SU48900A1 - Electric filter - Google Patents

Description

The present invention relates to an electrical filter.

In this filter, the elements are connected in an F-shaped pattern, and their values are chosen so that the filter has the same attenuation and the same phase constant as the known links of the “constant k” type, and the characteristic impedance would be the same as known filters such as t.

In FIG. 1 and 2 depict the proposed filter in two versions; FIG. 3 and 4 well-known filters, the so-called ladder type (see T. Shi, “Four-port networks and filters. Moscow. Svizkhizdat. 1934, p. 139). To accomplish the above task in the proposed filter, the first element of the sequential branch scheme

has resistance-4-Zj, the second element of the same branch has resistance

2fi

-7t- Zi first element to the left

The branch has a resistance (2 - p) Zg, the second element of this branch has series-connected co), 2l (2Z, (FIG. 1).

rifle

4 (1 - l) 1 - In case of replacement of the containers used in the filter of FIG. 1, self-induction parallel connections are replaced by series (Fig. 2) and vice versa.

Using methods for determining the parameters of quadrupoles developed by E. V. Zelkh in the work. Parameters of quadrupoles most frequently encountered in electrical engineering (see Scientific and Technical Collection of the Leningrad Electrotechnical Institute of Communications, MB b, 1934, Table X,. The four polar. No. 22), it can be found that the circuits of FIG. 1 and 2 are symmetrical quadrupoles, with the constant transmission being expressed for both schemes in the same way:

  Arch (l +). . . (one)

and the characteristic impedance is expressed as:

AZj-Zai / l

+ -2 4Z,

1 + «- 4Z2

(2)

Zt

Zi

1-f n

4Z,

for the circuit of FIG. 1 and in the form:

г „(1 +„ А). ... (3)

For the circuit of FIG. 2, where ZT and Zn respectively denote the characteristic impedances of the circuits of FIG. 3 and 4:

L / Z, Z,

-2t

4Z ,,

 g-.

I / 1+

4Z,

Here, Zi and Zg-resistances are the same as in classical filters of the so-called ladder type; n is a constant number.

Equalities (2) and (3) completely coincide with the expressions for the wave impedance of type t filters invented by Zobel (see the cited book of Shea, p. 194 and 197), if you count:

pt

Thus, the new filter has the same attenuation and the same phase constant as the links of the circuits P and T (Fig. 3 and 4), while its wave resistance has the properties of the wave resistances of type m filters.

At the same time, the new filter completely coincides in properties with the so-called .double filters, recently described donuts (see Matrumae and. Matrumoto, Elektr. Nachricht Technik. No. 5, 1934 or also T. Laurent Ericsson Technics No. 5, 1934 ).

However, the proposed filters contain a smaller number of elements and therefore are superior to double filters with their economy.

The proposed filter can be successfully applied where constant wave impedance is required in a certain frequency range. At the same time, if you use an element of a Tobele link of type t or mm, etc., as a T and P, then the new filter will have an impedance of the type mm, ttt, etc. —Id along this path, you can get a filter whose impedance in the passband will be arbitrarily close to a constant value.

The new filter has a better phase response than the T type filter (see Laurenta job), which is of great importance for the filter operation in the setting mode.

Therefore, it can usefully be applied:

1) in intermediate amplifiers, where due to the fact that the number of amplifiers connected in series is large, the effects of the installation may become noticeable, for example, with automatic dialing of a far subscriber;

2) in instruments for measuring the amplification of translation (see the author's certificate of E. V. Zelkh No. 27953, class 21z,

41);

3) in the transmission of images and artistic broadcasting;

4) in devices for frequency wiring and transmission of pulses, etc.

The subject matter of the invention.

Claims (1)

1. An electrical filter, characterized in that its elements are connected in an F-shaped pattern, and their values are chosen so that the filter has the same attenuation and the same phase constant as the constant A link, the same as for filters, for which the first element on the left of the sequential branch has resistance - Zj, where p is any fraction; the second element of the same branch has resistance 2-- / g - Zi, and the first element on the left is paral2i A branch has resistance (2 - n) Zj, while the second element of the same branch has / ((2 -)) „in series. 2 p g all resistances, and Z ,. 4 (L-n) 1- 2. The filter change according to claim 1, wherein the capacitances are replaced by self-induction, and the parallel connection is serial and vice versa. to the author's testimony of E, V. Zel ha and M. G. Zimbalisti № 48900 2 figs d, V 7 /  g-1g-o-i - Т Ч-СЭf /, kd   - figo I, CD .P “R. FIG. four and ji.