US1909751A - Transmitter - Google Patents

Description

May 16, 1933. w. BUSCHBECK TRANSMITTER Filed Feb. 29, 1952 INVENTOR WERNER BUSCHBE BY 5 ATTORNEY Patented May 16, 1933 UNITED STATES FATZEN'T @FFEQE.

SCI-IAFT FUR DR-AHTLOSFZ PORA'IION OF GERMANY TELEGRAa -1 IE 11E. B. H... 035 BERLIN, GERMANY, A COR- TRANSMITTER Application filed February 29, 1932, Serial No. 595,893, and. in Germany Ianuary 9, 1931.

This invention relates to a circuit arrangement adapted. to reduce high-frequency energy losses in plate protective resistances in push-pull transmitters.

The invention will be described by reference to the attached drawing throughout which like reference numerals indicate like parts and in which, Fig. 1 shows a trans mitting circuit in which the novel features of the present invention are included; while Figs. 2, 3 and 4 show modifications of the arrangement of Fig. 1.

It is known from the practical use of water-cooled tubes that inter-tube flashovers are occasionally produced whenever the plate potential is high. In order that the tube may escape damage upon the arising of such fiashover it is necessary to provide means and ways intended to limit the current in the flashover, and this end may be insured by the aid of protective resistances included in the plate circuit. Across these resistances naturally a direct current fall of potential and as a result direct our- 4 rent losses are caused. Losses in radio frequency energy may be diminished to a harmless level by shunting the radio frequency energy around the protective resistances. Thus in a well known manner the radio frequency current flowing by way of the radio frequency choke-coil D (Fig. l) is drained by way of the condenser C2 or by series-connection of C1 and C3 to the filament without passing the resistance. In this scheme C1 shunting the source S must mostly be high compared with C2 and C3.

Such shunting. however. is on the other hand undesirable when it is desired to suppress certain disturbing waves which flow through the direct current electromotive force since in the absence of the radio frequency shunts or lay-passes the plate protection resistances lie inside the said circuit carrying troublesome waves so that the latter are suppressed. In a circuit scheme of the kind shown in Fig. 1 it is, however, not feasible to entirely prevent radio frequency energy losses in the plate protective resistances without radio frecniency shunting.

An arrangement similar to the scheme rent source S around the protective resistances are shunted or bridged. This inconvenience according to the invention may be avoided and at the same time means may be provided for shunting or by-passing the fundamental wave around the resistances by connecting the middle of the two condensers G2 which in this case be combined into a single unit together and disconnecting them from the filament as shown in Fig. 3. What is furtherohtained by this arrangement is a reduction in cost of the condensers C2 inasmuch as these will no'longer carry any direct current under normal working conditions. This is not true of the scheme shown in Fig. 2 where the condensers C2 are con stantly connected all the time with the full direct current-potential. 'In fact, these con densers should be designed merely for a test potential equal to the plate direct current potential since this potential would arise across the terminals thereof in case of a tube flashover.

When using a plurality of paralleled tubes for each sideof the transmitter, the chokecoils of pairs of opposite tubes are embraced by one condenser as shown in Fig. 4. In the arrangement. of Fig. l the terminals of each choke'coil D remote from the plate electrode of the tube to which it supplies charging potential is connected as shown to the corresponding terminal of another tube similarly located in groups of push-pull tubes through a condenser C2 as indicated. This perm. s the radio frequency currents to pass .hrough the circuits without passin through the resistances 9", wherein losses would occur. At the same time the condensers C not being connected to the filaments of the tubes are cated in Fig. 1. The same is true of the electrodes of the tubes V, V1 of the symmetrical arrangements of Figs. 2, 3 or i.

The tank circuit of each modification ma be connected with any load circuit, for example, an aerial system as indicated in Fig. 1 or an amplifier as indicated in Fig. 3.

Having now described the natrre off my invention and the operation thereof 1 claim as novel:

1. An alternatin current -relay including, a pair or" hermionic tubes, each having an anode and a cathode, the cathodes being connected together, an alternating current circuit there bein connecting the anodes of said tubes in pushpull relation, said alternating current circuit being completed by a direct connection to the cathodes of tubes, a source of direct current potential, a separate circuit for applying direct current potential between the anodes and cathodes of said tubes comprising, a connection between one terminal of said source and the cathodes of said tubes, connections between the other terminal of said source and the anode electrode of each of said tubes, a resistance and a choke coil in series in each of said connections in the order given, the resistance acting to prevent flashover between said tubes when the applied direct current potential is too high, the choke coil acting to substantially prevent alternatcurrent from said alternating current circuit from reaching said resistance in said direct current source, and means for shunting any alternating current which gets through said choke coils around said source and said resistance including a capacity connecting the adjacent terminals of the resistance and choke coil in one of said connections to the adjacent terminals of the resistance andchoke coils in the other of said connections.

'2. A radio frequency relay including, a pair or thermionic tubes, each having an anode and acathode, the cathodes being connected together, an alternating current circuit including an inductance connecting the anodes of said tubes in push-pull relation, a pair of capacities in parallel with said inductance, and means for completing said alternating current circuit including, a connection between adjacent electrodes of said capacities and the cathodes of said tubes, a

source of direct current potential, and means for applying potential from said source between the anode and cathode of each of said tubes including, a connection between a negative terminal or said direct current source and the cathodes of said'tubes, a resistance and an inductance in series in the order given connecting the positive terminal of said source to the anode of one of said tubes, a second resistance and a second inductance in series in the order given connecting the positive terminal of said source to the anode of the other of said tubes, the purpose of said resaid second named resistance and said second named inductance, and a capacity connected in parallel with said source.

3. An arrangement as recited in claim 1 in which there are a plurality of pairs of tubes, each pair having its anode circuit connected in push-pull relation byan alternating current circuit, as set forth in claim 1, and in which each pair of tubes has its anode electrodes connected to said direct current source by direct current energizing circuits, as recited in claim 1.

a. An arrangement as recited in claim 2 in which there are a plurality of pairs of tubes, each pair having its anode electrodes connected in push-pull relation with the same alternatingcurrent circuit, and in which each pair of tubes has its anode electrodes connected to said direct current source by direct current energizing circuits, as recited in claim 2.

WERNER BUSCHBECK.

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