DE1182712B - Tuning unit for overlay receivers to receive very short electromagnetic waves - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENTAiVlT

DISPLAY

Boarding school Kl .: H 03 h;

German class: 21 a4 - 69 "

Number. 1182712,

File number: T 24354IX d / 21 a4

Filing date:, 24; for 1963

Open date: December 3, 1964

The invention relates to a tuning unit for heterodyne receivers for reception very short electromagnetic waves (decimeter wave range), which contains at least one λ / 2-pot circle, which is determined by the tube or switching capacitance and is geometrically shortened by the tuning capacitor and at the points of the inner conductor, at which the voltage node is formed at the lowest or highest tuning frequency, depending a trimmer capacitor is connected.

The voting units mentioned, which are preferably used in television sets, are different possibilities have already become known to connect the individual pot circles with one another or to couple the pot circle with the following mixer. These arrangements became more special It is important that the coupling takes place in such a way that as little bandwidth change as possible during the Voting arises. As is well known, the 'voltage node or current bulb moves capacitively tunable A / 2-pot circle along the inner conductor, so that the coupling factor and thus the Bandwidth depends on the frequency set in each case.

Voting unit for overlay receivers
for receiving very short electromagnetic waves

Applicant::

Telefunken patent collecting company
mb H., Ulm / Danube, Elisabethenstr. 3

Named as inventor:

Dipl.-Ing. Hans Qcker, Ulm / Danube

According to the invention this is achieved in that in the Absiimineinäbeat described at the beginning required coupling element for coupling the next cup circle or the mixer between the one trimmer capacitor and the tuning capacitor or between the tube-side end d d d Tikd

To avoid this disadvantageous phenomenon 35 of the inner conductor and the other trimmer condenser, a two-point coupling is already used. sator is arranged.
This arrangement allows the coupling of the
Circles individually set, but the balance is

very difficult in series production and requires one

This should be done in the will be explained in more detail below.

In Fig. 1 is a large amount of time according to the invention. 30 built AbstkameMteit shown It consists of Furthermore, one already has an inductive coupling z ^ i X / 2 cup circles coupled to one another. Of the for 2/2 pot circles made so that the heads - - - - ■ - - ■ · - - - - - - - - ·

pelschleife is designed and arranged such that

g is the belly of current migrating along the inner conductor

The end is geometrically shortened by the separator A1. The pot circle Tl is coupled with a further pot circle Γ 2. This second, quick-acting cup circle is labeled "T 1. It has an inner conductor II on which two trimmer condensers 2> 11 and Tr 12 are closed off. The cup circle

over the entire adjustable frequency range of _{35 wu} - (j ^ its tube-side end E is covered by the loop surface Adjustment of the series produced! Voting units of a large _

Time required by bending the coupling · »40 circle Γ 2" also has "an inner conductor 12, the loop to achieve the desired coupling factor: ', at one end with a tuning capacitor-The also known band filter coupling is connected with the aid of A 2 . 7V21 and 7V22 denote two trimmer capacitors from punched-out slots in the common. The erfor partition of the two A / 2-cavity resonators have the disadvantage derliche coupling element K, which is, for example be in the exemplary part that no individual coupling possibility overall 45 for coupling the second cavity resonator Tl, so that the optimum power amplification to the first cavity resonator Tl is used, is in the case of such a tuning unit (UHF tuner) not created embodiment can be reached by an adjustable one. Realized condenser, which through an opening in

The aim of the invention is therefore to show a coupling of the common wall W of the two cup circles, which is passed through while maintaining the shape. According to the invention, the connection points of the coupled electrical values of the elements K described above lie between the disadvantages avoided. . corresponding trimmer capacitors TrIl resp.

409 730/251

YY3Ü

Tr 21 and the tube-side ends E of the two inner conductors / 1 and 12, respectively.

Instead of the embodiment shown in the figure, the coupling element K can also be implemented by a coupling loop. It is also possible to form the coupling element through a correspondingly dimensioned opening in the common wall W of the two pot circles T1 and T2. If the tuning unit consists of a cup circle with a downstream mixer, the mixer can be connected to the A / 2 cup circle in the same way.

In Fig. 2, the voltage distribution of a capacitively tunable 2/2 pot circle is shown. Here, two pronounced voltage profiles were recorded along the inner conductor 71. The solid curve represents the voltage profile at the lower adjustable frequency limit f _u . It can be seen that a voltage node results for this frequency at point α. The dashed line ao represents the voltage curve at the highest adjustable frequency f _{0 of} the tuning unit. The voltage node occurs here in point &. In the tuning units used so far, a trimmer capacitor is connected to the inner conductor at points α and b. The trimmer capacitor TrIl of the first pot circle Tl of FIG. 1 is used to define the lower end of the frequency band and is located in the voltage node of the upper end of the frequency band. In an analogous manner, the trimmer capacitor Tr 12 is used to determine the upper end of the frequency band of the tuning range of the tuning unit; it is located in the voltage node of the lower limit frequency / ". The voltage distribution along the inner conductor / 1 also continues outside the area limits indicated by points α and b. Since, according to the invention, the coupling element is arranged between the trimmer capacitors arranged at points α and b and the tube-side end E of the inner conductor or the tuning capacitor, the migration of the voltage node during the tuning process has only an insignificant effect on the coupling factor. The reason for this is to be found in the fact that the pot circle is greatly shortened on both ends by the capacitive load on the part of the tube or the tuning capacitor. If the required coupling element is thus arranged between points b and c or α and d , one can get along with inductive coupling with such a small coupling loop that this coupling loop can be adjusted in a very short time. Since the shortening of the pot circle at the tube end is greater than at the opposite end, where the tuning capacitor is located, it is particularly expedient to provide the coupling element at the tube end between "points α and d" .

If a very firm head voltage is required, it is advisable to connect the coupling element directly to the ends d or c of the inner conductor II. -

The design of the coupling according to the invention eliminates the disadvantages outlined at the beginning in the serial adjustment of voting units for superimposition receivers to reception very short electromagnetic waves avoided.

Claims (5)

Patent claims: 1. Tuning unit for superimposition receivers to receive very short electromagnetic waves (decimeter wave range), which contains at least one A / 2 drip circle, which is geometrically shortened by the tube or switching capacitance and by the tuning capacitor and at the points of the inner conductor which the voltage node forms at the lowest or highest tuning frequency, a trimmer capacitor is connected, characterized in that the required coupling element (K) for coupling the next pot circle or the mixer between the one trimmer capacitor (Tr 12) and the tuning capacitor ( A 1) or between the tube-side end (E) of the inner conductor and the other trimmer capacitor (TrIl) is arranged. 2. voting unit according to claim 1, characterized in that the coupling element through a coupling loop is formed. 3. voting unit according to claim 1, characterized in that the coupling element through a correspondingly dimensioned opening is formed. 4. Tuning unit according to claim 1, characterized in that the coupling element (K) is an adjustable capacitor connected between the trimmer capacitor (TrIl) serving to adjust the upper end of the tuning range and the tube-side end (E) of the inner conductor (/ 1) is. 5. voting unit according to claim 1 with maximum fixed coupling, characterized in that the coupling element is connected to the ends (d or c) of the inner conductor (/ 1). Documents considered: German Auslegeschrift No. 1100 723; "Funk-Technik", No. 24/1962, p. 815. 1 sheet of drawings 409 730/251 11.64 Q Bundesdruckerei Berlin