DE366910C - Circuit arrangement for telephony with undamped oscillations - Google Patents

Description

GERMAN EMPIRE

ISSUED JANUARY 13, 1923

REICH PATENT OFFICE

PATENT LETTERING

CLASS 21 a GROUP 25

(D 38057 VIII'12

Deutsche Telephonwerke G. m. B. H. in Berlin.

Circuit arrangement for telephony with undamped oscillations.

Patented in the German Empire on July 23, 1920.

The invention relates to an arrangement for high-frequency telephony on lines, wherein to avoid influencing neighboring lines during quiet speech and for reporting accidental interference, multiple traffic on the line entering the Radiofrequency energy going overhead is usually compensated so that none Wave in the line flows, and the line only becomes live when the microphone

is put into use. In particular, the compensation is with the help of a capacitive one Coupling of the long-distance line carried out in such a way that the long-distance line through at least four capacitors are coupled so that there are no coils involved in the circuits of the Frequency sources belong to Hegen between the branches of the line. The type of high frequency generation is arbitrary, and it can ίο either two high frequency sources or one such source can be used in combination with one or two cathode tubes.

The capacitors used for capacitive coupling are advantageously paired in of the known type combined into a variable capacitor, the four plate systems of which (two fixed, two movable) overlap each other.

The invention is illustrated in some embodiments in the drawing.

In Fig. I, the two high-frequency sources A, B are each connected to the long-distance line F via a pair of capacitors K ₁ , K _% and K ₃ , K _i , and indeed the capacitors are balanced in such a way that no high-frequency energy passes into the line F. . The transformer t, which couples the microphone circuit m, β, is located in the circuit of one source A. As soon as someone speaks into the microphone, the compensation is disturbed and high-frequency energy flows in the rhythm of the speech currents into the line F. Fig. 2 shows the same arrangement as Fig. 1 with the difference that the capacitors K ₁ , K ₂ form a variable capacitor DK ₁ and also the capacitors K _s , K _{4 are combined} to form a variable capacitor DK ₂ . This makes the adjustment easier.

In Fig. 3 only one high-frequency source A is provided, which, however, feeds _{two identical cathode tubes B 1} , R _2. The anodes of the tubes are marked with a, the hot cathodes with k, their heating batteries with b and the grids with g . The source A feeds both grid circuits, while the anode circuits are each coupled and compensated by a variable capacitor of the type shown in Fig. 2 with the long-distance line ^. The high resistors W ₁ , W _{2 are} provided so that the capacitors can discharge properly. The microphone transmitter t is located in the anode circuit of the tube R _1. In Fig. 4 only a cathode tube R is used as an aid. The high frequency power source A supplies here inductively firstly immediately above the variable capacitor DK _1, the pipeline F, and secondly the grid circuit of the tube R, which is matched by the oscillation circuit 5 to the source A. The tube for its part supplies high frequency from its anode circuit into the long-distance line F via a second variable capacitor Z) i £ ₂ . However, both energies are compensated. The microphone transmitter t , which disrupts this compensation and thereby causes the speech currents in the line F, is arranged in the anode circuit.

In general, the microphone transmitter t can be in one or the other compensation circuit; The microphone circuit can also be coupled to both compensation circuits at the same time in such a way that it acts on them in the opposite sense, thereby doubling the disturbance that has been caused and producing a stronger effect in the long-distance line.

Claims (4)

Patent Claims: 1. Circuit arrangement for telephony with undamped oscillations, characterized in that two sources (A, B) of high-frequency oscillations are capacitively connected by at least four capacitors to the long-distance line (F) in such a way that they compensate each other, but speech transmission comes about when the Coupling circuit of one or the other source or both at the same time can be influenced in the opposite sense by the microphone circuit (m) . 2. Circuit arrangement according to claim 1, characterized in that the compensation capacitors (DK) are designed in pairs as rotary capacitors with four overlapping plate systems. 3. Circuit arrangement according to claim 1 and 2, characterized in that only one source of the high-frequency oscillations is provided and _{feeds two coordinated cathode tubes (A 1} , R ₂ ) whose grid or anode circuits are capacitively compensated according to claim 1 and influenced differently by the microphone circuit are (Fig. 3). 4. Circuit arrangement according to claim 1 to 3, characterized in that only one source of high-frequency oscillation is provided, which firstly directly feeds the long-distance line (F) via a compensation capacitor (DK) and secondly a cathode tube (R) , which in turn feeds waves into the long-distance line (F) transmits via a compensation capacitor (DK ₂ ) , whereby the mutual influence on the long-distance line is compensated when the speech is quiet (Fig. 4). 1 sheet of drawings.