 must have a number of turns that is smaller by a factor of u than that of the secondary winding 6. If the first secondary winding of the

On carrier U 2 is the normalized number of turns to 1, it has the primary winding 4, the winding number M _3, and the second secondary winding 7, the number of turns of U ^_2; that is, the transformer U 2 has the transmission ratios U ₂ : U ₃ : 1, if you consider it in the order of the windings 7, 4, 5.

As it turns out, the circuit according to FIG. 2 is equivalent to the circuit according to FIG. 2 in terms of its electrical mode of operation. 1, however, it has the advantage that, instead of three coils, only two coils combined to form the transformers U1 and Ul are required, whereby a considerable reduction in the overall volume required for the entire circuit can be achieved. In addition, the capacitor C also receives capacitance values which are considerably smaller than the capacitance value C ₂ in the circuit according to FIG. 1, so that for the capacitor C in the circuit of FIG. 2 readily tangible components with relatively narrow tolerances of their capacitance value are available.

The transmission ratio U ₂ is freely selectable, so that a capacitor can be used in any case, the capacitance value C of which is available in standard components. The optimal dimensioning of the remaining gear ratios and the switching elements of a circuit according to FIG. 2 results when the following relationships are observed:

u, -u ^U + L ₂ L ₂ + L ₃ L ₂ ' L ₂ L ₁ (L ₁ + L ₂ ) ² ■ - U ₂ U ₁ L ₁ L _{1 +} I ■ 2 L ₁ = τ 2 L ₁ Ln L ₂ (L ₁ + L ₂ ) L ₃ C ₂ L ₁ + c U? L ₂ Q

In the above formulas means

U _{2 is} the freely selectable transmission ratio of the secondary windings 7.5 of the second transformer U 2,

U _{3 is} the transformation ratio of the primary winding 4 to the first secondary winding S of the second transformer t / 2,

β, the transmission ratio of the secondary winding 6 to the primary winding 3 of the first transformer l / l,

L _{x is} the self-inductance of the secondary winding 6 of the first transformer U1.

L _{n is} the self-inductance of the first secondary winding S of the second transformer U 2,

C is the capacitance of the series capacitor.

L ₁ , L ₂ and L _{3 are} the inductance values, and C] is the capacitance value for the switching elements in FIG. 1 equivalent branch circuit shown.

The in Fig. The circuit shown in FIG. 2 can also be earthed on one side and thus designed as a circuit that is unbalanced to earth. To do this, it is only necessary to connect the input terminal Γ and the output terminal 2 'directly to one another and to connect the self-contained circuit of the secondary winding 6 of the capacitor C and the secondary winding 7 to the through-connected terminals 1' and T. This possibility of an unbalanced structure is shown by the dashed line connections.

The circuit according to FIG. 2 can also be designed symmetrically to the earth if necessary. For this purpose, only the primary winding 3 of the transformer U 1 needs to be halved and the two halves are switched so that one half is in the position shown in FIG. 2 remains, while the second half in the on the clamp! ' incoming connection line is switched. Of course, all of them are there

ίο Winding parts on the same coil core.

The transformer U1 does not necessarily have to be designed in such a way that the individual windings are separated from one another. Rather, the transformer Ul can also be used as an economy transformer.

»Form 5; it is only necessary to ensure that the transmission ratio of the individual windings which the economy transformer takes on its own values, so that the economy transformer is similar to a transformer with separate windings.

If higher damping requirements have to be met, ie if the basic term according to FIG. 2 generated attenuation is below the specified requirements, then two structurally similar basic links can be connected in a chain, whereby it is only necessary to ensure that the output terminals 2. T of successive links are directly connected to each other, so that the output terminals 2, T the mirror line of the total quadrupole resulting from the chain connection. If the capacitors are given different values, the pole resonance frequencies are also at different frequency points, so that a high-pass filter with two attenuation poles is obtained. Analogously, the chain connection of two basic links according to FIG. 1, in which the capacitors C _{2 have} different values. In the mirror-image chain connection of two structurally similar links according to FIG. 2, in order to save a transformer, the transformers U 2 assigned to the individual links will be combined into a single transformer.

The F i g. 3 shows the mirror-image chain connection of two basic links symmetrical to earth, with the second transformer U1 in each case being at the same time

Saver transformer is formed. As already mentioned in connection with FIG. 2 was explained, the primary winding of the transformer U 1 or U Γ is divided into two halves 3a and 3f> or 3c and 3d , of which one half 3a is in the line going out from the input terminal 1, while the second half 31 »is in the line from the second input terminal Γ. The transformer Ui 'of the second element is designed analogously, so that one half of the winding 3r lies in the line leading to the output terminal 1, while the other half 3d lies in the line leading to the other output terminal 1. The secondary windings 6 and 6 'of the

Trager Ul and Ul 'are of the same type as in the exemplary embodiment in FIG. 2 arranged. The dashed lines assigned to the transformers Ul and Ul 'indicate that the primary windings 3a and 3b or 3c and 3d which are halved are magnetically fixedly coupled to one another. The secondary windings 6 and 6 'are in turn with the interposition of capacitors Cbzw. C ″ connected to one another via a winding of an economy transformer U 2 that acts as a primary winding, so that they each form a self-contained circuit only that here, too, the voltage induced on the secondary windings 6 or 6 'of the transformer U1 or U1' is directed in the opposite direction to the voltage induced by the one winding 8 in the second winding 9 of the economy transformer U 2 It is possible to obtain two attenuation poles in the blocking range at different frequency points even if the two capacitors C and C have the same capacitance values.

If it is important, for example, to switch from a balanced line to a unbalanced line, a balanced and unbalanced basic link can be connected in a chain. A corresponding embodiment is shown in FIG. 4 shown. The basic element containing the input terminals 1, Γ corresponds practically to that in FIG. 2 already explained basic element, only with the slight difference that the primary winding of the transformer U1 is divided into two halves 3 ″ and 3b and connected in such a way that - as in the exemplary embodiment of FIG. 3 - an erusymmetric link is created. The remaining

«O Individual components of the circuit are identical Reference numbers as in FIG. 2 provided. The base member containing the output terminals 1 and Γ is Designed to be unbalanced to earth and thus completely similar to the circuit according to FIG. 2 built. The those Output terminals 2 and 2 'of the individual basic links containing transformers are labeled U2 and U2' designated. The chain connection must now be carried out in such a way that the output terminals 2, 2 'contain Windings 5 of each basic link are connected to one another, as indicated by the dashed line registered lines 10 is identified. Similar to the embodiment of FIG. 3 can also be used in the embodiment of FIG. 4 the two transmitters U 2 and U 2 'into a single one Combine the transformers so that the windings associated with the transformers U 2 and U 2 ' are applied to a common magnetic core. If necessary, this common Train the transferor as a savings transferor as well

1 sheet of drawings

S09 618/9

Claims (1)

1 804 9S6 Patent claims: 1. In the manner of a four-pole high-pass filter for electrical oscillations, the input terminals of which are connected to one another via the series connection of the primary windings of two transformers, characterized in that the output terminals (2, T) of the four-pole via a secondary winding (5) of the second transformer (1 / 2) are connected to each other so that the series connection of the secondary winding (6) of the first transformer ~ {UI) with a capacitor {Q and a second secondary winding (7) of the second transformer form a closed circuit and that the winding direction of the secondary winding (6) of the first transformer (U 1) is selected such that the voltage induced on this secondary winding is opposite to that on the second secondary winding (7) of the second transformer (t / 2). 2. High-pass filter according to claim 1, characterized by the following dimensioning of the switching elements like basic links with the output terminals (2, T) of the four-pole as a mirror line. 6, cooking pass filter according to one of claims 1 to 4, characterized by the chain connection of a balanced-to-earth and unbalanced-to-earth basic link in such a way that the secondary windings (S) of the individual basic links connecting the output terminals (2, T) are connected to one another. 7. HochpaßfiUer according to claim 5 or 6, characterized in that ■ the transformer (U2, U2 ') connecting the output terminals (2, T) of the basic members are combined into a single transformer.